Effect of Pork Endogenous Lipase on Dairy Products Flavor by Electronic Nose Combined with GC-MS

In order to study the effect of endogenous pork lipase on the flavor of dairy products,the volatile flavor compounds of two kinds of dairy products before and after lipase treatment were identified and compared by electronic nose combined headspace solid-phase microextraction(HS-SPME-MS)and gas chromatography-mass spectrometry(GC-MS). The results showed that compared with the dairy products without lipase,the response values of the two kinds of dairy product processed by lipase each sensor were higher than those of the untreated group.The two kinds of dairy products treated with lipase were identified by GC-MS,it was found that the relative contents of aldehydes,ketones,esters,heterocyclic compounds and aromatic compounds increased significantly(p<0.05):the aldehydes and ketones in the yoghurt samples increased from 0.71% to 0.95%,the esters from 13.89% to 18.12%,the heterocyclic and aromatic compounds from 20.15% to 23.69%;the aldehydes and ketones in milk shellfish samples increased from 9.26% to 13.22%,the esters increased from 30.39% to 34.71%,the heterocyclic and aromatic compounds increased from 6.34% to 11.36%.The relative contents were increased,including 2-undecanone,2-heptanone and 2-nonanone which contributed a lot to the flavor of milk,so that the flavor of dairy products was improved.