Dairy Technology and Food Science

A study was conducted to find out the effect of citric acid on total monomeric anthocyanins and antioxidant activity of liquor made from unprocessed purple-leafed TRFK 306 Kenyan tea, brewed at various time/temperature combinations. Most purple tea consumers usually brew the tea leaves then add some lemon juice before consuming it. Citric acid was used here to mimic the use of lemon juice. Documentation on the quality of such a brew is scanty and the effect of acid on its quality is equally scanty. The current study used brewing time/temperature combinations of 5, 10 and 15 minutes with 70˚C and 92˚C drinking water. Total monomeric anthocyanins were analysed using UV-1800 spectrophotometer (Shimadzu, Japan) while DDPH method was used to assay for antioxidant activity. Citric acid concentration of 0, 0.1% to 0.5% was used to check their effect on the brews with the highest total anthocyanins and antioxidant activity. The results showed that brewing temperature of 70˚C had 9.5 mg/L to 27.7 mg/L, with 5 minutes brewing time being the highest. Temperature of 92˚C had 37.5 mg/L to 92 mg/L with 5 minutes brewing time having the highest total monomeric anthocyanins. Antioxidant activity of 92˚C brewing temperature ranged from 90.7% to 92.0%. Total monomeric anthocyanins increased with increased citric acid concentration up to 0.3% before it decreases while for antioxidant activity, it decreased with addition of citric acid. It was concluded that for maximum anthocyanins extraction, 5 minutes brewing time is the best while ten minutes brewing time could give optimum antioxidant activity.

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Evaluation ofthe sensory and meat quality was performed on Kenya Agricultural and Livestock Research Organization (KALRO) improved chicken (KIC) fed on diets incorporated with ground Prosopis juliflora pods (GPJP. Breast and thigh samples were obtained from chicken fed on GPJPbased diets substituting whole diet at 0% (PJP-0), 10 % (PJP-10), 20% (PJP-20) and 30 % (PJP-30). Organoleptic characteristics were evaluated using questionnaires for attribute profiling and affective tests using trained and miniature consumer panels. Continuous anchored attribute scales and hedonic scale were used for sensory tests while meat quality was determined by Honikel method. Increasing the levels of GPJP had similar effect on Breast pH but PJP-20 had higher pH than cockerels offered PJP-0 and PJP-10 and pullets offered PJP-30. At 14 th day, pullet meat from PJP-0 had lower water holding capacity as compared to all other samples apart from cockerel samples from the same treatment. Pullets offered PJP-0 performed better in thigh and breast. In general acceptability (GA), 6.9% and 12.33% could be attributed to the effect of GPJP in thigh and breast in pullet and cockerel samples respectively. Results indicate that cockerels' meat had more favorable sensory effect than pullets' meat. Inclusion of 20% of GPJP in diet could be used to feed chicken while at the same time maintaining high quality meat desired by the consumers.

Pumpkin is a multi-purpose fruit and leafy vegetable with abundant nutritional value and economic potential as a food and industrial crop. Cucurbita moschata is the most common, heat-tolerant, better thriver in tropical Africa, but remains under-utilised. Food preservation prolongs consumption period, diet variety and income generation for manufacturing companies. However, preservation is a central problem facing developing countries, with huge post-harvest losses of perishable commodities. Food availability that decreases just a few months after harvest limits development of high-value agri-business industries specializing in highly perishable products. Although processing and preservation treatments lead to high convenience, the subsequent nutritional loss remains a challenge. There is need to find ways of minimizing nutritional losses. Subsequently, the present study grew and subjected mature pumpkin fruits to three open solar (OSD), oven electric (OED) and enhanced solar (ESD) d...

Evaluation ofthe sensory and meat quality was performed on Kenya Agricultural and Livestock Research Organization (KALRO) improved chicken (KIC) fed on diets incorporated with ground Prosopis juliflora pods (GPJP. Breast and thigh samples were obtained from chicken fed on GPJPbased diets substituting whole diet at 0% (PJP-0), 10 % (PJP-10), 20% (PJP-20) and 30 % (PJP-30). Organoleptic characteristics were evaluated using questionnaires for attribute profiling and affective tests using trained and miniature consumer panels. Continuous anchored attribute scales and hedonic scale were used for sensory tests while meat quality was determined by Honikel method. Increasing the levels of GPJP had similar effect on Breast pH but PJP-20 had higher pH than cockerels offered PJP-0 and PJP-10 and pullets offered PJP-30. At 14 th day, pullet meat from PJP-0 had lower water holding capacity as compared to all other samples apart from cockerel samples from the same treatment. Pullets offered PJP-0 performed better in thigh and breast. In general acceptability (GA), 6.9% and 12.33% could be attributed to the effect of GPJP in thigh and breast in pullet and cockerel samples respectively. Results indicate that cockerels' meat had more favorable sensory effect than pullets' meat. Inclusion of 20% of GPJP in diet could be used to feed chicken while at the same time maintaining high quality meat desired by the consumers.

Crude sesame oil (CSO) is the widely used unrefined edible oil. Storage instability, off-flavour, and discoloration are, however, challenges in the industry. The purpose of this study was to map the sesame value chain, assess the suitability of CSO extraction plant, and analyze the microbial quality of CSO and premises environment. A structured Questionnaire and checklist were used to assess the sesame value chain and evaluate the suitability of the CSO extraction plant. Microbiological quality assessment was conducted using standard analytical methods. Stakeholders in the sesame value chain were inclusive of farmers, market mediators, traders, regulatory, extension workers and researchers. Though, illiteracy, inadequate technology, and infrastructure were the drawbacks. The CSO extraction plant was suitable apart from inadequate ingredients and CSO handling and unhygienic practices. Total aerobic bacteria (4.34-5.06 log 10 CFU/m 2 on swap surfaces, 2.44 log 10 CFU/g in CSO), total Coliforms (5.81 log 10 CFU/g of animal manure and 1.36 log 10 CFU of indoor air after extraction), yeasts and moulds (2.31 log 10 CFU/g of sesame seed and CSO and 4.47 log 10 CFU/m 2 of swap sample), Aspergillus species (1.17-1.33 log 10 CFU/g of sesame seed/CSO, 3.37-3.50 log 10 CFU/m 2 of swap samples), and Staphylococcus aureus (2.09 log 10 CFU/g of CSO, 2.56-3.22 log 10 CFU/m 2 of surface swaps, 3.26-3.77 log 10 CFU/protective clothing, 0.74-1.82 log 10 CFU of the indoor and outdoor air) were detected. Escherichia coli, Salmonella and Shigella were not detected. In conclusion, potential microbial pathogens were detected to impose food safety problems and economic loss. To improve the sesame value chain and CSO quality workers training on good handling and hygienic practices and thoughtful regulatory implementation are significant.

Phytoestrogens (PE) are weakly estrogenic compounds synthesized in plants, especially in climatic adversity. The endocrine disruptive activity of PEs and some of their human metabolites are of concern as they have been associated with positive and more so negative health effects.

Purpose: Phytoestrogens (PE) are weakly estrogenic compounds synthesized in plants, especially in climatic adversity. The endocrine disruptive activity of PEs and some of their human metabolites are of concern as they have been associated with positive and more so negative health effects. Methodology: The transcriptional activities (TAs) of ten PEs (apigenin, daidzein, daidzin, equol, enterodiol, formononetin, genistein, genistin, glycitein, and matairesinol) were measured as induction of the expressed luciferase activity which is correlates with biological effects. These effects were compared to transcription caused by 17β-estradiol (5 nM) hormone (standards) in vitro. This was done by the use of estrogenic receptors in the MMV-Luc cell line using a reporter gene assay tool.  Findings: Standard curves for hormone standards were determined and the EC50 for 17β-estradiol was (4.5 x 10-11M). The order of PEs potency for the ER (ERα and ERβ)  in the MMV-Luc cell line, as determined fro...

Sesame (Sesamum indicum L.) is an annual oilseed crop that is widely used for crude sesame oil (CSO) extraction. CSO is unrefined, thus, may impact the storage stability due to the uncontrolled processing and handling conditions, and absence of preservatives. The purpose of this study intends to analyze the fatty acid profile and oxidative stability of CSO. In a complete randomized (2*2*2) factorial design, clean sesame seeds (3.92% moisture content) were used for oil extraction with/without roasting treatment (200°C). The fatty acid profile and oxidative value of the CSO were analyzed. The roasted sesame seed oil extraction yield was higher (50.9%) and composed of 83.15% unsaturated fatty acids with an omega‐6 to omega‐3 ratio of 95.3. The ratio of polyunsaturated fatty acids (PUFAs) to saturated fatty acids (SFAs) was 2.9, while the moisture content of the CSO was 0.37%, exceeding the tolerable limit. The predominant fatty acids of CSO include palmitic, stearic, oleic, and linolei...