Antioxidant and anti-Salmonella activities of eggplant peel compounds obtained by solvent-free calcium-based extraction

Abstract

Fresh products demand natural preservatives without solvent traces. Calcium-based extraction of bioactive compounds from eggplant peels (EP), could be used as an alternative solvent-free natural antimicrobial food preservative agent. In this study, we extracted bioactive compounds from EP using different calcium salts (CaSO4, CaCO3, and CaCl2) and evaluated the total phenolic and flavonoid contents, antioxidant activity, and bactericidal activity against Salmonella Typhimurium. The EP extracts obtained using 1% CaCO3 exhibited the highest total phenolic content and pronounced antioxidant activity. All EP extracts decreased Salmonella concentration after 10 and 12 h. In infected-lettuce leaves, the 1% CaCO3 EP extract inhibited bacterial growth at similar levels as a commercial disinfectant. The main compound identified in this EP extract was the chlorogenic acid. The extracts from EP obtained using calcium salts, represent a natural novel alternative preservative agent for the food industry, with antioxidant properties and potentially positive effects on human health.

Keywords

• agroindustrial waste
• natural extraction
• antimicrobial agent
• salmonella typhimurium