Li Ya, Yang Yan, Yu Ai-Nong, Wang Kui
School of Chemistry & Environmental Engineering, Hubei University for Nationalities, Enshi, 445000 China.
Food Sci Biotechnol. 2016 Feb 29;25(1):97-104. doi: 10.1007/s10068-016-0014-x. eCollection 2016.
The degradation behavior of L-ascorbic acid (ASA) was investigated under different parameters of temperature, time, and pH. Higher temperatures and longer times accelerated the ASA degradation. Degradation product distributions changed with different pH values. As solution pH of 4.5 was beneficial for formation of uncolored intermediate products with an absorbance maximum at 294 nm. Formation of brown products was promoted at pH values from 5.8 to 6.8 with an absorbance maximum at 420 nm. Under different pH conditions, volatile products formation varied. Furfural and derivatives of furan were primary products due to the effects of pH. The non-enzymatic selfdegradation behavior of ASA was characteristic of first-order kinetics based on a classic dynamic model. Activation energy values varied under different pH values. An ASA degradation mechanism and pathway are proposed.
研究了L-抗坏血酸（ASA）在不同温度、时间和pH参数下的降解行为。较高温度和较长时间会加速ASA降解。降解产物分布随不同pH值而变化。溶液pH为4.5有利于形成在294nm处有最大吸收的无色中间产物。在pH值为5.8至6.8时促进棕色产物的形成，其在420nm处有最大吸收。在不同pH条件下，挥发性产物的形成有所不同。由于pH的影响，糠醛和呋喃衍生物是主要产物。基于经典动力学模型，ASA的非酶自降解行为具有一级动力学特征。不同pH值下的活化能值有所不同。提出了ASA的降解机制和途径。
