Document Type : Full Research Paper


Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology.


Introduction: The Spangled emperor (Lethrinus nebulosus) is one of the valued fish species in Persian Gulf, which due to its high nutritional quality and excellent sensory properties, is preferred by the customers in the south of Iran. Because this species is consumed domestically, it is very important to extend its shelf life, which is normally quite limited when kept refrigerated. Vacuum packaging (VP) is one of the methods of the natural preservation in order to delay the degradation and maintain the quality of the products longer. VP is widely used as a supplement to ice or refrigeration to decrease the supply of oxygen to the aerobic bacteria in the flesh to extend the shelf life of product. Chitosan have been used in seafood products to inhibit the growth of bacteria in stored fish in refrigerator and retarded the oxidation of unsaturated fatty acids in fish muscle before vacuum packaging. Chitosan, a linear polysaccharide of randomly distributed β-(1-4)-linked D-glucosamine and N-acetyl-D-glucosamine, is a biocompatible polysaccharide obtained from deacetylation of chitin. Edible coating is a thin layer of edible material formed as a coating on a food, while an edible film is a preformed thin layer which once formed can be placed on or between food components. In food industry, chitosan coatings have been used successfully because of some advantages such as edibility, biodegradability, aesthetic appearance and barrier properties, being nontoxic and non-polluting, as well as carrier of foods additives (i.e.: antioxidants, antimicrobials). Therefore, these coatings can retain quality of raw, frozen and processed foods including fish items by preventing bacterial growth and delaying lipid oxidation.
Materials and methods: Lethrinus nebulosus with an average weight of 500 g was caught with gill net in the Persian Gulf, Khorramshahr, Iran in July 2016. Fish samples were placed in crushed ice with a fish/ ice ratio 1:3 (w/w) and transported to the fish processing laboratory with 2-3 h after catch. They were washed with tap water and two fillets were obtained from each fish after removing the head and gutted. Chitosan solution was prepared with 1% (w/v) chitosan (Sigma Chemical Co., medium molecular weight, viscosity 200-800 cP) in 1% v/v acetic acid. To achieve complete dispersion of chitosan, the solution was stirred at room temperature to dissolve completely. Glycerol was added at 0.75 ml/g concentration as a plasticizer and stirred for 10 min. All films were obtained by casting 100 ml film forming solution on a nonstick surface (16*27cm), dried at ambient temperature (20˚C) until a firm surface but still with adhesive properties was obtained. After evaporation the films were peeled off from the plates. Fillet samples were randomly assigned into four treatment lots consisting of: one control lot (un-coated), second lots packaged with VP, third lots wrapped with films prior to VP, fourth lots immersed for 30 s in chitosan solution. Then the fish fillets were removed and allowed to drain for 2 h at ambient temperature (20˚C) in order to form the edible coating. All samples were stored at 4±1˚C for 12 days. Chemical, microbiological and sensorial analyses were performed at 3-day intervals to determine the overall quality of fish.
Results and discussion: Combination of vacuum packaging and chitosan treated samples effectively retarded the TVB-N and TMA values and inhibited the growth of total viable count and psychrophilic count bacteria during refrigerated storage. Therefore, to extend the shelf life and delay the deterioration of fresh Spangled emperor fillets during refrigerated storage, chitosan coating prior to vacuum packaging is more appropriate. These coatings and films also showed antioxidant effects, since TBA and FFA values was lower than control samples at the end of the storage. There was no significant difference between coating and film in reducing TBA of fillets and bacterial contamination. Therefore, chitosan coating and film prior to vacuum packaging provides a type of active packaging that can be utilized as a safe preservative for fish under refrigerated storage.


اجاق، س. م.، رضایی، م.، رضوی، س. ه و حسینی، س. م. ه. 1389. اثر پوشش های آنتی میکروبی در افزایش ماندگاری ماهی قزل‌آلای رنگین‌کمان (Oncorhynchus mykiss). فصلنامه علوم و صنایع غذایی، 34
تاج الدین، ب. (1380). بسته‌بندی مواد غذایی با اتمسفرتغییر یافته (ترجمه). سازمان تحقیقات، آموزش و کشاورزی، تهران، 401 صفحه.
جواهری بابلی، م.، ولایت زاده، م.، جاگیر، م و پاشای، ا. 1394. تأثیر بسته‌بندی تحت خلاء بر کیفیت و ماندگاری فیله ماهی فیتوفاگ طی دوره نگهداری در دمای یخچال (Hypophthalmichthys molitrix). بهداشت موادغذایی، 1.
Anelich, L. E., Hoffman, L.C., and Swanpoel, M.J. 2001. The influence of packaging methodology on the microbiological and fatty acid profiles of refrigerated African catfish fillets. Journal of Applied Microbiology. 91: 22-28.
AOAC. 1995. Association of Official Analytiacal Chemists 15th (ed).Washington DC, Chapter, 35: 7-9.
Arashisar, S., Hisar, O., Kaya, M., and Yanik, T. 2004. Effects of modified atmosphere and vacuum packaging on microbiological and chemical properties of rainbow trout (Oncorynchus mykiss) fillets. International Journal of Food Microbiology, 97: 209– 214.
Ashie, I. N. A., Smith, J. P., and Simpson B. K. 1996. Spoilage and shelf life extension of fresh fish and shellfish. Critical Reviews in Food Science and Nutrition. 36: 87-121.
Aubourg, S. 2001. Fluorescence study of the proxidant activity of free fatty acids on marine lipids. Journal of the Science of Food and Agriculture. 81: 385-390.
Basiri, S., Shekarforoush, S. S., Aminlari, M., Abhari, Kh., and Berizi, E. 2013. Influence of combined vacuum packaging and pomegranate peel extract on shelf life and overall qualityof pacific white shrimp (Peneous vannamei) during refrigerated storage. Iranian Journal of Veterinary Research. 15: 23-29.
Chytiri, S., Chouliara, I., Savvaidis, I. N., and Kontominas, M. G. 2004. Microbiological, chemical and sensory assessment of iced whole and filleted aquacultured rainbow trout. Food Microbiology. 21: 157-165.
Connell, J.J. 1980. Marinades. Control of Fish Quality, Scotland: Torry Research Station Aberdeen, 102-105.
Egan, H., Krik, R. S., and Sawyer, R. 1997. Pearson´s chemical Analysis of food. 9th. pp: 609-634.
Erkan, N., Ozden, O., and Inugur, M. 2007. The effects of modified atmosphere and vacuum packaging on quality of chub mackerel. International Journal of Food Science and Technology. 42: 1297-1304.
Fan, W., Sun, J., Chen, Y., Qiu, J., Zhang, Y., and Chi, Y. 2009. Effects of chitosan coating on quality and shelf life of silver carp during frozen storage. Food Chemistry. 115: 66-70.
Feng, F., Liu, Y., Tian, F., Zhao, B., and Hu, K. 2004. Advances in researches on chitosan materialsin bone repair. Materials Review. 18: 65-68.
Goulas, A. E., and Kontominas, M. G. 2005. Effect of salting and smoking-method on thekeeping quality of chub mackerel (Scomber japonicus). Biochemical and sensory attributes. Food Chemistry. 93: 511–520.
Goulas, A.E., and Kontominas, M. G. 2007. Combined effect of light salting, modified atmosphere packaging and oregano essential oil on the shelf-life of sea bream (Sparus aurata) Biochemical and sensory attributes. Food Chemistry. 100: 287-296.
Hernandez, M. D., Lopez, M. B., Alvarez, A., Ferrandini, E., GarciaGarcia B., and Garrido, M. D. 2009. Sensory, physical, chemical and microbiological changes in aquacultured meagre (Argyrosomus regius) fillets during ice storage. 54: 223-227.
Huss, H.H. 1995. Quality and quality changes in fresh fish. In FAO Fisheries Technical, Food and Agriculture Organization of the United Nations, Rome, 202 p.
Jeon, Y. J., Kamil, J. Y. V. A., and Shahidi, F. 2002. Chitosan as an edible invisible film for quality preservation of herring and Atlantic cod. Journal of Agricultural and Food Chemistry. 50: 5167-5178.
Kachele, R., Zhang, M., Gao, Z., and Adhikari, B. 2017. Effect of vacuum packaging on the shelf-life of silver carp (Hypophthalmichthys molitrix) fillets stored at 4 ºC. LWT-Food Science and Technology. 80: 163-168.
Kawai, T. 1996. Fish flavour. The Critical Review. Food science and Nutrition. 36: 257-298.
Kykkidou, S., Giatrakou, V., Papavergou, A., Kontominas, M. G., and Savvaidis, I. N. 2009. Effect of thyme essential oil and packaging treatments on fresh Mediterranean swordfish fillets during storage at 4oC. Food Chemistry. 115: 169-175.
Li, T., Hu, W., Li, J., Zhang, X., Zhu, J., and Li, X. 2012. Coating effects of tea polyphenol and rosemary extract combined with chitosan on the storage quality of large yellow croaker (Pseudosciaena crocea). Food Control. 25: 101-106.
Losada, V. Barros-Velazquez, J., and Aubourg, S.P. 2007. Rancidity development in frozen pelagic fish: Influence of slurry ice as preliminary chilling treatment. LWT- Food Science and Technology. 40: 991–999.
Manju, S., Jose, L., Srinivasa Gopal, T. K., Ravishankar, C. N., and Lalitha, K.V. 2007. Effects of sodium acetate dip treatment and vacuum-packaging on chemical, microbiological, textural and sensory changes of Pearlspot (Etroplus suratensis) during chill storage. Journal of Food Chemistry. 102: 27-35.
Masniyom, P., Soottawat, B., and Visessanguan, W. 2005, Combination effect of phosphate and modified atmosphere on quality and shelf-life extension of refrigerated seabass slices. Journal of Food Science and Technology. 38: 745-756.
Mastromatteo, M., Danza, A., Conte, A., Muratore, G., and Nobile, M.A.D. 2010. Shelf-life of ready to use peeled shrimps as affected by thymol essential oil and modified atmosphere packaging. International Journal of Food Microbiology. 144: 250-256.
McMeekin, T.A., Olley, J. N., Roos, T., and Ratkowsky, D.A. Predictive microbiology theory and application. Resaerch Studies Press Taunton, Specified Spoilage level, 1993: 199-200.
Mendes, R., and Goncalvez, A., 2008. Effect of soluble CO2 stabilisation and vacuum packaging in the shelf life of farmed sea bream and sea bass fillets. Journal of Food Science and Technology. 43: 1678-1687.
Mohan, C. O., Ravishankar, C. N., Lalitha, K. V., and Srinivasa Gopal, T.K. 2012. Effect of chitosan edible coating on the quality of double filleted Indian oil sardine (Sardinella longiceps) during chilled storage. Food Hydrocolloids. 26 (1): 167-174.
Nowzari, F., Shabanpour, B., and Ojagh, S.M. 2013. Comparison of chitosan–gelatin composite and bilayer coating and film effect on the quality of refrigerated rainbow trout. Food Chemistry. 141: 1667-1672.
Ojagh, S. M., Rezaei, M., Razavi, S. H. and Hosseini, S. M. H., 2010. Effect of chitosan coatings enriched with cinnamon oil on the quality of refrigerated rainbow trout. Food Chemistry. 120: 193-198.
Ozogul, Y., Ozyurt, G., Ozogul, F., kuley, E., and Polat, A. 2005. Freshness assessment of European eel (Anguilla anguilla) by sensory, chemical and microbiological methods. Food Chemistry. 92: 745-751.
Pearson, D., 1976. The chemical analysis of food (7th ed). London Churchill living stone Publishing. E. U. Essien-Udom, 1995p.
Perez-Alonso, F., Aubourg, S. P., Rodriguez O., and Barros-Velazquez, J. 2004, Shelf life extension of Atlantic pomfret (Brama brama) fillets by packaging under a vacuum skin system. Journal of Food Research Technological. 218: 313-317.
Rajesh, R., Ravi Shankar, C. N., Srinivasa Gopal, T. K., and Varma, P. R. G. 2002. Effect of vaccum packaging and sodium acetate on the shelf life of Seer fish during iced storage. Journal of Packaging Technology and Science. 15: 241-245.
Rodriguez, O., Barros-Velaazquez, J., Pinòeiro, C., Gallardo, J. M., and Aubourg, S.P. 2006. Effects of storage in slurry ice on the microbial, chemical and sensory qualityand on the shelf life of farmed turbot (Psetta maxima). Food Chemistry. 95: 270–278.
Sallam, K.I. 2007. Antimicrobial and antioxidant effects of sodium acetate, sodium lactate and sodium citrate in refrigerated sliced salmon. Food Control. 18: 566-575.
Shahidi, F., and Zhong, Y. 2005. Lipid oxidation: measurement methods (Memorial university of New foundland, Canada, 357-385.
Stamatis, N., and Arkoudelos, J. S. 2007. Effect of modified atmosphere and vacuum packaging on microbial, chemical and sensory quality indicators of fresh, filleted Sardina pilchardus at 3 ◦C. Journal of Food Science and Agriculture. 87: 1164-1171.
Woywoda, A.D, Shaw, S. J., Ke, P. J., and Burns, B.G. 1986. Recommended laboratory methods for assessment of fish quality. Canadian technical report of fisheries and aquatic sciences, 1448 p.
Yu, D., Regenstein, J.M., Zang, J., Jiang, Q., Xia, W., and Xu, Y. 2018. Inhibition of microbial spoilage of grass carp (Ctenopharyngodon idellus) fillets with a chitosan-based coating during refrigerated storage. International Journal of Food Microbiology. 285: 61-68.