Gluconic acid

GLUCONIC ACID

Botrytis can oxidise glucose in grapes to produce gluconic acid. As gluconic acid is not utilised by yeast or bacteria it is sometimes used as an indicator of Botrytis infection. Gluconic acid is present at low levels in musts and in wines derived from a usual harvest at levels not exceeding 200 – 300 mg/L. At elevated levels it can contribute to a sour taste in musts or wine.  Early detection of elevated levels > ~300 mg/L of gluconic acid associated with Botrytis cinerea infection allows for effective screening of grapes pre-harvest, and gives the winemaker the opportunity to determine the most appropriate winemaking strategy.

This method involves determining D-gluconic acid using a commercial enzymatic kit and a Discrete Analyser. The lower limit of reporting for gluconic acid with this method is 50 mg/L and the upper limit is 5,000 mg/L. Results outside these limits will be reported as < 50 mg/L or > 5,000 mg/L. Grape or juice samples can be submitted fresh or frozen, and juice must be submitted in a plastic container.

Prices per analysis
Analysis Per sample (excluding GST) Volume required Target response time
Gluconic acid $50.00 10 mL/50 g 24 hours

For more information please contact AWRI Commercial Services on (08) 8313 6600 or e-mail commercialservices@awri.com.au