Nutritional Characteristics, Glycaemic Index and Blood Glucose Lowering Property of Gluten-Free Composite Flour from Wheat (Triticum aestivum), Soybean (Glycine max), Oat-Bran (Avena sativa) and Rice-Bran (Oryza sativa)

Abstract

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by increased blood glucose levels due to either lack of insulin production or inefficient as in the activity of insulin. Hence, this study aimed to produce and evaluate nutritional quality, glycaemic index, carbohydrate hydrolyzing enzymes and blood glucose lowering potential of composite flour samples from wheat, soybeans and rice-bran and oat-bran. The precooked wheat, soycake, rice-bran and oat-bran flour samples were blended (wheat 70% and soycake 30% (WSC); wheat 70%, soycake 25% and rice bran 5% (WSR); wheat 70%, soycake 25% and oat bran 5% (WSO); and wheat 70%, soycake 20%, rice bran 5% and oat bran 5% (WSRO) using material balance equation with reference to 25% of daily requirement for protein (14 g/day) and fibre (5 g/day) for adults. Formulated foods and controls (Cerolina (CERO) & 100% wheat (WF)) were evaluated for nutritional quality, glycaemic index, carbohydrate hydrolyzing inhibitory and antidiabetic potentials using standard methods. Nutritional parameters of formulated composite flour samples showed that WSRO exhibited higher protein content (23.94 g/100g), biological value (98.01%) and growth performance in rats than other food samples including controls, i.e., WF (14.56 g/100g; 66%) and CERO (17.59 g/100g; 97.59%). The α-amylase and α-glucosidase enzyme inhibitory activity of the experimental food samples ranged from 49.25% - 66.75% and 37.53% 57.40% in WS and WSRO, respectively. While glycaemic load and glycaemic index of the food samples varied from 24.64 - 28.50% and 40.03 - 46.41%, while that of CERO were 25.63% and 40.05%, respectively. Antidiabetic potential of experimental foods showed that WSRO (79.62%) had the highest blood glucose lowering activity; while those rats fed on WS sample (65.65%) had the least activity. However, the antidiabetic activity of WSRO was significantly (p<0.05) higher than that of ACAR (Acarbose) (75.07%), CERO (73.87%) and WF (59.10%), respectively. In conclusion, sample WSRO exhibited high nutritional quality, low glycaemic index and ability to lower blood glucose concentration. Hence, this formulated food mighty be suitable as an alternate to synthetic antidiabetic agent in managing diabetes.