Stability and Bioactivity of Polyphenols from Cabernet Sauvignon Grape Seeds in Vitro

With Cabernet Sauvignon grape seeds as raw materials, grape seed polyphenols were extracted and purified, the stability of grape seed polyphenols under different pH, light, temperature, carbohydrate, stabilizer, oxidant reducing agent, preservative and metal ion were studied during processing and storage conditions, and the biological activity in vitro was also discussed. The results showed that grape seed polyphenol was the best stability under the condition of low temperature (4 ℃), weak acid (pH4~6), avoiding light and low temperature (4 ℃), and the retention rate of grape seed polyphenols was above 95%. High concentration (40%~50%) of sucrose and glucose had enhanced effect on the stability of polyphenols, lactose concentration had no significant effects on the stability of polyphenols (P˃0.05), and different concentrations of starch could significantly reduce the stability of polyphenols (P<0.05). Compared with Tween-80, sodium thiosulfate, a stabilizer, was more destructive to polyphenols. Both oxidants and reducing agents had certain destructive effects on polyphenols, and the destructive effect of reducing agents on polyphenols was obviously stronger than oxidants. When 0.15% sodium benzoate and 0.1% potassium sorbate were added, the polyphenol retention rates were 87.95% and 89.44%, respectively. Potassium sorbate was more conducive to the stability of polyphenols. Among metal ions, Al³⁺, Fe³⁺ and Cu²⁺ had the strongest destruction degree to polyphenols, and the polyphenol retention rates decreased by 66.11%, 43.38% and 82.15% after 30 days of storage compared with the 0th day, respectively. Furthermore, grape seed polyphenols had strong antioxidant capacity and α-amylase inhibition ability. When the concentration was 2.5 mg/mL, the α-amylase inhibition rate could reach 97.97%. These results could provide theoretical basis for further development and utilization of grape seed polyphenols.