Abstract: The purpose of this study was to investigate the formation of and changes and differences in volatile flavor compounds in diced Tan sheep meat during stir-frying, shallow-frying and deep-frying. Headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the volatile compounds and partial least squares-discrimination analysis (PLS-DA) was used to identify the composition of volatile components in meat samples cooked by the three methods at different processing stages. The results showed that an electronic nose could discriminate the odors of cooked meat samples at different processing stages. For stir-frying, shallow-frying and deep-frying, the strongest response values of electronic nose occurred in the rendering phase, after 1 min and after 3 min, respectively. Totally 273 volatile compounds were identified from the three cooked meat samples by GC-MS, 174, 158 and 134 of which were identified in the stir-fried, shallow-fried and deep-fried samples, respectively. A large number of volatile flavor compounds were produced at the early stage of shallow-frying and deep-frying and at the later stage of stir-frying. PLS-DA score scatter plots discriminated the volatile compounds in raw meat and the cooked samples, with each having obvious odor characteristics. Aldehydes were the main volatile compounds in the three cooked meat samples, with hexanal being the most abundant one. The number and amount of volatile flavor compounds in stir-fried meat were increased in the rendering stage, which contributed the most to the overall flavor, especially to acids, esters and heterocyclic compounds.

Key words: Tan sheep meat; stir-frying; shallow-frying; deep-frying; gas chromatography-mass spectrometry; electronic nose; volatile compounds