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

## TL;DR

This paper explores the nutritional and functional properties of proteins from barley malt by-products, showing their potential for use in food products.

## Contribution

The study is the first to comprehensively characterize the techno-functional and nutritional properties of proteins from barley malt rootlets.

## Key findings

- Barley malt rootlet proteins have high lysine content and good digestibility, comparable to legume proteins.
- The water holding capacity of these proteins is higher than other plant proteins, making them suitable for liquid food formulations.
- While foaming and emulsifying abilities are lower than soy and pea proteins, solubility is comparable in certain pH ranges.

## Abstract

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), and fat absorption capacity). Data were further compared with those obtained on common plant‐derived proteins such as soy, pea, and rice, to elucidate the potential application of proteins from malt rootlets in novel food formulations. Nutritionally, significant levels of lysine were detected (–7.0 g/100 g proteins) with comparable digestibility data to other legume protein sources (–75%). The solubility trend aligned with soy and pea proteins, being close to 90% in the pH range 11–12. Foaming and emulsifying abilities were 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.

The study provides an insight into the functional properties of proteins in barley malt rootlets.

Results support the up‐cycle of brewing by‐products for the recovery of high‐proteins ingredients