Formation of flavor volatile compounds at different processing stages of household stir-frying mutton sao zi in the northwest of China

Abstract

The aim of this study was to investigate the flavor changes of household stir-frying China mutton sao zi, and to evaluate the feasibility of electronic nose (E-nose) and gas chromatography mass spectrometry (GC-MS) in discriminating mutton sao zi at different stir-frying stages. The optimal processing parameters were obtained by sensory evaluation and tenderness analysis of the three stages, stir-frying to remove water (SFRW), stir-frying fat (SFF) and mixed stir-frying (MSF). E-nose was used to recognize mutton sao zi odors at different processing stages, solid phase microextraction (SPME) combined with GC-MS to identify the individual volatile compounds, and data from the samples of both methods further correlated with the fatty acids and crude composition (moisture, fat, protein). A total of 174 volatile compounds were detected by GC-MS, of which 59 key were screened by t-test (P < 0.01). The W1W, W1S, W2W and W2S sensors of E-nose gave higher responses to all samples, and effectively discriminate the samples. The analysis of E-nose and GC-MS confirmed that W1S, W1W, W2S, W2W and W3S sensors were in positive correlations with the abundances of volatile components. Fat exhibited strong positive correlation with octanal, heptanal, 2,3-butanediol, 1-octen-3-ol, 1-pentanol, 2-methyl-3-octanone and 2-nonanone. Hence, this study, for the first time, explored the flavor changes of household stir-frying mutton sao zi with the methods of E-nose and SPME-GC-MS, providing some profound insights for the industrial production and flavor control stir-frying machine of stir-frying mutton products with household flavor.