外界环境和食品体系对菊苣酸稳定性的影响

Stability of Cichoric Acid Influenced by Different Physical Factors and Food Environments

本实验研究pH值、温度、金属离子、紫外线以及不同食品体系(果汁饮料、奶粉和果冻)对菊苣酸稳定性的影响。菊苣酸的含量由高效液相色谱法(high performance liquid chromatography,HPLC)测定。结果表明:随着pH值(3、5、7、9)和温度(60、70、80℃)的升高,菊苣酸的稳定性逐渐降低;相同浓度的Na+和K+对菊苣酸的稳定性无显著影响,但Ca2+溶液遇菊苣酸会瞬间发生变色反应;菊苣酸对紫外线敏感度较高,且在甲醇中的异构化率明显高于在水中的异构化率;菊苣酸在果汁饮料中,室温(25℃)贮藏3个月后保存率约为85%,4℃贮藏3个月后含量无明显变化;室温下避光贮藏3个月,菊苣酸在奶粉和果冻体系中能够保持相对稳定。不同食品体系对菊苣酸稳定性的影响有差异,总体上食品体系能在一定程度上维持菊苣酸的稳定性,保护其免受降解。

This research was aimed to determine the stability of cichoric acid when it was added to different food environments （juice, beverage, milk powder and jelly） during 3 months of storage, and investigate the influences of pH （3, 5, 7 and 9）, temperature （60, 70 and 80 ℃）, metal ions （Na＋, K＋ and Ca2＋） and ultraviolet （253.7 nm） on the stability of cichoric acid. HPLC was used to measure the content of cichoric acid. The results showed that cichoric acid became more and more unstable as pH and temperature went up; the influences of Na＋ and K＋ at the same concentrations on the stability of cichoric acid were not significantly different, but exposure of cichoric acid to Ca2＋ caused an instantaneous color change; ultraviolet rays led to stronger degradation of cichoric acid in methanol than in water; in fruit drinks for 3 months, cichoric acid remained 85% of its original level when stored at 25 ℃, but it was relatively stable at 4 ℃, and also had a relatively god stability in milk powder and jelly during the storage period.