Esterification of black bean anthocyanins with unsaturated oleic acid, and application characteristics of the product

• Published in: Food chemistry 2024-08, Vol.448, p.139079-139079, Article 139079
• Main Authors: Zhang, Mianzhang, Huang, Zixin, Jayavanth, Pallavi, Luo, Ziming, Zhou, Hua, Huang, Caihuan, Ou, Shiyi, Liu, Fu, Zheng, Jie
• Format: Article
• Language: English
• Subjects: Anthocyanins; Anthocyanins - chemistry; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Antioxidant activity; Antioxidants - chemistry; Antioxidants - pharmacology; Antitumor activity; Black bean seed coat; Enzymatic acylation; Esterification; Hep G2 Cells; Humans; Lipophilicity; Molecular Structure; Oleic Acid - chemistry; Phaseolus - chemistry; Plant Extracts - chemistry; Stability; Unsaturated fatty acid
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2024.139079

•Enzymatic acylation of low purity anthocyanin extract with oleic acid.•Acylation rate of the reaction reached 54.3% at optimal conditions.•Oleic acid acylation improved antioxidant and antibacterial activities of product.•Acylated product showed potential antitumor activity.•Stability of product showed pH dependent behavior to various environments. Esterification of anthocyanins with saturated fatty acids have been widely investigated, while that with unsaturated fatty acids is little understood. In this study, crude extract (purity ∼ 35 %) of cyanidin-3-O-glucoside (C3G) from black bean seed coat was utilized as reaction substrate, and enzymatically acylated with unsaturated fatty acid (oleic acid). Optimization of various reaction parameters finally resulted in the highest acylation rate of 54.3 %. HPLC-MS/MS and NMR analyses elucidated the structure of cyanidin-3-O-glucoside-oleic acid ester (C3G-OA) to be cyanidin-3-O-(6″-octadecene)-glucoside. Introduction of oleic acid into C3G improved the lipophilicity, antioxidant ability, and antibacterial activity. Further, the color and substance stability analyses showed that the susceptibility of C3G and C3G-OA to different thermal, peroxidative, and illuminant treatments were highly pH dependent, which suggested individual application guidelines. Moreover, C3G-OA showed lower toxicity to normal cell (QSG-7701) and better inhibitory effect on the proliferation of HepG2 cells than C3G, which indicated its potential anti-tumor bioactivity.