Effects of leaf removal and UV-B on flavonoids, amino acids and methoxypyrazine

Abstract

Flavonoids, amino acids and methoxypyrazine levels in grape berries differ in response to leaf removal and UV-B. Flavonoid levels are dependent specifically on UV-B exposure throughout development. Amino acids and methoxypyrazine levels are not influenced by UV-B. However, leaf removal reduces the total amount of amino acids and can alter the relative amino acid composition. Methoxypyrazine levels are highest pre-veraison, but vary between seasons in response to leaf removal. Importantly Brix levels show little overall change under these conditions. The results suggest berry biochemical composition can be manipulated by canopy management and this knowledge could contribute to developing different wine styles.