An In Vitro Estimation of Glycemic Index of White Bread and Improvement of the Dietary Fiber

Abstract

Consumers of products preferably demand minimally processed products that do not contain chemical preservatives and maintain health benefits. These encourage the use of dietary fiber (DF) to combat some metabolic disorders like diabetes and other immunological compromisings. This study indicates the potential of DF to satisfy the lowering of estimated glycemic index from improved white bread. The sources were selected from crude fiber composition of different cereals and fruits. Fruits of ripen avocado mesocarps and baobab pulps composed of total pectin composition 13%, 30% respectively and selected as good sources. Analysis of total dietary fiber (TDF), insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) were car-ried out according to the manufacturer megazyme total dietary fiber kit protocol and methods described in Association of Official Analytical Chemists (AOAC). Improvement of DF was observed by enhancing on white breads (WB) based on the daily requirement of soluble fibers (pectin) composition, i.e. 6 g/day. Samples of avocado improved bread (AVB) and baobab improved bread (ADB) were made by mixing in proportion of wheat flour to avocado/baobab pulps (97:3); (94:6); (88:12). Analysis of proximate composition and in vitro estimation of hydrolysis index (HI) and glycemic index (GI) were done for products to evaluate the quality and impact on blood glucose level. Significant differences were observed for predicted GI be-tween improved bread and controls, 82.84±0.37 (WB), 80.63±0.21 (ADB), 78.50±0.30 (AVB). As a result, the reductions in GI for the improved white breads indicate the delay in release of glucose from absorption by the cell due to the viscous nature of dietary fiber component. Thus, the improved white breads with appropriate soluble dietary fiber (pectin) content, reveals the potential for the reduction of blood glucose level and can be considered as functional foods (nutraceuticals) along with its moderate level degree of likeness or sensory acceptability. In general, the study has indicated that the soluble fibres can have a potential to reduce the post-prandial glucose by delaying absorption in cells.