Assessment Of Brewing Wine Quality By LF-NMR

This work was the key scientific and technological projects of Science and Technology Commission of Shanghai Municipality(LM2013251).In this paper,firstly,Study on the relaxation characteristics of water-ethanol system by LF-NMR.And,water and water-ethanol systems of inorganic salt samples of different kinds and concentrations were developed according to LF-NMR relaxation characteristic using principal component analysis.Then,the brewing process of different metabolites of water-ethanol system of LF-NMR relaxation characteristics was studied.At last,LF-NMR relaxation characteristics of samples in different brewing process and different kinds of brewing wine was analyzed.A method of discrimination of brewing wine was developed by using LF-NMR relaxation characteristic analysis.The major results were as follows:1.The 1H LF-NMR and molecular simulation methods were adopted to investigate the water-ethanol solution with different water concentrations.The results indicated that the interaction between hydrogen bond association and water content in water-ethanol solution could caused the relaxation characteristics change.The result indicated that the proposed methodology was a useful tool to authenticate the water-ethanol systems of different concentrations.Meanwhile,the developed method has a good possibility to be used to assess the brewing wine quality in the future.2.Principal component analysis(PCA)was used to analyze the LF-NMR(T2)relaxation characteristics of water and water-ethanol systems of 3 kinds(MgSO4、NaOH、NaCl)of inorganic salt samples of different kinds and concentrations.The results indicated that application of PC A to the LF-NMR data allowed a good differentiation between water and ethanol-water system,different kinds of inorganic salt samples could be poperly differentiated.As the concentration increased,the distribution of the samples moved based on the principal component scores.Due to the different types and different concentrations of inorganic salt,its physical and chemical properties,solubility,degree of ionization,ionic charge and ionic radius were difference.Those could be affected the interaction between hydrogen bond association in the systems.This can be used as a test basis to evaluation and control the brewing wine system.3.To simulate complex hydrogen bond association of brewing wine system,this article explores some of the main metabolites of brewing wine(glucose,lactic acid,ethyl lactate,beta phenylethyl alcohol,phenol,benzaldehyde)added into the water-ethanol system,which LF-NMR relaxation characteristics was studied.The study found that different metabolites were different influenced of the LF-NMR relaxation characteristics of water-ethanol system,the concentration of metabolites could also affected.Because of different metabolic products,the physical and chemical properties and solubility in water,ethanol were different.This leaded to the system of hydrogen bond association was different.And also can explained the characteristic peak of the multicomponent relaxation map(T2),which was a comprehensive effect of some materials of hydrogen proton composition.The peak represented some kinds substance of the system.4.Water to the rice milk,for the first time fermentation,the second fermentation,fried wine and aging wine samples were detected by LF-NMR.The results showed that the samples in different stages of brewing process,the relaxation characteristics of T2 were difference.In the brewing process,the system would occur a series of physical and chemical reaction,the system of compositions such as inorganic salt,alcohol,aldehyde,ester,were in different kind and contents.Finally,leaded to the interaction between hydrogen bond association in water-ethanol system could changed.The LF-NMR relaxation characteristics were different.Different brands,alcohol and brewing aging according to the LF-NMR tests,relaxation characteristics were different.Also due to the the samples system of the complexity and the intensity of hydrogen bond association were different.The LF-NMR detection technology,which was a good method,could be used to assess brewing wine of different brand,different alcohol and different aging.