The Formation And Change Of Volatile Flavor Compounds From Tan Sheep Meat During Cooking

The formation and changes of volatile flavor compounds in the fat and muscle of Yanchitan Tan sheep meat during cooking were studied in this paper by Purge and Trap(P&T),gas chromatography-mass spectrometer(GC-MS)and gas chromatography-olfactometry(GC-O).The achievements obtained in this study can provide guidance for the research and development of flavor control technology for industrial processing of Ningxia characteristic Tan Sheep meat products such as hand-held mutton and stewed mutton.Fifty-one volatile compounds,including aldehydes(20),ketones(8),alcohols(12),acids(3)and heterocyclic compounds(8),were detected in the cooking process of Tan sheep fat.The above compounds were classified,and their relative contents were analyzed by P&T-GC-MS and GC-0 techniques.The results showed that the types of volatile flavor compounds increased with the increase of cooking temperature and cooking time.The oil-flavored(E,E)-2,4-decadienoaldehyde,nut-flavored(E)-2-octenal and mutton-flavored benzyl methyl sulfide contributed greatly to the overall flavor of Tan sheep fat.Volatile flavor compounds were produced in the cooking process of Tan sheep fat,and which relative content increases first and then decreases.Based on the mechanism of lipid oxidation reaction,the pathway of fat flavor substances transformation from main precursors(linolenic acid,linoleic acid,oleic acid)and intermediates(hydrogen peroxide)was analyzed.42 volatile compounds were detected,including aldehydes(16),ketones(6),alcohols(5),acids(3)and heterocyclic compounds(12).The classification and content of each compound in the cooking process of Tan sheep muscle were determined by P&T-GC-MS and GC-O techniques.The results showed that the percentage of aldehydes,ketones and alcohols was higher at 50-80?,and decreased after 90?.With the prolongation of cooking time,the percentage of pyrrole,pyridine,thiazole and other heterocyclic compounds produced by Maillard reaction and thiamine degradation increased after the muscle of Tan sheep was boiled.Volatile flavor compounds such as 2-undecanolaldehyde,4-ethyl octanoic acid,2-pentyl furan,2,3,5,6-tetramethylpyrazine,dimethyl disulfide and benzyl methyl sulfide were identified as unique flavor compounds of Tan sheep muscle by GC-O technology.As mentioned above,74 effective volatile flavor compounds including 25 aldehydes,13 ketones,14 alcohols,6 acids and 16 heterocyclic compounds were detected during cooking of fat and muscle of Tan sheep.The production of aldehydes,ketones and alcohols was more in the early stage of muscle cooking,while the production of meat-flavored heterocyclic compounds was more in the late stage of cooking.Furthermore,by comparing the volatile flavor compounds produced by Tan sheep fat and Tan sheep muscle,it was found that the overall flavor of Tan sheep fat was becoming more greasier due to the production of octanal,2-amyldecanone,1-octanol and nonanoic acid.It is worth mentioning that the volatile flavor compounds produced by the muscle of Tan sheep are less,so their contribution to the overall flavor appears to be small.This study provides a theoretical reference for the rational selection of muscle and fat ratio in cooking,the selection of cooking time,temperature and heat transfer rate,and lays a theoretical foundation for the research and development of industrialized processing flavor control technology.