Effect of enzymatically hydrolysed brewers' spent grain supplementation on the rheological, textural and sensory properties of muffins

Brewers' spent grain (BSG) is the major co-product of the brewing industry having a high content of protein and fibre. Enzymatic modification improves the properties of different ingredients when they are incorporated into confectionary products. This study characterised the rheological, textural and sensory properties of unmodified BSG (BSGA) and enzymatically modified BSG (BSGB, i.e., proteinase and carbohydrase modified BSG) when substituted at different levels (5, 10 and 15%) in a muffin ingredient mix. Rheological assessment showed a lower viscosity for the BSGB compared to the BSGA batters. Baked BSGB containing muffins had lower hardness values compared to BSGA and control without added BSG. Sensory assessment showed no significant differences in liking of the different attributes tested (overall appearance, texture, smell, colour and taste) between the 5% BSGA and BSGB supplemented muffins. Incorporation of BSGB at 10% had no negative impact on the sensory attributes in comparison to BSGA 10%. Overall, low level substitution of enzymatic modified BSG beneficially reduced batter viscosity and muffin hardness and gave comparable sensory attributes to those of unmodified BSG supplemented muffins. Therefore, prior enzymatic modification can enhance the ingredient functionality of BSG in confectionary products.