Comprehensive Utilization Of Tilapia Scraps

Tilapia scraps include fish backbone and internal organs. Fish belly has huge fat but must destroy the combination of protein and fat so that the fat can be easy to extract. The fish innards mainly contains cod liver oil, and is suitable for hydrolysis extraction. To use the tilapia fish processing co-products and increase the value of tilapia produce effectively, this paper use tilapia fish processing co-products to extract fish oil, screen enzyme to act fish protein and get hydrolysis polypeptide with better emulsification and emulsion, study enzymolysis polypeptide’effect of improving lipd antioxidation after add oil and emulsified and spray drying the embedding grease. The experimental results will give datas to improve fish oil process and reduce POV of fish oil during the process, and give datas to the development of the new food additives.The part of extracting fish oil:Fish bone is used as cooking method; fish visceral is used as potassium hydrolysis method to extract fish oil, studying the relationship between fish oil extraction rate and peroxide value(POV) on different process conditions. As the result, when cooking the fish bone, pH, water ratio, cooking time, are effecting the fish oil extraction and the peroxide value of the fish oil. Optimum cooking conditions is the pH9.0, water rate 1.0 for cooking 30min. Fish oil extraction rate was 2.85%,the POV of the fish oil is 0.74meq/kg under the optimum conduction. However pH, hydrolysis temperature, salt, hydrolysis time can effect the fish oil extraction and the POV of the fish oil. Optimum hydrolysis condition is that pH8.0,3%salt, on 60℃ hydrolysis for 35min. Fish oil extraction rate was 5.60%%, the POV of the fish oil is 3.64meq/kg under the optimum conduction.The part of hydrolysis:Screening of different kinds of proteases to hydrolysis fish protein to get hydrolytic polypeptide with good emulsification and good emulsion stability. Studying the relationship between different degree of hydrolysis(DH) and different polypeptides and its emulsification and emulsion stability. Using freeze drying method to purify hydrolyzed polypeptide and its concentration, pH and NaCl concentration, which are the factors affecting the emulsifying activity index (EAI) and emulsifying stability index (ESI) of hydrolyzed polypeptide of Tilapia, are studied. The effect of solubility and hydrophobicity on emulsifying activity and emulsifying stability is also studied by processing in different pH.The affects of different hydrolytic polypeptide, different DH of the hydrolyzed peptides, and hydrophobic of the polypeptides on hydrolytic polypeptide emulsifying activity and emulsifying stability are studied. As the result, Neutrase 0.8L and Flavourzyme are selected to obtain hydrolysates of high emulsifying activity and emulsifying stability, while at DH (5%) emulsifying activities are 62.05% and 67.46% respectively, and emulsifying stabilities are 28.90%、44.89% respectively. Hydrolyzed polypeptide concentration, pH and NaCl concentration, affecting the emulsifying activity index (EAI) and emulsifying stability index (ESI) of hydrolyzed polypeptide of Tilapia. The pH conduction change the solubility of the hydrolyzed polypeptide, the more polypeptide dissolve the bigger value of EAI and ESI are. The stronger hydrophobicity the higher emulsifying performance it is.After added oil to emulsify and study polypeptide ability to improve oil’s antioxidation. Using polypeptide as wall material to microcapsule oil. The hydrolyzed polypeptide of tilapia have the ability to remove peroxide. Using 70% of the ratio of 1:292032/ hydrolysates denatured starch and 30% malt dextrin as wall material, to microencapsule the 30% peanut oil. The rate of surface oil 8.70%, leaching oil is 8.90%, moisture content is 1.80%, the embedding rate is 73.95%, peanut oil peroxide value is 3.16meq/kg. By scanning electron microscope observation, the surface of peanut oil microencapsulation is almost smooth spherical and a few with surface sag, shrinkage phenomenon and with no obvious crack which showing good embedding effect.