Determination of vitamin B-6 and pyridoxine-glucoside in selected Malawi foods and the effect of preparation techniques on vitamin B-6 and pyridoxine-glucoside content
There were two main purposes to this study. The first was to determine the vitamin B-6 and pyridoxine β-glucoside content of selected foods commonly consumed in Malawi. The second was to examine the effect of preparation procedures of foods in Malawi on the content of vitamin B-6 and pyridoxine β- glucoside in foods. Seventeen plant foods commonly eaten in Malawi were determined for vitamin B-6 and pyridoxine β-glucoside using a microbiological assay. In addition, two commercial weaning foods, roasted maize-soy bean blend and extruded maize-soy bean blend, were also determined for vitamin B-6 and pyridoxine β-glucoside contents. Among all the foods analyzed, whole maize flour contained the highest amount of vitamin B-6 (0.66 mg/100 g), therefore, an excellent source of vitamin B-6 content in foods. Cooking decreased vitamin B-6 in pinto beans, kidney beans, sugar beans and cow peas by 34%, 45%, 14% and 48%, respectively. Roasting decreased vitamin B-6 in chick peas and soy beans by 59% and 38%, respectively. Soaking and fermentation reduced vitamin B-6 in soaked maize flour and cassava flour by 86% and 89 %, respectively. Therefore, these data suggest that some of the preparation procedures practiced in Malawi have a negative impact on the vitamin B-6 content of the processed foods. Cooked and roasted foods contained lower total amount of pyridoxine-glucoside than that of the raw food. The high pyridoxine β-glucoside content have adverse impact on the bioavailability of vitamin B-6 content. Based on typical diets for the urban and rural populations in Malawi, the rural diet contained less vitamin B-6 compared to that of urban diet. Therefore, the rural population may be at risk of inadequate vitamin B-6 intake compared to the urban population
