Effect of Evening Prime Rose (Oenothera biennis) Leaves Extract on Spoilage Microorganisms in Apple Juice

In this study, phenolic compounds of evening primrose leaves (Oenothera biennis) were extracted with aceton 70%, ethanol 70% and methanol 70%. Total phenolic content of aceton extract was significantly higher than the ethanolic and methanolic extracts. Extracts were tested for their antimicrobial activity against Lactobacillis plantarum and Saccharomyces cerevisiae, using micro broth dilution method. All extracts showed good antimicrobial activity against tested microorganisms. Aceton extract had the most efficient antimicrobial activity. Lactobacillis plantarum was found to be more sensitive to aceton extract than Saccharomyces cerevisiae. The MBC values of aceton extract for Lactobacillis plantarum and Saccharomyces cerevisiae was 0.5 and 1 (μg/ml), respectively. The antimicrobial activity of aceton extract (0.25, 0.5 and 1 μg/ml) was also evaluated in apple juice inoculated using Lactobacillis plantarum and Saccharomyces cerevisiae during 35 days storage at ambinent temprature. Concerning microbial data in apple juice, the extract was able to control Lactobacillis plantarum and Saccharomyces cerevisiae growth. Aceton extract also showed higher inactivation effect on Lactobacillis plantarum in apple juice. Phenolic compounds did not change during 35 days of storage. No change in organoleptic quality of apple juice treated with aceton extract (0.25 μg/ml) was observed, according to sensory evaluation.