Influence of processing methods on the quality attributes of bio-fortified sweet potato products

Bio-fortified sweet potato (BSP) is one of the crops that can be used to address the problems of vitamin A deficiency in the Sub-Saharan Africa but it’s currently being underutilized. This study seeks to evaluate the effects of different heat processing methods on the quality of products made from BSP in order to increase its utilization. Freshly harvested tubers were purchased from a Research Farm in Federal University of Agriculture, Abeokuta (FUNAAB), Nigeria and brought to the Processing Centre, Nigerian Stored Products Research Institute (NSPRI), Ilorin. The sample was taken through some standard pre-processing operations of sorting, peeling, washing, slicing (2.11 mm), and deep frying (3 minutes) while some portions were boiled immediately after sorting with or without skin for 10–15 minutes. Each treated sample was analysed for sensory, proximate, vitamins and mineral compositions following standard methods. Results showed that fried sample had highest acceptability for aroma (7.25) and crispiness (7.00) while sample boiled without skin (15 min) was rated with least scores in colour (5.30), appearance (5.40), texture (4.95), crispiness (4.65) and overall acceptability (5.70). Protein, vitamin C, phenolics, flavonoids and reducing sugar contents were 6.53–18.52%, 10.89–76.69 mg/100 g, 0.57–3.15 mg/L, 94.64–383.91 mg/L and 43.05–237.12 g/100 g respectively while some minerals such as Na, K and Zn ranged from 8.42–17.45, 5.12–9.30 and 0.03–0.09 mg/L respectively. Different heat processing at different durations affected the sensory attributes, nutritional and mineral compositions of BSP. Key words: Post-harvest, food security, potato, heat treatment, qualit

Assessing efficacies of insect pest management methods to preserve nutritional composition of bagged maize in storehouses located in markets in Nigeria

Maize needs to be stored using effective and safe postharvest management measures to prevent physical insect damage as well as ensure stability of nutritional quality during storage. In this study, conducted in February–December 2016, insect pest management methods for bagged maize preservation in storehouses located in markets in Nigeria were evaluated for their ability to preserve nutritional quality. Study locations were inthree grain markets, namely Eleekara market in Oyo town and Arisekola market in Ibadan, Oyo State, South West Nigeria, and Ago market in Ilorin, Kwara State, North Central Nigeria. Treatments comprised Piper guineense (Botanical), Bularafa diatomaceous earth (DE), permethrin powder (Rambo™) (Permethrin), PICS bags (hermetic) and ZeroFly® bags (non-hermetic). The study also had negative control (Control) comprising untreated maize in polypropylene bags. In general, as a result of insect infestation, protein content increased in all treatments except PICS which had the least infestation. After 11 months of storage, Permethrin and PICS treatments had the lowest insect infestation levels and the highest energy levels. Energy level in the Botanical treatment was also high and similar to levels in Permethrin and PICS treatments most likely due to fats and essential oils in P. guineense being adsorbed and/or absorbed by kernels. Fat content was lower in the Control and DE treatments likely due to the Control having the highest insect infestation and the DE adsorbing and/or absorbing fat from kernels. During storage carbohydrate content decreased in all treatments except the Control. However, even in the Control, there was a clear trend of decrease in carbohydrate content. Because the Control had the highest insect (Sitophilus zeamais) infestation and insect damaged kernels (IDK), this trend in decrease in carbohydrate content may be insect related. Ash content increased in the ZeroFly treatment, was unchanged in Botanical, Control, and PICS treatments, and decreased in DE and Permethrin treatments. Nutritional quality variables in this study were within or close to the known value ranges for maize. Therefore, use of maize that had been fumigated well and had a relatively low initial grain MC (9.1%), in addition to the effects of the treatments most likely slowed down population growth of the several insect species that were found and contributed to preserving nutritional quality. The relatively low insect populations in all treatments, including the Control, during the February–September period probably reduced the clarity of effects of infestation onnutritional composition reported in this study

Effect of drying temperatures on the proximate composition and sensory attributes of chicken egg

A study was conducted to dry chicken eggs in order to determine the effect of drying temperatures on the proximate composition and sensory attributes of dried eggs. The albumen, yolk and whole egg were dried separately at temperatures of 50, 55 and 60oC. The drying time for the samples ranged from 7hrs20mins to 13hrs50mins. The protein and fat contents of the dried whole egg at the drying temperatures ranged from 47.52 - 50.90% and 35.12 - 35.88%; for dried egg white, 79.32 - 79.58% and 5.28 - 5.7% and for dried egg yolk, 36.08 -36.36% and 53.56 - 54.52% respectively. Results of the proximate composition showed that the nutritional qualities of the dried eggs were retained during drying thus the drying temperature did not affect the quality of eggs. The moisture contents of the dried whole egg, dried egg yolk and dried egg white at the different temperatures range from 6.25 -7.23%, 3.51-3.62% and 6.96 - 8.84%. The low moisture contents indicate that dried eggs are shelf stable. No significant difference was observed in the proximate composition and sensory attributes of the dried whole egg, egg yolk and egg white except in the aroma of the eggs dried at different temperatures.Keywords: Albumen, yolk, egg, protein, fa

Chemical and physico-chemical properties of orange fleshed sweet potatoes (OFSP) chips dried using solar dyers

In this study, drying technology was employed to process fresh orange fleshed sweet potatoes (OFSP) into dried slices using NSPRI improved solar tent dryer, parabolic shaped solar tent dryer in comparison with open air drying and its effect on the chemical, physico-chemical and mineral constituents of dried OFSP slices was investigated. Results showed that the dried-OFSP contained ash (3.69-4.09 %), fat (4.09-5.09 %), crude fibre (4.69-5.15 %), protein (5.87-8.28 %), carbohydrate (78.22-82.21 %), vitamin C (8.55-20.49 mg/100g), phenolics (0.1-1.28 mg/kg), flavonoids (984-145 mg/kg) and reducing sugar (35.01-82.23 g/100g). The total titratable acidity of the dried OFSP slices varied between 0.56-0.89 %, total soluble solids ranged between 5.70-7.00 °Brix while pH ranged between 4.94-6.47. Zinc, magnesium, potassium, calcium, sodium, iron were present in varying levels but aluminium, lead and cadmium were not detected in all the samples. This study therefore showed that good quality dried OFSP slices with appreciable nutrient content can be obtained from drying in NSPRI solar tent dryers especially with the use of the parabolic shaped solar tent dryer. Thus, the parabolic solar tent dryer is recommended for drying crops. Keywords: Drying technology, Orange fleshed sweet potato, NSPRI solar dyers, Physicochemical propertie