COATING EFFECTS OF ORANGE AND POMEGRANATE PEEL EXTRACTS COMBINED WITH CHITOSAN NANOPARTICLES ON THE QUALITY OF REFRIGERATED SILVER CARP FILLETS MEHDI ZAREI 1,3 , ZAHRA RAMEZANI 2 , SHEKUFEH EIN-TAVASOLY 1 and MILAD CHADORBAF 1 1 Department of Food Hygiene, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz 61355-145, Iran 2 Nanotechnology Research Center, Jundishapur University of Medical Sciences, Ahvaz, Iran 3 Corresponding author. TEL: +98-917-302-1142; FAX: +98-611-336-0807; EMAIL: zarei@scu.ac.ir Received for Publication December 17, 2014 Accepted for Publication January 21, 2015 doi:10.1111/jfpp.12462 ABSTRACT The coating effects of orange and pomegranate peel extract combined with chitosan nanoparticles on the quality of silver carp (Hypophthalmicthys molitrix) fillets during refrigerated storage at 4C were evaluated. Solutions of orange and pomegranate peel extracts (1%, w/v) was used for dip pretreatment, and nanochitosan solution (2%, w/v) was used for the coating. The control and the coated fish samples were analyzed periodically for microbiologic (total mesophilic and psychrotrophic count), physicochemical (pH, total volatile basic nitrogen, thiobarbituric acid reactive substances) and sensory attributes. The results indi- cated that nanochitosan coating was effective for the preservation of silver carp fillets during refrigerated storage. However, a dip pretreatment in orange or pome- granate peel extract combined with nanochitosan coating were significantly inhib- ited the development of lipid oxidation in fish samples. In this context, pomegranate peel extract was significantly stronger than orange peel extract. PRACTICAL APPLICATIONS The combination of orange or pomegranate peel extract and chitosan nanoparticles can be utilized as a safe preservative for fish under refrigerated storage. INTRODUCTION Fish is perceived as an important part of a healthy diet among nutrition and food scientists as well as consumers (Brunsø et al. 2008). In the last decades, the consumption of this food group increased and became available to consum- ers far away from the coastal areas. However, fresh fish is a highly perishable product because of its biologic composi- tion. Thus, the development of preservation methods in order to extend the shelf life of fresh fish products and carry them safely to the consumers would be desirable. Edible films and coatings are possible opportunities to prolong the shelf life of perishable food products such as fish fillets. Chitosan (poly-b-(1–4)-D-glucosamine) and its derivatives, alone or in combination with biologic or not biologic materials are good candidates for this purpose. They have been found to be nontoxic, biodegradable, biofunctional and biocompatible biopolymer. Chitosan- based edible coating provides excellent oxygen barrier prop- erties along with its antimicrobial activity (Lopez-Caballero et al. 2005; Kim and Thomas 2007; Kong et al. 2010; Ojagh et al. 2010; Domard 2011). Recently, we synthesized and used chitosan nanoparticles as edible coating for the preser- vation of silver carp fillets during refrigerated storage (Ramezani et al. 2015). We showed that both chitosan and nanochitosan coatings were effective for the preservation of silver carp fillets during refrigerated storage. However, nanochitosan exhibited higher antimicrobial activity than chitosan during the storage period. Furthermore, nanochitosan showed a stronger ability to inhibit the total volatile basic nitrogen (TVB-N) content than chitosan (Ramezani et al. 2015). Moreover, chitosan and nanochitosan films and coatings can be used as a vehicle for incorporating natural or chemi- cal antimicrobial agents, antioxidants, enzymes or func- tional substances such as plant extracts, probiotics, minerals or vitamins (Ye et al. 2008; Ojagh et al. 2010). As consumers are increasingly aware of the risk for health because of the Journal of Food Processing and Preservation ISSN 1745-4549 Journal of Food Processing and Preservation •• (2015) ••–•• © 2015 Wiley Periodicals, Inc. 1