通过比较马齿苋鲜榨汁和冷藏1年后的马齿苋榨汁的抗氧化性，探究冷藏对马齿苋榨汁抗氧化性的影响。将冷藏1年的马齿苋榨汁和马齿苋鲜榨汁，采用 DPPH 自由基清除法 ( DPPH法) 和铈离子还原比色法（CERAC法)来评价其抗氧化性的变化，利用半数有效浓度（EC50）比较抗氧化性。4℃储存1年的马齿苋榨汁清除DPPH自由基的EC50 为21.0%，马齿苋鲜榨汁清除DPPH自由基的EC50为19.7%；储存1年的马齿苋榨汁对还原Ce(Ⅳ)的EC50为35.0%，马齿苋鲜榨汁还原Ce(Ⅳ)的EC50为28.3%。因此冷藏对马齿苋榨汁的抗氧化活性的有着一定的影响，使其抗氧化性降低。
The antioxidant activity of purslane juice was compared with that of purslane juice after keeping in cold storage for one year. The juice of Portulaca oleracea and fresh juice of Portulaca oleracea were extracted after one year of cold storage, and the changes of antioxidant activity were evaluated by DPPH radical scavenging method (DPPH) and cerium ion reduction colorimetry (CERAC). Median effective concentration (EC50) was used to compare the antioxidant activity. The EC50 of purslane juice stored at 4℃ for one year to scavenge DPPH free radical was 21.0%; the EC50 of purslane fresh juice scavenging DPPH free radical was 19.7%; the EC50 of purslane juice reduced to Ce (Ⅳ) after storage for one year was 35.0%, and the EC50 of purslane fresh juice reduction to Ce (Ⅳ) was 28.3%. Therefore, cold storage had a certain effect on the antioxidant activity of purslane juice, which could decrease the antioxidant activity of Portulaca oleracea juice.