Study on nutrient components and the extracting condition of the skin gelatin of tilapia

The nutrient content was analyzed in th skin of tilapia and the conditions of gelatin extraction from the skin of tilapia were studied in this paper through the orthogonal experiment and the main physicochemical properties and microorganisms were also tested. The results showed that the contents of protein and collagen in the skin were 33.14% and 27.8%, respectively. Collagen accounted for 83.9% of all protein.The optimal conditions for gelatin extraction were established by soaking in 2.5% (W/V) NaOH solution for 3.5 h and in 0.02% (V/V) HCl for 3 h and incubated at temperature 55℃. Extraction yield of fish gelatin was 26.5%, gel strength was 468 g and the content of protein was 82.43%. The total number of bacteria was 1.3×10⁵ CFU · g^-1 and coliform bacteria indicated negative.