Study On The Enzymic Hydrolysis And Antioxidant Capacity Of The Schizothorax Prenanti Tchang

The muscle of Schizothorax prenanti Tchang was subjected to chemical composition analysis and nutritional evaluation. papain,flavourzyme,animal protease,alkali protease,and pancreatin were used to enzymatic muscle of Schizothorax prenanti Tchang.Two kinds of enzymes were selected as better enzyme at the target of reducing power and sensory flavor evaluation. Synchronous and step enzymatic hydrolysis conditions were optimized by single factor experiment and response surface method.The optimum hydroylsis condition of hydrolysates were separated with ultrafiltration.And the antioxygenic properties of Schizothorax prenanti Tchang hydrolysates were sdudied in vitro.The results showed that the enzymatic hydrolysates had good reducing power,scavenging abilities on hydroxyl radical(OH),superoxide anion radical(O2-·) and a,a-diphenyl-β-picrylhydrazyl radical (DPPH-). Investigate the change of the amino acids and the degradation of Schizothorax prenanti Tchang protein by Tricine-SDS-PAGE electictropherogram.The examination results indicated that the nutrients of moisture,fat,protein and ash in muscle of Schizothorax prenanti Tchang were 79.57%、1.88%、6.87% and1.48%.Fish measured 17 kinds of amino acids,including 7 kinds of essential amino acids(content of 39.87%) and 10 kinds of non-essential amino acids. The constitutional rate of the essential amino acids satisfied FAO/WHO reference standards. Animal protease and Flavourzyme were selected as the better enzyme,and animal protease as the main action of the enzyme.By using response surface method analysis,the optimum conditions of synchronous enzymatic hydrolysis were as follows:material-to-liquid ratio1:3,hydrolyzing temperature 55℃,pH7.8, hydrolysis time 3.85h,enzyme dosage 6000U/g(flavourzyme 2800U/g,animal protease 3200U/g).The reducing power of hydrolysis was 0.817 at the optimum hydrolysis conditions.The optimum conditions of stepwise enzymatic hydrolysis were as follows:material-to-liquid ratio 1:3,hydrolyzing temperature 55℃,pH7.7,enzyme dosage 6000U/g(flavourzyme 2000U/g, animal protease 4000U/g),hydrolysis time 5h(flavourzyme 2.81h,animal protease2.19h).The reducing power of hydrolysis was 0.805 at the optimum conditions.The hydrolysates which was pruducted under the optimum conditions were separated into synchronization enzymatic component Ⅰ (molecular weight>10KD) and component Ⅱ (molecular weight<10KD),and points step enzymatic component Ⅰ (molecular weight>10KD),component Ⅱ (molecular weight<10KD).The antioxidant properties of crude enzyme and component Ⅰ, Ⅱ were determined in vitro.The results showed that hydrolysate had certain antioxidant activity in vitro.Concentration of 2 mg/mL synchronous crude enzyme and component Ⅰ, Ⅱ, the scavenging rates to hydroxyl free radical were 26.71%、24.49%、39.74%;the scavenging rates to superoxide anion free radical were 69.35%、63.69%、74.55%;the scavenging rates to DPPH free radical were 42.81%、38.18%、47.76%;and had certain reducing power. Concentration of 2 mg/mL the crude enzyme hydrolysis step solution and component Ⅰ Ⅱ, the scavenging rates to hydroxyl free radical were 27.17%、22.15%、36.54%; the scavenging rates to superoxide anion free radical were 71.71%、68.29%、76.58%; the scavenging rates to DPPH free radical were 38.33%、35.04%、40.14%;and had certain reducing power.Hydrolysates contain 17 kinds of amino acids,and the proportion of essential amino acid were more than 40%.Hydrolysates rich hydrophobic amino acids(Gly,Leu,Ala) and acidic amino acid(Glu,Asp).The antioxidant activity of hydrolysates may be relevant to the hydrophobic amino and acidic amino acid.Electrophoretic analysis showed that macromolecular proteins of fish protein had degradation,and the smallest molecular weight was 5.85KDa.