Combination of Kaempferia galanga and Piper longum water extracts improves the antioxidant capability of myofibrillar protein

The research focused on examining how kaempferia galanga water extract (KGE) and piper longum water extract (PLE) influence the antioxidant properties of myofibrillar protein (MP) when exposed to malondialdehyde-induced oxidation. Non-target metabolomics identified 150 compounds. Among them, the primary antioxidants in KGE as cinnamic acid derivatives (including ethyl 4-methoxycinnamate, trans -2, 3, 4-trimethoxycinnamate and ethyl- trans -cinnamate), bornyl acetate and kaempferol. The main antioxidant substances in PLE are amide alkaloids, including piperine and its derivatives, tetrahydropiperine, piperanine, piperic acid. The addition of 2 g/100 mL KGE and 2 g/100 mL PLE resulted in a 20% decrease in carbonyl compound content, a 1.26-fold increase in sulfhydryl content and the production of cross-linked polymers in MP induced by MDA oxidation; as well as a 53% decrease in hydrophobicity, a 3.21-fold increase in solubility, and an increase in fluorescence spectral intensity and UV spectral intensity of MP. It was shown that KGE and PLE affected the antioxidant capacity of MP through synergistic effects, and the compound type and content were the main reasons for the differences in antioxidant effects. The research findings can serve the production of healthy and nutritious Sichuan-style braised meat and improve the economic benefits of meat industry. • Excessive addition of plant water extracts will lead to protein aggregation. • Some plant water extracts have synergistic effects on antioxidant capability. • Cinnamic acid derivatives, Piperine and its derivatives were the main antioxidant components • Some plant water extracts can combine with sulfhydryl group.