Sustainable valorization perspective of legume hulls to enhance the nutritional and functional properties of pasta

Abstract

Legume hulls, often considered byproducts, are sustainable sources of phenolics and minerals. Their utilisation targets the sustainable development goals by reducing waste and improving the nutritional value of conventional foods. In the present study, pasta was prepared by replacing semolina with legume (chickpea, black gram, and moong bean) hulls at 10%, 20%, and 30% levels. Hull incorporation significantly (p < 0.05) influenced the cooking quality, increasing the minimum cooking time (11.3–14.3 min), water absorption (121–157%), volume expansion (up to 233%), and gruel solid loss (up to 5.31%), with more pronounced effects observed at higher substitution levels. Sensory evaluation also revealed significant changes in the acceptability upon an increase in hull incorporation levels. Principal component analysis concluded that pasta containing 20% legume hulls achieved the optimum balance in cooking and organoleptic qualities; therefore, these samples were further analysed for their nutritional and technofunctional properties. The incorporation of legume hulls resulted in increased ash, fat, and fibre contents; however, the carbohydrate content decreased. The amino acid profile revealed an enhancement in the lysine, tyrosine, tryptophan, valine, leucine, and threonine contents in hull-incorporated pasta, while in vitro protein digestibility showed minor variation. Moreover, hull incorporation modulated the mineral and phenolic profiles; notably, black gram hull pasta showed an enrichment of catechin, syringic acid, and coumaric acid. The pasting profile revealed reduced peak and final viscosities, while FTIR and SEM analyses demonstrated fibre-induced disruption of the starch–protein matrix while preserving the functional groups and overall structural integrity. The present study highlights the potential of legume hulls as sustainable functional ingredients, supporting circular bioeconomy strategies while advancing the development of nutrient-dense staple foods.