The Australian Wine Research Institute’s Analytical Service - Analyses

Other analyses

Diglucosides (hybrids check)

The presence of anthocyanin diglucoside pigments in red or rosé wine, particularly malvidin diglucoside, is used as an indication of whether the wine has been made using fruit other than Vitis vinifera species, which do not contain appreciable quantities of diglucosides. These diglucosides are detected by means of their fluorescence under ultra-voilet light and can also be quantified using HPLC. This analysis is required for all wine that is exported to Europe. The specified limit for the European Union is 15 mg/L, and any wines that are close to this limit using the qualitative method should be quantified using HPLC. Chambourcin which is a hybrid variety has recently been approved by the EU and provides the exception to the rule.

Laccase activity

Wines made from grapes affected by Botrytis cinerea may contain laccase, an enzyme which, due to its relative stability in wine, is capable of causing serious oxidative damage. Knowledge of its presence can lead to corrective action. Laccase results are reported in units/mL. Culley and Eschenbruch (1987) considered that an activity above 3 units/mL was ‘significant’, while the Novo kit instructions indicates that 2 or more units/mL in wines presents a risk of oxidation.

Iland et al. (2000) indicates that for dry white and red table wines, values in the order of 5 to 10 units/mL indicate that it is likely that there will be some influence of laccase activity. Above 10 units/mL, any influence is likely to be more apparent.

Pinking susceptibility

This analysis measures the wines' susceptibility by inducing pinking using hydrogen peroxide and measuring the susceptibility and the precursor content.