David Garcia, Qun Sun,* Sonet Van Zyl, Qiao-Hong Chen, Stella Sommer
*California State University, Fresno, 2360 E Barstow Ave, M/S VR89, Fresno, CA, 93740 (qsun@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 much agricultural waste, some in the form of grape canes, which can contain notable amounts of trans-resveratrol. Thousands of dollars’ worth of this high-value compound are potentially being burned or left to dry in the vineyards each season. In this work, a series of Cabernet Sauvignon vineyards in Cal­ifornia were investigated for the first time for their trans-resveratrol concentrations in grape canes in the 2021 and 2022 growing season. The purpose of this project was to analyze trans-resveratrol in grape canes with different forms of extraction techniques. The influence of selected pre-extraction parameters on resveratrol concentrations were also investigated; for example, time of storage, age of vineyard, location, and water stress levels. Specifically, we intend to use the results from high-performance liquid chromatography (HPLC) analysis to determine resveratrol concentration. A microwave-induced atomic emission spectrometer (MP-AES) was used to analyze the drought stress markers calcium, magnesium, sodium, and potassium in the grape canes and a combustion analyzer was employed to determine the content of carbon and nitrogen in the grape canes before and after extraction, which gives an indication of the suitability of the waste material to be used as fertilizer.

Funding Support: Qun Sun & PLD Marketing