WINETECH Technical Yearbook 2020

Grape flavan-3-ol evolution under altered light and temperature conditions in Cabernet Sauvignon (PART 1)

SEPTEMBER 2020

ERNA BLANCQUAERT: Department of Viticulture and Oenology, Stellenbosch University, Stellenbosch KEYWORDS: Flavonoids, flavan-3-ol biosynthesis, grape ripening

there are still important research ques­ tions that should be addressed. One such question is about the impact of light quality and quantity in interaction with temperature on berry flavonoid evolution/ biosynthesis at the microclimatic/bunch level. Flavonoids perform major roles in plants, such as pollen fertilisation, auxin transport regulation, pigmentation, de­ fence against pathogens and pests, and protection from ultraviolet (UV) radiation (Blancquaert, 2019). The three main groups of flavonoids identified in red grape berries are flavan-3-ols (tannin), antho­ cyanin and flavonols.

This study aimed to investigate flavan-3-ol biosynthesis under altered microclimatic conditions in Cabernet Sauvignon grown in the Stellenbosch Wine of Origin District. This was part of a larger study in which flavonoid evolution and composition by manipulating the light in the fruit zone were investigated. INTRODUCTION Cabernet Sauvignon is one of the most planted red grape cultivars globally, which is also true for the Stellenbosch Wine of Origin District in South Africa. Despite the importance of this variety for winemaking,

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