Analysis of Volatile and Flavor Compounds in Grilled Lean Beef by Stir Bar Sorptive Extraction and Thermal Desorption—Gas Chromatography Mass Spectrometry

A method of stir bar sorptive extraction (SBSE) and thermal desorption (TD) with gas chromatography–mass spectrometry (GC-MS) has been developed for qualitative and quantitative analysis of volatile and flavor compounds in grilled beef. To achieve optimum extraction and analysis performance for volatile and flavor compounds, desorption temperature and solid extraction conditions of the method were studied. Grilled beef and grilled beef dripping were analyzed by the developed method with short analysis program, and a total of 57 volatile (31 flavor) compounds, including 12 aldehydes, 13 hydrocarbons, 12 alcohols and ketones, 9 nitrogen- and sulfur-containing compounds, and 10 pyrazine compounds, were identified with little variation in triplicates. Four typical flavor compounds: hexanal, methional, 2-ethyl-pyrazine, and nonanal, were selected from main flavor group for quantitative analysis, and the method showed good linearity within the tested concentration range from 2 ng/g to 0.2 μg/g (n = 3, RSDs < 8 %) with good correlation coefficient (R² > 0.998) and good recovery at 38∼45 % by spiked standards of 100 ng/g (n = 3, RSDs ≤ 11 %) in ground grilled beef. The limits of detection (LOD) range was 0.17–0.26 ng/g (S/N = 3, n = 3), and the limits of quantification (LOQ) range was 0.56–0.88 ng/g (S/N = 9, n = 3) for flavor analysts. The simple, fast, and solvent-less method allows us to obtain reliable qualitative and quantitative data of volatile and flavor constituents which are necessary for the beef quality evaluation.