不同介质溶液对维生素C稳定性的影响研究

Study on the effect of different medium solutions on the stability of Vitamin C

利用紫外分光光度法研究了无机盐、羧甲基纤维素钠、β-环糊精和聚乙二醇等介质溶液中维生素C的稳定性,并探索了上述介质溶液延缓维生素C被氧化的作用机理。结果表明,氯化镁、氯化钾、氯化钠、羧甲基纤维素钠均能较显著地提高维生素C的稳定性,而羧甲基纤维素钠对人体安全、使用量很少且效果显著,可广泛应用在化妆品、食品、医药等领域用以保护维生素C的稳定性。聚乙二醇、β-环糊精与维生素C的混合溶液中起始溶氧量与空白维生素C溶液相近且随时间延长下降很明显,而氯化钠、羧甲基纤维素钠和维生素C的混合溶液中起始溶氧量则远低于空白维生素C溶液并随时间延长下降很慢,这些现象与上述介质对维生素C的保护效果是一致的。介质溶液中起始溶氧量的高低及下降速度快慢影响了维生素C的稳定性,无机盐离子种类和浓度影响溶液中溶氧量,而羧甲基纤维素钠、聚乙二醇、β-环糊精等溶液的相对黏度则对溶氧量存在影响。

The stability of Vitamin C in different medium solutions such as inorganic salts,sodium carboxymethyl cellulose,β-cyclodextrin and polyethylene glycol was studied by ultraviolet spectrophotometry,and the mechanism of the above mediums retarded the oxidation of Vitamin C was also explored. The results show that magnesium chloride,potassium chloride,sodium chloride and sodium carboxymethyl cellulose can significantly improve the stability of Vitamin C. While the sodium carboxymethyl cellulose is safe,less dosage and has significant effect to protect Vitamin C,it can be widely used in cosmetics,food,medicine and other fields to protect the stability of Vitamin C. The amount of initial dissolved oxygen content in the mixed solution of polyethylene glycol,β-cyclodextrin and Vitamin C is similar to that of the blank Vitamin C solution,and it significantly decreases with time. However,the amount of initial dissolved oxygen content in the mixed solution of sodium chloride,carboxymethyl cellulose and Vitamin C is much lower than that of the blank Vitamin C solution and it decreases very slowly with time. These phenomena are consistent with the protective effect of the above medium solutions on Vitamin C. The level of initial dissolved oxygen content in the medium solutions and the speed of decline affect the stability of Vitamin C. The type and concentration of inorganic salt ions affect the amount of dissolved oxygen content in the solution,while the solution viscosity has the effect on the dissolved oxygen content in water-soluble polymer solutions such as sodium carboxymethyl cellulose,polyethylene glycol andβ-cyclodextrin.