Metabolites Characterization Of The Dry Red Wines By NMR Spectroscopy Analysis And Antioxidant Activity Research

Wine is a complex mixture of several hundred compounds prescent at different concertrations. As a microbial proscess production, wine contains many metabolites observed from grapes and from the alcoholic and malolactic fermentations. Many factors, including geographical origin, grape varieties, wine making technologies and ageing time et al, contribute to the chemical compositon of metabolites in wine and thus affect wine quality. Powerful analytical methods for the determinant ion of the metabolites in wines are needed. Due to the ever-increasing attention paid to wine, a large number of researches have been focused on characterizing the metabolites in wines vinified in different continental ares and from differert grape varieties and vintage, identifing geofraphical origin and species by NMR, and identification of wine adulteration, evaluating the nutritional health benefits of wine by EPR.In the present work, we have applied NMR and EPR approaches to study the metabolites and the antioxidant properties of five monoverietal dry red wine samples (Merlot. Shirze, Zinfandel, Ruby Cabernet and Cabernet Sauvignon from the Shacheng viticultural region of China). Results are as follows:1、The first part of this artical, we prescent a simple and fast method based on the combination of1H NMR and pattern recognition methods for characterizing the metabolites in wines vinefied with grapes harvested from the same vinyard and same vintage and investigating through integration of1H NMR date.1、Using the advantages of NMR experiment itself to optimize the repression method of the water peak in the’H NMR detection. Noesygpprld suppress technology was used to eliminate the interference of water for detecting samples. 2、In this paper, we combined with literature data and our spectras obtained by one-dimensional, two-dimensional NMR experiments to analysis’H NMR spectra of dry red wine. We identifed17kinds of metabolites in wine.3、Preparation methods were compared by PCA and PLA-DA analysis, the result showed that lyophilization can eliminate most of the water and ethanol in the sample. Singnal of trace substances in the1H NMR spectra was enhanced after lyophilization.Their1H NMR spectra data was information rich.’H NMR spectra data of the unfreeze-dried samples had poor ability to identify differert species, it’s not conducive to analysis the differences of the metabolites.Therefore, we choose the freeze-dried samples to compare metabolite differerces in different varieties of dry red wine.4、It was demonstrated here that combination of1H NMR spectroscopy and pattern recognition approaches was possible to achieve an excellent classification of the type of the dry red wines. PLS-DA were applied to’H NMR spectra dataset to visualize correlation patterns between metalolites of the freeze-dried wines vinified from different grape cultivars and to describe the effcets of grape variety on the chemical composition or metabolites in wines. The result showed that the major metabolites of the Merlot wine different with other varieties was pro line, lactic acid, valine. glucose and polyphenols:Shirze:2.3-butanediol, lactic acid, acetic acid; Zinfandel:2,3-butanediol, succinic acid, glucose; Ruby Cabernet:valine, lactic acid, succinic acid, pro line and polyphenols and the largest contribution to the variety identification metabolite in Cabernet Sauvignon were2.3-butanediol. proline. succinic acid, acetic acid, glucose.11、The second part of this artical. we investigated the antioxidant properties of five monoverietal dry red wine samples by Electron Paramagnetic Resonance (EPR) spectroscopy using1,1-diphenyl-2-picrylhydrazyl (DPPH) radical as oxidants, and their total polyphenols content were analyzed by FC method.1、Generally, the total polyphenols content of Merlot was the highest at3044.43mg·L-1Ruby Cabernet3026.92mg·L-1, Cabernet Sauvignon2886.81mg·L-1, Shiraz2085.51mg·L-1and Zinfandel1647.64mg·L-1.2、The dry red wines which were diluted200folds showed high antioxidant in5min reaction time, the DPPH scavenging rate of Cabernet Sauvignon was72.31%which was the highest, Ruby Cabernet72.23%, Merlot68.31%, Shiraz59.03%and Zinfandel56.34%; It is an efficient method in detecting the antioxidant capacities of wines by EPR method. The DPPH scanvenging activity from dry red wines showed obviously difference.3、There was a linear correlation between the antioxidant activities and the total polyphenols content, y=0.01116x+37.327665, rGAE/DPPHequiv=0.91753.