微波辅助法提取火龙果果皮色素及其功能活性研究

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

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VC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。

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.