The effect of chitosan-gelatin coating on the quality of shrimp (Litopenaeus vannamei) under refrigerated condition Fatemeh Farajzadeh a, * , Ali Motamedzadegan b , Seyed-Ahmad Shahidi a , Shabnam Hamzeh c a Dept. of Food Science and Technology, Ayatollah Amoli, Islamic Azad University, P.O. Box 678, Amol, 46351-43358 Mazandaran, Iran b Dept. of Food Science, Sari Agricultural Sciences and Natural Resources University, P.O. Box 578, Sari, Mazandaran, Iran c Dept. of Food Science, Tajan Institute, P.O. Box 47617964, Mazandaran, Ghaem-shahr, Iran article info Article history: Received 21 August 2015 Received in revised form 16 February 2016 Accepted 23 February 2016 Available online 27 February 2016 Keywords: Edible coating Chitosan Gelatin Shrimp storage abstract The effect of a coating solution based mixture including gelatin and chitosan as natural preservatives was studied on the shelf-life of shrimp during 14 days at refrigerated condition. The coating increased the shelf-life of the shrimp by decreasing the total and psychrotrophic bacteria, with inhibition greater than 3 log cycles at the end of storage. On the day of sensory; rejection for uncoated samples, the formation of total volatile base nitrogen (TVB-N) was less; by 57% for coated shrimp. In addition, the muscle lipid oxidation decreased with the storage; period for the coated samples as measured by the peroxide value (PV) and Thiobarbituric; acid index (TBA). Upon the coating, a significant (P < 0.05) reduction in weight loss of 58% was; observed for coated shrimp at the end of the storage. The coating improved the texture and; color properties significantly compared to uncoated samples. The sensory quality was maintained up to 13 days for coated shrimp, compared to only 7 days for uncoated samples. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Shrimp are highly perishable due to the biochemical, microbi- ological or physical changes during Post-mortem storage, which results in limited shelf life of the product (Asik & Candogan, 2014). Traditional methods for shrimp preservation such as cold storage, freezing and chilling can’t suppress effectively spoilage (Arancibia, Lopez-Caballero, Gomez-Guillen, & Montero, 2015). In addition, synthetic preservatives such as antioxidants, chelating agents and antimicrobial compounds may be applied to improve shelf life of foods. Due to consumer demand for preservative-free foods, re- searchers have concentrated on new natural materials (Jeon, Kamil, & Shahidi, 2002). Recently, there has been an increasing interest to develop materials with film- forming capacity and having antimi- crobial properties which help improve food safety and shelf life (Dutta, Tripathi, Mehrotra, & Dutta, 2009). Edible coatings can improve the quality of food products by retarding lipid oxidation, preventing the loss of protein functionality, reducing off-odours, discoloration and moisture loss (Arancibia et al., 2015). Chitosan is a polysaccharide obtained by the deacetylation of chitin, which is the principal component of the crustacean exoskeletons (Pereda, Ponce, Marcovich, Ruseckaite, & Martucci, 2011). Compared to other polymers, chitosan has numerous advantages, such as biocompatibility, biodegradability and non-toxicity (Dutta et al., 2009). Technically, chitosan has a number of functional properties including antimicrobial and antioxidant activities,film-forming ability, texturizing and binding actions (Lopez-Caballero, Gomez- Guillen, Perez-Mateos, & Montero, 2005). Several studies have demonstrated the beneficial effects of chitosan applied in food systems (Jeon et al., 2002; Fan et al., 2009; Mohan, Ravishankar, Lalitha, & Srinivasa Gopal, 2012). However, the main drawback of chitosan is its water vapour permeability, which limits the uti- lisation as self-standing packaging material. Crosslinking by some chemical treatments is a method to modify the water resistance of chitosan, but it has been confirmed that an increase in the cross- linking diminishes the antimicrobial capacity of chitosan films (Gomez-Estaca, Gomez-Guillen, Fernandez-Martín, & Montero, 2011). One of the effective methods to improve physical, func- tional and barrier properties of chitosan films is to blend them with another polysaccharide or protein (Benbettaïeb, Kurek, Bornaz, & Debeaufort, 2014). Gelatin obtained by a partial degradation of collagen has film-forming capacity and can be used as an outer * Corresponding author. Tel.: þ98 9350613635; fax: þ98 1143217041. E-mail address: Farajzadeh.sh.f@Gmail.com (F. Farajzadeh). Contents lists available at ScienceDirect Food Control journal homepage: www.elsevier.com/locate/foodcont http://dx.doi.org/10.1016/j.foodcont.2016.02.040 0956-7135/© 2016 Elsevier Ltd. All rights reserved. Food Control 67 (2016) 163e170