橘子中维生素C稳定性的研究

Study on the Stability of Vitamin C in Orange

采用高效液相色谱法(HPLC)检测了保鲜储存半年的橘子中维生素C(简称VC)的含量,并对不同条件下VC的稳定性进行了研究。建立了HPLC检测VC的方法:采用C 18柱,在检测波长为255 nm,流动相为0.1%草酸溶液、流速为1.0 mL/min的条件下,对VC标准样品进行分析。结果表明,VC浓度在0.10~6.00 mg/L范围内具有良好的线性关系,相关系数R 2为0.9996,RSD为1.424%,LOD为0.087 mg/L;对市售橘子进行分析,测得100 g橘子中VC的含量为28.5 mg,平均加标回收率为105.8%。橘子中VC的含量随着放置时间的增长而逐渐减少,且分解速率呈一级动力学,而避光和低温下则有利于VC的稳定存在;在橘子的水溶液中添加碱性物质以及蔗糖溶液对VC的分解有加速作用,盐对VC分解的影响不大,而酸性条件则对VC的长时间保存具有积极作用。本研究可对人们合理储存和食用橘子提供科学依据,也可为今后研究其它果蔬中的VC含量及稳定性提供参考。

High performance liquid chromatography(HPLC)was used to detect the content of vitamin C(L-ascorbic acid,VC)in oranges stored for half a year,and the stability of VC under different conditions were studied.A HPLC method for the determination of VC was established.VC standard samples were analyzed using a C 18 column with a detection wavelength of 255 nm,a mobile phase of 0.1%oxalic acid solution,and a flow rate of 1.0 mL/min.The results showed that the VC concentration had a good linear relationship at the range of 0.10~6.00 mg/L.The linear regression equation was expressed with y=33032 x+3233.3,the correlation coefficient R 2 was 0.9996,the RSD was 1.424%and the LOD was 0.087 mg/L.Through the analysis of oranges sold in the market,the content of VC in 100 g orange was 28.5 mg,and the average spike recovery was 105.8%.When using this method to analyze the peeled oranges,it was found that the content of VC in oranges decreases with the increase of the standing time,and the decomposition rate was a first-order reaction.However,the stable existence of VC is beneficial from the conditions away from light and low temperature.It also can be found that the decomposition of VC was accelerated under alkaline conditions and sucrose solution.Salt had a little effect on the decomposition of VC,whiler acidic condition had positive effect on the long-term preservation of VC.These findings can provide a scientific basis for people to eat and store oranges reasonably,and can also provide a reference method for studying VC content and stability in other fruits and vegetables in the future.