Enhancing the potential of brewer's spent grain utilization in human nutrition through pulsed electric field-assisted protein extraction

Abstract

Brewer's spent grain (BSG), the main by-product of beer production, represent a promising source of proteins suitable for human nutrition, aligning with global efforts to reduce food industry waste and support a sustainable economy. However, given the complexity and heterogeneity of the matrix, protein extraction is challenging. The present study proposes to evaluate the impact of BSG pretreatment with pulsed electric fields (PEF) on protein extraction and functional properties of protein extracts at different pH values (3, 5, and 7). The protein extraction yield with the best PEF pretreatment condition of 120 pulses (71.4 %) was not significantly improved compared to unpretreated extraction (74.0 %). However, extracts pretreated with PEF demonstrated structural differences compared to conventional ones. Those differences led to significant improvements in functional properties. Indeed, protein solubility was improved by up to 81 %, and the foaming capacity and stability were increased by 104 % and 21 %, respectively, compared to the control extract. PEF pretreatments also showed an improvement in water-holding capacity (up to 11.5 g/g) compared to unpretreated extract (3.9 g/g), which confirms their potential for uses in food formulations.