Abstract: Aiming at the easy contamination of pork by microorganisms along with a short shelf life， flavonoid compounds were extracted from Purslane through enzymatic hydrolysis， followed by ultrasonic-assisted alcohol extraction， and the antioxidant and bacteriostatic activity of the resultant Portulaca oleracea extract was investigated. The Portulaca oleracea extract and PVA composite film were applied for the preservation of pork to verify its bacteriostasis and preservation effects. The results indicated that the flavone extract of Portulaca oleracea L. had a scavenging activity on the OH and DPPH free radicals， and the scavenging rate of DPPH free radical was over 90 % at a flavone concentration of 0.02 mg/mL， exhibiting a high bacteriostasis effect on Staphylococcus aureus. When the ratio of Portulaca oleracea extract to PVA was 20∶30， the growth rates of total colony count， pH， H2S， MDA and TVB-N contents of chilled meat could be significantly inhibited， prolonging its shelf life.

Key words: flavonoid, antioxidant activity, antimicrobial, composite film, preservation