Inhibitory activity of aqueous extracts of pomegranate peel products and juice powder against Salmonella enterica
Weifan Wu, Kevin Mis Solval, Jinru Chen
Abstract
Pomegranate peel contains high amounts of polyphenols that could potentially be used as natural preservatives. This study evaluated the inhibitory effect of aqueous extracts of three commercial powdered peels, a whole peel, and a juice powder, against strains of Salmonella Tennessee and S. Enteritidis. Cells of the two Salmonella strains (4.88–4.96 log CFU/ml) were treated in tryptic soy broth containing 9 or 23% of the extracts prepared by two different methods for 5, 10, or 24 h at 25 °C, and reduction in Salmonella population compared to the untreated control was determined. The extracts from the three powdered peels were significantly more effective (P ≤ 0.05) in reducing the Salmonella population (1.67–2.03 Log CFU/ml) than the extracts from the whole peel (1.05 Log CFU/ml) and juice powder (0.94 Log CFU/ml). The higher dose of the extracts resulted in a greater reduction in the Salmonella population (3.02 Log CFU/ml) than the lower dose (1.47 Log CFU/ml). The level of Salmonella population reduction correlated positively with the total polyphenolic content (R2 0.66–0.99) and titratable acidity (R2 0.72–0.98) in the treatment system. The study suggests that pomegranate peels have the potential to be used as preservatives in foods.