Prediction method for determining the carbon stable isotopic composition of berry sugars in the original must of Chardonnay wines

Carbon stable isotopes of glucose during the degradation of rice by the koji fungus Aspergillus oryzae

“…Although the δ 13 C values of glucose are retained from the ingredient rice throughout saccharification, the resulting sake after SSF exhibits δ 13 C values of glucose that are ∼1 ‰ more positive than that of the ingredient rice [ 25 ]. This discrepancy is roughly half of the carbon isotope discrimination observed during the single fermentation step of winemaking, where grape sugar is converted to ethanol [ [35] , [36] , [37] ]. These results suggest that sake production can be attributed to the combined effects of: (1) the enrichment of the substrate with isotopically more positive glucose arising from kinetic effects during fermentation, and (2) the incorporation of the original glucose due to limited carbon isotope discrimination during saccharification by A. oryzae enzymes, as confirmed by this study.…”

Authentication and Geographical Characterisation of Italian Grape Musts through Glucose and Fructose Carbon Isotopic Ratios Determined by LC-IRMS

“…The correlation between the δ 13 C of grape must sugars and ethanol deriving from its fermentation is reported in the literature [ 26 , 27 ]. Therefore, the data obtained might also be used to build the official isotope data banks, which must be built every year by member countries, as required by European legislation [ 4 ].…”