ISSN:
1431-4630
Keywords:
Key words Adulteration
;
Carbon-13
;
Citric acid
;
Ethanol
;
Malic acid
;
Tartaric acid
Source:
Springer Online Journal Archives 1860-2000
Topics:
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract The δ13C-values of organic acids and their correlations to those of the sugar and ethanol, respectively, from 57 EU data bank wines of the Rheinpfalz area (years 1991 – 1993) and from some of their corresponding musts have been determined. In addition to the well established difference between fermented sugar and ethanol (Δδ13C = –1.7±0.2‰), a new constant correlation was found in wine for ethanol and citric acid (Δδ13C = +2.4±0.4‰). From this result a fixed δ-value difference for citric acid in wine to the fermented sugar of +0.7±0.6‰ can be deduced. The δ13C-values of L-malic acid and L-tartaric acid in must were not altered by the alcoholic fermentation; they should therefore directly provide access to the δ13C-value of the natural sugar in must. However, in non-adulterated wines the expected δ13C-value differences between these acids and ethanol showed unsatisfactory correlation coefficients. For L-malate this is attributed to the secondary (partial) degradation of this acid by the malolactic fermentation; a corresponding correction is envisaged in order to make L-malate available as an internal standard. As a reason for the unsatisfactory correlation between L-tartaric acid and ethanol, it is supposed that the time of its maximum biosynthesis period does not coincide with that of glucose in the grape ripening period.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002170050145
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