The Dectection Of Aroma Compounds In Sesame Oil And Its Application In The Aroma Formation And Quanlity Evaluation

Sesame oil is one of vegetable oils which are popular in the world and volatile compounds are one of the important components which decide the quanlity and flavor of them. In history a lot of researchers studied sesame oil, but most of them did research about nutrition. Therefore, furthermore study need to be done about the typical flavor. In this paper, we studied the extraction methods of sesame oil aroma, formation rules of sesame oil volatile compounds during processing and the volatile compounds of different quanlity sesame oil. Finally, we finded the key steps which influenced the sesame oil flavor during processing and explored a method which were impersonality, simple and covinience to assess the sesame oil quanlity. The main results of this paper are as follows:1. The extraction method and analysis technique Simultaneous distillation extraction ( SDE ) and solid-phase microextraction ( SPME ) combined with gas chromatography/mass spectrometry (GC-MS) were used to analyze the volatile compounds of sesame oil. The gas chromatography/mass spectrometry (GC-MS) conditons were optimized and the fibers of solid-phase microextraction ( SPME ) were carefully selected. The results showed that the important aroma components of sesame oil were pyrazines, pyrroles, furans, aldehydes. Simultaneous distillation extraction (SDE) could extract more compounds, especially ones which were difficultly volatlile and had high boiling point. Solid-phase microextraction (SPME) could extract the compounds which were easily volatile and possessed low boiling point. Compared with Simultaneous distillation extraction (SDE), although solid-phase microextraction (SPME) extracted few compounds, it also could extract most of the important sesame oil aroma.Therefore, as a novel extraction method, solid-phase microextraction (SPME) could generally reflect the composition of sesame oil flavor.2. The formation rules of aroma in the sesame oil during processing Solid-phase microextraction (SPME) combined with gas chromatography/mass spectrometry (GC-MS) were used to analyze the influence of roasting conditions and extraction methods on the volatile compounds in the sesame oil of three sesame varieties. The results showed that there were significant different in the content and compositions of volatile compounds with different processing. For example, pyrazines were yielded in relatively high concentrations with high roasting intensities and 2-methoxy-4-vinylphenol reduced at higher roasting intensities. Application of statistical models (principal component analysis, PCA) and sensory evaluation observed that the sesame oils with different roasted degrees have distinct aroma. Besides, in the sesame oil extraction technology, solvent extraction method extracted the fewest volatile compounds and the number of aroma compositions of the ground sesame oil is the maximum. Sensory evaluation demonstrated that ground sesame oils had strong flavor. Pressing sesame oils taked the second place and the solvent extraction methods had the worst flavor. The results of the present study suggest that controlling the roasting conditions and the extraction methods can prepare the sesame oil with preferable flavor.3. Evaluation of the quanlity of sesame oil The volatile compounds of nine sesame oil were analyzed by headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The extraction conditons were optimized and sixteen compounds of them were verified as important odors of sesame oil flavor. Furthermore, the 16 odor compounds were used as variables and principal component analysis (PCA) was applied to create evaluation model of characteristic flavor of sesame oil. The flavor quanlity of nine sesame oil were evaluated by the principal component analysis(PCA)model. Sensory evalution was also utilized to test the PCA model and the results were consistent with that obtained by the PCA method. It proves that the PCA method is feasible and provides a new method to evaluate the quanlity of sesame oil flavor.