Fingerprint Of Volatile Flavor Compounds From South Stinky Tofu Brine

Stinky tofu,a kind of traditional snack,can not be industrialized producted.Due to the open type of natural fermentation of its brine made it difficult to determine the degree of fermentation and quality control.Headsapce solid phase microextraction(HS-SPME)combined with gas chromatography-mass spectrometry(GC-MS)is an advanced and analytical technique for the analysis of flavor compounds in food,Which can be used for the more complex Component separation judgment;The gas chromatography profile was carried out with good reproducibility and high resolution,by using fingerprint technology,the quality of brine in the hybrid material group can be controled with the "integrity" and "fuzzy" analysis."Comonness" and "difference" of different brands of brine were digged out too.Fingerprints combined with HS-SPME-GC-MS were used in the study of stinky tofu brine for the first time.In this paper,brine of five brands were collected by headspace solid-phase microextraction combined with gas-mass spectrometry.The spectral peak calibration,Shannon entropy,correlation coefficient method and principal component method PCA were used to obtained the following conclusions:1.The best extraction conditions of South stinky tofu brine with headspace solid phase microextraction : column selection polar column Rtx-WAX;extraction head selection of black 75 ?m Carboxen / PDMS extractor and white 85 ?m Polyella extractor,extraction temperature 60 ?;warm-up time 20 min;extraction time 40 min.2.The initial characteristics of the flavor substances from five brands of brine has been identified,and the common smell of substances and different substances were summarized.A Stinky tofu brine flavor characteristics,dominant effect not only depends on some key flavor compounds,such as significant difference of 3-methylindole and 4-methyl phenol content in different brands of brine,but also depends on the content and proportion of flavor balance between a large number of volatile compounds.3.After the calibration of five brands brine's fingerprints,the effect of drift spectrum calibration can be clearly identified by the comparing the partial amplification of the map before and after calibration,a single fingerprint of the five brands' brine can be obtained after calibration.4.The quantity of the chromatographic fingerprint's information is calculated by using the calculation method of the information quantity of the time analysis signal,and the information characteristic of the fingerprint is evaluated by Shannon entropy,and the Shannon entropy of the brine extracted by the white extraction head is the largest Chromatographic fingerprints,which has the highest amount of information and the highest resolution of the peaks.5.The correlation coefficient method was used to analyze the integrity of the fingerprints.The similarity of the three brands of brine samples was more than 90%,which proved that the single brand brine fingerprints had good stability and reliability.The correlation coefficient of fingerprints between Luojia brine and Wangcheng brine reached 0.5344 ~ 0.7649,which can be speculated that the brine flavor characteristics of Luojia brine and Wangcheng were similar.6.Using the PCA method of principal component analysis on five brands of brine fingerprint,the result of principal component analysis chart can be effectively distinguished between five brands of brine.There some overlapping area between Wangcheng brine and Luojia brine,which can further infered that the raw material and the ratio of two brands of brine have big similarity.