College of Traditional Chinese Medicine, Yunnan University of Chinese Medicine, Kunming, Yunnan, China.
Department of Pharmacy, Baoshan Hospital of Traditional Chinese Medicine, Baoshan, Yunnan, China.
J Food Sci. 2024 Jul;89(7):4312-4330. doi: 10.1111/1750-3841.17129. Epub 2024 Jun 12.
The aim of this experiment was to investigate the effect of storage temperature and pH on phenolic compounds of Phyllanthus emblica juice. Juice was stored at different temperatures and pH for 15 days and sampled on 2-day intervals. The browning index (BI, ABS), pH, centrifugal precipitation rate (CPR), and phenolic compounds were evaluated. The results showed 4°C and pH 2.5 could effectively inhibit browning and slow down pH drop of P. emblica juice. The result of orthogonal partial least square-discriminant analysis showed P. emblica juice stored at 4°C and pH 2.5 still had a similar phenolic composition, but at 20°C, 37°C, and pH 3.5, the score plots were concentrated only in the first 3 days. Additionally, gallic acid (GA) and ellagic acid (EA) were screened out to be the differential compounds for browning of P. emblica juice. The contents of GA, epigallocatechin (EGC), corilagin (CL), gallocatechin gallate (GCG), chebulagic acid (CA), 1,2,3,4,6-O-galloyl-d-glucose (PGG), and EA were more stable at 4°C and pH 2.5. Overall, during storage at 4°C and pH 2.5, it could inhibit the increase of GA and EA and decrease of CL, GCG, CA, and PGG, whereas EGC did not show significant difference between storage conditions. The CPR was higher at 4°C, while pH 2.5 could reduce the CPR. In conclusion, in order to maintain stability of phenolic compounds and extended storage period, the P. emblica juice could be stored at low temperature and adjust the pH to increase the stability of juice system.
本实验旨在研究贮藏温度和 pH 值对余甘果汁酚类化合物的影响。将果汁分别贮藏在不同温度和 pH 值下，每隔 2 天取样一次，共 15 天。测定褐变指数（BI，ABS）、pH 值、离心沉淀率（CPR）和酚类化合物。结果表明，4℃和 pH 2.5 可有效抑制褐变，减缓 pH 值下降。正交偏最小二乘判别分析结果表明，4℃和 pH 2.5 贮藏的余甘果汁酚类组成仍相似，但在 20℃、37℃和 pH 3.5 下，得分图仅在前 3 天集中。此外，筛选出没食子酸（GA）和鞣花酸（EA）为余甘果汁褐变的差异化合物。GA、表没食子儿茶素（EGC）、柯里拉京（CL）、没食子儿茶素没食子酸酯（GCG）、诃子酸（CA）、1,2,3,4,6-O-没食子酰基葡萄糖（PGG）和 EA 在 4℃和 pH 2.5 下含量更稳定。总体而言，在 4℃和 pH 2.5 贮藏条件下，可抑制 GA 和 EA 增加，CL、GCG、CA 和 PGG 减少，而 EGC 在贮藏条件间无显著差异。CPR 在 4℃时较高，而 pH 2.5 可降低 CPR。结论：为了保持酚类化合物的稳定性和延长贮藏期，余甘果汁可在低温下贮藏，并调节 pH 值以提高果汁体系的稳定性。
