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

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 âˆ¼ 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.

Identification of adducts formed between acrolein and alanine or serine in fried potato crisps and the cytotoxicity-lowering effect of acrolein in three cell lines.

In physiological and thermally-processed conditions, alanine and serine efficiently eliminate acrolein to generate two main adducts, 2-(5-formyl-3,6-dihydropyridin-1(2H)-yl) propanoic acid and 2-(5-formyl-3,6-dihydropyridin-1(2H)-yl)-3-hydroxypropanoic acid, with amounts of 81.6 ± 4.24 µg/kg and 23.72 ± 0.40 µg/kg in fried potato crisps, respectively. Adduct formation markedly decreased the cytotoxicity of acrolein against Caco-2, GES-1 and HUVEC cells. The cell viability of them remained approximately100% after incubation with 200 µmolL-1 adducts, while the IC50 values for acrolein in the three cells were 66, 54, and 16 µmolL-1 respectively. The adducts express the protective effects by tremendous reduction of cell apoptosis, reactive oxygen species (ROS) production, and DNA damage.