Effects of gamma irradiation and stearic acid, alone and in combination, on functional, structural, and molecular characteristics of high amylose maize starch

The effects of gamma irradiation and stearic acid, alone and in combination, on functional, structural, and molecular characteristics of high amylose maize starch (Hylon VII, 60% amylose) were studied. Stearic acid (0, 1.5, and 5%) was added to Hylon VII starch, and then irradiated at 0, 30, and 60 kGy. Gamma irradiation significantly (p 0.05) increased solubility, water absorption capacity, and oil absorption capacity as well as decreased swelling power (at 90 and 95°C) of Hylon VII starch. These changes related well with increased amylose and decreased amylopectin content, decreased MW, and decreased transition endotherms of the starches due to gamma irradiation. Stearic acid addition significantly increased (p 0.05) water and oil absorption capacities, relative crystallinity as well as decreased solubility and swelling power of Hylon VII. Gamma irradiation had more effect on the molecular structure of Hylon VII compared with stearic acid. Gamma irradiation alone and with stearic acid did not seem to change the XRD pattern and microstructure of Hylon VII. The similar XRD pattern and morphology observed for irradiated and non-irradiated Hylon VII suggests that gamma irradiation depolymerizes amylose, and amylopectin mostly in the amorphous region of the starch to produce less branched or unbranched amylopectin. Gamma irradiation with stearic acid has potential in Hylon VII modification.This research was funded in part under the International Atomic Energy Agency (IAEA) Technical Cooperation (TC) project and Ghana Atomic Energy Commission (GHA/0/010, Government of Ghana).http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1521-379Xhb201

Determining the effect of heat treatment on iron fortified soybean gari blend and its potential bioavailability

Gari is a cassava based food product which lacks most essential nutrients needed to promote good health and growth. An easy-to-adopt strategy widely accepted and used by most low-income household to improve nutritional intake is to blend nutrient dense and nutrient-poor agricultureal produce in a meal. Soybean is used in food blends, as it contributes to caloric source especially supplementary protein. Micronutrient deficiency has been a major challenge in middle and low income countries. The most prominent of micronutrient deficiencies is iron deficiency, which has a potential harmful developmental effect especially on infants, adolescent girls, pregnant women and the elderly. Gari is widely consumed in Ghana and along the West African coast, therefore can be a good medium for food fortification to improve nutrition. The objective of the study was to fortify defatted soybean gari blend with iron and evaluate the effect of heat treatment on anti-nutrient content, estimated iron bioavailability and colour of the products. A known quantity of commercial food grade ferric sodium (FeNa) EDTA was added to cassava mash (with or without commercial food grade defatted soybean flour) before and after processing into gari. The elemental composition, anti-nutritional properties, estimated iron bioavaliability and colour of the product were determined using appropriate analytical methods. Results showed that fortification with iron improved the iron content of the gari samples (with or without defatted soybean flour). Addition of iron to defatted soybean gari blend before heat treatment significantly (p<0.05) decreased the lightness (L*) and yellowness (b*) of the end product. Blending gari with soybean flour elevated its anti-nutrient content; however the estimated molar ratios of anti-nutrients to iron and zinc contents were within acceptable levels as stipulated by USAID and FAO guidelines. Iron fortification of soybean gari blend has huge potential to reduce iron deficiency anaemia and protein-energy malnutrition among gari consumers in Africa

Effects of two pre-treatments, blanching and soaking, as processing modulation on non-enzymatic browning developments in three yam cultivars from Ghana

Non-enzymatic browning develops in dry-cooked foods and those with high carbohydrate develop acrylamide, a neurotoxin and potential carcinogen. However, some non-enzymatic browning products have reducing properties. We hypothesized that non-enzymatic browning and reducing power, a measure of antioxidant activity, of processed yam are affected by pre-treatment. Peeled yam cultivars (KM, RKD and SO89) in chunks were pre-soaked (0, 3, 6, 12, 18, and 24 h) in distilled water or pre-blanched (0, 1, 2, 3, 4, and 5 min) in steam. Pre-treated samples were deep-fried at 180 °C for 15 min or roasted at 220 °C for 30 min. Soluble solids, titratable acidity and pH of yam tissues and soaking water were determined. pH of the soaked yam tissues showed a positive relation with non-enzymatic browning. Pre-soaked fried KM and roasted RKD showed a significant decrease in non-enzymatic browning intensities. The reducing power of the cooked yams ranged between 78.94 and 185.92 % of ascorbic acid, and was affected by the different pre-treatment and dry-cooking methods