Dynamic in-vitro system indicates good digestibility characteristics for novel upcycled plant protein; correlation to techno-functional properties

An increasing global population demands the broadening of the plant-based protein portfolio. The high volume of by-products produced across the food industry presents the opportunity to reduce food waste while reclaiming valuable nutrition. The current study examines a novel protein, BRP, extracted from brewers spent grains regarding its techno-functionality and digestibility, in comparison to a variety of proteins including whey, soy, rice and two pea protein sources. Compositional, foaming, emulsifying, structural and rheological properties were examined, while digestion kinetics were determined using the dynamic tiny-TIM in vitro digestion model. BRP performed similarly to whey protein in many respects, demonstrating a high solubility, high nitrogen bioavailability (>90%) and comparable N digestion kinetics, however BRP exhibited no rheological changes over heating. The digestible Indispensable amino acid score for BRP was 67% with lysine as the sole limiting amino acid, a higher value than soy, rice and one of the pea proteins investigated. The production of a protein ingredient from a plentiful and otherwise low-value food processing by-product presents an opportunity for an increased shift towards more sustainable protein sources for the food industry. This protein displays enhanced nutritional characteristics when compared to variety of plant protein sources, and promising functional properties such as a high solubility. This study offers an examination of a novel, upcycled protein ingredient as a potential tool for food manufacturers in the shift towards a more sustainable and secure food future. •Spent grain protein isolate (BRP) is highly digestible (90% N bio-availability) and has a DIAAS of 67 %•BRP behaves similarly to whey protein isolate regarding high protein solubility, foaming capacity and surfactant properties.•BRP provides a near complete amino acid profile with Lysine as the single limiting amino acid•BRP exhibits the highest oil binding capacity of all examined protein ingredients