Impact of purslane (Portulaca oleracea L.) extract as antioxidant and antimicrobial agent on overall quality and shelf life of Greek-style yoghurt

This study investigated the effect of purslane (Portulaca oleracea L.) leaves extract on Greek-style yogurt. Purslane extract showed higher antioxidant values and antimicrobial activity against Escherichia coli ATCC25922; Salmonella typhimurium ATCC14028. The fortified of Geek-style yogurt with lyophilized purslane extract 2.2g/L (S1) and 4.4g/L (S2) significantly increased the antioxidant capacity. Greek-style yogurt made with 4.4g/L lyophilized purslane extract received the highest antioxidant capacity and lowest sensory acceptability comparing with control and low dosage of lyophilized purslane extract. DPPH scavenging activity % of S1 and S2 samples had no obvious change during storage period, while, FRAP values were decreased in all treatments after 14 days of storage.The treatment of Geek-style yogurt fortified with 2.2 g/L lyophilized purslane extract was the most preference in sensory acceptability. This study recommended that the increasing of shelf life and antioxidant capacity and stability of all-natural Greek-style yogurt, a dosage of lyophilized purslane extract 2.2g/L should be incorporated. Moreover, the P. oleracea could be used in functional foods as it has some bioactive components.