Study On Process Optimization And Flavor Of Essence Product Prepared By Thermal Reaction Of Bovine Bone

The bone skeleton of Qinchuan cattle is big,hard,cheap and inconvenient to store,which wastes resources and pollutes the environment after being abandoned.The comprehensive utilization rate and added value of cattle bones in Ningxia are low,and a large-scale comprehensive utilization system of intensive processing of cattle bones has not been established yet.Therefore,in this paper,Qinchuan beef bones were used as raw materials to prepare meat flavor.The main research results are as follows:1.Optimization of enzymatic hydrolysis technology of bovine bone.Neutral protease,flavor protease,papain,alkaline protease,pepsin and trypsin were used to hydrolyze beef bones respectively.Taking the degree of hydrolysis as an index,it was determined that neutral protease had the best hydrolysis effect,followed by flavor protease.In order to improve the enzymatic hydrolysis effect of beef bones and provide flavor basis for the subsequent Maillard reaction,neutral protease and flavor protease were combined for enzymatic hydrolysis.The optimum conditions for enzymatic hydrolysis were as follows:the ratio of enzyme to enzyme was 4:1,the amount of enzyme was 7000 U,the initial pH value was 7.2,the enzymatic hydrolysis temperature was 50℃,the enzymatic hydrolysis time was 4 h,and the substrate concentration was 20%.Under the optimum conditions,the hydrolysis degree of bovine bone enzymatic hydrolysis reached 20.14%.The results showed that compared with single protease hydrolysis,the size of bovine bone peptides(BBPs)obtained by double enzymatic hydrolysis was smaller,and the compactness was effectively reduced.The tertiary structure is stretched,the peptide molecular weight is small,the enzymolysis is thorough,and the content of free amino acids in the enzymatic hydrolysate with double enzymes is the highest,especially the content of sulfur-containing amino acids which can produce beef flavor is more.To sum up,the enzymatic hydrolysis with double enzymes is better than that with single protease,which is beneficial to the subsequent thermal reaction to prepare flavor products.2.Ultrasonic-assisted technology can further improve the degree of enzymatic hydrolysis of beef bones.Compared with the common enzymatic hydrolysis with double enzymes,the enzymatic hydrolysis product with ultrasonic-assisted protease has looser texture,smaller peptide molecular weight,higher content and variety of free amino acids,more thorough enzymatic hydrolysis and shorter enzymatic hydrolysis time.Through single factor and response surface optimization design,the optimum technological conditions of ultrasonic-assisted enzymatic hydrolysis of beef bones were determined as follows:solid-liquid ratio of 1:7.78,ultrasonic time of 57.48 min,ultrasonic power of 453.12 W and ultrasonic temperature of 50.73℃.Under the optimum conditions,the degree of hydrolysis of bovine bone enzymatic hydrolysate reached 20.73%.Eight groups of samples with different degrees of hydrolysis and the enzymatic hydrolysate obtained under the optimal conditions were selected from response surface experiment for volatile flavor determination and electronic nose analysis.The results showed that the contents and types of volatile components obtained from the samples under the optimal conditions were the most,and the electronic nose showed that their response values were larger.The tertiary structure of bovine bone protein peptide showed that with the increase of ultrasonic temperature,time and power,more tryptophan was exposed,the fluorescence intensity increased,and the protein structure was more stretched.3.Optimize Maillard reaction conditions to prepare essence products.By designing single factor and orthogonal experiment,taking sensory evaluation and browning degree as indexes,the optimum conditions of Maillard reaction were determined as follows:the amount of reducing sugar was 2%,the reaction time was 55 min,the reaction temperature was 125℃,the amount of cysteine was 2%,and the ratio of D-xylose to D-glucose wasl:1.The best formula of beef flavor essence was determined as follows:salt 2%,spice 0.2%,I+G0.4%,beef fat 10%.The prepared meat flavor essence has lasting fragrance and good stability.The flavor and volatile substances in Maillard reaction products under different conditions were detected and analyzed.The results showed that the meat flavor obtained at 125℃and 70 min had stronger flavor.Comparing the volatile components of homemade flavor,boiled beef and commercial flavor,it was found that they all contained the characteristic flavor of beef.Compared with the commercial flavor,the self-made flavor detected more thiol compounds with beef flavor,less acid substances with little contribution to flavor,and better quality.