Research on the Optimization of Microwave Extraction Process of Natural Red Pigment from Pitaya Peel and Its Application

火龙果果皮中的天然红色素具有多种生物活性和功能，有望代替人工合成色素应用于食品工业。本文采用微波加热法提取火龙果果皮中的天然红色素，通过单因素试验，探究提取剂的浓度、火龙果外皮粉末和乙醇的料液配比、色素溶液的pH值、微波提取功率、微波提取时间五个因素对色素提取效果的影响。在此基础上，通过正交优化确定提取火龙果果皮中天然红色素的最佳工艺，并进一步研究了提取色素的稳定性。研究结果表明：50%的乙醇浓度、1:40火龙果外皮粉末和乙醇的料液配比、480 W的微波提取功率、50 s的微波提取时间、5.0的色素溶液pH值为最优提取工艺参数。此时测得色素提取液的平均吸光度为1.791。此外，适量添加酸味剂和甜味剂对火龙果果皮中天然红色素的稳定性具有积极影响。对添加红色素后的酸奶感官评定结果表明，适量添加天然红色素可以改善酸奶的感官品质。综上，本研究开拓了火龙果果皮资源的高值化利用新领域，并展望了其产业应用前景，同时为天然色素替代人工合成色素在食品工业中的实践奠定了理论基础。The natural red pigment in the peel of pitaya fruits possesses various biological activities and functions, and it is expected to replace synthetic pigments and be applied in the food industry. This paper extracted the natural red pigment from the pitaya peel by microwave heating. Through single-factor experiments, the effects of five factors, namely the concentration of the extraction agent, the ratio of pitaya outer skin powder to ethanol, the pH value of the pigment solution, the microwave extraction power, and the microwave extraction time, on the pigment extraction effect were studied. On this basis, the optimal extraction process of the natural red pigment from pitaya peel was determined by orthogonal optimization, and the stability of the extracted pigment was investigated. The research results showed that the optimal extraction process parameters were 50% ethanol concentration, 1:40 ratio of pitaya outer skin powder to ethanol, 480 W microwave extraction power, 50 s microwave extraction time, and 5.0 pH value of the pigment solution. At this time, the average absorbance value of the pigment extraction solution was 1.791. In addition, the addition of acid and sweeteners in appropriate amounts had a certain impact on the stability of the natural red pigment in pitaya peel. The sensory evaluation results of yogurt after adding red pigment showed that the addition of natural red pigment in appropriate amounts can improve the sensory quality of yogurt. In summary, this study has opened up a new field for the high-value utilization of pitaya peel resources and has a prospect for its industrial application. At the same time, it has laid a theoretical foundation for the practice of replacing synthetic pigments with natural pigments in the food industry.