Improvement of functional and antimicrobial properties of brewery byproduct hydrolysed enzymatically

Abstract

The aim of this study is to investigate the characteristics of brewer's spent grain (BSG) hydrolysates. Hydrolysis was performed using a Bacillus cereus sp. extracellular peptidase. The proteins were hydrolysed for 2, 8 and 24 h, achieving degree of hydrolysis ranging from 2.65 to 21.80%. During enzymatic hydrolysis, average peptide chain length decreased rapidly and the soluble forms increased. Solubility of the hydrolysates showed a good correlation with turbidity. The water/oil holding capacity, the emulsifying properties and the foaming expansion were analysed, and improved functional properties were found respect to the control. For the studied hydrolysates concentrations no gel formation were obtained. However, BSG hydrolysates exhibited also desirable rheological properties making their good candidate for many food formulations. Thermal characterization revealed the energy recovery by the enzymatic hydrolysis process. The understanding of hydrolysates antimicrobial properties may lead to utilize their as potent natural antimicrobial against Escherichia coli O157:H7. In the light of the results, hydrolysates made from BSG can be converted into a high value protein food ingredient.