乙醇法提取紫背天葵红色素液的稳定性研究

The stability of red pigment extract from Begonia fimbristipula hance with ethanol

探讨以紫背天葵为原料 ,2 7 5 %乙醇为溶剂、原料粒度为 2× 3mm、按 1 :2 (鲜叶质量分数 ,g/溶剂体积分数 ,ml)料液比在 5 2 5℃恒温条件下浸提 3h的红色素提取液稳定性。结果表明 ,紫背天葵提取液的红色素随pH值的变化而变化 ,表现为在pH值≤ 4 1条件下 ,提取液基本保持鲜艳的紫红色 ;当pH值 >4 1 ,红色逐渐消褪。紫背天葵红色素只能作为酸性食品的着色剂 ,成品不适宜采用含铁锌离子的容器包装 ,且应置低温条件或室温避光环境中贮放 ,加热或高温时易氧化褪色。

The stability of red pigment extracted from Begonia fimbristipula Hance with 27 5%(volume percent) ethanol aqueous as extracts was investigated.The experiments undergo with, material size of 2 mm×3 mm, the ratio of material to extracts 1:2 (percent of fresh leaves, g/volume percent of extracts, ml)at temperature 52 5℃,3h. The results indicate that the red pigment changes as pH value varies. Under pH≤4 1,the extraction almost remained bright-purple; while pH>4 1, its color gradually faded. As a result, the Begonia fimbristipula Hance's red pigment can only be used as coloring matter for acid food and can not be packaged in a container which contains Zn2 and/or Fe3,and should be preserved in low or normal temperature and far from sunshine for its oxidation by heating or high temperature.