Flaxseed and sprouted lentil seeds as functional ingredients in the development of nutritionally fortified “clean-label” gluten-free breads

Abstract

A “clean-label” gluten-free bread (GFB) was developed by replacing the commonly used hydrocolloid additive, methylcellulose, with an aqueous flaxseed slurry (FSS), known for its structure-forming properties, at 3 or 4.5 % levels into GFB formulations; for further nutritional improvement of GFB, the inclusion of 5 or 10 % roasted-sprouted lentil flour (SLF) was also investigated. FSS and SLF addition increased hardness, consistency, storage and loss moduli, and viscosity of the composite batters. The specific volumes of fortified breads were reduced, compared to control bread containing methylcellulose; however, they were greatly improved compared to bread made without any added hydrocolloid. Fresh breads containing solely FSS (3, 4.5 %) and that made with 3 % FSS-5 % SLF exhibited crumb textural characteristics similar to the control; the 3 % FSS-5 % SLF fortified sample showed similar textural changes upon storage (48 h, 25 °C) and slightly lower amylopectin retrogradation, compared to control bread. Further to increasing the contents of protein and total dietary fiber, FSS incorporation into GFB decreased the glucose release upon in vitro starch digestion, whereas inclusion of both FSS and SLF weakened this effect. Moreover, the “nutty” and “roasted legume” flavor-aroma notes, introduced by FSS and SLF, reduced the typical flat “rice” flavor-aroma of GFB, thus contributing to the higher overall consumer acceptability scores received for breads containing solely FSS as well as those fortified with 3 %FSS-5 % SLF. Overall, both FSS and SLF appear to be promising functional ingredients for production of “clean-label” GFB, having higher contents of macronutrients, improved sensorial characteristics, and acceptable textural attributes.