Analysis Research Of The Volatile Compounds In Sesame Oil

Edible and medicinal value of sesame oil is very high, and it is peoples’favorite. The main characteristic of sesame oil different from other seasoning oil is its unique flavor. Sesame oil flavor is an important part of sesame oil quality standard, is an important index of the sesame oil of good quality. The different production technology, different production conditions for sesame oil flavor has important implications.Discussing on sesame flavor material foundation, as well as the different process conditions on the sesame oil flavor impact, to reveal the sesame oil flavor composition and origin, objective evaluating of sesame oil quality and optimization of sesame oil production process have great significance.However, review the literatures, the researches of sesame oil flavor mainly confined to the single active ingredient or index constituents of qualitative and quantitative analysis, lacking of flavor components of effective group analysis, as well as various process conditions on the effect of sesame oil flavor.This research through the optimization of the experimental conditions, determine the sesame oil flavor components in detection of solid phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS)analysis method system; in the establishment of the analysis system on the basis of, through a large number of samples, constructed the sesame oil flavor components of fingerprint system, determine the main feature of composition in the flavor components of sesame oil; the characteristic constituents as index, inspected oil preparation technology, pressing temperature, flavor and storage time on sesame oil effect on the flavor components, and combined with chemometric method, explore the sesame oil flavor composition and production process correlation, established the correlation between the two equation. This study was to reveal the sesame oil flavor compositions, sources and further optimization of sesame oil production technology has important significance.(1)The SPME-GC-MS analysis system for sesame oil flavor components.By solid phase microextraction-gas chromatography-mass spectrometry, test, parameter optimization, determined the testing conditions of SPME-GC-MS in sesame oil flavor. The optimized experimental conditions are as follows:1m L of sesame oil was placed in a4mL vial. The vial was immersed in a wat er bath at60℃for20min. Then, the fiber needle penetrated the septa of the vial and the fiber was exposed in the sample headspace for1h at60℃.Aft er extraction, the fiber was removed and inserted into the injection port of the GC for thermal desorption of the volatile components (250℃for6min).Heli um was used as carried gas at a constant flow of0.8mL/min. The oven tempe rature was initially held at30℃for5min, and increased to100℃by10℃/m in,100℃for7min. Subsequently, the temperature was increased to180℃at15℃/min and180℃for7min.The method’s precision, repeatability and stability are verified,6consecuti ve measurements, the relative retention time and relative peak area of RSD bo th in0.01%-0.17%and3.83%-11.70%range, the method is stable, reliable, an d can be used in analysis of flavor components of sesame oil.(2) The research of the GC-MS fingerprint of the sesame oil flavor components.Through the57sesame oil samples for SPME-GC-MS analysis,we obtained25common fingerprint material, in which methyl-pyrazine is most stable,as the reference peak. The similarity of chromatographic fingerprints is greater than0.850, indicating the samples similarity with fingerprint technology requirements.Therefore, to establish the GC-MS fingerprint can be used as sesame oil flavor quality control reference standard.25common fingerprint material includes:acetone,2-butanone, acetic acid, pentanal, vinylfuran, pyrazine, dimethyl-disulfide, pyridine,hexanal,4-methylthia zole,methyl-pyrazine,2-(2-propenyl)-furan,2-furanmethanol,1,2-ethanediol,diace tate,2,4-dimethyl-thiazole,2,3-dimethyl-pyrazine, ethenyl-pyrazine,(E)-2-hepten al,5-methyl-2-furancarboxaldehyde, methyl-2-furoate,2-pentyl-furan,3,5-dimethy1-isoxazole,3-ethyl-2,5-dimethyl-pyrazine,2-methoxy-phenol,5H-5-methyl-6,7-dih ydrocyclopentapyrazine.(3)The effect of the different process conditions on sesame oil flavor.In the establishment of the fingerprint system, to determine the25fingerprint peaks as the study object, the flavor components of absolute content and the relative proportions of the constituent as an index, the effects of different processing conditions(oil producing technology, pressing temperature, flavor and storage time) for sesame oil flavor impact. The results show that:the change of oil producing technology of sesame oil flavor substances of the peak area and relative content have great impact. Method of water content in sesame oil in area and is superior to the other two kinds of technology. Different pressing temperature on sesame oil flavor substances of small effect. And high temperature press is easy to damage the sesame oil flavor. The differences of flavor have a large effect on the peak area of the sesame oil flavor substances, without affecting its relative content. Sesame oil flavor components, small molecular weight, low polarity material as the storage time increases,its contents decreased. While the molecular weight, highly polar material is relatively stable.(4) Study the correlation between sesame oil flavor components and oil processing technology.The results show that:different oil preparation technology of sesame oil in the volatile components in the different. Among them:methyl-pyrazine,hexanal,3,5-dimethyl isothiazolone,2-heptenal,5H-5-methyl-6,7-dihydrocyclopentapyrazine,2-methoxy phenol and aldehyde with these seven substances content difference, directly affect the sesame oil preparation technology classification.57sesame oil samples according to the different processes are clustered together, and do not cross.