Study On The Preparation Of Pork Flavoring By Hydrolyzing Soybean Protein

Meat flavoring is a kind of food flavoring having special meat flavor,which have been widly applied in meat products,convenience food, condiment and so on,to increase or improve the meat flavor of food.The aim of this research is to prepare the pork meat flavors which is closely resembling aroma of natural pork meat flavoring using the soybean protein by technology of enzymatic hydrolysis and thermal reaction.The major aspects of my studies are the followings:1 Different enzymes were used individually and two among them. Flavourzyme and enzyme for vegetable protein (EVP)were selected after preliminary tests as the best one,and then they were used in combination based on the degree of hydrolysis (DH). The optimum total amount of enzymes were 1% and the optimum time of hydrolysis were 10 hours .The optimum hydrolysis conditions of enzyme combination were investigated with response surface methodology (RSM). The optimum concentration of the ratio of EVP to Flavourzyme ,substrate , temperature and initial pH were 60.4%(the propotion of EVP), 8.1%,47.5℃and 7.7, respectively. Soybean protein was hydrolyzed at optimum conditions ,DH reached 30.14%.2 The materials and reaction conditions of model Maillard reaction were studied by monofactorial test and Plackett-Burman test design. The optimum reaction reactants and conditions were investigated using orthogonal design.The optimized conditions for the of model Maillard reaction were obtained as following: Cysteine hydrochloride monohydrate 2g, xylose 2g, glucose 3g, glycine 1g, alanine 1g, arginine 0.5g, Serine 1g, enzymatically hydrolyzed soybean protein 40ml, VB1 0.6g, VC 0.6g; pH-value of the model: 6.0; reaction temperature:110℃; reaction time:60min.3 The optimum conditions of the controlled oxidation of lard aimed at preparing meat flavor were obtained by some single factor experiments and orthogonal test.The optimum conditions for the lard controlled oxidation are as following:the temperature of reaction is 130℃,the proper reaction time is 2 hours , the mixing speed 200r/min and the amount of VE is 0.1g(100 g lard),without water and NaCl.4 Box-Behnken experimental design was used to optimize the ratio of model Maillard reaction materials, oxidation lard and flavor enhancer I+G.The results showed that the best condition is model Maillard reaction materials43g, oxidation lard1.7g and I+G 2.2g.According to the analysis of SDE, HSand GC-MS, the pork meat flavors obtained under the optimum conditions were evaluated by head space (HS), simultan-eous distillation and extraction(SDE) and gas chromatography-mass spectrometry(GC-MS). Ninty five compounds were identified from the volatile constituents. The results showed that forty six identified compounds were important to pork meat flavors,especially the compounds: Bis(2-methyl-3-furyl)disulphide,2-methyl-3-furanthiol and 4-methyl-5-thiazoleethanol etc. which were identical with the published ones.On the basic of above research, a model was established based on principal component analysis method for assessing and ranking the aroma quality of pork meat flavors samples. This result was consistent with conventional sensory evaluation. The results indicate that the model is acceptable and available for assessing the aroma quality of pork meat flavors.