玫瑰茄花色苷的纯化及其热降解稳定性

Purification and Thermal Stability of Anthocyanin from Hibiscus sabdariffa L.

摘要:

本实验以玫瑰茄花色苷为原料，研究了花色苷纯化的条件，以及添加不同稳定剂下花色苷溶液的热降解稳定性。结果表明：纯化花色苷的优化条件为上样浓度为600 mg/L，平衡3 h，上样体积为183 mL；洗脱剂为60%乙醇，洗脱流速为1 mL/min。纯化后的玫瑰茄花色苷冻干粉末，其色价为43.10±2.17，回收率为83.62%±5.72%，花色苷含量为216.50±1.83 mg/g。添加1.0%海藻酸钠、羧甲基纤维素（Carboxymethylcellulose，CMC）和β-环糊精的三组玫瑰茄花色苷溶液在80、90和100 ℃三个温度下的降解均符合一级动力学方程，降解速率常数均随着温度的升高而增大，半衰期随着温度的升高而减小。β-环糊精具有很好的延缓花色苷降解的潜力，随着β-环糊精浓度的增加，花色苷的降解速率越来越小。80 ℃下加热150 min后，花色苷溶液中a*值减小，b*值增加，β-环糊精的浓度增加有利于维持花色苷的红度，其中1.5% β-环糊精组的护色效果最佳。

Abstract:

In this study, the conditions for the purification of anthocyanins from Hibiscus sabdariffa L. and the thermal stability of these anthocyanins in the presence of different stabilizers were investigated using roselle anthocyanins as raw materials. The results showed that the optimized conditions for the purification of anthocyanins were: Loading concentration, 600 mg/L; Equilibrium time, 3 h; Loading volume,183 mL; eluent, 60% aqueous ethanol; elution flow rate, 1 mL/min. The color value of the lyophilized powder of purified anthocyanins was 43.10±2.17, with a recovery of (83.62±5.72)% and anthocyanin content of 216.50±1.83 mg/g. The degradation of three systems containing roselle anthocyanins together with 1.0% sodium alginate, carboxymethylcellulose (CMC) or β-cyclodextrin at 80, 90 or 100 ℃ all followed the first-order kinetics. The degradation rate constant increased with elevated temperature while the half-life decreased with increasing temperature. β-Cyclodextrin had the potential to delay the degradation of anthocyanins. The degradation rate of anthocyanins became smaller and smaller with an increase of β-cyclodextrin concentration. After heating at 80 ℃ for 150 min, the a* value of the anthocyanin solutions decreased while the b* value increased. An increase of β-cyclodextrin concentration facilitated the maintenance of the redness of anthocyanins, and 1.5% β-cyclodextrin exhibited the most effective protection.