Bioactive constituents, microstructural and nutritional quality characterisation of peanut flat bread

Abstract

Flat bread is a popular staple food consumed in India prepared from whole wheat. This research is an attempt to add peanut (Arachis hypogaea) flour (10–40%) prepared by processing the peanut meal in wheat flour to enhance bioactive constituents, textural and nutritional properties of the resultant flat bread. Stickiness and spreadability of dough was slightly increased with increasing levels of peanut flour (PF). Flat bread substituted with PF exhibited significantly higher total phenolic content and total flavonoid content, antioxidant activities by scavenging DPPH and ABTS free radicals than control. Farinograph, textural and sensory assessment of flat bread, recommended substitution of 30% PF. Flat bread prepared from this level of PF had superior protein (22.89%), ash (9.34%), fat (3.52%) and mineral content. An enhanced in vitro protein digestibility (85.73%), higher dietary fiber content (8.60%) and lower glycemic index (42.39) were recorded as compared to that of control flat bread. The microstructure of flat bread containing 30% PF showed disrupted gluten matrix with protein aggregates whereas in case of control flat bread aggregates of starch granules overlapping one another were observed. The X-ray diffraction spectra showed V-type polymorphism with one diffraction peak at 2θ = 20.1°, displaying a lower degree of crystallinity.