i EFFECT OF DIFFERENT EDIBLE COATINGS ON QUALITY OF TOMATOES (Solanum Lycopersicum) STORED AT DIFFERENT TEMPERATURES. BY UWAMAHORO ANGELIQUE ID: 10803067 THIS THESIS IS SUBMITTED TO THE UNIVERSITY OF GHANA, LEGON IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF MPHIL IN CROP SCIENCE DEGREE (POSTHARVEST TECHNOLOGY). DEPARTMENT OF CROP SCIENCE SCHOOL OF AGRICULTURE UNIVERSITY OF GHANA, LEGON 2022 University of Ghana http://ugspace.ug.edu.gh ii DECLARATION I, hereby declare that, except the references to the works of other researchers, which have been duly cited, this work is the result of my own original research and has neither been Presented either in whole or in part for the award of any degree. 13 October 2023 …………………… ….……………….... UWAMAHORO Angelique (Student) Date Approval of my University supervisors: 13 October 2023 …………………… ……………………. Dr. Gloria Essilfie (Supervisor) Date 13 October 2023 ………………………………. ………………………... Prof. V. Eziah (Co-Supervisor) Date University of Ghana http://ugspace.ug.edu.gh iii ACKNOWLEDGEMENTS I thank God for granting me the protection and wisdom throughout my MPHIL programme in the University of Ghana. I thank my supervisors Dr. G. Essilfie and Dr. V. Eziah for their support, guidance and correction. I am also grateful to Mr. Sowah Nicholas and technical staff of Department of Biochemistry, Cell and Molecular Biology Lab and Postharvest Lab staff for their support. Finally, I extend profound gratitude to ARISE II project and to my husband for his love and support throughout this study. University of Ghana http://ugspace.ug.edu.gh iv LIST OF ABBREVIATION CS- Cassava starch CA- Citric Acid CS:CA- Cassava starch and Citric Acid P: Pectomech variety of tomato W: Wosowoso variety of tomato FAO: Food and Agriculture Organization FAOSTAT: Food and Agriculture Organization Statistics U.S.: United State PH: Potential of hydrogen TA: Titratable acidity NAOH: Sodium hydroxide TSS: Total soluble solid FASDEP: Food and Agricultural Sector Development Policy document University of Ghana http://ugspace.ug.edu.gh v ABSTRACT This study was conducted to determine the effect of different edible coatings, packaging materials on shelf-life and quality of two varieties of tomatoes (Pectomech and wosowoso). Due to its perishability, tomato is associated with many postharvest loss issues which can be attributed to lack of good management practices (use of poor varieties, packaging and improper storage) which result in poor quality and short shelf-life. The study, was conducted using two tomato varieties (Pectomech and wosowoso), baskets and polyethylene bags were used as packaging materials, edible coatings such as cassava starch (CS), citric acid (CA) and their mixture were used to apply the coatings on two varieties of tomatoes before their storage at different temperatures (4oc and 28oC). The treatments used were two varieties of tomatoes (Pectomech and wosowoso), three edible coatings with different concentrations: 1. Cassava starch (1%, 2%, 3%); 2. Citric acid (0.5%, 1%); 3.Cassava starch + Citric acid (1:0.5; 1:1; 2:0.5; 2:1; 3:0.5, 3:1); two method of applications (Dipping and brushing), two packaging materials, two storage temperatures (28oC, 4oC) and control. The results indicated that the coating material in maintaining quality of pectomech tomatoes was the samples dipped in cassava starch mixed with citric acid at a ratio of 3:1 (3:1 CS+CA, dipping). The shelf life of pectomech tomatoes was longer than shelf life of wosowoso in all treatments and the shelf life in refrigeration storage was longer than room storage for both varieties. Polyethylene packaging was better than control and basket in terms of weight loss, lycopene, pH, TA and vitamin c during 21 days of storage. Considering all the sensory attributes, for the two varieties of tomatoes, consumers preferred tomato fruits packed in polyethylene packaging material. University of Ghana http://ugspace.ug.edu.gh vi Farmers and traders should be encouraged to apply edible coatings such as cassava starch and citric acid to coat tomatoes at right coating concentration (3:1 CS+CA, dipping) before packing them in polyethylene bags and at room temperature respectively. Key words: Tomatoes, edible coating, storage temperature, packaging materials University of Ghana http://ugspace.ug.edu.gh vii TABLE OF CONTENTS DECLARATION .............................................................................................................................. ii ACKNOWLEDGEMENTS ............................................................................................................... iii LIST OF ABBREVIATION ............................................................................................................... iv ABSTRACT .................................................................................................................................... v TABLE OF CONTENTS .................................................................................................................. vii LIST OF TABLES ......................................................................................................................... xiii CHAPTER ONE: INTRODUCTION .................................................................................................... 1 1.1.Background of the study .................................................................................................... 1 1.2 Problem statement ............................................................................................................. 3 1.3 Justification ....................................................................................................................... 3 1.4 Objectives .......................................................................................................................... 5 1.4.1 Main objective ...................................................................................................................... 5 1.4.2 Specific objectives ................................................................................................................ 5 CHAPTER TWO: LITERATURE REVIEW ............................................................................................ 6 2.1 History of tomato ............................................................................................................... 6 2.2 Health benefits of tomatoes ................................................................................................ 6 2.3 Production of tomatoes ...................................................................................................... 7 2.4 Tomato production in Ghana ............................................................................................ 7 2.5 Postharvest losses ............................................................................................................ 10 University of Ghana http://ugspace.ug.edu.gh viii 2.6 Preservation methods .......................................................................................................... 11 2.6.1 Drying............................................................................................................................ 12 2.6.2 Edible coatings ............................................................................................................... 13 2.6.3 Packaging materials ....................................................................................................... 16 2.7 Nutritional value .................................................................................................................. 17 2.8 Quality indices of tomato (physical chemical properties) ....................................................... 17 2.8.1 The weight of tomato..................................................................................................... 18 2.8.2 Potential of hydrogen (pH) ............................................................................................. 18 2.8.3. Titratable acidity (TA).................................................................................................... 19 2.8.4 Total Soluble Solid (TSS) ................................................................................................. 19 2.8.5 Lycopene ....................................................................................................................... 20 2.8.6. Fruit firmness ............................................................................................................... 21 2.8.7 Shelf life ........................................................................................................................ 21 2.8.8 Vitamin c (Vit. c) ............................................................................................................ 22 CHAPTER THREE: MATERIALS AND METHODS ............................................................................. 23 3.1 Collection of samples ............................................................................................................ 23 3.2. Preparation of samples and coating materials ...................................................................... 24 3.2.1. Tomatoes ..................................................................................................................... 24 3.2.2. Coating materials .......................................................................................................... 24 3.2.2.1 Cassava starch ................................................................................................................. 24 3.2.2.2 Citric acid ........................................................................................................................ 25 3.2.2.3 Cassava starch and citric acid combination ................................................................. 25 University of Ghana http://ugspace.ug.edu.gh ix 3.3. Coating of tomatoes ............................................................................................................ 25 3.4. Determination of physicochemical properties of coated tomatoes ........................................ 27 3.4.1. Shelf- life ...................................................................................................................... 27 3.4.2. Weight loss ................................................................................................................... 27 3.4.3 Firmness ........................................................................................................................ 28 3.4.4 Total soluble solids (TSS) ................................................................................................ 28 3.4.5 Potential of hydrogen (pH) ............................................................................................. 29 3.4.6 Titratable acidity (TA) .................................................................................................... 29 3.4.7 Lycopene ....................................................................................................................... 30 3.4.8 Vitamin C ....................................................................................................................... 30 3.5. Sensory evaluation .............................................................................................................. 31 3.6. Statistical data analysis ................................................................................................... 31 CHAPTER FOUR .......................................................................................................................... 32 4.0. RESULTS .............................................................................................................................. 32 4.1. Experiment One ............................................................................................................... 32 4.1.1 Effect of edible coatings on shelf-life of pectomech tomatoes stored at room temperature and at refrigeration ............................................................................................... 32 4.1.2 Effect of edible coatings on weight loss of pectomech tomatoes stored at room temperature and at refrigeration ............................................................................................... 34 4.1.3: Effect of edible coatings on the total soluble solid (TSS) of pectomech tomatoes stored at room temperature and at refrigeration. ............................................................................... 36 University of Ghana http://ugspace.ug.edu.gh x 4.1.4 Effect of edible coatings on firmness of pectomech tomatoes stored at room temperature and at refrigeration ............................................................................................... 39 4.1.5. Effect of edible coatings on the lycopene of pectomech tomatoes stored at room temperature and at refrigeration ............................................................................................... 43 4.1.6 Effect of edible coatings on potential of Hydrogen (pH) of tomatoes stored at room temperature and at refrigeration ............................................................................................... 45 4.1.7. Effect of edible coatings on the Vitamin c of tomatoes stored at room temperature and refrigeration. ........................................................................................................................ 48 4.1.8. Effect of edible coatings on titratable acidity (TA) of tomatoes stored at room temperature and refrigeration ................................................................................................... 51 4.2. Experiment Two .................................................................................................................. 54 4.2.1. Effects of packaging materials on shelf-life of coated varieties of tomatoes stored at room temperature and at refrigeration ............................................................................................ 55 4.2.2. Effects of packaging material on weight loss of coated varieties of tomatoes stored at room temperature and refrigeration ..................................................................................... 56 4.2.3 Effects of packaging materials on lycopene of coated tomato varieties stored at room temperature and at refrigeration .......................................................................................... 58 4.2.4 Effects of packaging material on Vitamin C of coated tomato varieties stored at room temperature and at refrigeration. ......................................................................................... 59 4.2.5 Effects of packaging material on total soluble solids of coated tomato varieties stored at room temperature and at refrigeration ................................................................................... 61 4.2.6 Effects of packaging material on potential of Hydrogen (pH) of coated tomato varieties stored at room temperature and at refrigeration. ................................................................... 63 University of Ghana http://ugspace.ug.edu.gh xi 4.2.7 Effects of packaging material on titratable acidity (TA) of coated tomato varieties stored at room temperature and at refrigeration ................................................................................... 64 4.3 Sensory evaluation of tomato varieties following different packaging materials and storage places. ....................................................................................................................................... 66 CHAPTER FIVE ............................................................................................................................ 69 5.0 DISCUSSION .................................................................................................................. 69 5.1 Effect of edible coatings on shelf-life of tomatoes stored at room temperature and at refrigeration. ......................................................................................................................... 69 5.2. Effect of edible coatings on weight loss of pectomech tomatoes stored at room temperature and at refrigeration. ......................................................................................... 70 5.3. Effect of edible coatings on the total soluble solid (TSS) of pectomech tomatoes stored at refrigeration and at room temperature ................................................................................. 71 5.4. Effect of edible coatings on firmness of pectomech tomatoes stored at refrigeration and at room temperature ................................................................................................................. 72 5.5. Effect of edible coatings on lycopene of pectomech tomatoes stored at refrigeration and at room temperature ................................................................................................................. 73 5.6. Effect of edible coatings on potential of Hydrogen (pH) of pectomech tomatoes stored at refrigeration and at room temperature ................................................................................. 74 5.7. Effect of edible coatings on Vitamin C of pectomech tomatoes stored at refrigeration and at room temperature ............................................................................................................. 75 5.8. Effect of edible coatings on titratable acidity (TA) of pectomech tomatoes stored at refrigeration and at room temperature ................................................................................. 76 5.9. Effect of packaging materials on shelf life of pectomech and wosowoso varieties of tomatoes stored at refrigeration and at room temperature .................................................... 77 University of Ghana http://ugspace.ug.edu.gh xii 5.10. Effect of packaging materials on weight loss of tomatoes varieties stored at refrigeration and at room temperature. ..................................................................................................... 78 5.11 Effect of packaging materials on lycopene value of varieties of tomatoes stored at refrigeration and at room temperature ................................................................................. 79 5. 12. Effect of packaging materials on Vitamin c value of tomatoes varieties stored at refrigeration and at room temperature ................................................................................. 80 5. 13. Effect of packaging materials on total soluble solid (TSS) value of varieties of tomatoes stored at refrigeration and at room temperature .................................................................. 81 5. 14. Effects of packaging material on potential Hydrogen value (pH) of coated tomato varieties stored at room temperature and at refrigeration temperature. ............................... 82 5. 15. Effects of packaging material on titratable acidity (TA) of coated tomato varieties stored at room temperature and at refrigeration temperature. ............................................. 82 5.16. Sensory Evaluation ....................................................................................................... 83 CHAPTER SIX .............................................................................................................................. 84 6. CONCLUSION AND RECOMMENDATIONS ................................................................ 84 CHAPTER SEVEN ......................................................................................................................... 88 7.1 REFERENCE .................................................................................................................. 88 University of Ghana http://ugspace.ug.edu.gh xiii LIST OF TABLES Table 3.1 DESCRIPTION OF MATERIALS AND TREATMENTS RATIOS ..................... 25 Table 4.1: Changes in TSS according to different coating materials. ..................................... 38 Table 4.2: Changes in firmness according to different coating materials. ............................... 42 Table 4.3: Effect of edible coatings on the pH of tomatoes stored at room temperature (280C) and at refrigeration (40C) ......................................................... Error! Bookmark not defined. Table 4.4: Effect of edible coatings on the Titratable acidity (TA) of tomatoes stored at room temperature and in refrigeration temperature .......................................................................... 53 Table 4.5: Effects of packaging material on lycopene of coated tomato varieties stored at room temperature and in refrigeration temperature. ......................................................................... 59 Table 4.6: Effects of packaging material on TSS of coated tomato varieties stored at room temperature(40C) and in refrigeration temperature(280C) ....................................................... 62 Table 4.7: Effects of packaging material on pH of coated tomato varieties stored at room temperature and in refrigeration temperature. ......................................................................... 64 Table 4.8: Effects of packaging material on titratable acidity (TA) of coated tomato varieties stored at room temperature and in refrigeration temperature(40C). ......................................... 65 University of Ghana http://ugspace.ug.edu.gh xiv LIST OF FIGURES Figure 3.1: Laboratory scale used by measuring the weights of tomatoes every two days. .... 27 Figure 3.2: The pH meter used for measuring the pH of tomatoes.......................................... 29 Figure 4.1: Effect of edible coatings on shelf life of tomatoes stored at room temperature (28o C) and in refrigeration (4oC) with dipping method. ................................................................. 33 Figure 4.2 Effect of edible coatings on shelf-life of tomatoes stored at room temperature (28oC) and in refrigeration (4oC) with brushing method. .................................................................... 33 Figure 4.3: Effect of edible coatings on weight loss of tomatoes stored at room temperature (28oC) and in refrigeration (4oC) with dipping method. .......................................................... 35 Figure 4.4: Effect of edible coatings on weight loss of tomatoes stored at room temperature (28oc) and in refrigeration (4oC) with brushing method. ......................................................... 36 Figure 4.5: Effect of edible coatings on lycopene of tomatoes stored at room temperature (28oC) and in refrigeration (4oC) with dipping method. ...................................................................... 44 Figure 4.6: Effect of edible coatings on lycopene of tomatoes stored at room temperature (280C) and in refrigeration (40C) with brushing method. .................................................................... 45 Figure 4.7: Effect of edible coatings on vit. c of tomatoes stored at room temperature (28oC) and in refrigeration (4oC) with brushing method. .................................................................... 50 Figure 4.8: Effect of edible coatings on vit. c of tomatoes stored at room temperature (280C) and in refrigeration (40C) with brushing method. .................................................................... 51 Figure 4.9: Effects of packaging material on shelf-life of coated tomato varieties (pectomech and wosowoso) stored at room temperature(280C) and in refrigeration temperature(40C). .... 56 Figure 4.10: Effects of packaging material on weight loss of coated tomato varieties stored at room temperature and in refrigeration temperature; Rt: Room temperature(28oC); Rft: refrigeration temperature(4oC). ................................................................................................ 57 University of Ghana http://ugspace.ug.edu.gh xv Figure 4.11: Effects of packaging material on Vit C of coated tomato varieties stored at room temperature and in refrigeration temperature(40C). ................................................................. 61 Figure 4.12: The sensory evaluation of pectomech and wosowoso tomatoes packed in room(280C) and refrigeration temperature(40C). ..................................................................... 68 University of Ghana http://ugspace.ug.edu.gh 1 CHAPTER ONE: INTRODUCTION 1.1. Background of the study Tomato (Solanum lycopersicum) is a major horticultural crop and climacteric fruit that continues to ripe after harvesting (Zapata et al., 2008). It is one of the most widely consumed vegetables worldwide and it contains significant amounts of vitamin C and lycopene (Chapagain and Wiesman, 2004). Vitamin C is anti-oxidant, which reduces the risk of arteriosclerosis, cardiovascular diseases and some form of cancer. Tomatoes (Solanum lycopersicum) is a good source of minerals and vitamins (Nasrinet al., 2008, & Babalola et al, 2010) and it is also known to be a major source of antioxidants; hence consumption of tomato/tomato products may help reduce the risk of cancer and cardiovascular diseases (Giovannucci et al., 2002). Lycopene is an antioxidant found in tomato and it is responsible for the red colour in tomatoes (Borguini and Ferraz, 2009; Kotikova et al., 2011; Vallverdu-Queralt et al., 2011). Tomato is a vegetable of high economic importance in many countries (Obeng- Ofori, et al., 2007). Postharvest losses have been highlighted as one of the determinants of the food problem in most developing countries (Babalola et al., 2008). According to Gil et al., (2006), loss of nutritional quality in tomato fruits can be observed depending on storage conditions. Post-harvest loss of tomatoes is mostly caused by decay and external injury during handling and storage. According to Salami et al. (2010), about 30-40% of fruits and vegetables are lost or discarded after leaving the farm gate. The Shelf life is the period in which a product can continue to survive without deterioration or other changes during storage. The Shelf-life is a function of time, environmental factors, and susceptibility of product to quality change (Labuza and Szybist, 2001). One of the factors that is known to affect shelf-life and quality of tomatoes during storage is the temperature (Bachmann and Earles, 2000). Fully ripe tomato University of Ghana http://ugspace.ug.edu.gh 2 fruits can be stored at 2 – 5 0C to avoid chilling injury (Passam et al., 2007). As tomato is a climacteric and perishable produce, good and protective methods are required to increase their self-life and physical qualities (Saeed et al., 2010). One of the good protective methods that can be used, is the use of edible coatings which are thin layers of material applied to edible food products play an important role in the preservation of the foods (Falguera et al., 2011). The use of edible coatings with low-temperature storage minimizes deterioration of tomatoes (Gozalez-Agilar et al., 2010). Edible coatings have been used for extension of postharvest storage time of fruits and vegetables (Allegra et al. 2016; Raffo et al. 2002; Singh et al. 2016). Coatings forms a semipermeable barrier around fruits, reduce solute migration, gas exchange, moisture evaporation, respiration and oxidative reaction rates and suppress physiological disorders in fruits (Wu and Chen, 2013). Examples of edible coatings are citric acid and cassava starch. Locally available materials such as cassava starch that are cheap, tasteless, odourless, colourless, non-toxic, biodegradable, safe, and have low permeability to oxygen are best for use in developing countries (Pareta and Edirisinghe, 2006). The use of citric acid as edible coating is very important because it is known to also act as antimicrobial agent. Citric acid is generally regarded as safe and since it is an organic acid, it can be used as a food additive (Sommers, et al., 2003). Second is the use of proper packaging such as the use of polyethylene and plastic packaging materials have also been observed to extend shelf life of tomatoes (Srinivasa, et al., 2006). Tomato fruit quality is defined by fruit firmness, uniformity and glossy colour as well as good appearance with no signs of mechanical damages, withering and bruises (Chattopadhyay and Paul, 2012). University of Ghana http://ugspace.ug.edu.gh 3 1.2 Problem statement The shelf life of tomatoes is relatively short due to different postharvest physiological, physical and chemical changes that occur during storage (Fagundes, et al., 2015; Hoeberichts, et al., 2002). Quality of most fruits and vegetables is affected by water loss during storage, which depends on the temperature and relative humidity conditions (Perez et al., 2003). Major losses in the quality and quantity of fresh vegetable and fruit products occur between harvest and consumption (Brooks, et al., 2008). Post-harvest loss of tomatoes is mostly caused by decay and external injury when they are handling and storing them. The nutritional quality of fresh tomatoes has been determined to be affected by postharvest activities such as handling and storage practices (Addo, et al., 2015). Postharvest qualitative loss in tomato can have a negative impact on many parameters like consumer acceptability and nutrient value of fruits. Tomato being a climacteric fruit has a relatively short postharvest life. The major factor associated with tomato postharvest shelf life is increased respiration that results in high fruit ripening and deterioration of tomato quality (Bailén, et al., 2006). Therefore, this study was aimed at determining the effect of different edible coatings with various packaging materials on shelf-life and quality of tomatoes stored under different conditions. 1.3 Justification As tomato is a climacteric fruit and as such continues to ripen even after harvest, it tends to have a rather short shelf-life. Deterioration of tomato quality during storage is a serious post- harvest problem for traders and consumers. Thus, the requirement of technology development to reduce post-harvest losses and extending shelf-life of tomatoes is needed (Gonzalez- Aguilar, et al., 2009). The development of different preservation technologies is required to University of Ghana http://ugspace.ug.edu.gh 4 avoid losses and deterioration of tomatoes. Good and protective storage methods are required to enhance their shelf life as well as their physical qualities (Saeed, et al., 2010). Edible coatings have been used for extension of self-life of fruits and vegetables (Allegra, et al., 2016; Raffo, et al., 2002; Singh, et al., 2016). The use of citric acid and cassava starch in this study, is because cassava starch is cheap, tasteless, odourless, colourless, non-toxic, biodegradable, safe, and have low permeability to oxygen (Pareta and Edirisinghe, 2006). Citric acid is cheap, easily obtained and safe for consumption. Citric acid also acts as antimicrobial agent on different products. Since bacteria are unable to grow in an acidic environment, citric acid is often added to different agricultural products as a form of preservation. The edible coatings can reduce moisture loss, solutes migration, respiration and oxidative reaction rates (Colla, Sobral and Menegalli, 2006; Rojas-Graü, et al., 2008). However, there is little information available in literature about the application of edible coatings on fruits (González-Aguilar, et al., 2008; Sothornvit and Rodsamran, 2010). Cassava starch and citric acid were used in this study as edible coatings because edible coating is one of the modified atmosphere methods that have shown promising results for preserving fruits quality (Guimaraes, et al., 2018). An ideal edible coating can provide a partial barrier to water movement that can reduce moisture loss from the fruit surface and modify the atmosphere around the fruit by acting as a barrier to gas exchange (Jongsri, et al., 2016). Cassava starch edible coating is tasteless, odourless, colourless, non- toxic, biodegradable, cheap, safe, and shows low permeability to oxygen (Pareta and Edirisinghe, 2006; Chiumarelli, et al., 2010). The use of citric acid can avoid enzymatic browning of plant tissue, thereby reducing the product appearance loss, without changing its minimally processed condition (Andrés, Giannuzzi, and Zaritzky, 2002; Brennan, Le Port and GormLey, 2000; Moda, et al., 2005). Therefore, this study will focus on the use of edible coatings applications on tomato to extend their shelf life and conserve their quality. University of Ghana http://ugspace.ug.edu.gh 5 1.4 Objectives 1.4.1 Main objective The main objective of this study was to determine the effectiveness of different edible coatings in extending the shelf life and quality of tomatoes. 1.4.2 Specific objectives 1. To determine the optimum concentration of coating materials to be applied on tomatoes. 2. To determine the combined effects of temperature and packaging material on the physicochemical properties and shelf life of coated tomatoes. 3. To determine consumer acceptability of tomato coated with different edible coatings. University of Ghana http://ugspace.ug.edu.gh 6 CHAPTER TWO: LITERATURE REVIEW 2.1 History of tomato Tomato (Solanum lycopersicum) has its origin in South American Andes (Naika et al., 2005) which is Peru of today. It was taken to other parts of the world by explorers where it was used for ornamental purpose but not eaten because they took it as poisonous. They were accepted it as edible crop in Europe in 1840 (Paran and Van der Knaap, 2007). Today different benefits of tomato are known where it is consumed wherever in different recipes. 2.2 Health benefits of tomatoes Tomato serves as a medicine crop. Consumption of fruits and vegetables is linked to the lower risk of several types of cancer. Tomatoes contains higher amounts of lycopene, a type of carotenoid with anti-oxidant properties (Arab and Steck, 2000) which is beneficial in reducing the incidence of some chronic diseases (Basu and Imrhan, 2007) like cancer and many other cardiovascular disorders (Freeman and Reimers, 2010). Lycopene is believed to be the main contributing compound in tomatoes responsible for lower risk of prostate cancer (Pohar, et al., 2003). Lycopene in tomatoes enhance fertility by improving the quality and swimming speed of sperm while reducing the number of abnormal sperm in men (Innes 2014). Consumption of tomatoes can prevent old-age related diseases like dementia, osteoporosis, Parkinson’s and Alzheimer’s (Freeman and Reimers, 2010). Tomatoes have high sources of vitamin C which is used in cell division and cell wall synthesis (Gest, et al., 2012). Ascorbic acid is an important micronutrient and antioxidant for human diet. University of Ghana http://ugspace.ug.edu.gh 7 2.3 Production of tomatoes Tomato production is a source of income in all areas of the world. Although there are more benefits from tomatoes, its production is not enough due to postharvest losses. Global tomato production increased during the 1920s as a result of breakthroughs in technologies that made mechanised processing possible (Tan, et al. 2010). According to different series of genetic research findings, tomato is from the solanum genus. Tomato is an herbaceous perennial, but according to different growing environmental conditions they can behave as annuals (Denham, 2014). A large produced quantity of tomatoes is processed in different final products such as tomato ketchup, tomato paste, canned tomatoes, sun-dried tomatoes, etc. Some tomato varieties that can be produced are Pectomech, Wosowoso, Tropimech, Laurano etc. The pectomech variety is the most suitable for processing (Robinson and Kolavalli, 2010). The low productivity of tomato is due to different reasons such as short shelf life, season of production, lack of rapid market access, and lack of sales for farmers leading to financial losses (Robinson and Kolavalli, 2010). Tomato production accounts for about 4.8 million hectares of harvested land area globally with an estimated production of 162 million tonnes (FAOSTAT, 2014). 2.4 Tomato production in Ghana Tomato is very important component in Ghana as cash crop and in diets. Tomato cultivation has been one of the most important income-generating vegetables produced in Ghana (Asante, et al., 2013). The production of tomato is concentrated in the Greater Accra, Ashanti, Brong Ahafo, Volta and Upper East regions under both rain-fed and irrigated systems. Its production in Ghana seems to have declined while the increase of tomato paste imports since 2000s is very high. The low productivity and high prices put pressure on domestic processing and domestic University of Ghana http://ugspace.ug.edu.gh 8 agriculture (Wilkinson and Rocha, 2006). Ghana demand high imported paste than domestic fresh tomato due to the low efforts in processing tomato domestically. The trade of fresh tomato is limited with some closed neighbours of Ghana such as (Burkinafaso, Cote d’Ivoire, and Togo). Farmers like production of tomato than other vegetables due to its high multiple harvests, which bring high benefits per unit area. Tomato is characterised by its shape, size, colour, fresh thickness, number of locules and fruit quality which differ in acceptability, quality and storability in the local area. The Food and Agricultural Sector Development Policy document of Ghana (FASDEP) reported that post-harvest losses are high due to very little processing and strategies in marketing (2007). Since the country’s consumption of tomato is increasing, tomato has to be stored and transported very well at various distances to consumers. Inappropriate methods of Packing, transportation and storage result in deterioration of tomatoes. For the case study of Ghana, the available data suggests that Ghana imports 100 thousand tonnes per year of tomatoes from Burkinafaso (OCED Headquarters, Paris; 2010). The perishability of tomato increases the post-harvest losses which force farmers to accept low prices. Boriss and Brunke (2005) reported that the price of tomato depends on availability and shortage of supply. In Ghana’s tomato sector, production seasonality, the dominance of rainfed agriculture, high perishability of the fruits combined with no storage facilities, and poor market access, have resulted in low average yields due to high spoilage. The low price of tomatoes in Ghana is due to their high perishability (Bell, et al., 1999; Orchard and Suglo, 1999). In Ghana the packaging of tomatoes is done by using oversized crates after removing the poorest fruit qualities and varieties. In late December through April/May Ghana’s Upper East region and Burkina Faso supply almost all the fresh tomato in the country. Irrigated tomato from Greater Accra dominates the market later in the year. Even Ghana relies on tomato from Burkinafaso, there are three large-scale tomato processors in Ghana that, when functioning, provide an additional market for tomato farmers: Wenchi in Brong Ahafo; Northern Star (formerly named University of Ghana http://ugspace.ug.edu.gh 9 Pwalugu) in Upper East; and Expom (formerly named Trusty Foods) in Greater Accra (Robinson and Kolavalli, 2010). The yield of tomato in Ghana, is lower than 10 t/ha and is not enough like other African countries (Robinson, et al., 2010b). This yield of tomatoes is slightly above 10 t/ha from 1970 and 1980 but are lower than the estimates reported by Wolff (1999). Due to this low yield Ghana is a net importer of fresh tomato fruits from neighbouring countries like Burkina Faso and Ivory Coast in the dry seasons and processed tomato products, mainly canned tomato pastes from China and Italy (Monney, et al., 2009; Horna, et al., 2006). The import of processed tomato in Ghana from the EU increased by 628% from 3,713 tons to 27,015 tons between 1993 and 2003 (Donkor, et al., 2013). Tomato is produced in the whole parts of the country of Ghana such as Akomadan and Afrancho of the Offinso District of the Ashanti Region; Techiman, Wenchi and Dormaa-Ahenkro Districts of the Brong Ahafo Region; Ga West, Dangme East and Dangme West District of the Greater Accra Region; Fanteakwa, Kwahu South and Yilo Krobo District of the Eastern Region and Bolgatanga, Kasena Nankana and Talensi Nabdam Districts of the Upper East Region (Monney et al., 2009). The different tomato varieties that they cultivate include Pectomech VF, Power Rano, Heinz, Paul, “five-five”, Pectofake, Wosowoso, Techiman, Ada Lorry Tyre, Nimagent F1, Deca 1, Meenagiant, and Rasta (Clottey et al., 2009; Monney et al., 2009). The improved varieties such as pectomech, are suitable for processing, preferred by consumers and have the high price than other varieties. The good variety is the one which shows the high yield, tolerate disease and has long shelf-life. The longer the shelf life, the more preferred the variety (Monney et al., 2009). Navrongo and Wosowoso are supplied by some seed companies in the nation of Ghana. University of Ghana http://ugspace.ug.edu.gh 10 2.5 Postharvest losses Tomato is a vegetable which is highly perishable, spoiling within 4 to 6 days after harvest depending on the variety leading to huge economic losses to growers (Ellis et al., 1998). After harvesting loss is known as a quantitative and qualitative loss of a product along the post- harvest chain (DeLucia and Assennato, 1994). It is the change in food availability, edibility and quality that reduce its consumption (FAO and UNEP, 1981). The reason for that loss, is the proximity of processing facilities to farms and inaccessibility to markets are major post- harvest challenges (GOG, 2003). The main factors of losses in tomato post-harvest, is the adoption of poor varieties with low shelf-life, harvesting at improper stage, improper care at harvest, packaging in bulk without sorting and grading of tomatoes, improper transportation and storage which result in pathogenic infestation and long periods of market distribution (Adubofour et al., 2010; Mujibur Rehman et al., 2007; Ellis et al., 1998). Literacy is the factor which comes in famer’s decision adoption of new technologies. Thus, to adopt new technologies and innovations, they need some education. The other challenge they have is that, most farmers are not land owners but are rather tenants (Mujib ur Rehman et al., 2007). Therefore, the result is the non-improved productivity because farmers don’t like to invest at long term thinking that they are tenants. The skilled labour plays an important role in post- harvest losses where they pick and handle the produce with good care and little damage. The non-skilled labourers must work under the supervision of the farmers who hire them (Mujib ur Rehman et al., 2007). When tomatoes are red ripe it is the time for harvesting which is done two or three times a week, according to the variety and yield (Monney et al., 2009). The packaging must be done in the appropriate way because it can affect the stability of products in a truck during transportation. Good packaging protects the products from damage (McGregor, 1987). The use of wooden crates crush tomatoes and lead to post-harvest losses. The movement of tomatoes must be done with proper packaging in order to minimize their University of Ghana http://ugspace.ug.edu.gh 11 deterioration and bruising during transportation (McGregor, 1987). Post-harvest losses are very high in less industrialised countries due to lack of good technologies, and lower in developed countries where the time between harvesting and consumption of the produce is shorter and transportation of produce needs to be done over shorter distances to the market (Mujib ur Rehman et al., 2007). The high moisture content of vegetables especially tomatoes makes their handling, transport, storage and marketing a big problem especially in the tropics (Babalola et al., 2010). The nutritional value, taste, flavour and quality of these fresh produce like tomato is affected by postharvest handling and storage condition (Sablani et al., 2006; Shankara et al., 2005). In Ghana the loss of tomatoes is between the range of 30% and &70% (Ellis et al., 1998). Osei et al. (2010) reported that the postharvest loss for tomatoes is 19%. In the year 2003, Ghana exported 4,368 metric tons of tomatoes, accumulating a foreign exchange of $427,000 to the country; however, this earning dwindled to $56,000 in 2004 as a result of post- harvest losses. To reduce post-harvest losses, farmers traders and consumers need to be trained about the new methods of preservation, packaging and appropriate storage needed to increase the shelf-life of produce especially tomato which is perishable. Roads also need to be improved in order to minimize losses during transportation. 2.6 Preservation methods Preservation is a technique that is used to increase the shelf-life of produce by getting their maximum benefits. Each step of handling, processing, storage, and distribution affects the characteristics of food, which may be desirable or undesirable (Rahman, 2007). In Ghana the traditional food preservation methods are drying, curing, smoking, salting and fermenting. The new methods of preservation include canning, pasteurization, freezing, addition of chemicals such as edible coatings, baking and irradiation (Desrosier and Singh, 2011; Tucker, 2008). Preservation of tomato is a way of increasing income and ensuring availability of tomatoes all University of Ghana http://ugspace.ug.edu.gh 12 year round and providing variation in diet (Rahman, 1999). The most common methods of preservation of tomatoes in Ghana are refrigeration, freezing, storage at ambient and drying mainly in the Upper East Region of Ghana (Adimabuno, 2010). The local variety of tomatoes produced in Ghana is not good for processing because it has high moisture content, low total soluble solid whereas the improved one for processing must have everything in high quantity (Robinson et al., 2010). The shelf-life of tomatoes can be increased longer depending on the processing technique, packaging material and storage conditions (Shankara et al., 2005). Consequently, there is a need to develop suitable technology for processing and preservation of tomato by reducing losses and generate additional revenue for the country (Ghavidel and Davoodi, 2010). 2.6.1 Drying Drying is one of the oldest and important methods of food preservation (Esehaghbeygi and Basiry, 2011) from microbiological spoilage as well as pathogens (Tucker, 2008). Drying or dehydrating is a process of slowly removing moisture from a produce in order to inhibit the growth of microbes that cause spoilage and to reduce enzymatic activities (Mukhtar, 2009). This method is appropriate for tomatoes where it is used in Ghana to extend the shelf life of highly perishable produces especially vegetables after harvesting and makes them available throughout the year (Eklou et al., 2006; Habou et al., 2003). Dried tomato may be stored at room temperature in a cool, dark place (Tucker, 2008; Rahman, 2007; Holdsworth, 1971). There are different types of drying such as sun, oven and solar drying but sun drying is the most common practice (Agoreyo et al., 2011; Matazu and Haroun, 2004). Removal of water by heat in produce has been stated to affect the nutrient contents of produce, where it can increase some nutrients or decrease them (Hassan et al., 2007; Morris et al., 2004; Ladan et al., 1997). The rate of drying affects the final quality of dehydrated product (Ghavidel and Davoodi, 2010). Sun drying is defined as open air drying whereas solar drying (artificial University of Ghana http://ugspace.ug.edu.gh 13 drying) use solar energy where more than 250, 000 000 tons of fruits and grains are dried by solar energy per annum (Rahman, 2007; Olurunda et al., 1990). Drying of vegetables is the simplest and cheapest method of preserving vegetables. 2.6.2 Edible coatings Even drying is the traditional method of preserving vegetables in Ghana, it can be supported by the other method of extending the shelf life of tomatoes, which is the use of edible coatings. Edible coatings are thin layers of material applied to edible food products that play an important role in the preservation of foods (Falguera and others 2011). The use of edible coating is one of techniques used to conserve stored tomatoes. The mechanism by which edible coatings preserve fruits and vegetables is the establishment of a modified atmosphere around the product, which serves as a partial barrier to Oxygen (O2) and Carbon dioxide (CO2), water vapour and aroma compounds, decreasing the respiration rate of the fruit, water loss, preserving texture and flavor (Olivas and Barbosa-Canovas, 2008). They protect vegetables especially tomatoes by controlling respiration rate; reducing moisture and texture loss; transporting antimicrobials, antioxidants and other preservatives; controlling microbial growth; and maintaining fruit quality for a longer period. Edible coatings have been used for extension of postharvest storage of fruits and vegetables (Allegra et al., 2016; Raffo et al., 2002; Singh et al. 2016). Edible coatings reduce fruits respiration and oxidation reaction rates. Gum-based coatings have been used widely to extend the shelf life of fruit (El-Anany et al., 2009; Maqbool et al., 2010). The edible coating is applied on the fruit surface by dipping or brushing the coating solution. An ideal edible coating can provide a partial barrier to water movement that can reduce moisture loss from the fruit surface and modify the atmosphere around the fruit by acting as a barrier to gas exchange (Jongsri, et al., 2016). An edible coating is one of the modified atmosphere methods that have shown promising results for preserving fruits quality University of Ghana http://ugspace.ug.edu.gh 14 (Guimaraes, et al., 2018). The use of edible coatings in conjunction with low- temperature storage appears to be a promising approach to minimize many postharvest problems and preserve the freshness of tomatoes (Gonzalez-Aguilar, et al., 2010a). Materials for making coatings can be one type or a mixture of different types. One of coating materials is cassava starch which is used in less amount with low price than other starches. Cassava represents an important starch source and the cassava starch is cheap and safe (Chiumarelli et al., 2010; Garcia et al., 2010). Cassava starch edible coating is tasteless, odourless, colourless, non-toxic, biodegradable and safe, and shows low permeability to oxygen (Pareta and Edirisinghe, 2006). The use of citric acid can avoid enzymatic browning of plant tissue, thereby reducing the product appearance loss, without changing its minimally processed condition (Andrés, Giannuzzi, and Zaritzky, 2002; Brennan, Le Port, and GormLey, 2000; Moda, et al., 2005). According to Gonzalez-Aguilar and others (2008), the incorporation of antioxidants into edible coatings can delay the negative effects of minimal processing of fruit, increasing product shelf life. Application of ascorbic acid (1%) and citric acid (0.5%) solution in fresh-cut pineapple was effective to control browning (Antoniolli, 2004). Some edible coatings used in past studies are cassava starch and citric acid. According to Ariela, et al. (2016), 3% concentration of cassava starch was used alone and in combination of propolis on bioactive compounds in strawberries stored at 4oC for 16 days where 3% CS + 66% ethanolic propolis extract promoted higher vitamin C content than other treatments. According to Lorena et al. (2009) three different concentrations of cassava starch (1%, 2%, and 3%) and two concentrations of potassium sorbate (0.05% and 0.10%) were used in the coatings of strawberries where it was observed for 2% and 3% starch concentration represented a possibility to extend the shelf life of fruits. University of Ghana http://ugspace.ug.edu.gh 15 To increase product shelf-life of strawberry, cassava starch–based edible coatings (3%), added or not with potassium sorbate (0.05%), were applied on minimally processed strawberries stored up to 15 days at 5oC where cassava starch edible coatings resulted in delaying weight and firmness loss of strawberries during storage and good sensorial acceptance up to 12 days of storage. According to Julia, et al. (2020), the use of edible chitosan and citric acid (CHI– CA) coating is a promising strategy for improving the postharvest quality of fresh-cut guava fruit where the fresh-cut guava coated with CHI–CA maintained quality parameters during storage and preserved their sensorial characteristics. Therefore, the use of CHI–CA as a coating is a promising strategy for improving postharvest quality of fresh-cut fruits and preserved their sensorial characteristics. Coating material Composition Fruit/vegetable Effect of coating References Prolong Mixture of sucrose fatty acid esters, sodium CMC, and mono and diglycerides Mango Retard ripening, reduce weight loss, and chlorophyll loss Motlagh and Quantick, 1998 Pear Retention of firmness, green skin color, and titratable acidity Farber et al., 2003 Tal Prolong Mixture of sucrose fatty acid esters, sodium CMC, and mono and diglycerides Mango Delayed ripening with extended shelf life Nisperos-Carriedo et al., 1992 Chitosan Chitosan and Tween 80 Strawberry, cucumber, and bell pepper Antimicrobial coatings El-Ghaouth et al., 1991a, 1991b Apple, pear, plum, and peach Act as gas barrier Elson and Hayes, 1985; Davies et al., 1989 Litchi Reduced weight loss and browning, improve storability Zhang and Quantick, 1997 Carrot Reduced decay and improve appearance Cheah et al., 1997; Li and Birth, 1998 Tomato Reduced respiration rate, ethylene production, and increase titratable acidity El-Ghaouth et al., 1992 Pear Reduced ethylene production and delay ripening as indicated by high content of titratable acidity Li and Yu, 2000 Zein Corn zein protein Tomato Delayed color change, loss of firmness and weight, and extend shelf life Park et al., 1994 Nutri-save N,O carboxyl methyl chitosan Apple, pear, pomegranate Increased shelf life Lau and Meheriuk, 1994; Kittur et al., 2001; Srinivasa et al., 2002; Farber et al., 2003 Brilloshine Sucrose esters and wax (shine) Apple, avocado, melons, and citrus Protected, increased shine and extended shelf life Baldwin, 1994 Nu-coatFlo, Ban-seel Sucrose esters of fatty acids and sodium salt of CMC Apple, banana, cucumber, guava, melon, pear, and plum Protected, increased shine and extended shelf life Baldwin, 1994 Citrashine Sucrose ester and wax Mandarins Increased shine and extend shelf life Ahmad and Khan, 1987 University of Ghana http://ugspace.ug.edu.gh 16 2.6.3 Packaging materials Good packaging preserve food through the prevention of product spoilage and wastage, and by protecting products until they have performed their function (Coles et al., 2003). The primary roles of packaging are to provide product containment, preservation by maintaining quality, presentation and convenience, protection and to provide information to the user. Materials that can be used as packaging include paper and board, glass, metal and plastics. The benefits of packaging may include the prevention of product damage and food spoilage, thereby saving vital nutrients, reduces or eliminates the risk of tampering and adulteration and presents food in a hygienic and often aesthetically attractive way (Manalili et al., 2011). Fresh produce quality generally decreases after harvest. Due to the increased consumption of tomatoes, there is an increased demand of different methods to improve the quality of fresh produce. Several methods including temperature control, use of efficient packaging materials, edible coatings and the use of fruits with initial good quality contribute to the reduction of postharvest losses of fruits and vegetables. Packaging can markedly extend the storage life of many fresh fruits and vegetables through the inhibition of physiological deterioration and reducing weight loss (Shetty et al., 1989 and Risse et al., 1985). Packaging and temperature are very important in terms of tomato colour and firmness as major factors in the consumer preference of tomatoes. Extending the shelf life of tomatoes is very important for domestic and export marketing. Extension of the shelf life can be achieved by the use of packaging materials like polyethylene films in storage of tomatoes. Ripening and shelf life of tomato fruits can be delayed by an Casein Calcium caseinate Bell pepper Effective gas barrier to internal O2 and CO2, inhibited color change and reduced decay Lerdthanangkul and Krochta, 1996 Sodium caseinate and stearic acid Reduced moisture loss Krochta et al., 1993 Cellulose MC and glycerol Carrot Extended storage life, resulting more carotene than control Li and Barth, 1998 University of Ghana http://ugspace.ug.edu.gh 17 enclosure of tomato fruits in polyethylene or other forms of plastic packaging materials (Srinivasa et al., 2006). 2.7 Nutritional value There is a wide variety of nutrients from tomatoes which provide many benefits to the body. Tomato constitutes an essential part of people’s diet when consumed. It is rich in vitamins, minerals, sugars, essential amino acids, iron, dietary fibres and phosphorus (Ayandiji et al., 2011). Tomato is a source of many nutrients, where it is rich in minerals, sugars, vitamins, iron, dietary fibers and phosphorous (Ayandiji et al., 2011).Tomato is an important cash and industrial crop in many parts of the world (Ayandiji et al., 2011) not only because of its economic importance but also its nutritional value to human diet and subsequent importance in human health (Willcox et al., 2003). 2.8 Quality indices of tomato (physical chemical properties) Depending on their temperature and harvest maturity, tomato quality can change after harvesting. Postharvest losses in tomatoes can be either quantitative or qualitative. There are different postharvest factors that can affect qualities and shelf life of stored tomatoes. It is good to take care to them, in order to conserve the optimum quality needed. The factor that affect the chemical properties of tomato include variety, environmental conditions such as temperature, light, infection, mineral nourishment and air composition and cultural norms (ripening period at harvest and irrigation scheme) (Raiola et al.,2014). Some of the major physicochemical properties of tomatoes include fruit weight, PH, Total soluble solid, and lycopene content (Srivalli et al., 2016). Quality of most fruits and vegetables University of Ghana http://ugspace.ug.edu.gh 18 is affected by water loss during storage, which depends on the temperature and relative humidity conditions (Perez et al., 2003). 2.8.1 The weight of tomato The weight is the quality that everyone (farmer, Seller and Consumer) consider when they are selling or buying tomatoes, and this differ according to the varieties. The variation of tomato weight depends on different varieties (Srivalli et al, 2016). The weight loss in wrapped tomato showed a decreased in weight loss and fruits were more firm than non-wrapped tomatoes (Shettyet al., 1989; Risseet al., 1985). The weight loss of fruits and vegetables depends on the temperature and relative humidity conditions (Perez et al., 2003). Wilson et al., (1999) reported that Transpiration is a major cause of deterioration because it results in direct weight loss due to loss of water. Maalekuu et al., (2004) reported that the effect of weight loss in sweet pepper and other vegetables cause damage to fruit appearance and subsequent loss of market value. 2.8.2 Potential of hydrogen (pH) The acidity of fresh tomatoes is ranging between 4.3 - 4.9% according to the centre for food safety and Applied Nutrition at the U.S. Food and Drug Administration (2007). The pH of matured tomato fruits can exceed 4.6 (Tigist et al., 2012). The pH and TA are used to indicate the development of microorganisms in tomatoes which are responsible to deterioration and decay of tomatoes. The pH increases as the TA decrease due to changes to the loss of citric acid in tomatoes (Anthon et al., 2011; Das et al., 2013). The term pH is used to express the concentration of free H3O+ in a sample and results from Dissociation of the acids present. A lower pH value indicates acidity and a higher pH value indicates base. Shahid et al. (2011) reported that increase in pH in wax treated fruits might be due to high rate of metabolic activities, hence acidity decreased but pH increased and result in University of Ghana http://ugspace.ug.edu.gh 19 high TSS contents. A pH < 4.5 is required for processed tomato because microbial growth is inhibited. The pH of the fruit increases throughout development (Padmini, 2006). The pH of tomato increases as the storage time increase (Tigist et al., 2013). 2.8.3. Titratable acidity (TA) Titratable acidity (TA) is the measure of the total acid content in a food or beverage. The pH and TA are used to indicate the development of microorganisms in tomatoes which are responsible to deterioration and decay of tomatoes. The pH increases as the TA decrease due to changes to the loss of citric acid in tomatoes (Anthon et al., 2011; Das et al., 2013). Acidity in fruits is an important factor in determining maturity. According to Hu et al., (2011), wax treatment reduced titratable acidity of pineapple kept under cold storage conditions by approximately 6% and 5 % compared with the control at 21 days of storage. Similar works by Jiang and Li (2001) showed that the wax coating on longan fruit decreased their titratable acidity during storage. Over the years it has been shown that titratable acidity and pH contribute to the acid taste. 2.8.4 Total Soluble Solid (TSS) The Total Soluble Solid (TSS) is the sugar content (Brix) available in tomato. Where brix is a measure of total soluble solids in a product. The high increase of TSS is due to high moisture loss. The TSS of studied tomato cultivars is ranging between 6.53o Brix to 6.93o Brix (Srivalli et al., 2016). The TSS increases when tomatoes are mature and ripen (Tigist, et al., 2013). The total soluble solids increase during ripening due to degradation of polysaccharides to simple sugars thereby causing a rise in total soluble solids (Naik et al., 1993). The TSS is ranging from 4.47 to 6.57o Brix (Teka, 2013). Where 6.57 is for ripen tomatoes and 4.47 for mature green tomato fruit. The total soluble solid of tomatoes increases at different temperatures and packaging materials (Park et al., 2004; Jeong et al., 2005; Nei et al., 2005). The total soluble University of Ghana http://ugspace.ug.edu.gh 20 solids of tomatoes increased at different stages, temperatures and packaging materials (Shehla and Masud, 2007; Abdullah et al., 2004). The soluble solids content is the amount of sugar and soluble minerals present in fruits and vegetables. According to Alleyne and Clark (1997), the soluble solid content is a parameter determinant of fruit quality. Soluble solids content varies between cultivars and between stages of ripeness (Hibler and Hardy, 1994). Total soluble solid content increases with ripening, but may increase or decrease during storage as carbohydrates are utilized during fruit respiration and may increase due to the action of sucrose phosphate syntheses which is activated by the ripening process itself, by ethylene, and by cool storage (Mitchell et al., 1991). Fruit with high dry matter content usually also have higher soluble solids, and thus have better taste and flavour (Hao et al., 2000b). 2.8.5 Lycopene Lycopene is a natural antioxidant in tomato responsible to the protection against epithelial cancers (Brandt et al., 2006). It is the pigment which is predominantly responsible for the red colour of ripe tomato fruits (Shi and Maguer, 2000). It works as a micronutrient and other health benefits (Viuda-Martos, 2013). The antioxidant helps to prevent prolonged diseases connected to oxidative trauma, like cancer and coronary artery disease. Lycopene has also been shown to be the most potent antioxidant produced by the carotenoid’s pathway (Cox, 2001). Lycopene is depending on some environmental factor like temperature where the temperature around 300c cause the loss of lycopene in tomatoes. The lycopene content of tomatoes samples ranged from 1.21 to 6.43 mg/100 g for fresh tomato (Hamulka and Wawrzyniak, 2004). It is also ranging between 6.88- 7.83 mg/100g for different varieties (Mohammed et al. (2017) the same with Mohammed and Malami (2013) where lycopene is ranging between 3.79- 17.53 mg/100g). The storage conditions may reduce the lycopene content, degrade it completely, thus rendering the food undesirable to the consumer (Xianquan et al., 2005). Sesso et al., (2003) also found that lycopene might help reduce risk of heart disease. Some researchers found that University of Ghana http://ugspace.ug.edu.gh 21 women who ate at least seven servings a week of tomato-based products had a 30% reduced risk of cardiovascular diseases. Lycopene content of tomatoes remained unchanged during the multistep processing operations for the production of juice or paste and remained stable for up to 12 months of storage at ambient temperature (Honglei et al., 2001). Lycopene is also the key colouring agent for the red colour of tomatoes (Lavelli and Scarafoni, 2011; D’Sousa et al., 2008). At higher temperatures the lycopene content decreased more, and losses of 17.1% were observed at 130°C (Miki and Akatsu, 1970). 2.8.6. Fruit firmness Firmness determines whether or not fruit can be transported to distant markets without deterioration. Tomato fruit becomes very soft during ripening (Hanson, 2001). The firmness is one of quality indices related to fruit development, maturity, ripening and storage potential. (Dobrzansk and Rybezyski, 1998) firmness is the principal characteristic of fruit, important for quality, harvest, maturity, and storage and shelf- life. High quality fruits have a firm appearance, uniform and shiny colour, without signs of injury, 21hrivelling or decay (Sargent and Moretti, 2002). Bosland (1993) stated that, firmness can be affected by ripening process, post-harvest handling and also the temperature). Lownds et al. (1993) indicated that the fruit firmness was increased as the weight loss increase during prolonged storage of pepper and other vegetables. 2.8.7 Shelf life Shelf life is defined as the period in which a product should maintain a predetermined level of quality under specified storage condition. The shelf life is a period of time which starts from harvesting and extends up to the start of rotting of fruits (Mondal, 2000). Gonzalez-Aguilar et al., (2010a), reported that mineral oil wax could is good for preserving the quality and extending the shelf life of fresh tomato fruit. Shahid et al., (2011) also reported that the effect University of Ghana http://ugspace.ug.edu.gh 22 of bee wax coating was very effective in improving the overall quality and extending the shelf life of sweet orange fruits at room temperature. Nurul (2012) revealed that the effect of cassava starch coating on fresh- cut pineapple delayed the change in colour, maintain quality of the pineapples and prolong the storage life. The rapid quality loss at relatively short period of 4-7 days is the main reason to reduce post-harvest losses of fruits and improve the quality and acceptability in the consumer market (Thompson et al., 1998). Sugri et al. (2010), also noted that shea butter as a food-grade wax on plantain 2.8.8 Vitamin c (Vit.c) Tomato is a very important source of vitamin c. Post-harvest handling and storage conditions may cause changes in vitamin c. Vitamin c minimize the risk of some diseases such as arteriosclerosis, cardiovascular disease and some form of cancer (Harris, 1996). Vitamin c of tomatoes can be destructed or reduced by their handling and storage conditions (Arias, et al., 2000). Some of factors which cause the loss of Vitamin c include extended storage, high temperature, physical damage and chilling injury (Lee and Kader, 2000). The average vitamin c concentration in tomatoes is about 23 mg/100 g. Steven (1974) found that the vitamin c concentration of 98 tomato varieties ranged from 13 to 44 mg/100 g. University of Ghana http://ugspace.ug.edu.gh 23 CHAPTER THREE: MATERIALS AND METHODS The methodology aimed at determining the effect of cassava starch, citric acid and their combinations as edible coatings. Polyethylene and plastic bags as packaging materials on quality of two varieties of tomatoes. The 1st experiment studied the effect of coatings on the quality of tomatoes. Tomato samples which showed desired quality in the 1st experiment were taken in the 2nd experiment to check the quality of two varieties of tomatoes (pectomech and wosowoso) when coated and covered in polyethylene and plastic bags. Tomato samples in the two experiments were kept at room and refrigeration temperatures. 3.1 Collection of samples The samples that were used in the study were two varieties of tomatoes, Pectomech (P) and Wosowoso (W). They were purchased according to uniform size and colour from Madina market, Accra, Ghana. They were packed into polyethylene bags and brought to the Post- harvest laboratory of Crop Science department, University of Ghana, Legon, Ghana for further treatments. The coating materials used, were cassava starch, citric acid and their combination (cassava starch and citric acid). The non-coated tomatoes were used as a control. The following concentrations were used: 1, 2 and 3% for cassava starch, 0.5 and 1% for citric acid and finally 1:0.5, 1:1, 2:0.5, 2:1, 3:0.5 and 3:1 ratio for cassava starch: citric acid. The two packaging materials used were polyethylene bags and plastic baskets. The coated and non- coated tomatoes were stored at 4oC in the refrigerator and at 28oC at room temperature. Tomatoes, cassava starch, polyethylene bags and plastic baskets were purchased from Madina market, Accra, Ghana. University of Ghana http://ugspace.ug.edu.gh 24 3.2. Preparation of samples and coating materials 3.2.1. Tomatoes All purchased tomatoes were sorted to remove tomatoes showing softness, physical damages, sunburn, decay, cracks, non-red colour. The stems were detached from the tomatoes. Wanted tomatoes were manually washed 3 times in tap water to remove dust, mud, dry leaves, stems, applied chemicals (ex.:pesticides) and other external non chemical contaminants. Washed tomatoes were stored at 4oC in the refrigerator until further treatments. The solid and liquid wastes were disposed in appropriated bins provided in the laboratory. 3.2.2. Coating materials The coating materials used in the study were cassava starch and citric acid. Cassava starch was purchased from Madina market, Accra, Ghana, and citric acid was provided in the Post-harvest laboratory of Crop Science Department, University of Ghana, Legon. 3.2.2.1 Cassava starch The concentrations of cassava starch used for the experiment were 1, 2 and 3%. The preparation of the concentrated cassava starch was performed according to Wheatley and Zakhia (2003). Cassava starch slurry at 1% was prepared by mixing 10g of cassava starch with 990 mL of distilled water. This was then heated on an electric stove (capacity: 12 inch, ID22270119188, India) up to a temperature of 80 °C until it gelatinized (C.C. Wheatley and N. Zakhia 2003). The slurry was then allowed to cool to 40oC before it was applied on the tomatoes. The same procedure was used to prepare the different concentrations (2% and 3%) by using 20 g and 30 g cassava starch in 980 and 970 mL of distilled water respectively. University of Ghana http://ugspace.ug.edu.gh 25 3.2.2.2 Citric acid Citric acid concentrations used were as follows: 0.5 and 1%. The 0.5% of citric acid solution was prepared by mixing 5g of citric acid with 995ml of distilled water, and 1% by mixing 10g of citric acid with 990ml of distilled water. 3.2.2.3 Cassava starch and citric acid combination The concentration for the combination of citric acid (CA) and cassava starch (CS) were 1:0.5, 1:1, 2:0.5, 2:1, 3:05 and 3:1 ratio. The 1:0.5 ratio was prepared by mixing 10g of cassava starch with 5g of citric acid to obtain their mixture of 15g. This mixture of CS and CA was mixed with 985ml of distilled water. This was heated on an electric stove up to a temperature of 80oC until it gelatinized. The slurry was also allowed to cool to 40oC before it was applied to the tomatoes. The same procedure again was used to prepare the remaining concentrations (1:1, 2:0.5, 2:1, 3:0.5, and 3:1) by using 20 g, 25g, 30g, 35g, and 40g of mixture in 980, 975, 970, 965 and 960 mL of distilled water respectively. 3.3. Coating of tomatoes Tomatoes were coated with prepared solutions of cassava starch and citric acid (See table 3.1) by using the method of Menezes and Athmaselvi (2016). Tomatoes were dipped for 2 min and allowed to dry in open air. The 1st category of dry tomatoes was not packed and the 2nd category was packed in polyethylene bags and plastic baskets. Both categories were kept at 4oC in refrigeration and at 28oC in open air. University of Ghana http://ugspace.ug.edu.gh 26 Table 3.1 DESCRIPTION OF MATERIALS AND TREATMENTS RATIOS Coating material Percentage and ratio Method of Application Cassava starch (CS) 1% Dipping Cassava starch 1% Brushing Cassava starch 2% Dipping Cassava starch 2% Brushing Cassava starch 3% Dipping Cassava starch 3% Brushing Citric acid (CA) 0.5% Dipping Citric acid 0.5% Brushing Citric acid 1% Dipping Citric acid 1% Brushing Cassava starch + Citric acid 1:0.5 Dipping Cassava starch + Citric acid 1:0.5 Brushing Cassava starch + Citric acid 1:1 Dipping Cassava starch + Citric acid 1:1 Brushing Cassava starch + Citric acid 2:0.5 Dipping Cassava starch + Citric acid 2:0.5 Brushing Cassava starch + Citric acid 2:1 Dipping Cassava starch + Citric acid 2:1 Brushing Cassava starch + Citric acid 3:0.5 Dipping Cassava starch + Citric acid 3:0.5 Brushing Cassava starch + Citric acid 3:1 Dipping Cassava starch + Citric acid 3:1 Brushing Control - Dipping Control - Brushing University of Ghana http://ugspace.ug.edu.gh 27 3.4. Determination of physicochemical properties of coated tomatoes The quality indices that were measured were shelf-life, weight loss, firmness, total soluble solids, pH, titratable acidity, vitamin C and lycopene. 3.4.1. Shelf- life The shelf life of four tomatoes from each sample was determined by counting their life number of days before deterioration during their storage time. 3.4.2. Weight loss According to the weight loss, four tomatoes from each treatment were weighed at the start of the experiment as initial weight (Wi) and every two days fruits were reweighed for final weight (Wf). To determine the weight loss in the fruits during 37 days of storage time, the weight was measured using the weighing laboratory scale (ID: 2945712791, India MART). Figure 3.1. Laboratory scale used by measuring the weights of tomatoes every two days. The weight loss was expressed as percentage using the following equation: % weight loss = {(Wi – Wf)/Wi} ×100. (Hosseini et al., 2019). University of Ghana http://ugspace.ug.edu.gh 28 3.4.3 Firmness Firmness was determined by using an FT 011, 0–11 lb, penetrometer (Facchini, Alfonsine, Italy). The replicates were three tomatoes sampled randomly from each treatment and their firmness was determined according to the manufacturer’s instructions. To determine the resistance of the fruit to penetration with a rod of 8.0 mm diameter for soft fruits. The rod was placed perpendicularly on the tomato and the fruit was pressed to cause a gradual visible cut, at which point the measurement was recorded (OECD 2009). 3.4.4 Total soluble solids (TSS) The total soluble solids (TSS) was determined by a hand-held refractometer (JENA 178512) where the TSS was determined in triplicate according to the reference method 920.151 reported by AOAC (1997). The portable refractometer was calibrated with distilled water and 3 drops of juice from the homogenized and filtered sample were placed on the prism of the refractometer and the readings were taken and expressed in 0Brix. University of Ghana http://ugspace.ug.edu.gh 29 3.4.5 Potential of hydrogen (pH) The pH was determined by using a pH meter (Mettler Tolledo EL20-Kit Benchtop Education pH Meter). The pH values were measured from juice of three different tomatoes taken randomly in each sample and pH values of their juice were measured according to Association of Official Analytic Chemist (AOAC) method (1990). The Buffers 4,7,10 were used to calibrate pH meter where the sensor electrodes were rinsed with distilled water and soaked in a glass that contained a solution of water and buffer until the pH level stabilized and the pH meter correctly matched the pH value of the calibration solution. Figure 3.2: The pH meter used for measuring the pH of tomatoes 3.4.6 Titratable acidity (TA) The titratable acidity was determined by titration with bromthymol blue indicator following this way: 20.00 cm3 of sample was pipetted for the analysis, 2.00 cm3 of working solution of indicator was added and titrated by the solution of potassium hydroxide till changing the indicator colour. Three titrations were done and average consumption of the base solution was University of Ghana http://ugspace.ug.edu.gh 30 calculated (Daničić, 1984). Titration with indicator phenolphthalein was also done in the same way, till the colour changing to pink (Rajković and Novaković, 2005). 3.4.7 Lycopene The lycopene was determined using the Spectrophotometric method. A mixture of hexane: ethanol: acetone at 2:1:1 (v/v) was used for lycopene extraction (Sadler et al. 1990). In this procedure, 1 gram of tomato juice and 100 ml of the mixed solvents were used. An aliquot of tomato homogenate was weighed into a flask, the solvent was added and the lycopene was allowed to extract over the next 15 to 30 min. Water was added (15ml per 100ml of solvent) to cause a phase separation. The upper hexane phase contained all the lycopene was quantified spectrophotometrically as it has been used by other investigators (Sharma and Le Maguer, 1996; Arias et al., 2000; Gordon and Diane, 2007; Godwin, et al., 2015). 3.4.8 Vitamin C Vitamin c was determined by using Indophenol Method (Zvaigzne G., Karklina.D, Seglina D. and Krasnova I, 2009) 10 g of each of the tomato samples was accurately weighed and ground using mortar and pestle with an additional of 20 ml of metaphosphoric acid acetic acid. The mixture was further ground and strained through muslin and the extract was made up to 100 ml with the metaphosphoric-acetic acid mixture. 5 ml of the metaphosphoric acid-acetic acid solution was pipetted into three of the 50 ml Erlenmeyer flask followed by 2 ml of the samples extract. The samples were titrated separately with the indophenol dye solution until a light rose pink persisted for 5 s. The amount of dye used in the titration were determined and used in the calculation of vitamin C content. University of Ghana http://ugspace.ug.edu.gh 31 3.5. Sensory evaluation The visual quality of stored coated and packed tomatoes was assessed by 10 trained panellists from Family and Consumer Sciences department, School of Agriculture, College of Basic and Applied Sciences, University of Ghana, Legon. A five – point hedonic scale was used to score samples for appearance, texture, colour and overall acceptability. 3.6. Statistical data analysis In the 1st experiment, the Pectomech tomatoes were stored at room and refrigeration temperatures after coating them with cassava starch, citric acid and their combinations in different concentrations by brushing and dipping. The coated tomato samples which showed desired quality in the 1st experiment were taken in the 2nd experiment as two varieties (pectomech and wosowoso) to be packed in polyethylene and plastic bags during storage at room and refrigeration temperatures. A 12x2x2 factorial experiment layout in a completely randomized design with 48 samples was used in experiment 1 (coating of tomatoes) and a 2x2x2x2 factorial experiment layout was used for experiment 2 (packaging of tomatoes) with 16 Samples. All treatments were replicated 3 times. All data obtained from the laboratory experiments and the sensory evaluation were analysed using analysis of variance (ANOVA) with computer GenStat program and the means were separated using Duncan multiple range test at a level of significance of P< 5%. University of Ghana http://ugspace.ug.edu.gh 32 CHAPTER FOUR 4.0. RESULTS 4.1. Experiment One The present results are for the 1st experiment in which different coatings and coating techniques were used to preserve uncovered tomato varieties during storage at room and refrigeration temperatures. The Pectomech tomato were coated with cassava starch and citric acid and their combinations in different concentrations by brushing and dipping. 4.1.1 Effect of edible coatings on shelf-life of pectomech tomatoes stored at room temperature and at refrigeration Figure 4.1 and 4.2 show the shelf-life of pectomech tomatoes coated with different edible coatings and stored at room temperature (28oC) and refrigeration temperature (4oC) for up to 35 days. From the results, it was observed that the control samples had shorter shelf life than other tomato samples. For dipping method (figure 4.1), tomatoes which showed the longest shelf life (35 days) at refrigeration storage were coated with 2% CS; 1:0.5 CS:CA; 2:0.5CS:CA; 3: 0.5 CS:CA and 3:1 CS:CA while at room storage, tomatoes with the longest shelf life (21 days) were coated with 0.5% CA; 1% CA; and 3:1% CS: CA. For brushing method (figure 4.2), tomatoes which showed longest shelf life (35 days) at refrigeration temperature were coated with 1%Cs; 0.5% CS; 1% CA; 1:1 CS:CA and 2:1 CS:CA while at ambient temperature, tomatoes which showed the longest shelf life (28 days) were coated with 1% CS; and 1:1 CS:CA. University of Ghana http://ugspace.ug.edu.gh 33 Figure 4.1: Effect of edible coatings on shelf life of tomatoes stored at room temperature (28o C) and in refrigeration (4oC) with dipping method Note: CS: Cassava starch coating, CA: citric acid coating, Brush: brushing method, Cntrl: control; Days Rt: days of storage in room temperature (28oC), Days Rft: Days of storage in refrigeration temperature (4oC) 1CS Dipp: 1% concentration of cassava starch coating with dipping method. The same with the others respectively. Figure 4.2 Effect of edible coatings on shelf-life of tomatoes stored at room temperature and in refrigeration with brushing method. 0 5 10 15 20 25 30 35 40 1% CS Dip. 2% Cs dip. 3% Cs dip 0.5% CA Dip. 1CA Dip. 1: 0.5 Dip. 1:1 Dip. 2:0.5 Dip. 2:1 Dip. 3:0.5 dip. 3:1 Dip. Cntrl Dip. D ay s o f st o ra ge Treatments Shelf life of stored and coated pectomech tomatoes(Dipping method). Days Rt Days Rft 0 5 10 15 20 25 30 35 40 1CS Brus 2Cs Brus 3Cs Brus 0.5CA Brus1CA Brus 1:0.5 Brus 1:1 Brus 2:0.5 Brus 2:1 Brus 3:0.5Brus 3:1 Brus Cntrl Brus D ay s o f st o ra ge Treatments Shelf life of stored and coated pectomech tomatoes(Brushing method) Days Rt Days Rft University of Ghana http://ugspace.ug.edu.gh 34 Note: 1CS Brus: 1% concentration of Cassava starch coating with brushing method 0.5 CA Brus: 2% concentration of Citric acid coating with brushing method 1:0.5 Brus: 1% Cassava starch mixed with 0.5 Citric acid coating with brushing method... 4.1.2 Effect of edible coatings on weight loss of pectomech tomatoes stored at room temperature and at refrigeration Figure 4.3 and 4.4 show the weight loss of pectomech tomatoes coated with different edible coatings by dipping and brushing methods, and stored at room temperature (28oC) and refrigeration temperature (4oC) for up to 35 days. The results, indicated that, there was a significant increase (P<0.05) in weight loss value of stored tomatoes. From the results, it was observed that for control samples which were dipped in distilled water had a low weight loss compared to samples brushed in distilled water. For both method of applications, the weight loss at refrigeration temperature was lower than that at room storage. For samples which were stored at room temperature (28oC) and refrigeration temperature (4oC) and dipped in cassava starch (2% CS), showed the lower weight loss than samples dipped in 1 or 3% CS treatments. The samples which were stored at room temperature (28oC) and refrigeration temperature (4oC) and brushed in cassava starch (1% CS), showed the low weight loss than samples brushed in 2 or 3% CS treatments. Comparing both method of applications, in dipping method (2% CS) showed lower weight loss than brushing method (1% CS). For citric acid coating, the samples which were stored at room temperature and refrigeration temperature, and dipped in 0.5% CA treatment, had low weight loss than samples dipped in 1% CA, while the samples which were stored at room temperature and refrigeration temperature, and brushed in 1% CA treatment showed low weight loss than 0.5% CA University of Ghana http://ugspace.ug.edu.gh 35 treatment. Comparing both method of applications, brushed samples in 1% CA showed the low weight loss than samples dipped in 0.5% CA. For cassava starch mixed with citric acid, the samples which were stored at room temperature and dipped in 1:1 CS+CA treatment showed low weight loss than other treatments, while in refrigeration 3:1 CS+CA was the one which showed the low weight loss than other combinations. The samples which were stored at room temperature and refrigeration temperature and brushed in 3:1 CS+CA treatment showed the low weight loss than other combinations. Comparing both method of applications, The samples which were stored in room and brushed in 3:1% CS+CA showed the low weight loss than samples dipped in 1:1CS+CA, while the samples which were stored in refrigeration, and dipped in 3:1 CS+CA showed the low weight loss than samples brushed in 3:1 CS+CA. Figure 4.3: Effect of edible coatings on weight loss of tomatoes stored at room temperature and in refrigeration with dipping method. 0 10 20 30 40 50 60 70 80 1 % 2 % 3 % 1 % 2 % 3 % 0 .5 0 % 1 % 0 .5 0 % 1 % 0 1 :0 0 .5 0 1 :0 1 0 2 :0 0 .5 0 2 :0 1 0 3 :0 0 .5 0 3 :0 1 0 1 :0 0 .5 0 1 :0 1 0 2 :0 0 .5 0 2 :0 1 0 3 :0 0 .5 0 3 :0 1 RT Rft RT Rft RT Rft RT Rft Dipp. Dipp. Dipp. Dipp. Contrl CS CA CS+CA W e ig h t lo ss v al u e s Treatments Weight loss of stored pectomech tomatoes(Dipping method) Days 7 Days 14 Days 21 Days 28 Days 35 University of Ghana http://ugspace.ug.edu.gh 36 Figure 4.4: Effect of edible coatings on weight loss of tomatoes stored at room temperature and at refrigeration with brushing method. 4.1.3: Effect of edible coatings on the total soluble solid (TSS) of pectomech tomatoes stored at room temperature and at refrigeration. Table 4.1 (a,b) shows the changes in total soluble solid of pectomech tomatoes coated with different edible coatings and stored at room temperature (28oC) and refrigeration temperature (4oC) for up to 21 days. The results, indicated that, there was a significant increase (P<0.05) in total soluble solid (TSS) value of stored tomatoes. 0 10 20 30 40 50 60 70 80 1 % 2 % 3 % 1 % 2 % 3 % 0 .5 0 % 1 % 0 .5 0 % 1 % 0 1 :0 0 .5 0 1 :0 1 0 2 :0 0 .5 0 2 :0 1 0 3 :0 0 .5 0 3 :0 1 0 1 :0 0 .5 0 1 :0 1 0 2 :0 0 .5 0 2 :0 1 0 3 :0 0 .5 0 3 :0 1 RT Rft RT Rft RT Rft RT Rft Brush. Brush. Brush. Brush. contrl CS CA CS+CA W e ig h t lo ss v al u e s Treatments Weight loss of stored pectomech tomatoes (Brushing method). Days 7 Days 14 Days 21 Days 28 Days 35 University of Ghana http://ugspace.ug.edu.gh 37 From the results it was observed that the control samples which were dipped in distilled water and stored at room temperature (28oC) or at refrigeration temperature (4oC) had a TSS value of 7.25 and 6.31 on day 7 respectively whereas the control samples which were brushed in distilled water and stored at room temperature (28oC) or at refrigeration temperature (4oC) had a TSS value of 5.13 and 3.18 on day 14 respectively. The coated samples which were dipped in 1% CS and stored at room temperature (28oC) or at refrigeration temperature (4oC) had a TSS value of 4.15 and 2.59 on day 14 respectively while the samples which were brushed in 1% CS and stored at room temperature (28oC) or at refrigeration temperature (4oC) had a TSS value of 4.54 and 4.43 on day 14 respectively. The coated samples which were dipped in 3% CS and stored at room temperature (28oC) or at refrigeration temperature (4oC) had a TSS value of 4.46 and 4.34 on day 7 respectively while the samples which were brushed in 3% CS and stored at room temperature (28oC) or at refrigeration temperature (4oC) had a TSS value of 4.40 and 3.00 on day 7 respectively. The coated samples which were dipped in 0.5% CA and stored at room temperature (28oC) or at refrigeration temperature (4oC) had a TSS value of 5.69 and 4.91 on day 21 respectively, while the samples which were brushed in 0.5% CA and stored in refrigeration temperature (4oC) had a TSS value of 2.94 on day 21 The coated samples which were dipped in citric acid (1% CA) and stored at room temperature (28oC) or at refrigeration temperature (4oC) had a TSS value of 6.99 and 4.64 on day 21 respectively, whereas the samples which were brushed in 1% CA and stored at refrigeration temperature (4oC) had a TSS value of 5.58 on day 21. The coated samples which were dipped in cassava starch mixed with citric acid (3:1 CS+CA) and stored at room temperature (28oC) or at refrigeration temperature (4oC) had a TSS value University of Ghana http://ugspace.ug.edu.gh 38 of 4.92 and 4.65 on day 21 respectively, whereas the samples which were brushed in (3:1, CS + CA) and stored at refrigeration temperature (4oC) had a TSS value of 4.59 on day 21. Table 4.1(a). Changes in TSS according to different coating materials Coating material Method of application Storage place % Days 0 7 14 21 Control Dipping Rt 3.77c 7.25n N/A N/A Rft 3.23a 6.31m 5.13jk N/A Brushing Rt 3.64abc 4.100cd 3.81b 4.37bc Rft 3.23a 3.80de 2.59ab N/A Cassava starch Dipping Rt 1 3.68bcde 4.99ij 4.15cde N/A 2 3.8cdef N/A N/A N/A 3 3.63abc 4.46ghij N/A N/A Rft 1 3.65 abc 4.24cde 2.59ab N/A 2 3.23a 3.68bc 4.10fgh 3.58ab 3 TSS 3.93ef 4.34efgh 5.43h 4.80cd Brushing Rt 1 3.80cdef 5.37h 4.57defg 4.41c 2 3.63abc 4.88f 6.07i 5.51e 3 3.53bcd 4.40efgh N/A N/A Rft 1 3.45b 4.18defg 4.43hij 3.54ab 2 4.18cde 4.82ij 4.41hij 5.13de 3 3.23a 3.00a 3.73abc N/A Citric acid Dipping Rt 0.5 3.76cdef 3.60bc 5.15g 5.69efj 1 3.34abc 4.53fghi 6.96 l 6.99j Rft 0.5 3.81bc 3.06a 4.67efg 4.91d 1 3.89bc 4.35def 5.18gh 4.64cd Brushing Rt 0.5 3.31ab 4.92fgh 4.57fg N/A 1 4.79jk N/A N/A N/A Rft 0.5 3.01a 4.29de 4.15cde 2.94a 1 3.64abc 5.64kl 5.39hi 5.58ef University of Ghana http://ugspace.ug.edu.gh 39 Data are presented as means±SD. Means within a column with different letters are significantly different at P≤0.05 Notes: N/A: Not Applicable; measurement was not taken because tomatoes were already spoilt; TSS: total soluble solid; Rt: Room temperature (28oC); Rft: Refrigeration temperature (4oC) Table 4.1(b). Changes in TSS according to different coating materials Coating material Method of application Storage place Ratio Days 0 7 14 21 Cassava starch +Citric acid Dipping Rt 1:0.5 3.70bcd 5.63kl N/A N/A 1:1 3.25a 5.18hijk 4.95fgh N/A 2:0.5 4.15fgh 4.94gh N/A N/A 2:1 3.50bc 4.99gh 4.96fgh N/A 3:0.5 3.82def 4.13cdef 4.96k 4.42c 3:1 3.24ab 5.94 l 4.88jk 4.92d Rft 1:0.5 3.86bc 3.28a 3.89efg 3.94b 1:1 3.66def 4.99gh 4.36ghij 4.65cd 2:0.5 3.62abc 4.15cdefg 4.10fgh 4.40c 2:1 3.36ab 4.99gh 4.84hij N/A 3:0.5 3.52bc 3.99bcd 4.49def 4.07abc 3:1 TSS 3.73bcde 4.75fg 4.31cdef 4.65cd Brushing Rt 1:0.5 3.55bcd N/A N/A N/A 1:1 3.99ef 4.61efg 5.99ijk 4.10bc 2:0.5 3.67def N/A N/A N/A 2:1 4.01efg 4.70ghij N/A N/A 3:0.5 3.19a 5.94 l 5.77i N/A 3:1 3.10a 6.15lm 4.72hij N/A Rft 1:0.5 3.36ab 3.95cde 3.46ab 5.46ef 1:1 3.15a 3.59bc 2.36a 3.94b 2:0.5 3.71a 5.17jk 3.95bcd 5.26ef 2:1 3.20a 3.96b 4.33ghi 5.23def 3:0.5 3.77bc 5.46l 2.43a 4.10bc 3:1 3.74b 4.96gh 3.84cde 4.59bcd Data are presented as means±SD. Means within a column with different letters are significantly different at P≤0.05 Note: N/A: Not Applicable; measurement was not taken because tomatoes were already spoilt; TSS: total soluble solid; Rt: Room temperature (28oC); Rft: Refrigeration temperature (4oC) 4.1.4 Effect of edible coatings on firmness of pectomech tomatoes stored at room temperature and at refrigeration University of Ghana http://ugspace.ug.edu.gh 40 Table 4.2 (a,b) shows the changes in firmness of pectomech tomatoes coated with different edible coatings and stored at room temperature (28oC) and refrigeration temperature (4oC) for up to 21days. The results, indicated that, there was a significant decrease (P<0.05) in the firmness of coated stored tomatoes. For the control samples which were dipped in distilled water and stored at room temperature (28oC) or at refrigeration temperature (4oC) had the firmness value of 3.44 and 7.19 on day 7 respectively, while the samples which were brushed in distilled water and stored at room temperature (28oC) or at refrigeration temperature (4oC) had the firmness value of 2.28 and 2.95 on day 14 respectively. For the samples which were dipped in Cassava starch (1%) and stored at room temperature (28oC) or at refrigeration (4oC) showed the firmness value of 2.73 and 5.80 on day14 respectively, however the samples dipped in Cassava starch (3% CS) and stored at room temperature (28oC) or at refrigeration (4oC) had the firmness value of 2.64 and 10.66 on day7 respectively. The samples which were brushed in Cassava starch (1%) and stored at room temperature (28oC) or at refrigeration (4oC) showed the firmness value of 2.57 and 2.87 on day 21 respectively. However, the samples brushed in Cassava starch (2% CS) and stored at room temperature (28oC) or at refrigeration (4oC) showed the firmness value of 3.30 and 3.79 on day 21 respectively while the samples brushed in Cassava starch (3% CS) and stored at room temperature (28oC) or at refrigeration (4oC), showed the firmness v