New approach for wine authenticity screening by a cumulative

New methodological approach for rapid control of wine authenticity without sample preparation, based on the quantitative NMR spectroscopy (qNMR) of the protium 1H and deuterium 2H nucleus is suggested. The content of dominant (e.g. water, ethanol) and some minor (e.g. glycerol, organic acids) components of wine are determined from qNMR 1H spectra for authentication of molecular composition. The sum of all exchanging hydrogen atoms of wine's components provide the 1H signal with a chemical shift of 4.8 ppm. Accounting for their content from 1H spectrum allows us calculate the 2H isotopic content in wine water from integral intensity of corresponding signal in the 2H qNMR spectrum using an internal or external standard with a known content of the 2H isotope. The possible addition of water can be found from comparison of this value with values of surface and/or ground waters from corresponding viticulture areas. This approach was used for white and red wines from the Black Sea region (Krasnodar area & Crimea peninsula). The 2H contents in investigated wines range from 157 to 165 ppm. The maximum 2H isotope content in surface waters does not exceed 148 ppm. A qNMR measurement of wine according to the proposed approach takes some minutes, that significantly exceeds the laboriousness of methods based on IRMS/SIRA (e.g. δ13C, δ18O). The error of qNMR measurements is less than 2.0%. The qNMR screening of deuterium (2H) in ethanol can be used for detection of possible wine chaptalization. This approach is similar to the known SNIF-NMR method. The positive difference with this method is the use of minimal quantity of enriched 2H standard and measurement of integral intensities of all signals instead of heights. It allows to reduce measurements' time as well as to measure the 2H content of all fragments of ethanol molecules – CH3−, CH2−, OH-groups. The publication has been prepared with the support of the “RUDN University Program 5–100”

New approach for wine authenticity screening by a cumulative 1H and 2H qNMR

New methodological approach for rapid control of wine authenticity without sample preparation, based on the quantitative NMR spectroscopy (qNMR) of the protium 1H and deuterium 2H nucleus is suggested. The content of dominant (e.g. water, ethanol) and some minor (e.g. glycerol, organic acids) components of wine are determined from qNMR 1H spectra for authentication of molecular composition. The sum of all exchanging hydrogen atoms of wine's components provide the 1H signal with a chemical shift of 4.8 ppm. Accounting for their content from 1H spectrum allows us calculate the 2H isotopic content in wine water from integral intensity of corresponding signal in the 2H qNMR spectrum using an internal or external standard with a known content of the 2H isotope. The possible addition of water can be found from comparison of this value with values of surface and/or ground waters from corresponding viticulture areas. This approach was used for white and red wines from the Black Sea region (Krasnodar area & Crimea peninsula). The 2H contents in investigated wines range from 157 to 165 ppm. The maximum 2H isotope content in surface waters does not exceed 148 ppm. A qNMR measurement of wine according to the proposed approach takes some minutes, that significantly exceeds the laboriousness of methods based on IRMS/SIRA (e.g. δ13C, δ18O). The error of qNMR measurements is less than 2.0%. The qNMR screening of deuterium (2H) in ethanol can be used for detection of possible wine chaptalization. This approach is similar to the known SNIF-NMR method. The positive difference with this method is the use of minimal quantity of enriched 2H standard and measurement of integral intensities of all signals instead of heights. It allows to reduce measurements' time as well as to measure the 2H content of all fragments of ethanol molecules – CH3−, CH2−, OH-groups. The publication has been prepared with the support of the “RUDN University Program 5–100”

Mass-spectrometric study on

The present study continues the 2015–2016 research project on biological characteristics of stable isotopes fractionation in grapes taking into account the agro-climatic growth conditions of this representative of the C3-pathway of photosynthesis group of plants in different geographical Black Sea regions. The first parts of the project were presented at the 39th and 40th Congresses of OIV in Bento Gonçalves (Brazil) and Sofia (Bulgaria). The scientific data on compositions of 13C/12C carbon and 18O/16O oxygen stable isotopes in carbohydrates, organic acids, and intracellular water were obtained for grapes of 2015–2016 growing seasons in the four areas of the Crimean peninsula as well as in several areas of the Don Basin and the Western Caspian region. This report presents the results of the 2017 season study of 13C/12C carbon and 18O/16O oxygen stable isotopes in carbohydrates and intracellular water of 12 red and white grape varieties (Aligote, Rkatsiteli, Sauvignon Zeleny, Chardonnay, Cabernet Sauvignon, Sauvignon Blanc, Merlot, Risling, Pinot Noir, Cabernet Franc, Sira, Krasnostop) as well as in ethanol of wines made from corresponding grapes from the Crimean Peninsula and South-West Coast of the Greater Caucasus. To measure the ratio of carbon isotopes 13C/12C in grape (must) carbohydrates and wine ethanol the Flash-Combustion technique (FC-IRMS/SIRA) has been used, while the method of isotopic equilibration (EQ-IRMS/SIRA) has been used for the measurement of 18O/16O oxygen isotopes ratio in the intracellular water of grapes (must) and in the water fraction of wine. The GC-Combustion technique (GC-IRMS/SIRA) has been used for the first time to measure the carbon isotopes 13C/12C distribution in ethanol of studied wines. It has been found that the δ13CVPDB values for carbohydrates of red and white grape varieties as a result of biological fractionation of carbon isotopes in the agro-climatic conditions of plant growth (2017 season) for the studied geographical areas formed the following quantitative ranges: from − 26.72 to − 23.35‰ (the Crimean Peninsula) and from − 25.92 to − 23.87‰ (South-West Coast of the Greater Caucasus). The δ13CVPDB values for wine ethanol are in the following ranges: from − 28.15 to − 24.47‰ (the Crimean Peninsula) and from − 27.29 to − 25.78‰ (South-West Coast of the Greater Caucasus). The δ18OVSMOW values in intracellular water of grapes of the 2017 season range from − 1.24 to 2.17‰ (the Crimean Peninsula) and from 1.08 to 4.09‰ (South-West Coast of the Greater Caucasus). The results of this study show, in comparison with the results of studies of the 2015 and 2016 seasons, a decrease in the δ13CVPDB values for carbohydrates of grapes and ethanol of wine, which is explained by the changed climatic conditions of grapes growing in the vegetation period of 2017

Mass-spectrometric study on13C/12C carbon and18O/16O oxygenstable isotopes distributions in grapes and wines from the BlackSea regions

The present study continues the 2015–2016 research project on biological characteristics of stableisotopes fractionation in grapes taking into account the agro-climatic growth conditions of this representativeof the C3-pathway of photosynthesis group of plants in different geographical Black Sea regions. The firstparts of the project were presented at the 39th and 40th Congresses of OIV in Bento Gonc ̧alves (Brazil) andSofia (Bulgaria). The scientific data on compositions of13C/12C carbon and18O/16O oxygen stable isotopes incarbohydrates, organic acids, and intracellular water were obtained for grapes of 2015–2016 growing seasonsin the four areas of the Crimean peninsula as well as in several areas of the Don Basin and the Western Caspianregion. This report presents the results of the 2017 season study of13C/12C carbon and18O/16O oxygen stableisotopes in carbohydrates and intracellular water of 12 red and white grape varieties (Aligote, Rkatsiteli,Sauvignon Zeleny, Chardonnay, Cabernet Sauvignon, Sauvignon Blanc, Merlot, Risling, Pinot Noir, CabernetFranc, Sira, Krasnostop) as well as in ethanol of wines made from corresponding grapes from the CrimeanPeninsula and South-West Coast of the Greater Caucasus. To measure the ratio of carbon isotopes13C/12Cin grape (must) carbohydrates and wine ethanol the Flash-Combustion technique (FC-IRMS/SIRA) has beenused, while the method of isotopic equilibration (EQ-IRMS/SIRA) has been used for the measurement of18O/16O oxygen isotopes ratio in the intracellular water of grapes (must) and in the water fraction of wine. TheGC-Combustion technique (GC-IRMS/SIRA) has been used for the first time to measure the carbon isotopes13C/12C distribution in ethanol of studied wines. It has been found that theδ13CVPDBvalues for carbohydratesof red and white grape varieties as a result of biological fractionation of carbon isotopes in the agro-climaticconditions of plant growth (2017 season) for the studied geographical areas formed the following quantitativeranges: from−26.72 to−23.35‰ (the Crimean Peninsula) and from−25.92 to−23.87‰ (South-West Coastof the Greater Caucasus). Theδ13CVPDBvalues for wine ethanol are in the following ranges: from−28.15to−24.47‰ (the Crimean Peninsula) and from−27.29 to−25.78‰ (South-West Coast of the GreaterCaucasus). Theδ18OVSMOWvalues in intracellular water of grapes of the 2017 season range from−1.24to 2.17‰ (the Crimean Peninsula) and from 1.08 to 4.09‰ (South-West Coast of the Greater Caucasus). Theresults of this study show, in comparison with the results of studies of the 2015 and 2016 seasons, a decreasein theδ13CVPDBvalues for carbohydrates of grapes and ethanol of wine, which is explained by the changedclimatic conditions of grapes growing in the vegetation period of 201