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 carried 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 between 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 postprandial glucose by delaying absorption in cells.

Relation between the Recipe of Yeast Dough Dishes and Their Glycaemic Indices and Loads

“…This product contained twice as much fibre as traditional waffles, and it might have increased the time needed to digest the carbohydrates present in the dough. The influence of dietary fibre and fat on the reduction of glucose levels in blood was also investigated by Borczak and Taye [39,42].…”

“…In a comparison to the glycaemic responses recorded after consumption of bread and biscuits made form a traditional recipe with those modified by introducing a dietary fibre mixture (70% inulin, 20% guar gum, 5% glucomannan and 5% wheat fibre) to the applied flour, Marangoni and Poli [44] and Taye [42] demonstrated that the fibre-enriched products had a lower GI [42,44]. Our own research also showed that the replacement of wheat flour with wholegrain wheat flour resulted in an increase in the content of dietary fibre and total ash in the studied dishes (Table 1).…”

In Vitro Starch Digestibility and Glycaemic Index of Fried Dough and Batter Enriched with Wheat and Oat Bran

“…Factors that affect starch digestibility include starch characteristics, enzyme inhibitors, amylose/amylopectin ratio, particle size of starch granule, processing method, starch gelatinisation, retrogradation and presence of other ingredients such as lipids, proteins and fibre [ 4 , 6 , 11 , 12 ]. Previous studies present persuasive evidence that certain dietary fibres noticeably reduced GI of foods, although the magnitude of GI reduction is dependent on the food type and processing involved [ 13 , 14 ]. Wheat (WB) and oat bran (OB) are cheap, easily accessible, fibre-rich food additives which, when incorporated into starchy foods, may reduce their GI.…”

“…The resistance of dietary fibres to amylolytic enzymes in the small intestine results in their transformation to short-chain fatty acids in the colon. These processes result in physiological benefits such as blood glucose regulation, laxative and prebiotic properties [ 14 , 19 ].…”