| In this study, we investigated the optimal conditions for enzyme-assisted extraction of proanthocyanidins from banana peeland evaluated the stabilityof the obtained proanthocyanidins under different environmental conditions. For enzymatic hydrolysis test, the optimal conditions were enzymedosage of 0.8%, hydrolysis temperature of 50℃ and hydrolysis time of 45 min. For extraction test, the optimal conditions were: material / liquid ratio of 1∶23 (W/V, g/mL), extraction temperature of 65℃ and extraction time of 75 min. Under the optimal conditions, the yield of proanthocynidins was 1.702%. Further study indicated that the stability of the obtained proanthocyanidins decreased as the storage temperature and time increased. A certain content of citric acid, malic acid or ascorbic acid could protect proanthocyanidins from activity loss to some extent. For the effects of metal ionic, Na+, Ca2+, K+, Cu2+ and Fe3+ were detrimental to the stability of proanthocyanidins, especially, Cu2+ and Fe2+, which displayed the strongest effects. The stability of proanthocyanidins decreased with the increase in the content of sodium benzoate and potassium sorbate, while the influence from low level of these preservatives was negligible. |
