Trypsin‐hydrolyzed Corn Silk Proteins: Antioxidant Activities, <i>in vitro</i> Gastrointestinal and Thermal Stability, and Hematoprotective Effects

<jats:p>The aim of this study was to examine the antioxidant capacity of Trypsin‐hydrolyzed corn silk proteins, specifically radical scavenging, ferric reducing and anti‐lipid peroxidation activities, as well as stability after heating and simulated gastrointestinal digestion. Among the 1–5‐h hydrolysates, the 1‐h Trypsin hydrolysate (T1H) was the strongest. T1H exhibited stronger H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub> [half maximal effective concentration (EC<jats:sub>50</jats:sub>) = 156.44 µg/mL] and superoxide (EC<jats:sub>50</jats:sub> = 0.33 mg/mL) scavenging activities than glutathione, carnosine and N‐acetylcysteine. Radical scavenging activities of T1H were heat‐stable (25–100°C), although lost by 20–58% after gastrointestinal digestion. Ferric reducing activity of T1H was heat‐stable, even enhanced by 20% after gastrointestinal digestion. Lecithin liposome assay found anti‐lipid peroxidation activity of T1H resistant to gastrointestinal peptidases. By contrast, 100°C incubation reduced anti‐lipid peroxidation activity of 0.5 mg/mL T1H to 3.5‐fold lower than that of 25°C incubation. At 30 µg/mL, T1H (3% hemolysis) was stronger than glutathione (32% hemolysis) in protecting human red blood cells. T1H was 1.5‐fold more potent than glutathione and carnosine in alleviating lipid peroxidation in the cells. Overall, T1H demonstrated strong, heat‐stable radical scavenging activities, besides partial resistance to gastrointestinal peptidases. T1H was also hematoprotective. T1H is a promising antioxidant for the development of functional food ingredients and nutraceuticals.</jats:p>