David Garcia*
*Fresno State, 260 6th St, Soledad, CA, 93960 (soledadkd@mail.fresnostate.edu)

Trans-resveratrol is a stilbenoid that is produced when grapevines are attacked by pathogens, under stress, or injured. The health benefits of trans-resveratrol make it a prime target of the cosmetic and medical business sectors. The California grape and wine industry generates a large amount of agricultural waste, some in the form of grape canes. Previous studies found that grape canes can contain notable amounts of trans-resveratrol. Therefore, thousands of dollars’ worth of this high-value compound are potentially being burned or left to dry out in the vineyards each season. A series of Cabernet Sauvignon vineyards in California were investigated for their trans-resveratrol concentrations in grape canes to demonstrate the potential of trans-resveratrol as an additional source of revenue for California grapegrowers. Grape canes were analyzed for trans-resveratrol content under different extraction conditions, and the influence of selected pre-extraction parameters on trans-resveratrol concentrations was investigated, including time of storage, age of vineyard, location, and water stress level. High-performance liquid chromatography analysis found significant differences in trans-resveratrol concentrations from year 1 to year 2 and from the five different locations across California. There were also significant differences in trans-resveratrol concentrations at different ethanol extraction rates. To further investigate the suitability of the material to be used as fertilizer, a combustion analyzer was employed to determine the content of carbon and nitrogen in the grape canes before and after extraction. A microwave-induced atomic emission spectrometer was used to analyze the drought stress markers calcium, magnesium, sodium, and potassium in the grape canes. Overall, the market analysis demonstrated a high demand for the anti-oxidant compound trans-resveratrol which, supported by the laboratory analysis, indicates the potential for significant additional revenue for California grapegrowers.

Funding Support: None