Sugar Adulterations Control in Concentrated Rectified Grape Musts by Finite Mixture Distribution Analysis of themyo- andscyllo-Inositol Content and the D/H Methyl Ratio of Fermentative Ethanol

Adulterations detection in concentrated rectified musts (CRM) could be strengthened by either making acceptance criteria capable of better reflecting the features of genuine samples or employing additional tracers suitable to ascertain the addition of exogenous sugars. In fact, thanks to their purity, CRM are an ideal substrate for adulterations with sugars of plants other than grape, in particular beet sucrose, able to emulate genuine samples. The present work shows that, moving from well-established standard methods like isotopic analysis of D/H and 13 C/ 12 C ratios and presence determination of myo -inositol, a better definition of genuineness characteristics could be achieved through a multivariate approach integrated with the measurements of myo -inositol and its isomer scyllo -inositol. The separation between adulterated and genuine samples has been obtained by implementing a multivariate version of the expectation−maximization (EM) algorithm, and the estimates have been later used to derive a classification rule based on generalized Mahalanobis distances. In this way it has been possible to highlight the effects of adulterations, in particular the dilution of polyalcohols, and the shortcomings of the present regulations. As a consequence, especially to solve the intermediate cases where attribution is normally difficult, we suggest a narrowing of the acceptance region by a true multiparametric approach integrated with scyllo -inositol.