Identification Of Adulteration Of Beef And Mutton Based On Nucleic Acid, Protein And Specific Flavor Substances

Meat is an important part of the human diet,because it is rich in protein,fat,iron,zinc and vitamin B6 and other human life essential substances,and widely loved by consumers.In recent years,with the rapid growth of meat consumption,adulteration has occurred from time to time.Adulteration of meat products refers to the substitution of some cheap and abundant available raw materials for actual ingredients,such as duck meat and chicken meat instead of expensive beef and mutton;Or,in some cases,food additives such as nitrite,pigment,and essence are added to make adulterated meat products more palatable to the senses.Therefore,it is of great significance to adopt accurate,efficient and sensitive identification technology to identify adulterated meat.The identification of adulterated meat mainly includes the following four aspects:1.Identification of meat sources(such as wild and farmed meat,organic and traditional meat,and geographical sources);2.Identification of meat substitution(meat components are replaced by other animal species,tissues,fats or proteins);3,identify non-meat ingredients additives(such as water,additives).With the rapid development of modern instruments and molecular biology,the methods of qualitative and quantitative identification of meat adulteration are more diversified.In order to study the different identification methods to identify fake beef and mutton sensitivity and accuracy,and find the advantages and disadvantages of different appraisal methods and the applicable scope,to beef and mutton as the research object,this paper respectively from the level of gene and protein level research,beef,lamb,chicken and duck the main characteristic of the material and the difference of their existence,and studied the beef,lamb,chicken,duck,beef flavor,mutton flavor difference in flavor,as well as the comparison of the beef,chicken and mix chicken essence in flavor types and characteristics of the differences of material,in order to meat food safety monitoring and market management provide certain theoretical basis and guidance.Based on bovine species specificity srrna and 12 species specificity CO046 sheep mitochondrial DNA gene as a template,respectively design specific primers,respectively for emission of NiuYuan,sheep,chickens and ducks source of DNA template amplification,and thereby to different sources of validation for beef and mutton,and the results show that the primers specificity and can distinguish red meat with other meats,but is not specific for different sources of red meat.Therefore,this primer is used to identify fake mutton and is applicable to beef from different sources.Identification of N compounds in beef,mutton and common fakes of chicken and duck meat.Beef,sheep,chicken and duck all have high protein and amino acids,especially the flavor amino acids.The content of essential amino acids,fresh amino acids and bitter amino acids in beef is higher,while the content of various amino acids in duck meat is the lowest.There was no significant difference in protein or amino acid levels between the four types of meat.According to sds-page results,the protein concentration of mutton was slightly higher than that of duck in the region of 25kD?40kD.There are molecular bands unique to duck meat at 66kD and 22kD.The small molecular bands of mutton with higher concentration were found at 80kD,75kD and 18kD.The similarity degree between beef and chicken is the highest in the region of 25kD?62kD,and the 180kD macromolecular band is the characteristic band of chicken.75kD and 10kD are the characteristic bands of beef,among which the content of 10kD small molecule bands is higher.Sds-page can distinguish beef,mutton and chicken and duck meat to some extent,but the characteristics are not particularly obvious.In this study,the volatile flavor substances of beef,chicken,beef essence and chicken mixed with beef essence were extracted and classified by headspace solid phase microextraction and gas chromatography-mass spectrometry.A total of 51 volatile flavor substances in beef were detected,which were classified into 7 categories.Among them,1-octanol,1-octene-3-alcohol,nonaldehyde and n-hexanal were high in content,which might be the characteristic flavor substances of beef.At least 22 kinds of hydrocarbon,14 kinds of aldehydes,12 kinds of esters,5 kinds of alcohols,4 kinds of ketones,1 kind of fatty acids and 5 kinds of other kinds(containing sulfur,nitrogen and heterocyclic compounds)were found in mutton.46 kinds of volatile flavor substances in chicken were detected,which were classified into 6 categories.Duck meat contains at least 30 kinds of hydrocarbons,23 kinds of esters,18 kinds of alcohols,8 kinds of aldehydes,2 kinds of ketones,1 kind of fatty acids and 8 kinds of other flavor substances(including sulfur,nitrogen and heterocyclic compounds).Forty-three volatile flavor compounds were detected in the flavor essence of beef,which could be classified into 8 categories.Mutton flavor of the communist party of China identified 80 species of volatile flavour compounds,including 29,esters 10 kinds of hydrocarbons,alcohols,11,a 12,aldehyde ketone of 5 and 9 kinds of fatty acids and other classes(containing nitrogen and sulfur heterocyclic compound)4,the types and contents of aldehyde and ester are higher,of which 4-methyl octylic acid ethyl ester,ethyl decanoic acid and octanoic acid ethyl ester content is more than 20%.The four kinds of meat all contain high nonaldehyde and n-hexanal,which may be the characteristic flavor of meat.This paper also compares the flavor difference of beef,beef flavor and chicken with beef flavor,trying to compare the difference between pure beef and fake beef from the type and content of flavor substance.Although chicken with beef essence is similar to beef in sensory aspects,it is quite different in flavor material categories.Pure beef has more alcohols and aldehydes,while the content of heterocyclic compounds and sulfur compounds is very small.However,chicken with beef flavor is significantly higher in sulfur compounds and heterocyclic compounds than pure beef because of the higher heterocyclic compounds and sulfur compounds in beef flavor.In terms of compound types,both beef and chicken with flavor have nonaldehyde and n-hexanal,while pure beef flavor does not.Both beef flavor and chicken with flavor have a large number of thioether compounds and compounds containing bran,while pure beef does not.Therefore,it can be used as the basis for the identification of real and fake beef.