Browsing by Author "Johnson, P.N.T."
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Item The extent of marketability and consumer preferences for traditional leafy vegetables – a case study at selected markets in Ghana(International Journal of Consumer Studies, 2009-05) Quaye, W.; Gyasi, O.; Larweh, P.; Johnson, P.N.T.; Obeng-Aseidu, P.This paper reports on a survey conducted at two major marketing centres in Ghana; Tamale in the dry savannah zone and Kumasi in the forest zone. One hundred traders were interviewed using a semi-structured questionnaire and focus groups discussions held on traders’ perceptions and consumer preferences, relative importance and indigenous nutritional knowledge of traditional leafy vegetables (TLVs). The survey established that, with the exception of Xanthosoma mafafa (cocoyam leaves), inter-market distribution of TLVs is limited because of their perishable nature, narrow utilization base and lack of storage techniques. Socio-culturally related factors limiting the distribution of TLVs include regional diversity and ethnic differences in the dietary patterns of the Ghanaian populace, inadequate knowledge about the methods of preparations as well as nutritional and medicinal values of TLVs. The most preferred TLVs as reflected in the consumers’ buying behaviour and traders’ perceptions are Xanthosoma mafafa (cocoyam leaves), Corchorus spp.(Ayoyo), Amaranthus spp (Alefu) and Hibicus sabdariffa (Bra). The order of preference in the forest zone is Xanthosoma mafafa (cocoyam leaves) > Corchorus spp.(Ayoyo) > Amaranthus spp (Alefu) > Hibicus sabdariffa (Bra), while the reverse order pertains in the savannah zone. © 2009 Blackwell Publishing Ltd.Item Instrumental and Sensory Texture Profile Attributes of Fufu from Cassava-Plantain Flour(Journal of Root Crops 33(1): 53-56, 2007) Oduro-Yeboah, C.; Johnson, P.N.T.; Sakyi-Dawson, E.; Abb, L.D.Texture is one of the key desirable sensory attributes of fufu, a cassava-based staple of most West Africans. To optimize the processing parameters for cassava-plantain fufu flour, a convenient form of traditional pounded fufu, the texture attributes of the reconstituted fufu flour were assessed and characterized using instrumental and sensory methods. Local foods that are common in Ghana were used as descriptors to exemplify the texture attributes being assessed and conventional pounded fufu was used as a control. Parameters assessed included hardness, adhesiveness, gumminess and springiness. Data were analyzed by analysis of variance and mean separations were calculated by the general linear model procedures. The ranges of values for some of the sensory attributes were: hardness: 1.24-1.99, gumminess: 2.43 - 4.00 and adhesiveness:1.57 - 2.71. With the exception of type of breakdown, all the texture attributes of the reconstituted fufu from the cassava-plantain flour samples were comparable with that of the pounded fufu. The study thus established that sensory texture profile analysis can be effectively used for assessing the texture attributes of cassava-plantain fufu.Item Occupational Health Hazards Associated With Gari Production and the Possible Environmental Effects Of The Resultant Effluent(University of Ghana, 2015-07) Adabie, D.F.; Johnson, P.N.T.; Fosu-Mensah, B.; University Of Ghana, College of Basic and Applied Sciences, School of Agriculture, Department of Crop ScienceCassava (Manihot esculenta, Crantz) is primarily grown for its starch containing tuberous roots, which are a major source of dietary energy in the tropics. It is highly perishable and begins to degenerate shortly after harvest. Cassava in the fresh form contains cyanide, which is extremely toxic to humans and animals. These factors make the processing of cassava into a dry form a necessity. Processing is essential for the removal of cyanides from cassava roots. This post-harvest necessity via gari production is coupled with several disturbing occupationally-related hazards. Exposure to volatile cyanide and smoke makes the frying stage of gari making the most dangerous. Effluent derived from gari production is noted to have a devastating effect on vegetation, as vegetation is hardly observed in areas where effluents are discharged. It also causes the eutrophication of surface water. This research aimed at determining processors’ awareness of occupational health hazards relating to their line of work, and their awareness of the environmental hazards associated with the discharge of untreated cassava effluent. The study further sought to determine the quality of cassava wastewater, and the possible generation of ethanol from the liquid waste using Saccharomyces cerevisiae in varying amounts. Processors from three gari producing districts in Ghana served as respondents. These gari-producing districts were; Awutu Senya, Central Tongu and Ayensuano Districts. Cluster sampling of each district was used in selecting the respondents. Ninety (90) gari producers served as respondents. Processors acknowledged health related hazards associated with their line of work, coupled with a low usage of protective clothing. Processors indicated several undesired effects the discharge of the effluent had on their immediate environment. Effluents obtained from these districts were assessed for wastewater quality, which showed values far outside EPA accepted limits; with the exception of PO4-P (0.125 mg/L) and NO3-N (0.070 mg/L), which were within acceptable limits. Mean values of the other quality parameters measured were; pH (4.02), Conductivity (12223.3 μS/cm), TSS (2078.3 mg/L), TDS (41597 mg/L), COD (60335 mg/L) and BOD (23493 mg/L). These very high wastewater quality parameters indicate that cassava effluent has a strong potential of being deleterious to vegetation and aquatic life. Optimum ethanol concentration (3.25%w/v) was obtained in baker’s yeast at 0.6%w/v. Optimum ethanol concentrations for the different yeast amounts used were obtained at 48 hours. Significant differences were observed (P<0.05) in the different amounts of baker’s yeast used. Appropriate stakeholder institutions should invest resources into educating gari producers on occupational safety and health. The EPA and WRI should develop guidelines relating to the treatment and discharge of the cassava effluent. Optimized fermentation approaches should be exploited in enhancing ethanol production from the cassava effluent.Item Physicochemical characterization of four commercial rice varieties in Ghana(Advance Journal of Food Science and Technology, 2011-06) Diako, C.; Manful, J.T.; Johnson, P.N.T.; Sakyi-Dawson, E.; Bediako-Amoa, B.; Saalia, F.K.This study evaluated the physical characteristics, proximate and mineral composition, and functional properties of four commercial Ghanaian rice varieties compared to two imported rice brands to provide data for quality improvement. Imported brands were significantly different (p<0.05) from local varieties in grain dimensions and colour. Local varieties had higher mean values for grain width (2.21-2.26 mm), 1000-grain weight (19.5-22.3 g) and bulk densities (0.87-0.91 g/mL). Physical properties that negatively affect grain quality - brokens (13.60-32.70%); moldiness (0.89-22.3%); chalkiness (0.17-0.44%); and immature grains (0.05-0.33%) - were also higher. However, the local varieties were nutritionally superior to the imported brands, having higher iron (5.0-8.2 mg/kg) and phosphorous (1166-1374 mg/kg) contents. All the samples were nonwaxy rice types with high gelatinization temperatures (83.8-88.2°C), soft gels (66-98 mm) with low to intermediate amylose content (15.9-22.7%). The competitiveness of locally grown rice can be enhanced by improving physical quality and adopting a marketing strategy that emphasizes the nutritional quality and suitability for specific foods. © Maxwell Scientific Organization, 2011.Item Preliminary assessment of shea butter waxing on the keeping and sensory qualities of four plantain (Musa aab) varieties(African Journal of Agricultural Research, 2010-01) Sugri, I.; Norman, J.C.; Egyir, I.; Johnson, P.N.T.Over the last few years, the production of plantain has been increasing due to the introduction of some high yielding varieties. Unfortunately, very high post-harvest losses are incurred annually due to lack of appropriate storage technologies. This study evaluated the effect of shea butter as a food-grade wax on the pre-climacteric life and sensory qualities of four plantain varieties (Apem, Apentu, Asamienu and Oniaba). Waxing was achieved by brushing shea butter on fruits surfaces. The fruit diameter before waxing (d1) and after waxing (d2) was measured and the difference (d2-d1) taken as the waxing thickness. Parameters assessed were the uniformity of ripening, gloss quality, incidence of off-flavours and disorders. Waxing thickness of 0.5 and 1 mm resulted in irregular ripening, green-soft disorder and off-flavours. However, thin layer waxing (<0.05mm) prolonged the pre-climacteric life to 22, 20, 17, and 15 days in Apem, Apentu, Oniaba and Asamienu respectively. A prolonged post-climacteric life from 4 to 6 days across varieties as well as firm texture at senescence was recorded. Shea butter waxing resulted in significant decrease (P<0.001) in physiological weight loss of 9.46% by 22 days after storage compared to control which had 21.25% by 10 days of storage. Principal component analysis of sensory attributes showed that mouth-feel, colour, flavour and tastes accounted for 36.67 % of data variation whist texture alone accounted for 21.1% of data variability. Due to increasing lobby against the use of post-harvest chemicals, as consumers now want products with high nutritional value rather than having just superior external qualities, the use of shea butter as a food-grade wax can be further explored since no safety or residual effect is foreseeable. © 2010 Academic Journals.