Effect Of Different Local Edible Coatings On The Physical, Chemical And Organoleptic Properties Of Canary Yellow Melon

Abstract

Melon has high export potential but is highly perishable. To meet the consumer's desire to eat melons free of chemicals and also extend the shelf life of the fruit, handlers along the value chain generally employ various postharvest practices to achieve positive results. This study sought to assess the influence of different local edible coatings on the physical, chemical, and organoleptic properties of canary yellow melon (Cucumis melo var. inodorus). The study was carried out in two phases -a survey involving farmers and traders and a laboratory analysis. In the first phase, postharvest handling practices along the yellow melon value chain in Afienya - Prampram District of Ghana was assessed. One hundred open-ended and close-ended questionnaires were administered to farmers and traders of yellow melon. For the second phase, the influence of different local edible coatings on the physical, chemical, and organoleptic properties of canary yellow melon were assessed. Eight (8) treatments were laid out in Completely Randomized Design (CRD) with three replications of 18 fruits per treatment. Seven waxing materials (Shea Butter, Neem Oil, Beeswax, Shea Butter + Beeswax, Shea Butter + Neem Oil, Neem Oil + Beeswax, Shea Butter + Beeswax + Neem Oil) were used for coating the yellow melon fruits. Treated fruits plus control fruits were kept at ambient condition (29.3–31.3 °C, 69.0–72.0% RH) till 21 days and assessed for various quality indices including weight loss, firmness, pH, total soluble solids (TSS), total titratable acids (TTA), vitamin C and shelf-life. Results obtained from phase I of the study showed that farmers ensured that there were available markets before the fruits were planted and even harvested. The majority of the farmers had access to extension services but the services rendered did not include postharvest technology. Postharvest losses were recorded throughout the value chain of the fruit. Some of the losses recorded were mechanical, physiological, and biological (rot and pest attack). Notably, 66% mechanical loss at harvest was reported by the respondents. At the sale point, 82% of traders recorded losses and the rate of spoilage was up to 98%. The total economic loss incurred by the farmers was estimated at GHȻ 17, 500 out of an expected income of GHȻ 80,000. While that of the traders was GHȻ 4,300 out of an expected income of GHȻ 15,000. Lack of appropriate vehicles for the transportation of fruits, lack of storage facilities and postharvest technology were among the challenges the handlers of the fruit faced. Respondents did not have any knowledge about waxing and did not know of any modern storage technology but were willing to adopt storage technologies. Results from the laboratory analysis indicated that all coated treatments were able to preserve fruits’uits quality indices during the storage period. Longer shelf-life was observed in fruits coated with BW (18 days) while the shortest shelf-life of nine days was recorded for the control (uncoated fruits). Fruits coated with BW, SB and BW and its combination maintain fruit firmness and also reduce percentage weight loss. Fruits coated with BW and SB + NO recorded lower Vitamin C loss. Sensory evaluation revealed the overall acceptability of waxed fruits and consumers’ willingness to purchase waxed fruits. BW can therefore be used to prolong the shelf-life, improve glossiness and attractiveness, ensure firmness and also reduce weight loss of yellow melon fruits. Regarding the pathogenicity of organisms associated with postharvest rot of melon fruits, the results showed that the pathogen that causes yellow melon rot is Lasiodiplodia theobromae. The pathogenic ability of the organism proved positive as it was able to cause decay and reduced the shelf-life when inoculated onto healthy fresh samples of the fruits causing postharvest losses. The symptoms that appeared on the diseased fruit made it both unmarketable and unwholesome for household use, therefore, causing financial and economic losses to both farmers and traders. The study made a number of recommendations to help reduced or curbed postharvest losses. First, an agreement between farmers and buyers before planting or harvesting should be documented to avoid future disappointment that will lead to losses. Along the value chain (harvesting, sorting, packaging, transportation, and storage) general care should be considered during fruit handling. Best results can be achieved when baskets are cushioned with soft material to reduce impact during handling and transportation, throwing fruits into baskets and overloaded should be avoided to reduce bruises, which result in losses. The presence of specialized temperature control vehicles and storage facilities can significantly reduce post-harvest losses. The use of black polythene sheets, nylon sacks, and tarpaulin for covering fruits during transportation and storage should be avoided to prevent the build-up of heat that will accelerate postharvest losses. Extension workers should include postharvest services to farmers and other food handlers to preserve the quality of the fruits and also reduce losses. Researchers should disseminate new postharvest findings to extension workers to enable them to carry out their services efficiently. Therefore, it is recommended that BW and its combination should be used to treat yellow melon fruits to prolong their shelf life and also preserve their physical, chemical, and organoleptic properties.