No abstract

Aims:The presence of natural or synthetic compounds that interfere with the absorption of nutrients called antinutrients causing itching in the mouth has, resulted in the underutilization of cocoyam and therefore requires some processing methods to reduce these limiting factors. Effect of drying at different temperatures on the proximate composition, functional properties and anti-nutritional factors (ANFs) and investigation into moisture reduction pattern of cocoyam flour were therefore studied.

In the developing countries animal proteins are very expensive and cannot meet with the protein requirement of the current explosive population trend hence, supplementing with plant protein is pertinent. Soybean, which is widely consumed when processed to flour and flour products, is one of the best substitutes if properly processed. This study, therefore, aimed at establishing the best thermal treatment among the commonly used methods that will conserve the protein content of soy flour maximally, result in high flour yield and acceptability. Four different methods: Roasting (ROA), Extrusion (EXT), Boil and Sun Dry (BSD) and Boil and Oven Dry (BOD), were used to prepare samples from Tax 1448 soybean variety obtained from International Institute for Tropical Agriculture (IITA) and mixed variety obtained from market. The samples were milled in an attrition mill and the flours obtained were subjected to proximate, sieve and organoleptic evaluations. The results of the experiment, showed a protein content of 40.5, 40.7, 40.1 and 40.3%, flour yields of 32.0, 3.7, 29.7 and 37.9%, and acceptability of 58.0, 61.0, 36.0, and 48.0% and protein content of 33.7, 34.4, 32.7 and 32.7%, flour yields of 17.0, 5.0, 14.1 and 12.3%, and acceptability of 64.0, 68.0, 48.0 and 60.0% for BOD, EXT, ROA and BSD respectively for Tax 1448 and mixed variety. These results indicated that BOD is a better method over others. EXT, though, has the highest acceptability and protein contents, these values (p < 0.05), have no significant difference from those of BOD. EXT however has a very low flour yield. This study has therefore established that BOD is the best of the commonly used domestic methods for producing acceptable soy flour of high protein content and flour yield.

The effects of smoking, toasting and oven drying methods on the physical and chemical characteristics of "pupuru", a fermented cassava product, were studied. Cassava tubers were manually peeled, washed and steeped in water for four days after which the water was decanted; the soft wet mash was packed into Hessian sack and pressed. One portion was moulded into small-sized (500 g) ball shape and smoked on wood fire for 72 hours (Traditional method). The second portion was moulded into 500 g size ball and dried in the hot air oven at 60 °C for 14 hours. The two products were pulverized and sieved with 60 mesh size into fine pupuru flour. The third wet meal was sifted and toasted on an aluminum pan over fire and then milled into fine toasted pupuru flour. The flours were subjected to physicochemical evaluations. There was reduction in drying time when pupuru was toasted compared to the tradition smoking method. The range of final moisture content achieved was 7.14-8.40% (db). Despite the shortness in the drying time, the toasted samples had the lowest moisture content. Irrespective of the drying methods, there were significant differences (p < 0.05) in the proximate composition. The crude fibre content was highest in smoked dried with 3.17% compared to the toasted and oven dried samples with 2.12% and 2.53% respectively. The titratable acidity increased by about 78% from 0.09 to 0.16 with corresponding decrease in pH from 5.34 to 4.18. The toasted product had the lowest pH value of 4.18 while smoked and oven dried had 4.67 and 4.63 respectively. The bulk densities for both loosed and packed \ were higher for toasted product with values of 0.54 and 0.62 g/ml respectively, while smoked dried had the least value of 0.21 and 0.40 g/ml. The swelling power was highest in the toasted pupuru with value 0.38 ml/g and water holding capacity was 259.42 ml/g. The cyanide content of the smoked, oven dried and toasted product were 0.42, 0.48 and 0.47 mg/100g respectively. The toasting method gave the best sample in terms of drying time, moisture content, physical properties and sensory qualities. It can be concluded that toasting drying method is a better alternative method of producing pupuru.

This study investigated the effect of different common drying methods on the chemical composition of osmotically dehydrated tomato. The quality of dehydrated tomato is often poor as a result of: collapse of structure, discoloration, tough texture and loss of nutritional values. In this study, osmotic dehydration was combined with other drying methods with a view to investigating the method that will produce high quality product. Combination of sucrose and salt solution was used to soak tomato at 40 0 Brix for 4hours. The osmotically dehydrated samples were subjected to open air (sun), solar cabinet, hot air cabinet and oven drying methods. The proximate composition, colour and vitamin C of the dried samples were determined. The proximate composition showed that the raw tomato contained fat 1.75%, Ash 27.97%, crude fiber 0.18%, Protein 28.95% and Carbohydrate 41.15% while the Sun dried sample contained fat 1.25%, Ash 42.71%, Crude fiber 0.19%, protein 15.74% and carbohydrate 40.11%. Solar cabinet dried sample contained fat 1.29%, Ash 42.88%, crude fiber 0.26%, protein 15.78% and carbohydrate 35.79%. Hot air cabinet dried sample contained fat 1.17%, Ash 33.95%, crude fiber 0.25%, protein 14.48% and carbohydrate 1.17%. Oven dried sample contained, fat 1.15%, Ash 49.34%, crude fiber 0.26%, protein 13.22% and carbohydrate 36.03%. The vitamin C and colour measurement for raw, sun dried, solar cabinet dried, hot air cabinet dried and oven dried are 156.7 mg/100 g and 600 nm, 79.2 mg/100 g and 610 nm, 67.4 mg/100 g and 610 nm, 66.6 mg/100 g and 615 nm and 50 mg/100 g and 620 nm respectively which indicate the level of red pigmentation. Osmotically dehydrated tomato subjected to solar cabinet drying and sun drying yielded the best quality product based on their proximate and vitamin C compositions.