Assessment of physicochemical properties, nutritional values, and sensory acceptability of pigeon pea flour substitution in chapati flat bread

Abstract

In recent years, an interest in plant–based protein increased dramatically. Pigeon pea (Cajanus cajan) is recognized as a good source of plant protein. The current study was aimed to develop pigeon pea flour (PPF) and whole wheat flour (WWF) blends, which were then used to make chapatis. The substitution levels of PPF for WWF ranged from 10%–40% w/w. The physical properties and nutritional values of the flour blends and the chapatis were investigated. The chapatis were also evaluated for sensory acceptability. Proximate analysis of the flours revealed protein content in PPF (26.10%) two times higher than that in WWF (13.52%). PPF had significantly higher yellowness (b* value), whereas had lower redness (a* value) and lightness (L* value) as compared to WWF (p<0.05). Substitution of WWF with PPF at 20%–40% caused a significant decrease in redness values of the flour blends (p<0.05). PPF showed lower total starch content and starch digestibility; had a higher release of amino–group–containing compounds as compared to WWF flour samples (p<0.05). Thereafter, the substitution of PPF for WWF into chapati presented higher yellowness and hardness of chapati as compared to the control (p<0.05). Chapati with PPF substitution at 20% and 40% attenuated glucose release under simulated digestion, corresponding to decreased predicted glycemic index (pGI) when compared to the control chapati (p<0.05). This may be due to the significantly reduction of total starch contents, and increase in resistant starch contents with the increased substitutions of PPF in the chapati (p<0.05). In ninhydrin assay, amino–group residues markedly elevated in chapati with 40% PPF substitution as compared to the control (p<0.05). Sensory evaluation revealed that taste, texture, aftertaste, and overall acceptability of chapati with 40% PPF were significantly decreased when compared to the control (p<0.05). For sensory evaluation, when compared between the types of consumers, regular consumers gave significantly higher scores in all parameters for 20% PPF chapati as compared to the new consumers (p<0.05). However, the overall acceptance of 20% PPF chapati showed no significant difference between consumer groups. These findings suggest that PPF can serve as a promising ingredient to improve nutrient values of plant–based chapatis with adequate consumer acceptability.