Gluconic acid as a tool for quality management in grapes
Abstract
The concentration of gluconic acid can be used as an indicator of ripeness and sanity of grapes. Grapes attacked by rotting produce musts with gluconic acid contents above 0.5 g L–¹. The objective of this study was to evaluate gluconic acid as a quality indicator of grape musts from the region of Campanha Gaúcha. In 2017 harvest, white grape musts presented lower levels of gluconic acid (mean 0.31 g L–¹) when compared to red grape musts (0.67 g L–¹). In some samples of white grapes such as Chardonnay and Sauvignon Blanc, gluconic acid was not detected. In contrast, ‘Pinotage’ red grape presented concentration of up to 3.4 g L–¹ gluconic acid. These results may be related to the subtropical climate, which favors the appearance of rot. Harvesting of white varieties is prior to red grapes, usually at the beginning of February, when accumulated rainfall did not exceed 40 mm, making it difficult to produce rot. For red grapes, harvested in March, the humidity may have favored the incidence of rot, since the accumulated rainfall exceeded 160 mm. The quantitation of gluconic acid is an important tool for monitoring grape maturation and sanity and can be determined quickly and efficiently by Fourier transform infrared spectroscopy.
Issue: GiESCO 2017
Type: Extended abstract
Format: Poster
Authors
1 Universidade Federal do Pampa, 21 de abril, 80, Dom Pedrito, Brasil
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Keywords
rot, grape sanity, Botrytis cinerea