การผลิตโปรตีนไฮโดรไลเซทจากเลือดเพื่อใช้ในอาหารสัตว์น้ำ / เพ็ญศิริ ธำรงลักษณ์ = Production of blood protein hydrolysate for aquaculture feed / Pensiri Thumrongluck
Factor affecting acid hydrolysis of blood protein were studied by varying the 4 M. HCl at 3,4 and 5% by weight ; the reaction time at 2, 4 and 6 hours ; and the temperature at 30 ๐C and 40๐C. The degree of hydrolysis (DH) and water stability of giant tiger prawn feed produced by using 2.5% of the resulting hydrolysate as binder , were used as indicator to select the most appropriate condition. The highest DH of 90.18 % and the water stability of 87.84% were obtained in sample produced with 5% HCl, at 30 ๐C, for 6 hours. The study of enzyme hydrolysis of blood protein was carried out by varying the quantity of alcalase (0.06 unit/g) at 0.5, 1.0 and 1.5 % by volume and the reaction time at 5,10,15 and 20 minutes. By using the same criteria as the acid hydrolysis, it was found that the highest DH of 96.08% and the water stability of 86.75 % were obtained when using 1.5 % alcalase and hydrolysing at 50๐C for 20 minutes. Drying of the hydrolysate was carried out by the air and vaccum oven methods. For both methods, the temperature was varied at 60๐C, 70๐C and 80๐C. The products were dried to 10% and 20 % final moisture contents. The best condition found for both methods was 80๐C drying to the 10% moisture content. The water stability of feeds produced by using air-oven-dried blood, acid hydrolysate and enzyme hydrolysate were 84.02 % , 84.84 % and 85.52 % while those dried by vacuum oven were 83.98 % , 85.72% and 87.42 %, respectively. The binding property of the enzyme hydrolysates from both drying methods were better than those of the acid hydrolysates. Results from storage test showed that at 30๐C,vacuum, the Eval film kept the product moisture to lower than 12 %, for 4 months while that of HPDE was limited to 2-3 months.