The 2011 ASHS Annual Conference

An experiment was conducted to investigate the effect of temperature and Abscisic acid (ABA) on skin anthocyanins in Cabernet Sauvignon grapes in 2009. Berries detached from rachis with intact pedicels were submerged for 10 minutes in ABA solution at 600 ppm for green-soft, pink and red berries at veraison, two weeks prior to harvest. Berries were then placed in plastic bags with small holes, incubated at 10, 20, 30, and 40°C for 4 days, and analyzed for individual anthocyanins, including delphinidin (De), cyanidin (Cy), petunidin (Pt), peonidin (Pn), and malvidin (Mv) -3-glucosides (3-G); -3-acetyle-glucosides (3-A-G); and -3-coumaroyl-glucosides (3-C-G). All the Mv based glucosides comprised 70-75% while all 3-G forms comprised 50-70% of the total anthocyanins. As skin anthocyanins increased during berry ripening, all forms of De, Pt, Pn, and Mv glucosides increased, but all forms of Cy glucosides as well as De-, Pt-, Pn- and Cy-3-C-G were at very low concentration or did not exist. The green-soft and pink berries did not accumulate non Mv based anthocyanins at 10°C after 4 days, either with or without ABA. De-, Pt-, Pn-3-G and Pn-3-A-G reached maximal at 20ºC, Mv-3-G and Mv-3-A-G at 30ºC and Mv-3-C-G at 40ºC with or without ABA. ABA enhanced the accumulation of Mv based anthocyanins at 30 and 40ºC as well as 3-G based anthocyanins at 20, 30 and 40ºC. The research suggests that ABA enhances skin anthocyanins at high temperatures possibly by preventing their degradation. It also demonstrates a greater degradation potential of non Mv based anthocyanins at higher temperatures while all 3-C-G were least affected by and least sensitive to temperatures.

We thank California State University - Agricultural Research Institute, Constellation Wine US, and Valent BioSciences Corporation for funding the research.