Optimization of Headspace Solid-Phase Microextraction (HS-SPME) Parameters for the Analysis of Pyrazines in Yeast Extract via Gas Chromatography Mass Spectrometry (GC-MS).

Yeast extract was analyzed through headspace solid-phase microextraction (HS-SPME) in combination with (GC-MS) for its pyrazine compounds. Four different types of SPME fibers with various polarities were selected for preoptimization. The three coated fiber 50/30 µm DVB/CAR/PDMS showed the maximum volatile extraction efficiency and was selected for further analysis. Twenty-eight volatile compounds were tentatively identified through GC-MS including eight pyrazines and were categorically characterized as major volatile compounds responsible for the flavor enhancing notes in YE. Response surface methodology encoded with face centered central composite design was employed to optimize the experimental design. Average peak area of selected pyrazines; methylpyrazine, 2,3-dimethylpyrazine, 2,6-dimethylpyrazine, 2-ethyl-5-methylpyrazine, trimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine, tetramethylpyrazine, 3,5-diethyl-2-methylpyrazine, and 2,3,5-trimethyl-6-ethylpyrazine were optimized through RSM-CCD to get the best conditions for HS-SPME. The HS-SPME variables X1 (equilibrium time), X2 (extraction time), and X3 (extraction temperature) were programed into the run sheets to opt an optimistic statistical approach. Among these, the variable X2 and X3 showed the most significant results with the response variable R and could be concluded as the most tantalize variables while practicing pyrazines extraction through HS-SPME method. Resultantly, the optimization methodology was successfully applied for the extraction of pyrazines from yeast extract. PRACTICAL APPLICATION: The selection of optimal conditions to conduct a HS-SPME experiment can dramatically affect the sensitivity and accuracy of aroma extraction process. Optimizing the SPME conditions is the best way to identify the role of all the possible factors that can fluctuate the volatile profile of any sample. This type of statistical approach to optimize the HS-SPME conditions for pyrazines in yeast extract was practiced for the very first time and could be considered as a prerequisite strategy to proliferate future projects related to some novel studies in terms of pyrazines flavor perception.