Study On Preparation Of Chicken Flavor By Thermal Reaction

Meat flavour which has the characteristics of meat fragrance is a mixture of flavor substances. It is widely used in instant noodles, chicken essence, tin cans, bacon, sausage, animal feed and pet food. The raw material of meat flavour is livestock and poultry meat and bone. The preparation technologies of meat flavour are biological enzymolysis technology and thermal response technology. Its characteristic is scent, taste stracture, flavor, lifelike, safety and containing nutrients such as amino acids and peptide. It is currently accepted natural security essence, having extremely broad market prospect.Through comparing the market acceptance of pork, beef, chicken and fish, protein content, price and other factors, I select chicken breast for raw materials which has good market acceptance, high protein content and cheap price. First, I use several kinds of protease to hydrolyze chicken for hydrolysate. Second, I use hydrolysate, reducing sugar, thiamin, etc as raw materials and use thermal response to prepare meat flavour. Third, I get meat flavour with meat smells, aroma natural and special chicken fragrance through discussing hot pretreatment on the influence of enzymolysis and optimizing enzymatic hydrolysis conditions and thermal response conditions. Finally, I analysed chicken flavor volatile flavor components by means of GC-MS. From the above, I get the following conclusion:1. I put the hydrolysis degree of hydrolysate as mainly inspects index and discuss hot pretreatment on the influence of enzymolysis. Results show that hot pretreatment can’t improve hydrolysis degree of hydrolysate and with the increase of heat treatment temperature hydrolysis degree has declining trend. Though hot pretreatment contribute to prevent microbial pollution, preparation chicken flavor is in autoclave pot, which can fully antiseptic effect of hydrolysate. From the above, when I prepare hydrolysate for the purpose to make meat flavour, hot pretreatment is not necessary.2. I use papain, neutral protease, alcalase and trypsin to hydrolyze chicken. Main evaluation index is hydrolysis degree of hydrolysate and sensory analysis is also an index. Through selecting five factors:hydrolysis temperature, pH, substrate concentration, quantity of protease and hydrolysis time to do single factor experiments, we get the suitable hydrolysis conditions of each protease. Through comparing hydrolysis degree and sensory analysis, optimal complex protease is composed by trypsin and papain and the ratio of the enzyme activity is 2:1. At last, the optimal hydrolysis conditions which are determined by Box-Behnken response surface method are quantity of protease of 4,000 u/g(protein), hydrolysis temperature of 54.9 ℃, pH of 7.0, substrate concentration of 12%, hydrolysis time of 6h. The hydrolysis degree is 18.92%. The hydrolysate is golden, its fragrance is very thick and delicious and it has no bitterness and odor in these conditions. Hydrolysis effect is good.3. Basic raw materials of thermal response which are determined by simple description inspection are reducing sugar of glucose and xylose, amino acids of L-cysteine HCL and L-alanine. Best ratio conditions (20g hydrolysate) which are determined by sorting inspection are reducing sugar additives of 3%, glucose and xylose proportion of 2:1, Amino acid additives of 2%, L-cysteine HCL and L-alanine proportion of 1:1, VB1 of 1%, chicken fat of 1.5%. The optimal thermal response conditions which are determined by Box-Behnken response surface method are reaction temperature of 110℃, reaction time of 58min, starting pH of 6.18. The chicken flavor has no odor and its meat fragrance and roast fragrance is very thick.4. Volatile flavor components of chicken flavor which are determined by GC-MS with top sample handling are ester, ketone, aldehyde, carboxylic acids, pyrazine, pyrrole, thiazole, etc. In these compounds, pyrazine, pyrrole and thiazole play an important role in the formation of chicken fragrance and these kinds of compounds and ester, ketone, aldehyde constitute a chicken flavor with comprehensive balance.