Determinação do d13C para avaliar a origem do CO2 de vinhos e espumantes

Abstract

The increasing in sparkling wine production and consumption is visible, many countries are promising to make this product and the Brazil has been highlighted internationally by presenting excellent quality sparkling wine. In this study a method was validated and established to evaluate the CO2 origin from the sparkling wines, through the CO2 δ13C determination, by isotope ratio mass spectrometry, aiming the control adulteration with industrial carbon dioxide (CO2). The δ13C characterization was based in the isotopic difference from the photosynthetic cycles of the plant that originated the product. Five industrial CO2, six carbonated water, 39 still wine (wine without apparent CO2) and 59 commercial sparkling wine were analyzed. Furthermore, an experiment with a Chardonnay base wine was realized to verify the δ13C isotopic variation from the beginning (base wine) and the final (sparkling wine) after the second fermentation. It was observed that the CO2 δ13C is selective for the sparkling wine production method, presenting difference among the traditional, tank and Asti (Moscatel) sparkling wine. Values more negative for CO2 δ13C from industrial CO2 were found, distinguishing the natural CO2 from still wine, allowing establish a limit of control between -25‰ to -20‰ for the Moscatel sparkling. Through the experiment realized, with the wine and sparkling wine from the same grape, could be verified that occurred CO2 δ13C isotopic variation of approximately 45% from the beginning (-22,2‰) to the final (-12,3‰) of the fermentation. With this parameters it was possible to estimate the control limit of -14‰ for the sparkling wine produced by traditional method, values bellow suggest carbonation. Six commercial sparkling wine showed evidence of adulteration, with industrial CO2 addition, and three Moscatéis sparkling presented results out of the highest control limit, in this Moscateis was found the sugar cane addition beyond that permitted by the Brasilian law. Therefore it was concluded that the method is appropriate and accurate for CO2 13C determination and it was possible to establish a method to evaluate the CO2 origin with limits estimates to Moscatéis and sparkling wine elaborated by the traditional method.