Australian table grape quality audit 2015-2016 (TG15502)

What was it all about?

The quality of table grapes can vary substantially early in the season with some grapes being immature and sour due to a low sugar to acid ratio.

To investigate the issue, this project conducted an audit of table grape eating quality in 2015/16 and compared results with the national table grape quality audit in 2014/15.

Weekly sampling of grapes from major retail outlets was conducted in Melbourne over 13 weeks and samples were tested for soluble solids concentration and acidity, as well as visual bunch quality.

The results were pleasing as they showed a substantial improvement from the year before. Overall eating quality of commercial table grape varieties in the domestic market was very good with the majority of fruit meeting consumer expectations for flavour and bunch colour. There were some problems, particularly with Menindee Seedless, early in the season.

To determine when grapes should be harvested to optimise eating quality, the sugar to acid ratio of Menindee Seedless bunches was monitored during the lead up to harvest in four vineyards in Emerald, Queensland.

This study demonstrated that sampling berries from grape bunches over the final four weeks prior to harvest is a simple and effective way to pinpoint maturity.

The research team developed a grower and retailer training package on measuring grape quality to further improve early season grapes in future seasons.