Preservation Effect of Ice-Glazing Using Pullulan and Bay Laurel Extract on the Quality Characteristics of Caspian Trout (Salmo trutta caspius) during Frozen Storage

Abstract

ABSTRACT The effect of ice-glazing using pullulan (IGP) and bay laurel extract (BLE) was examined on the shelf life of Caspian trout (Salmo trutta caspius) under storage conditions in the freezer (−20 ± 2 °C). Four treatments, including 1) control (without coating), 2) IGP, 3) IGP + BLE at 750 ppm, and 4) IGP + BLE at 1500 ppm were periodically evaluated in terms of microbiological (total amounts of bacteria and psychrotrophic bacterial count) and chemical (peroxide value, thiobarbituric acid amounts, total volatile basic nitrogen) parameters, color index, texture, and fatty acid profile of Caspian trout fillet placed in the freezer for four months. The highest levels for saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acid were palmitic acid (12.29%), oleic acid (60.98%), and linoleic acid (9.55%), respectively. IGP with the BLE decelerated the increasing trend of oxidative and microbial spoilage compared to the control treatment. Changes in texture, color index, and fatty acids were less in these treatments. Thus, ice-glazing with pullulan edible coating incorporated with BLE maintains the quality of Caspian trout fillet during storage in the freezer.