Analysis Of Quality Characteristics Of Intense-flavor Beef Tallow And Ordinary Beef Tallow Used For Hotpot Condiment

Beef tallow is the main raw material of hotpot condiment.The quality of the hotpot condiment is fundamentally determined by the quality of the beef tallow.Generally,the beef tallow used for hot pot in the market is divided into two types:intense-flavor hotpot beef tallow and ordinary beef tallow,and the two types of beef tallow have differences both in application and the flavor of a product.However,it is still unclear about the quality characteristics and distinguish methods of the two types of beef tallow.Therefore,according to meet the needs of hotpot condiment manufacturers,infrared spectroscopy,GC-MS（Gas chromatography-mass spectrometer）,GC-IMS（Gas chromatography-ion mobility spectrometry）and other methods were employed to comprehensively analyze the physical and chemical index,infrared spectroscopy characteristics,flavor characteristics,and volatile matter composition of the two types of beef tallow.Besides,multivariate statistical methods was combined to identify the characteristics of two types of beef tallow.Above results will provide scientific reference for the discrimination,quality control standards,and method establishment of different types of beef tallow.The main research findings are as follows:（1）The normal physico-chemical indicators and fatty acid composition of two types of beef tallow were analyzed using national standard analysis methods and GC-MS methods,and the differences between the two types of beef tallow were analyzed using OPLS-DA（Orthogonal partial least squares-discriminant analysis）method.The results showed that there was no significant difference in sensory characteristics,refractive index,saponification value,and insoluble impurities between the two types of beef tallow.Relative density,melting point,peroxide value,acid value,unsaponifiable matter,moisture,and volatile matter are the main characteristic index,and the physical and chemical characteristics of intense-flavor hotpot beef tallow are characterized by high relative density,melting point,acid value,unsaponifiable matter,moisture,and volatile matter（P<0.05）,while the physical and chemical characteristics of ordinary beef tallow are significantly higher in iodine value than old hot pot beef tallow（P<0.05）.（2）The chemical composition and structure of two types of beef tallow were compared using infrared spectroscopy combined with PCA（Principal component analysis）and cluster analysis,and significant differences were found in the infrared spectra of the two types of beef tallow.Among them,ordinary beef tallow has weak characteristic absorption peaks around 967 cm^-1,intense-flavor hotpot beef tallow has three obvious characteristic absorption peaks around 1013 cm^-1,1033 cm^-1,and 1056 cm^-1,weak characteristic absorption peaks at 1360 cm^-1,2053 cm^-1,and 2077 cm^-1,and four more complex absorption peaks at 3665 cm^-1,3681 cm^-1,397 cm^-1,and 3707 cm^-1.Based on content analysis,it can be concluded that the characteristic absorption peaks in ordinary beef tallow may be related to iodine value.The characteristic peaks in the three regions of intense-flavor hotpot beef tallow may be related to indicators such as peroxide value and unsaponifiable matter content.In addition,the results of PCA and cluster analysis indicate that based on the absorption peaks of two types of beef tallow features,PCA and cluster analysis can be used to distinguish between the two types of beef tallow.（3）The flavor characteristics of two types of beef tallow were compared using electronic noses,and the differences in flavor between the two types of beef tallow were analyzed using multivariate statistical analysis methods such as PCA and LDA（Linear discriminant analysis）.The results showed that PCA analysis cannot distinguish between the two types of beef tallow,electronic nose combined with LDA result show that there were differences in the flavor of the two types of beef tallow.The flavor characteristics of intense-flavor hotpot beef tallow were more prominent in nitrogen oxide and inorganic sulfide flavors.（4）GC-IMS was used to compare the flavor characteristics and volatile matter composition of two types of beef tallow,and cluster analysis and OPLS-DA were combined to analyze the differences in flavor and volatile matter between the two types of beef tallow.The results showed that there is a significant difference in volatile substances between two types of beef tallow,the main volatile compounds in the intense-flavor hotpot beef tallow were（E）-2-hexenal（dimer）,octanal（dimer）,（E）-2-heptenal（dimer）,（E）-2-octenal（monomer）,nonanal（monomer）,etc.Therefore,the typical flavor substances of beef tallow were more abundant,the floral and meat flavor are more prominent.The main flavor compounds of ordinary beef tallow are（E）-2-nonenal（dimer）,hexanal,ethanol,ethyl acetate,1-pentanol,（E）-2-hexenal（monomer）,and butyraldehyde,the cardboard and fruit-vegetable flavors are more prominent.