Is pinking susceptibility index a good predictor of white wines pinking phenomena?

Abstract

The concentration of anthocyanins in white wines from different grape varieties (Prosecco, Sauvignon Blanc, Pinot Grey, Chardonnay, Síria) from diverse countries (Italy, Moldova, and Portugal) was determined. Anthocyanins, mainly malvidin-3-O-glucoside, were detected in all wines (from 0.7 to 704 μg/L). No correlation between anthocyanins concentration and the Pinking Susceptibility Index (PSI) was observed contrarily to the colour of wines exposed to oxygen (r = 0.871, p < 0.00005). The oxidation of wines with hydrogen peroxide resulted in the formation of various compounds. PSI was correlated with compounds absorbing in the 400-480 nm region, probably more related to the browning than the pinking phenomenon. The lack of correlation between the PSI and anthocyanins concentration in white wines can be due to the different chemical compositions of white wines that yield various compounds after oxidation that might not be related to the natural wine pinking phenomenon.

Keywords: Anthocyanins; Pinking; Pinking susceptibility index; White wine.