Functional and Nutritional Properties of Proteins From Barley Malting By‐Products

Nowadays, global demand for alternative protein sources is rising, and exploitation of by-products can concurrently meet the challenges of integrating sustainability and circular economy in the food industry. Barley malt rootlets represent the main by product of the malting industry and are normally discarded as animal feed. In this work, the protein concentrates obtained after alkali extraction of industrial by-products were characterized (amino acid composition, SDS page and protein digestibility) with particular regard to the techno-functional properties (solubility, foaming and emulsifying abilities, water holding capacity (WHC), andfat absorption capacity). Data were further compared withthoseobtained oncommonplant-derivedproteinssuchassoy,pea, and rice, to elucidate the potential application of proteins from malt rootlets in novel food formulations. Nutritionally, significant levels of lysine weredetected(–7.0 g/100gproteins)withcomparabledigestibilitydatatootherlegumeproteinsources(–75%).The solubility trend aligned withsoyandpeaproteins,beingcloseto90%inthepHrange11–12.Foamingandemulsifyingabilitieswere weaker than soy and pea proteins, while WHC (–6 mL/g) exceeded that of other proteins thus evidencing its potential in liquid or semi-liquid formulations. Overall, both malt rootlets and malt rootlets pellet, the true industrial by-product, can potentially be up-cycled materials for protein rich ingredients with suitable nutritional and technological performance.