Antimicrobial effects of pomegranate peel extract on Lactobacillus plantarum and shelf life of Thousand Island dressing

Nowadays, consumers become interested to use the substitution of natural preservatives instead of chemical preservatives. It has been proven that pomegranate peel contains large amounts of antimicrobial and antioxidant compounds. In this study, the antimicrobial effect of ethanolic extract of pomegranate peel was evaluated on total microbial count, mold and yeast and Lactobacillus plantarum during 3 months storage of thousand islands dressing at 4°C. The treated sauce samples were containing different concentrations (0.05, 0.1 and 1%) of pomegranate peel extract and 0.07% sodium benzoate, potassium sorbate mixture (BS) as control. All samples were inoculated with bacterial suspension containing 105 cfu/mL of L. plantarum. MIC and MBC of pomegranate peel extract on L. plantarum were obtained 1 mg/mL. All concentrations of pomegranate peel extract significantly decreased total bacterial count (p < 0.05). The results showed that adding 0.05% pomegranate peel extract reduced 2 Log cfu/g of total mold and yeast counts compared to the control sample in souse. There was no significant difference of adding different concentration of extract on the survival of L. plantarum (p > 0.05). Adding 0.05% pomegranate peel extract did not cause undesirable sensory attributes. Pomegranate peel extract can increase the thousand islands dressing shelf life by its antimicrobial effects as a natural antimicrobial agent and preserving the probiotic properties of the product.