Establishment And Comparative Analysis Of Aroma Model Of Shedian Wine In Different Years

In recent years,the production and sale of vintage have attracted more and more attention of market and consumers,whereas there are few vintages that have been stored for years.Therefore,it is of importance to find out the specific ingredients and their content range in Shedian Wine with different cellaring ages so as to offer some suggestions to develop and authenticate aroma vintage wines.In this dissertation,the identification of aroma substances was employed as an index to compare the sample pretreatment method,and explore the column and its temperature-raising procedure.Using the best pretreatment method,the aroma of five different vintages was extracted.At the optimal chromatographic temperature procedure,GC/MS was used to analyze the aroma ingredients of Shedian wine through the search of NIST11 library.In addition,the butyl acetate internal standard method was adopted to quantify the aroma ingredients whose peak area was more than three times than the baseline noise value,and analyze the change of the aroma ingredient content in Shedian Wine and the intrinsic aroma mechanism.The main findings were as follows:First,CP-Wax57 CB column was selected by optimizing the temperature program of VF-Waxms and CP-Wax57 CB columns and comparing the effect of the column under the optimal chromatographic program.The results of comparing five pretreatment methods,i.e.,liquid-liquid extraction,ultrasonic-assisted liquid-liquid extraction,solid-phase microextraction,ultrasound-assisted headspace solid-phasemicroextraction,and headspace sampler direct injection,showed that ultrasound-assisted liquid-liquid was the best extraction method,the utilization of which identified 55 effective aroma ingredients(eliminating ingredients that did not contribute to the aroma of Shedian wine).The headspace solid phase microextraction was employed to identify 33 effective aroma ingredients,the least species of all.Meanwhile,headspace sampler direct injection method,liquid-liquid extraction,and ultrasound-assisted solid phase microextraction were utilized to identify 40,39,and36 effective aroma ingredients respectively.As a result,ultrasound-assisted liquid-liquid extraction was selected to deal with wine samples.Second,the ultrasonic-assisted liquid-liquid extraction method was used to extract the aroma ingredients of Shedian Wine that has been stored for five years,seven years,ten years,fifteen years,and twenty years respectively.NIST11 library was utilized to search the chromatography peaks.The results showed that a total of 67 effective aroma ingredients were detected in the 10-year-storage Shedian Wine,the most kinds of ingredients.Meanwhile,55,57,64,and 63 effective aroma ingredients were identified of Shedian Wine that has been stored for five years,seven years,ten years,fifteen years,and twenty years respectively.Third,using butyl acetate as the internal standard,it was found that RSD was below 10%,the recovery rate between 79% and 125%,and the regression equation correlation coefficient above 0.99,which indicated that all measured aroma ingredients were within the detection limit.Ethyl caproate was the highest esters among five vintages,followed by ethyl lactate and ethyl butyrate.Due to the fact thatthe ethyl lactate aroma did not have much contribution,the esters in Shedian Wine that determined scent were ethyl caproate and ethyl butyrate.Isopentanol was found to be the highest alcohol,followed by isobutanol and propanol.Hexanoic acid was discovered to be the most abundant acids,followed by acetic acid and butyric acid.Acetaldehyde was identified to the most abundant of all aldehydes and ketones,followed by Furfural.Finally,the total aroma ingredients increased with the storage years,but did not increase significantly in Shedian Wine that has been stored for more than ten years.On the whole,the ester increased with the storage years owing to the esterification occurred between alcohol compounds and acid compounds.The alcohol content did not keep a stable change.The acids increased first and decreased second with the storage years.This may be because the acids increased due to oxidation of aldehydes and ketones at first,but as the storage years increased,acid reacted with alcohol to generate ester,leading to the reduction of acids.The total aldehyde ketone also increased first and decreased second with the storage years,which may be because oxygen molecules in the air kept entering the wine during the storage,and caused a series of redox reactions,so the aldehydes and ketones increased.