热烫温度与pH值对香椿维生素C稳定性的影响  

Effects of Blanching Temperature and pH on the Stability of Vitamin C of Toona sinensis

作　　者：马正强[1] 张贝贝[1] 张京芳[1] 苗修港 余翔[1] 

机构地区：[1]西北农林科技大学林学院,陕西杨陵712100

出　　处：《西北林学院学报》2015年第3期201-205,共5页Journal of Northwest Forestry University

基　　金：林业公益性行业科研专项(201304811)

摘　　要：为了研究香椿热烫过程中维生素C的变化规律,分析了不同热烫温度(90、95℃与100℃)和pH值(5.5、6.0与6.5)对香椿维生素C保存率的影响。结果表明,香椿维生素C的稳定性易受温度和pH值的影响,且热烫温度对其的影响程度大于pH值的影响程度。升高热烫温度或增大pH值,均使香椿维生素C保存率降低,其热降解遵循一级动力学模型,其降解的活化能分别为62.022、58.489、54.741kJ·moL-1。相同pH值条件下,升高热烫温度,维生素C热降解速率常数增大,其半衰期缩短。增加pH值,维生素C热降解速率常数增大,其半衰期缩短。香椿加工中适当降低热烫温度及pH值有助于减少维生素C损失和延长维生素C保存时间,尤以降低烫漂温度效果更佳。To investigate thermal degradation kinetics of vitamin C in tender leaves of Toona sinensis during blanching, the effects of temperature on vitamin C degradation were measured at 90, 95 and 100℃with pH values of 5.5, 6.0 and 6.5, respectively. The results indicated that temperature and pH are important factors for the stability of vitamin C in the tender leaves of T. sinensis, and the influence of blanching temperatures was stronger pH. With the increase of blanching temperature and pH, the retention rate of vitamin C declined. Moreover, the degradation of vitamin C followed a first-order reaction with the activation energy （E.） of 62. 022, 58. 489, and 54. 741 kJ · mol^-1. Increasing blanching temperature at the same pH value, or raising pH value at the same blanching temperature would increase the degradation rate constant and reduce half-life value of vitamin C. Moderately decreasing blanching temperature and pH value, especially reducing blanching temperature were favorable for protecting vitamin C.

关 键 词：香椿 维生素C 热烫 热稳定性 PH值 

分 类 号：S792.99[农业科学—林木遗传育种]