The Analysis Of Pepper Flavor In Different Origin And Its Characteristic Aroma Fingerprints

Pepper is common fragrant seasoning in China,which is indispensable in Sichuan cuisine.The flavor and linen substance is crucial indicator for pepper quality.in This study,14 kinds of green pepper and red pepper were selected as research target,and their flavor characteristics(linen substance and flavor)were synthetically analyzed.Spectrophotometry was used to analysis of linen substance of pepper in different regions;electronic nose technology was used to analysis of the overall aroma of pepper in different regions;head-space solid phase micro-extraction and Gas chromatography-olfactometry-mass spectrography were used to analysis and identify the aroma substances of green pepper and red pepper,and the characteristic aroma fingerprints of pepper was established.The main contents and results of this study are as follows:(1)The optimal condition for pepper linen substance extraction: methanol as extraction solvent,the ratio of material to liquid(g:mL)was 1:10,the extraction time was 3.0h.The results showed that: the linen substance content of green pepper was higher than that of red pepper,and the linen substance content of red pepper in Sichuan was higher than red peppe in other regions.(2)The optimal condition for electronic nose detection pretreatment: pepper at 40?temperature,drying 2h,crushed to 40 mesh sieve.Combined with electronic nose response analysis and Principal Component Analysis and Linear Discriminant Analysis,the results indicated that: the main aroma substances were terpenes and their derivatives in the green pepper;the aroma composition of green pepper and red pepper in Sichuan were similar and thus difficult to distinguish;the aroma of red pepper in Sichuan and other areas(except Hebei Handan)were a little different,so the red pepper in some areas can be distinguished.(3)The aroma of red pepper were analyzed by HS-SPME-GC/MS : 83 Volatile were found in red pepper.Combined with GC-O analysis,34 characteristic aroma substances were identified,including 15 kinds of terpenes,13 kinds of oxygenated terpenes,and 1 alkane,2lipids,1 aldehyde,1 ketone,1 alcohol.(4)77 kinds of volatile substances were found by HS-SPME-GC/MS.in Four kinds of green pepper Combined with GC-O analysis,34 characteristic aroma substances were identified,including 9 kinds of terpenes,10 kinds of oxygenated terpenes,and 1 alkane,1lipids,2 aldehyde,1alcohol.(5)In 34 characteristic aroma substances of red pepper,terpenes accounted for 15% and oxygenated terpene derivatives accounted for 63.9%;the highest content was linalyl acetate,accounting for about 32%;followed by Linalool accounting for about 18.5%,finally?-terpinene 6.5% and Terpinyl acetate about 4.75%.In 24 characteristic aroma substances ofgreen pepper,terpenes accounted for 36.8% and oxygenated terpene derivatives accounted for58.1%;the highest content was linalool,accounting for about 50.3%,followed by limonene accounted for about 15%,finally Sabinene 5.3% and Germacrene D 5.4%;but the content of linalyl acetate was low,only about 2.3%.Comparative analysis indicated that: green pepper mainly contains three key aroma substances: sabinene,myrcene,limonene;however,red pepper contains more ?-terpinene,linalyl acetate,terpinyl acetate,trans-nerolidol as key aroma substances.Red pepper contains higher quantity of ?-terpinene,linalool,linalyl acetate,as key aroma substances in Sichuan(including Handan,Hebei)region;red pepper contains slightly higher level of sabinene,4-terpene alcohol,neryl acetate,terpineol,etc.than that in other regions.(6)9 red pepper samples were selected by cluster analysis,GC-O-MS technology was used to analysis and identify for these 9 red pepper samples.17 aroma compounds were screened out from total different red pepper samples.Therefore the fingerprint which can indicate different origins of red pepper characteristic flavor composition was set up.The correlation coefficients and vector angle method were used to evaluate the fingerprints,whicn can fully demonstrated the accuracy of the established ones.Combined with fingerprint information,all green pepper and red pepper were identified by PCA,which indicated that the method of combining pepper fingerprint information with PCA analysis can realize the effective detection and accurate discrimination of pepper in different origins.