Brewer's spent yeast extracts: Impact of beer style on phenolic compound adsorption, peptide profile, bioactivity, and performance in a food matrix under simulated digestion

Abstract

This study evaluated the phenolic compounds, bioactive peptides, and bioactivity of brewer's spent yeast (BSY) extracts obtained from three beer styles: American Pale Ale (BSY1), Golden Ale (BSY2), and Imperial Stout (BSY3), and their functionality in a precooked rice food matrix under simulated gastrointestinal digestion. BSY1 hydroalcoholic extracts contained the highest total phenolics (37.7 mg 100 g−1) among samples, being mainly proanthocyanidins (26.20 mg 100 g−1), while BSY2 exhibited elevated p-coumaric acid level (0.96 mg 100 g−1). Peptide analysis of water extracts showed that BSY1 was enriched in low-molecular-weight hydrophobic peptides. Bioactivity assays indicated that BSY1 exerted the strongest antidiabetic activity with the lowest IC50 (mg solids mL−1) inhibition of α-amylase (0.294), α-glucosidase (1.300), and dipeptidyl peptidase-IV, DPP-IV (1.080), and the highest antioxidant capacity. In contrast, BSY2 displayed the highest inhibition of angiotensin-converting enzyme I, ACE-I (IC50 = 0.311), suggesting antihypertensive potential. Both BSY1 and BSY3 showed marked inhibition of acetylcholinesterase (AChE), associated with neuroprotective effects, with IC50 values of 1.194 and 1.765, respectively. Incorporation of BSY extracts into precooked rice increased phenolic bioaccessibility and further enhanced α-amylase, α-glucosidase, and DPP-IV inhibition after digestion, accompanied by reduced maltose release, stronger antioxidant activity, greater ACE-I, and enhanced AChE inhibition. Overall, BSY, particularly from American Pale Ale brewing, emerges as a sustainable, multifunctional ingredient with potential to modulate glycemic response, oxidative stress, and cognitive function, and residue from Golden Ale brewing demonstrated antihypertensive effects.