Heliyon (May 2019)
Efficacy of olive leaf extract (Olea europaea L. cv Gentile di Larino) in marinated anchovies (Engraulis encrasicolus, L.) process
Abstract
In this study, the antimicrobial activity and the preservative properties of olive leaf extract (OLE) Olea europaea L. “Gentile di Larino” cultivar, were evaluated. The antibacterial activity was performed in vitro against spoilage bacterial strains: Pseudomonas fluorescens (ATCC 13525), Pseudomonas fragi (ATCC 4973), Pseudomonas putida (ATCC 17514), Brochotrix thermosphacta (ATCC 11509), Clostridium sporogenes (ATCC 11437), and Listeria innocua (ATCC 33090). About the preservative properties of OLE, they were evaluated in the marinating process of anchovy fillets. During the process have been determined the change of sensory characteristics and monitored these chemical parameters: pH, aw, salt content (% NaCl), thiobarbituric acid index (mgMA/Kg), total volatile basic nitrogen (mg/100g), and trimethylamine nitrogen (mg/100g). Moreover, were determined the spoilage bacteria on raw material, after 7 days and at the end of marination process, 22 days. The OLE exhibited an inhibitory effect against the bacteria tested. In marinated anchovy fillets, showed that the extract improves their shelf life without modifying the organoleptic characteristics of the product; this suggests that it could be considered in the food industry as a natural antioxidant and antimicrobial food additive.
