微波辅助法提取火龙果果皮色素及其功能活性研究

优化火龙果果皮色素的微波辅助法提取工艺,并对色素的功能特性进行初步研究。以火龙果果皮为原料,在单因素实验的基础上,采用正交实验设计对火龙果果皮色素的提取工艺进行优化,并研究了真空干燥色素的抗氧化活性和抑菌活性。结果表明:在料液比1∶50 (g/mL)、乙醇浓度20%、微波功率440 W、微波处理时间60 s的条件下,火龙果果皮色素的提取效果最佳,色素得率为1.074%;2~10 mg/mL提取物对羟自由基(·OH)、超氧阴离子自由基(O₂-·)和DPPH·均具有清除作用,其中对O₂-·的清除效果最好,比V_C的清除效果略低;提取物对大肠杆菌的最低抑菌浓度为1.25 mg/mL,最低杀菌浓度为2.5 mg/mL,抑制效果最好,其次金黄色葡萄球菌、副溶血弧菌、志贺氏菌和蜡状芽孢杆菌。本研究优化了微波辅助提取火龙果果皮色素的工艺条件,所得提取物有较好的抗氧化活性,且对常见食源性病原菌有较强的抑菌活性。

Microwave-assisted Extraction of Pigment from Pitaya Peel and Its Functional Activity

The microwave-assisted extraction of pigments from pitaya peel was optimized,and the functional characteristics of pigments were studied. The optimum conditions of microwave-assisted extraction were optimized by using orthogonal test,and then the extracts were freeze-dried in vacuum to analyze the antimicrobial and antioxidant activities. The results showed that the extraction effect of pigment from pitaya peel was the best when the ethanol concentration was 20%,the microwave power was 440 W,the microwave time was 60 s,the liquid ratio was 1∶50 (g/mL),and the maximum yield of pigment was 1.074%. The results of antioxidant test showed that the 2~10 mg/mL pigment extracts had scavenging effect on hydroxyl radical(·OH),superoxide anion radical(O₂-·)and DPPH·.Among them,the scavenging effect on O₂-· was the best,which was equivalent to the removal effect of V_C. The antibacterial test of the pigment extracts showed that the minimum inhibitory concentration of the extract on Escherichia coli was 1.25 mg/mL,and the minimum bactericidal concentration was 2.5 mg/mL. The inhibitory effect was the best on Escherichia coli,followed by Staphylococcus aureus,Vibrio parahaemolyticus,Shigella and Bacillus cereus. This study optimized the microwave-assisted extraction technology of pitaya peel pigment. The obtained extract has good antioxidant activity and strong antibacterial activity against common food-borne pathogens.