Fiber modification of brewers' spent grain by autoclave treatment to improve its properties as a functional food ingredient

The valorization of brewers' spent grain (BSG) as an ingredient has been reported to increase the nutritional value of various food items. However, it diminishes its mechanical properties, technological processing properties, and the acceptability of the final food products. This study aims to modify the dietary fiber composition of BSG by autoclave treatment (AT) in order to improve its functional properties. Different temperatures and time exposures were evaluated along with the involvement of pressure. The results show that AT is able to modify the composition of soluble and insoluble dietary fiber, hydration properties, oil holding capacity, and color, in addition to the proximate composition of BSG. FTIR spectrum confirms the changes in the microstructure of BSG, specifically in the hydroxyl and acid functional groups. AT increases the lightness of BSG, which allow for greater additions in food products. AT also decreased the Aw, thus inhibiting the degradation due to microbial growth and chemical reaction. Therefore, AT seemingly extends the safety of BSG during storage. In conclusion, autoclave treatment can be used to improve the quality of BSG, with the consideration that certain conditions need to be optimized. Further studies on food applications and specific biological compounds are expected.