Studon Volatile Comonents In Wheat In China’s Huanghuai Winter Wheat Zone

According to the standard of high quality wheat--strong gluten wheat and the standard ofhigh quality wheat--weak gluten wheat, choose the representative variety of strong glutenwheat, plain wheat and weak gluten wheat in Huanghuai winter wheat zone. The qualitativeand quantitative analysis of the volatile components in wheat were studyed by solid-phasemicro-extraction (SPME) and gas chromatography coupled with mass spectrometry (GC-MS)and the conditions of the SPME were optimized. Through statistical analysis the compositionand contents of volatile components in wheat flour, wheat germ and steamed bread wereanalysed. The difference of volatile components between different gluten wheat and differentparts of wheat kernels were studied, and more scientific method suitable for volatilecomponents research on wheat was explored, the aim was to lay the foundation for theresearch of wheat processing and quality control.Such results were drown out as followings:1.To lay a foundation for the accurate determination of the volatile compounds in wheatby solid-phase micro-extraction (SPME) and gas chromatography coupled with massspectrometry (GC-MS), the optimization of the SPME conditions affecting the total ioncurrent chromatographic peak area of wheat extract was investigated using response surfacemethodology based on Box-Behnken central design. On the basis of single-factorsexperiments,3factors and3levels were adopted in the response surface analysis.The optimalextraction conditions were obtained as follows: sample load17g and extraction temperature68℃for an extraction duration of52min.2. To study the flavor of wheat in Huanghuai winter wheat zone, the qualitative andquantitative analysis of the volatile components in the flour and bran of three different glutenwinter wheat varieties were studied by solid-phase micro-extraction (SPME) and gaschromatography coupled with mass spectrometry (GC-MS). The volatile components in flourwere mainly composed of cycloolefins which carbon number were more than10. Moreover,the volatile components in the bran of these varieties were mainly composed of alcohols andacids with small molecular weight. Wheat of different gluten differed in their volatilecomponents to some extent but had the same main aroma components, and their flours andbran differed in their volatile components. Different volatile components located in thedifferent parts of wheat.3. The qualitative and quantitative analysis of the volatile components in wheat flour andwheat germ were studyed. The results showed that the major constituents of volatilecomponents in wheat flour are hydrocarbons, aldehydes,alcohols, etc,.However, the majorconstituents of wheat germ are alcohols, phenols, hydrocarbons, etc. Especialy, phenols werehigh in wheat germ but not detected in wheat flour. Through the variance analysis found that,while there are some differences in volatile components of different gluten wheat samples, but the major components are the same. The volatile components in wheat flour and germ aredifferent. Different volatile components located in the different parts of wheat.4. Analysis showed that the type and content of volatile components in rice and wheatare quite different. The major constituents of volatile components in rice are aldehydes andalcohols, but hydrocarbons had a high content in wheat. Rice and wheat have some samevolatile components, but the content of these components in rice and wheat were significantlydifferent. Rice had high level of some components, but these components were not found inwheat, and vice versa.5. Different gluten properties were used to study the change of volatile components inthe processing of steamed bread. Analysed the volatile components in wheat flour, fermenteddough and steamed bread. The results showed that the volatile components changed greatly inthe processing of steam bread: the content of hydrocarbon decreased significantly, but it stillkept high level; ketones kept low levels and maintain stability. Alcohols, aldehydes andheterocyclics changed greatly. The content of alcohols decreased after steamed, but in thisprocess produced more aldehydes, heterocylics. After fermentation and cooking, the originalvolatile components in wheat react to produce new material, so the volatile composition andcontent changed greatly.6. Pprincipal component analysis (PCA) were adopted to investigate the flavors ofsteamed bread.The amodel was established based on PCA method for assessing and rankingthe aroma quality of steamed bread. Sensory evaluation was utilized to test the PCA modeland the results were consistent with that obtained by the PCA method, which proved that thePCA method was feasible to evaluate the quality of steamed bread.7. Test using principal component analysis to compare the volatile components of14kinds of strong gluten wheat, middle gluten wheat and weak gluten wheat, and select threeprincipal components whose contribution of variance accounted to81.139%, indicating thatthe top three principal components can reflect the original variables objectively.Comprehensive analysis of each component found that Z-2-heptenal,1-octene-3-ol,pentadecane, biphenyl,2,6-dimethyl-naphthalene,1,1’-methylenebis[4-methyl-Benzene andacetic acid were the main flavor substance of wheat flour. Volatile components of the14samples including alcohols, esters, acids, aldehydes,ketones,hydrocarbons, benzodiazepinesand heterocyclic substances. Take these eight categories of substances as observation to docluster analysis and has not achieved good results in the classification of the different glutenwheat. Results of clustering analysis and principal component analysis are consistent.