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The effect of delayed icing on the quality of Litopenaeus vannamei was assessed by chemical, microbiological and sensory evaluation. Shrimps were divided into three lots. One lot was immediately iced and the other two lots were subjected to delayed icing after keeping in ambient conditions (30 ± 2C) for 2 and 4 h, respectively. White shrimp had a moisture content of 77.21%, protein 18.80%, ash 1.47% and fat 1.30% on wet weight basis. Total volatile basic nitrogen, trimethylamine, thiobarbituric acid and K value showed increasing trend during chilled storage. It was observed that there is a significant (P < 0.05) decrease in the hardness of shrimp meat during storage. Sensory evaluation indicated that the shelf life of white shrimp iced immediately after catch and 2 h delayed iced was approximately 9 days, whereas 4 h delayed iced sample had shortened shelf life of 6 days. PRACTICAL APPLICATIONSShrimp is one of the most traded and consumed aquatic product worldwide. Shrimps are rich in protein, containing very little fat and have significant cholesterol content. Shrimp is more prone to deterioration because of its high content of free amino acids and other soluble nonprotein nitrogenous substances that can serve as easily digestible nutrients for microbial growth. Chilled or iced preservation helps in delaying or reducing the bacterial growth, preventing browning and prolonging the shelf life of shrimp. Delayed icing of the catch at the site results in downgrading of the shrimp. The present study provides information about a baseline investigation of the shelf life and quality of Pacific white shrimp due to delayed icing. It can be useful to quantify the quality and shelf life of fresh shrimp prior to the application of preservative treatments to extend the shelf life.

Microencapsulation of fish oil was done by spray drying. Commercially available milk was used to form microsized emulsion. Ginger essential oil (0.25%) was used as source of antioxidant. Fish gelatin and maltodextrin were tested for their ability to serve as wall materials for microcapsules with milk protein. Encapsulation efficiency was improved significantly (P < 0.05) by the addition of fish gelatin/ maltodextrin as wall material. Flow properties of fish oil encapsulate were passable to poor. Fatty acid composition of fish oil encapsulates showed protection of polyunsaturated fatty acids from oxidation. Oxidative stability of the fish oil encapsulates showed better protection against lipid oxidation (1.89 mg malonaldehyde/kg) for fish oil encapsulates prepared with fish gelatin and ginger essential oil and packed in vacuum condition than the control (5.41 mg malonaldehyde/kg) at refrigerated condition. It suggested that in addition to wall material, ginger essential oil also improved the oxidative stability of encapsulates.

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The effect of an addition of shrimp protein hydrolysate and shrimp powder on the physicochemical properties of extruded snack was studied. Rice flour and cornflour were used as base materials, and extrusion was done using corotating twin-screw extruder. A mixture response surface methodology was used to study the effect of ingredient mixture on the physical, functional and sensory properties of extrudates. Linear and quadratic mixture response regression model was fitted to the response variables, and it was evaluated using R 2 values. Based on the desirability function score, the optimum combination of ingredient was 47.75% rice flour, 38.64% cornflour, 5.95% hydrolysate and 7.67% shrimp protein powder. It was observed that an addition of shrimp hydrolysate more than 5% (7.5%) improved the crispiness. Sensory evaluation revealed that shrimp hydrolysate and shrimp powder can be used at 5-7.5% level for developing protein-rich extruded products without affecting sensory characteristics.