The Study Of Boiled Beef Flavor And The Research On Formation Mechanism Of Maillard Reaction

With the changes of meat productions concept in our country,beef has become the highest meat consumption due to its good flavor,high protein,low cholesterol and rich nutritional value.In order to deeply understand the boiling characteristics of beef,the specific research contents are as follows:1)The simultaneous distillation extraction,fast GC electronic nose,sensory evaluation combined with GC-MS and GC-O were used to analyze the volatile aroma compounds of stewed beef in five different parts and key aroma substances;The principal analysis,radar analysis by fast GC electronic nose are used to find that five parts of beef has a difference of the volatile compounds and flavor.98 volatile compounds were detected by SDE-GC-MS.Among them,aldehydes are the most abundant,then the alcohols and ketones,for example,2-furfural,?E?-2-hexenal,heptanal,3-methylthiopropanal,benzaldehyde,?E,E?-2-decadienal,and 2-pentylfuran,etc.A total of 39 key aroma compounds were identified by GC-O.There were 25 kinds of flavor substances with FD value greater than 27.The substances with the largest FD value were ethyl acetate,pyridine and 2-methylpyrazine.The OAV values of the 2-methyl-3-furanthiol,furanthiol,ethyl acetate and heptanal are high,indicating that these compounds have an important contribution to the aroma of boiled beef.2)Determine the content of basic components such as protein,fat,water,and ash in the raw meat of each part,it was found that the protein content and fat content were higher than those in other parts,the contents of free amino acids,I+G,acids,and soluble sugars are different.It was found that the protein contents are higher than other parts,the contents of glucose and fructose are increasing obviously from the raw brisket to brisket soap,tartaric acid,apple acid,citric acid and acetic acid are rich in high rib and brisket.The electric tongue and sensory evaluation were used to the taste of beef in different parts.Finally,the partial least squares method?PLSR?was used to determine the correlation between the taste and the sensory evaluation of the meat and broth,and the key aroma substances.3)Optimize the simultaneous extraction conditions and columns by single factor optimization method,the GC-MS,GC-FPD,GC-O were used to identify the volatile compounds of different batches of brisket and selected common components by spectral correlative chromatography to establish the fingerprint of boiled brisket.The common components are methyl mercaptan,pyridine,3-methyl-2-butanone,4-methyl thiazole,2-methylpyrazine,2-methyl-3-furanethiol,methional,furfuryl mercaptan,acetaldehyde,?E?-2-nonenal,decanal,2-pentylfuran,octanal,nonanal,tetradecanal,?E,E?-2,4-decadienal,1,2-dichlorobenzene,hexadecanal,tetradecanoic acid,2,5-dimethyl-4-hydroxy-3?2H?-furanone,dihydro-5-tetradecyl-2?3H?-furanone, octadecanal and hexadecanoic acid.The fingerprints were identified from the similarity coefficient,reproducibility,repeatability and stability,and then the principal component analysis and the scores were used in flavor fingerprint to distinguish the brisket from different parts of beef in important volatile compounds.4)The Maillard reaction of lipid oxidation products with amino acids and reducing sugars is known to be important for the characteristic aroma generation both in meat and meat-like process flavorings.SPME/GC-MS was used to analyze the volatiles produced from a solution of[¹³C₆]glucose,cysteine and lipid degradation product-?E?-2-nonenal,heated at 130°C for 90 min.Analysis of the mass spectra showed that the resulting 2-butyl-thiophene and 5-butyldihydro-2?3H?-furanone were ¹³C₆-labeled and hence stemmed from glucose.Glucose and?E?-2-nonenal were equally important for the formation of 2-pentylfuran,whether cysteine was present in the reaction or not.2-Furanmethanol,?E?-2-?1-pentenyl?-furan,2-hexanoylfuran,ethanethiol,5-methyl-2?5H?-thiophenone,1-methyl-5-mercaptotetrazole,4-pentyl-pyridine,2-pentyl-thiophene and 2-mercaptopropanoic acid were virtually ¹³C₁-¹³C₄ labeled suggesting their origin from both glucose and cysteine and/or?E?-2-nonenal carbons.Thus,the relative contribution of aldehyde to the C-skeleton of a particular aroma compound changed greatly,when both glucose and cysteine were involved in its formation.