USING  SERIEN  PROTEASES EXTRACTED FROM THE DIGESTIVE CANAL OF SILURIS GLANIS FISH IN PRODUCTION AND CHARACTERIZATION OF PROTEIN HYDROLYSATE FROM SILURIS GLANIS VISCERA

A.R. Shaker, Khalida; B. Mohamed, Zena

	USING SERIEN PROTEASES EXTRACTED FROM THE DIGESTIVE CANAL OF SILURIS GLANIS FISH IN PRODUCTION AND CHARACTERIZATION OF PROTEIN HYDROLYSATE FROM SILURIS GLANIS VISCERA
The Iraqi Journal of Agricultural Science
Article 1, Volume 44, Issue 3, 2013, Pages 404-413
Authors
Khalida A.R. Shaker; Zena B. Mohamed
Abstract
This study aimed to prepare protein hydrolysate from Siluris glanis viscera using the crude extract of serine pro-tease extracted from the same fish digestive duct after identifying the optimum pH and temperature of enzyme extract activity and stability ,then studying some of the obtained hydrolysates properties. The processing methods included four treatments, namely T1, T2 fish samples were digested with 0.2M acetate buffer and pH 4.5 at 6 and 12 hour, and T3, T4 were digested using the crude extract of serine protease 120 unitml and pH 6.5, 0.2 M at 6 and 12 hour respectively. The undigested residues were removed by centrifugation and the clarified digests were pasteurized at 80c°/10min, cooled and the solidified fat layer removed then the pH adjusted to 6.5. The obtained hydrolysate was dried under vacuum at 50c°, and four samples were obtained and designated as P1, P2, P3 and P4. The percentages of moisture, ash, fat and protein were for P1 6, 1.10, 0.40, and 92.5%, respectively, and for P2, P3 and P4 were 6.2, 1.45, 0.45, and 91.9 %, 5.4, 1.62, 0.48, and 92.5%, 5.3, 1.70, 0.5, 92,5%, respectively. The percentages of peptone nitrogen, total proteose nitrogen, secondary proteose nitrogen, primary proteose nitrogen and amino acid nitrogen were 3.1, 1.95, 0.30, 1.65 and 0.4% respectively for P1, 4.5, 3.01, 0.36, 2.65 and 0.6 % for P2, 5.1, 2.5, 0.37, 2.13 and 0.65 % for P3, for P4 7.3, 3.5, 0.40, 3.1and 0.8%. The degree of hydrolysis for P1 and P2 were 35.5and 39 % respectively, while for P3, P4 were 52.6 and 60.1% respactively. The results of functional properties showed that the water holding capacity was 2% for P1, P2, P3 and P4 respactively. The solubility values were 74.6, 85.5, 92.2, and 93.3% for P1, P2, P3 and P4, respectively. The emulsion capacity values were 22, 20, 16 and 14 ml for P1, P2, P3 and P4 respectively.
Keywords
Protein hydrolysate; fish enzymic hydrolysate

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