Study On The Characteristic Changes And Influencing Factors Of Stable Isotope In Wine And The Traceability Of Producing Area

In recent years,China’s wine production and consumption have greatly increased,and the origin of wine is one of the important factors that affect consumers’purchase of wine;mislabeling and adulteration of wine producing areas have a negative impact on the wine market,and they have damaged consumers’rights and interests and geographical protection signs of the producing areas.Therefore,a fast and steady method of origin verification is needed to ensure accurate identification of origin and consumers’confidence in the market.In this study,Cabernet Sauvignon wine grapes from four different wine producing areas in Xinjiang were collected and fermented into wine.The stable isotope ratios ofδ¹³C andδ¹⁵N andδ²H andδ¹⁸O in each sample before fermentation（whole fruit and juice and peel）and after fermentation（peel and wine）were determined,and the characteristics of stable isotope ratios were analyzed and the origin traceability was discriminated.The main research results are as follows:（1）The stable isotope ratios ofδ¹³C andδ¹⁵N of various samples before and after wine fermentation were measured by elemental analysis-stable isotope ratio mass spectrometry（EA-IRMS）,and the distribution characteristics and correlation ofδ¹³C andδ¹⁵N values in each sample before and after wine fermentation were analyzed.The results showed that the distribution ofδ¹³C andδ¹⁵N values in each sample before and after fermentation was stable,and theδ¹³C values in whole fruit before and after fermentation were positively correlated（P<0.01）.There is a negative correlation betweenδ¹³C value andδ¹⁵N value in each sample before and after fermentation.（2）Thermal conversion/elemental analysis-isotope ratio mass spectrometry（TC/EA-IRMS）was used to determine the stable isotope ratios ofδ²H andδ¹⁸O in various samples before and after wine fermentation,and the variation ranges and correlation ofδ²H andδ¹⁸O values were analyzed.The results showed that the variation range ofδ²H was large,and the variation trend ofδ¹⁸O value was stable within the range of 1‰and 2‰.In each sample before and after fermentation,except that theδ²H value in fruit juice had a negative correlation withδ²H andδ¹⁸O values in other samples,the remainingδ²H values had a very significant positive correlation withδ¹⁸O values（P<0.01）.（3）Combining the ratio of stable isotopes in wine with stoichiometry,the discrimination analysis of wines from four different producing areas in Xinjiang shows that the established discrimination model can effectively distinguish wines from four different producing areas in Xinjiang.Meanwhile,the overall discrimination rate in PLS-DA discrimination model reaches 90%.It shows that the combination of stable isotope ratio and chemometrics can be used to effectively discriminate the wines from four different producing areas in Xinjiang,and it is an effective method to trace the origin.