Antioxidant and prooxidant activity of acid‐hydrolyzed phenolic extracts of sugar beet leaves in oil‐in‐water emulsions

• Published in: Journal of the American Oil Chemists' Society 2024-08
• Main Authors: Ebrahimi, Peyman, Bayram, Ipek, Lante, Anna, Decker, Eric A.
• Format: Article
• Language: English
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1002/aocs.12891

This study aimed to enhance the oxidative stability of soybean oil‐in‐water emulsions using acid‐hydrolyzed and unhydrolyzed extracts obtained from sugar beet leaves. The optimum extraction process, which includes 8 min of ultrasonication followed by a 2‐h acid hydrolysis, released new phenolics (e.g., catechin, myricetin, etc.) and increased the total phenolic content (TPC) from 586.24 ± 11.45 to 982.42 ± 6.61 μmol gallic acid equivalent (GAE)/L, and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical inhibition from 46.63 ± 1.39 to 60.87 ± 1.12%. Acid hydrolysis increased the cupric chelating activity of the extracts while decreasing ferrous chelating activity and trans ‐ferulic acid concentration significantly ( p < 0.05). The acid‐hydrolyzed extract at a TPC of 100 μmol GAE/L prolonged the lag phase of hexanal accumulation in the emulsion from 0 to 8 days, while 400 μmol GAE/L TPC of unhydrolyzed extract increased the lag phase to 12 days. The results show that acid‐hydrolyzed extracts in high concentrations may act as prooxidants.