Roasted-sprouted lentil flour as a novel ingredient for wheat flour substitution in breads: Impact on dough properties and quality attributes

Abstract

Flours from lentil seeds, raw or sprouted (either lyophilized or roasted before grinding), were used for wheat flour substitution in breads. The physicochemical properties of the obtained flours and doughs as well as bread quality attributes and staling were examined. FTIR spectroscopy revealed that sprouting altered the secondary structure of the lentil protein matrix by decreasing β-turns and random coils, and increasing β-sheets, α-helices and aggregates, while roasting subsequently eliminated these changes. Calorimetry (DSC) showed that the roasted-sprouted lentil flour was partially gelatinized. Oscillatory and creep-recovery rheological tests showed that doughs fortified with roasted-sprouted lentil flour at 15 and 20% (flour basis) substitution level were more viscous and elastic. Breads made with 10% lyophilized-sprouted lentil flour exhibited the lowest specific volume, and the highest crumb hardening and starch retrogradation rates as well as the greatest increase in protein β-sheets in the composite protein-starch matrix. Instead, the formulation with 10% roasted-sprouted lentil flour did not show major changes in loaf specific volume and extent of starch retrogradation, following 4 days of storage, while exhibited significantly improved crumb textural characteristics compared to bread made with wheat flour alone, receiving the highest overall acceptability scores among all fortified products tested due to its pleasant roasted-like flavor note detected by sensory assessors. These findings suggest that a successive process of sprouting and roasting of lentil seeds could be an innovative approach to fortify wheat flour-based breads for improving their nutritional quality while maintaining desirable textural and sensorial attributes of the baked product.