紫色马铃薯花青素的提取和稳定性评价

Evaluation of Extraction and Stability of Anthocyanins from Purple Potato

紫色马铃薯是一种来源丰富、产量大、成本低的花青素提取原料,本试验采用超声波辅助法提取紫色马铃薯花青素并对其稳定性进行研究。试验表明,在液料比为20∶1(mL/g),乙醇浓度85%,提取温度65℃的条件下,紫色马铃薯中花青素得率为1.27%。考察pH值、光照和温度对紫色马铃薯花青素稳定性的影响发现:紫色马铃薯花青素在pH值为2.0和pH值为3.6时的稳定性较好;当pH值为7.4时,吸光度衰解率最大达到44.72%,稳定性最差。自然光下,花青素稳定性在2 h之内变化不大,长时间接受光照会显著降低其稳定性。常温有利于花青素保持其稳定性,超过80℃稳定性明显下降。因此,花青素保存和应用中尽量保持常温或常温以下避光环境。

Purple potato is a rich source of anthocyanins,which can be inexpensively extracted at high yields.In this experiment,an ultrasonic-assisted method was used to extract anthocyanins from purple potato and study their stability.The best extraction conditions included a liquid-to-solid ratio of 20∶1(mL/g),ethanol concentration of 85%,and extraction temperature of 65℃.Under these conditions,the yield of anthocyanins from purple potato was 1.27%.The effects of pH,light and temperature on the stability of anthocyanins were investigated.Stability was better at pH 2.0 and 3.6.At a pH of 7.4,the absorbance degradation rate reached 44.72%.Under natural light,the stability of anthocyanins was negligibly changed within 2 h.However,stability decreased significantly after prolonged exposure to light.Normal temperature was conducive to the stability of anthocyanins.Stability was significantly reduced when the temperature exceeded 80℃.These findings indicate that the preservation and application of anthocyanins from purple potato are best in the absence of light at room temperature or below.