Quality of gelatin from tilapia (Oreochromis niloticus) by-products and its effects as edible coating on fish sausage during chilled storage

Abstract

Gelatin is a hydrolysed collagen that can be used as raw material for edible coatings to protect perishable foods such as fish sausage. This study aims to examine the quality of gelatin from tilapia by products (skin, scale, bone) and determine the best source of fish gelatin as edible coating on quality of tilapia sausage during chilled storage. The process of made skin gelatin was demineralized with acetic acid while scale and bone were demineralized by hydrochloric acid. Gelatin was examined for yield, gel strength, and viscosity. After edible coatings were applied to the sausages by dipping method, the sausages were stored in the refrigerator at ±5°C for 21 days. Quality deterioration of sausages during storage were measured by sensory value, moisture content, TPC, gel strength and color. The results showed that the highest gelatin yield was obtained from tilapia scales, which was 6.87% while the yield of skin and bone were 4.33% and 1.47% respectively. The best material for edible coating was bone gelatin with gel strength and viscosity which were 325 bloom and 7.10 cP respectively. The application of sausage, where the appearance and texture of sensory value were still acceptable until 21st days of storage. Sausages with edible coating from tilapia bone also showed the highest gel strength about 2514,99-3716,05 g.cm.