Researchers at the University of California, Davis have developed a solar radiation assessment method for grapes that uses a flavonol profile. This method can be done using either HPLC or through the computer processing of the absorption spectra of a purified flavonol extract via a purification kit.
Sun exposure is a key driver for profitability in grape production, reducing fungal disease incidence and promoting ripening. However, overexposure can result in damage to the fruit. Current methods of determining sun exposure include directly measuring by placing a large amount of radiometers and data loggers across a field, or indirectly measuring by assessing canopy porosity, density, or size. Both methods are labor intensive and often inaccurate; either because sensors are limited or because canopies are dynamic and sun exposure changes over time. Lab methods for the analyses of grapes use HPLC, which is a technology that wineries have limited access to. There is a need for a sun exposure measurement system that is accurate, easily accessible, and cost effective.
Researchers at the University of California, Davis have developed a solar radiation assessment method for grapes that uses a flavonol profile, a group of plant secondary metabolites responsive to UV radiation. Assessing the naturally-occurring flavonol profile provides an accurate determination of accumulated solar radiation received by a specific grape skin. This method can be done using either existing HPLC technology or through the computer processing of the absorption spectra of a purified flavonol extract via a kit utilizing common winery instruments. This assessment can be done at no additional cost if HPLC technology is already available, and the kit is inexpensive. The assessment of sun exposure through this method allows growers to have a reference of how much solar radiation a batch of grapes has received, and establish a cause-effect relationship between the canopy management operations or variability in weather, and the quality of their wines.
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Flavonol, flavonol profile, HPLC, grapes, sun radiation, sun exposure, UV radiation