The Influence Of The Oxidation Degree Of Wine On Its Quality And The Construction Of Its Discriminant Model

Oxidation is one of the most common quality problems of wine,which will lead to the production of peroxide smells and browning turbid in wine.It is important to accurately discriminate the degree of oxidation of wine in the quality control of wine production and storage.In this study,Chardonnay,Italy Riesling and Cabernet Sauvignon were selected as experimental raw materials.Phenolic,aromatic substances,electrochemical and color parameters of three kinds of wines with different degree of oxidation were detected by high performance liquid chromatography,gas chromatography,multi-parameter analyzer and UV spectrophotometer.The effect of different degree of oxidation on the quality of wine was evaluated in this study.Meanwhile,the regression equation y for distinguishing the oxidation degree of three kinds of wines and the y value range of different degree of oxidation were obtained by combining the experimental datas with the partial least squares regression analysis.In the study of the influence of the degree of oxidation on the phenolic compounds of wine,it was found that the content of phenols in the three wines was significantly decreased in the process of oxidation.In Chardonnay dry white wine,the contents of total phenolics,gallic acid,syringic acid and caffeic acid were decreased with the exacerbation of the degree of oxidation.In Italian Riesling dry white wine,the content of total phenols,gallic acid,syringic acid,caffeic acid and catechins were decreased with the exacerbation of the degree of oxidation.The content of syringic acid and caffeic acid in Cabernet Sauvignon dry red wine was significantly decreased with the exacerbation of the degree of oxidation,but the gallic acid was more stable.The content of gallic acid in Cabernet Sauvignon dry red wine was almost unchanged during the process of oxidation.In the study of the influence of the degree of oxidation on the alcoholic esters of wine,it was found that the content of methanol in the three wines was significantly increased in the process of oxidation.In addition,the content of isoamyl alcohol in Chardonnay dry white wine was significantly decreased with the exacerbation of the degree of oxidation,but the contents of alcohol esters such as n-propanol,ethyl acetate,isobutanol,active amyl acohol and ethyl lactate were not decreased obviously.In Italian Riseling dry white wine,the content of ethyl acetate was decreased obviously,the contents of n-propanol,isobutanol,isoamyl alcohol,active amyl alcohol and ethyl lactate were not decreased significantly.Compared with the results of two dry white wines,the contents of alcoholic esters in Cabernet Sauvignon dry red wine were increased in the process of oxidation.In the study of the infuence of oxidation degree on the electrochemical parameters of wine,it was found that the content of dissolved oxygen of three wines increased in the early stages of oxidation and then decreased slightly.The conductivity of two dry white wines was stable,but the conductivity of Cabernet Sauvignon dry red wine was decreased with the exacerbation of the degree of oxidation.In addition,three wines'oxidation reduction potential were increased significantly,but the pH value has declined.In the study of the influence of the degree of oxidation on the color parameters of the wine,it was found that the color of wine had different degrees of browning in the process of oxidation.The chromaticity,a*,b*and C*values of two dry white wines were increased significantly,and the tone and L*values were decreased obviously.The chromatcity and tone of Cabernet Sauvignon dry red wine were increased significantly,and the values of a*,b*,L*and C*were decreased.The regression equation of predicting the degree of oxidation and the“y”value ranges of different degrees of oxidation of three kinds of wine were obtained by combining the experimental datas with the partial least squares regression analysis.The regression equation of distinguishing the degree of oxidation of Chardonnay:y=2.974407-0.836x₁-0.373x₂+0.259x₃+0.258x₄+0.268x₅-0.282x₆-0.419x₇+0.166x₈+?-8.327e-02?x₉-0.179x₁₀-0.184x₁₁-0.148x₁₂+0.512x₁₃,R²=0.9879.The regression equation of distinguishing the degree of oxidation of Italian Riesling:y=2.417384-0.105x₁+?7.244e-02?x₂+0.106x₃-0.106x₄-0.145x₅-0.113x₆+?4.984e-04?x₇+0.119x₈+?-7.938e-02?x₉+?2.131e-02?x₁₀-0.145x₁₁-0.105x₁₂-0.135x₁₃+?-8.827e-02?x₁₄+?-1.874e-02?x₁₅+?2.077e-02?x₁₆+?-9.842e-02?x₁₇+0.14x₁₈+0.15x₁₉-0.133x₂₀+0.151x₂₁+0.154x₂₂+?7.307e-03?x₂₃,R2=0.9893.The regression equation of distinguishing the degree of oxidation of Cabernet Sauvignon:y=2.439276+0.114x₁+?4.068e-02?x₂+0.103x₃+?-9.459e-02?x₄-0.207x₅+?3.590e-03?x₆+0.163x₇-0.171x_8-0.141x₉+0.160x₁₀+?8.773e-02?x₁₁+?1.2e-02?x₁₂+?8.115e-02?x₁₃+?6.718e-02?x₁₄+?6.368e-02?x₁₅+?6.398e-02?x₁₆+?7.149e-02?x₁₇+?-2.401e-02?x₁₈+?-1.775e-02?x₁₉-0.196x₂₀+?-7.74e-02?x₂₁+?7.5e-02?x₂₂+0.14x₂₃,R²=0.9795.The“y”value ranges of different degrees of oxidation of three kinds of wine were obtained by the datas after“normalization”into their regression equation“y”.The“y”value ranges of different degrees of oxidation Chardonnay:0 day?-0.41?y?0.56?;7days?1.85?y?2.50?;14 days?3.73?y?4.31?;21 days?5.70?y?250?.The“y”value ranges of different degrees of oxidation Italian Riesling:0 day?0.99?y?1.35?;7 days?1.78?y?2.21?;14 days?2.77?y?3.06?;21 days?3.60?y?3.88?.The“y”value ranges of different degrees of oxidation Cabernet Sauvignon:0 days?0.79?y?1.22?;7 days?1.97?y?2.08?;14 days?2.84?y?3.26?;21 days?3.67?y?4.00?.By combining the results of sensory evaluation,we can get the range of y value to judge the actual oxidation of three wines.When Chardonnay wine y?1.85,the Chardonnay wine is oxidized;when the elegant wine y?1.78,the Italian Riesling wine is oxidized;when the Cabernet Sauvignon y?1.97,the Cabernet Sauvignon wine is oxidized.