Formulation optimization of functional wheat bread with low glycemic index from technological and nutritional perspective

Inclusion of prebiotic compounds as indigestible dietary fiber in wheat bread has grown rapidly considering the increased public awareness about their impact on health. However, through their incorporation, the technological characteristics may adversely be influenced by gluten dilution impacts. This study was done to evaluate the impacts of long chain, native and short chain inulin (L-, N-, and S-type inulin, respectively) at 8%, 10%, 12%, 14%, and 16% w/w as inulin Reconstituted Wheat Flour (IRWF) with similar gluten: carbohydrate ratio of wheat flour (at 10%, 12.5%, 15%, 17.5%, 20% w/w) on technological and nutritional value of wheat bread. Results indicated that despite no gluten dilution induced by IRWF supplementation, technological characteristics were adversely influenced especially at higher substitution level of L-type-containing formulations which is attributed to their higher water absorption index (WAI). Reversely, the nutritional value was positively influenced in which the lowest hydrolysis index (26.64%); predicted Glycemic Index (51.93%) and fructan loss content (25.42%) were found at L-type inulin-containing IRWF at the highest substitution level (20% w/w). As the nutritional value of wheat bread as staple foodstuff is important, optimizing the bread-making process to decrease all reverse impacts induced by L-inulin-type inclusion seems to be required.