EFFECTS OF STEROL BIOSYNTHESIS INHIBITING FUNGICIDES ON THE AROMA OF GRAPE

The effects of two sterol biosynthesis inhibitor (SBI) fungicides, flu silazole and triforine, on the free and bound fractions of the aroma o f Muscat of Alexandria berries were tested over 2 years. Quantitative changes in the composition of the free and bound fractions were observ ed although no significant effect on sugar and acid contents were note d. The results suggest that SBI had no influence on the cytochrome P45 0 hydroxylation of free monoterpenes or related oxidation, but could i nfluence the monoterpene biosynthesis at an earlier step, i.e. during the isomerisation of geranyl pyrophosphate leading to linalool derivat ives. On the other hand, the results obtained on bound monoterpenols s uggest that SBI could also influence the glycosylation pathways in the plant.