Physico-chemical and techno-functional characterization of quinoa bran protein concentrate

Abstract

Quinoa is considered to be a superfood with enormous nutritional quality. Quinoa bran is an underutilized agro-processing by-product despite being a good source of high-quality proteins and nutritional properties. It contains 14% protein, which are poorly extractable as they are entrapped within the complex cell wall polysaccharide matrix. The current study attempts to improve the yield and recovery of quinoa bran proteins by enzymatic pre-treatment (cellulase and xylanase) and aqueous alkaline extraction. The physicochemical, techno-functional properties and bioactivity of the quinoa bran protein concentrate (QBPC) were studied to assess its potential as a good quality plant protein source. The yield of QBPC was enriched from 3.13 to 7.72% by enzymatic pre-treatment with a protein purity of 67.7%. The QBPC has 45.6% essential amino acids and showed 89.6% protein solubility, better foaming capacity (35 ± 5%), foam stability (76.4 ± 10.4%), emulsion ability (7.6 ± 2.8%) and stability (69 min). The nutritional parameters are as per FAO/WHO requirements. SDS-PAGE revealed the presence of 11S globulin chenopodin and 2S albumins. QBPC also showed 26.5% DPPH radical scavenging activity. These findings suggest that enzymatic pre-treatment improves protein extractability from quinoa bran, a low-cost, potential source of good-quality plant protein for supplementary food products.