调味饮料中维生素C在加工及贮藏过程中的变化

探讨了温度、pH、贮藏条件等因素对调味饮料中VC的影响。结果表明：温度单一因素对VC的影响并不明显,在不同的温度下加热0.5h,随着温度的升高,VC的含量轻微下降,最终保持在95%左右。温度与pH两因素结合对VC的破坏有着较大的影响,pH为12.0的饮料加热2.5h后,VC的含量仅存65%左右;在pH为6.0左右时,无论是在80℃还是100℃下加热,VC含量均较高也较稳定;相同的加热温度下,在pH 2～10的范围内,VC的最高含量可达90%。此外,贮藏条件对VC的破坏影响明显,研究表明：在不同贮藏条件下,饮料中的VC含量并不是在低温下才处于最佳保存状态,当样品在4℃下冷藏7d后,其VC含量下降趋势非常明显,冷藏到66d时,VC含量下降至22%左右;而在室温避光条件下贮藏却具有较好的稳定性,贮藏到66d时,VC含量达75%左右,表明室温避光条件下贮藏,有利于保持VC的稳定性。

Research on changes of Vitamin C in flavored beverages during processing and storage

The effects of temperature,pH,storage conditions,etc.on the changes of VC added to flavored beverages were studied.The results indicated that temperature as a single factor didn＇t affect VC level significantly： VC level decreased slightly with the increase of temperature on heating for 0.5 h at different temperatures,and the final level retained around 95%.Temperature and pH as a complex factor significantly degraded VC： VC in beverage samples of pH 12.0 maintained only at 65% after heated for 2.5 h;but in beverage samples of pH 6.0,VC was high and stable when heated at 80℃ or 100℃;the maximum VC level reached 90% when pH ranged from 2 to 10 under the same treatment conditions.Moreover,storage conditions had an evident degradation effect on VC in the beverages.The results showed that,under different storage conditions,a low temperature was not the optimal selection for the maintenance of VC,VC level decreased greatly after the beverage samples were stored at 4℃ for 7 d,and it was only 22% after stored at 4℃ for 66 d;but,when stored at room temperature in a dark place,VC retained around 75% after the beverage samples were stored for 66 d,which indicated that storage at room temperature in a dark place helped to keep the stability of VC.