Study On The Hydrolysis Process Of Tilapia

Tilapia was used as the main materials to study on the hydrolisis of protein in this paper, and hydrolysates was preparated, for the efficient use of the tilapia and further improvement of it's flavor, also its can provide a theoretical basis for natural seasoning and functional foods. Specific study as follows:1. the basic components of Tilapia:the protein content is 16.17%, crude fat 2.89%, moisture content 75.59%.2. Optimization of autolysis hydrolysis conditions on Tlilapia:Orthogonal experimental design wich is according to single factor experiment, was used to consider the temperature, time, pH, solid to liquid ratio on the hydrolysis of tilapia autolysis. Optimal hydrolysis conditions was:temperature 55℃, time 6h, the initial pH value is 4.0, solid to liquid ratio of 1:1. This included that tilapia may catalyze the hydrolysis on its own protein into peptides and amino acids by endogenous protease, and no corruption with the 10h period.3. The effects of food additives on the hydrolysis of Tilapia:Some food addictives could promoted the autolysis of Tilapia at a certain concentration range,over the range showed inhibition,that is:sodium benzoate≤0.02%(m/m), sodium sulfite≤0.03% (m/m), NaCl≤10%(m/m), citric acid≤0.20%(m/m).Calcium chloride and ascorbic acid acted the best promoting role in all.With the following concentrations:lactic acid≥1.00%(v/m), tartaric acid≥0.20%(m/m), EDTA (EDTA-2Na)≥0.03%(m/m), it shown an inhibitory effects. Glucose, potassium chloride, magnesium sulfate, magnesium chloride had no significant effect on the autolysis. Added sodium benzoate, citric acid, lactic acid and tartaric acid could reduce the bad smell and could slow its deterioration's coming.4. Study on hydrolysis of Tilapia protein by ginger juice.Ginger juice was used to hydrolyzed according to the technics of autolysis in this chapter. By using orthogonal experimental design and response surface experimental design to study the affecting fators:temperature, time, ginger, initial pH, solid to liquid ratio.A prediction mathematical model equation was found via regression analysis,which was about tilapia protein hydrolysis by ginger juice.Results shown that:temperature of 45.1℃, ginger volume 0.3mL/g, time 7.51h. Response surface analysis indicated that temperature, ginger amount and hydrolysis time showed interaction on index. Results of validated experiments showed that the degree of hydrolysis reached to26.00%, and this match with the model predicted value (26.0961%). That indicated that the model equation can predict the results of hydrolysis, furthermore ginger has the dual role of hydrolysis and antiseptic.The preservatives of different dosage for the effect of ginger tilapia hydrolysis results showed that: addition of sodium chloride, VC, and lactic acid could promote the degree of hydrolysis, further more the degree of hydrolysis can reach to the highest with the content of 5%,0.2%,0.8%. Sodium benzoate inhibited the hydrolysis besides concentration<0.1%.5. Antioxidation resistance of the hydrolysate which produced by Ginger juice.Antioxidant activity of hydrolysate was studied,which hydrolyzated by ginger,for the sake of providing a theoretical foundation to the appliances of the production. Prove that hydrolysis have determinated oxidation resistanc with a certain degree. Express by absorbance the reducing power could be 0.461, the clearance rate of the superoxide anion was 43.13%,scavenging capacity of hydroxyl radical 92.83%, ability of inhibitory polyunsaturated fatty acids 50.99%,96.17%of scavenge DPPH free radical.6. Study on the fermentation of Tilapia by Bacillus subtilisBy using single factor experiments and response surface design to optimize the fermentation process,which Bacillus subtilis acted as the strains, and obtained the prediction model of fermentation, the optimum fermentation conditions was as follow:temperature of 40.8℃, inoculum 23.79%,7.21% salt content. Response surface analysis showed that temperature, inoculum amount, the concentration of salt took significant interactive effects. Model validation results showed that amino nitrogen on hydrolysis reach 0.8900g/100g, and match with the model predicted values (0.901578 g/100g). Prove that the model equation can well predict the results of the fermentation on tilapia.