Brewers' spent grain (BSG) protein hydrolysates decrease hydrogen peroxide (H₂O₂)-induced oxidative stress and concanavalin-A (con-A) stimulated IFN-γ production in cell culture

The present study investigated the bioactivity of protein hydrolysates and fractionated hydrolysates prepared from brewers' spent grain (BSG) using proteases, including Alcalase 2.4L, Flavourzyme and Corolase PP. Hydrolysates were designated K-Y, including fractionated hydrolysates with molecular weight (m.w.) < 3, <5 and >5 kDa. Where computable, IC₅₀ values were lower in U937 (1.38-9.78%) than Jurkat T cells (1.15-13.82%). Hydrolysates L, Q and R and fractionated hydrolysates of U and W (<3, <5, >5 kDa) significantly (P < 0.01) protected against hydrogen peroxide (H ₂O₂)-induced reduction of superoxide dismutase (SOD) activity. A fractionated hydrolysate of W (<5 kDa) protected against H ₂O₂-induced DNA damage, P < 0.01. Hydrolysates K, N, P, U, U > 5 kDa, V, V > 5 kDa, W, W > 5 kDa significantly (P < 0.05) reduced a concanavlin-A (con-A) stimulated production of interferon-γ (IFN-γ). In conclusion, BSG protein hydrolysates demonstrate bioactivity in vitro; lower m.w. hydrolysates (<3, <5 kDa) show greatest antioxidant activity and unfractionated or higher m.w. hydrolysates (>5 kDa) possess anti-inflammatory effects.