TARTARIC ACID IN FROZEN MUSTS AND WINES - OPTIMIZATION OF REBELEIN METHOD AND VALIDATION BY HPLC

Rebelein's colorimetric method was adapted to determine tartaric acid in thawed samples of frozen musts and wines. The results were compared with those obtained by cation-exchange HPLC. This modification of Reb elein's method involved the elimination of the activated carbon step. Precipitated tartrates in the freezing stage were dissolved by acidifi cation to pH 1.0 before colour reaction development or HPLC analysis. The data obtained agreed with those shown by HPLC, both for model solu tions and for must and wine samples. The method was used to determine the tartaric acid content of thawed samples of frozen must and wines d uring vinification, making sure that the acidification of the samples achieved perfect redissolution of the tartrates.