红龙草红色素的特性研究

目的]为红龙草红色素的开发利用提供参考。方法]用浸提法从红龙草叶子中提取红色素,并对其稳定性进行初步研究。结果]红色素在可见光范围内的最大吸收波长为530 nm;红色素受pH值影响较大,在pH 3~7的酸性至中性范围内呈红色,而在pH>7的碱性区则颜色由浅紫红色变至黄绿色;随着温度上升,色素损失率明显上升,在70℃温度条件下加热30 min时,色素损失率超过1/2以上;随着光照时间的延长,色素损失率显著增加,到第4天,色素的损失率高达60.0%;氧化剂和还原剂在0.01%~0.20%浓度范围内对色素的稳定性有一定的影响,但影响程度不大;蔗糖、苯甲酸钠对色素的稳定性基本无影响,但维生素C、柠檬酸则对色素有一定的影响。结论]红龙草红色素在酸及蔗糖和苯甲酸钠等添加物中,具有较好的稳定性,但在碱、热、光、维生素C及柠檬酸等的作用下,则稳定性较差。

Study on Properties of Red Pigment of Alternanthera dentatacv.Ruliginosa

Objective] This research aimed to provide reference on development and utilization of red pigment of Alternanthera dentata cv.Ruliginosa.Method]The red pigment was extracted from the leaves of A.dentata,and its stability was studied.Result]The maximum absorption wavelength of the red pigment was 530 nm in visible light scope.The red pigment was influenced more greatly by pH value.It showed red at pH value of 3～7 and changed from light red to yellow-green at pH >7.Along with the temperature rising,the loss rate of red pigment rose obviously and was over 1/2 of the whole red pigment when heading for 30 minutes at 70 ℃.Along with sunlight extension,the loss rate of red pigment was significantly increased and was as high as 60.0% till 4th d.The oxidants and reductants had some influence on the stability of red pigment at the concentration of 0.01%～0.20%.Some common food additives exception of saccharose and sodium benzoate had some influence on stability of red pigment,such as VC and citric acid.Conclusion]The red pigment of A.dentata had a better stability at pH value of 3～7 and under adding saccharose and sodium benzoate additives,but was worse under the condition of the alkali,heat,light,VC and the lemon sour etc.