Biosynthesis of flavour compounds in Muscat Gordo Blanco grape berries

Abstract

Inflorescences of the floral grapevine cv Muscat Gordo Blanco (syn. Muscat of Alexandria) were grown on their own shoots until maturity or, after approach-grafting before flowering, on the shoots of the non-floral cv Shiraz (in the glasshouse) or Sultana (in the field). The flavour compounds of their berries were compared with those in the berries of the non-floral cultivars, grown either on their own shoots or, by grafting, on the shoots of the Muscat cultivar. For this, monoterpene glycosides were isolated from the fruits, enzymatically hydrolysed and the released monoterpene aglycons were liquid-liquid extracted and analysed by GC-MS. The Muscat Gordo Blanco berries of ungrafted bunches and of bunches grafted onto Shiraz or Sultana vines yielded fruit with monoterpenes at levels and types typical of this floral grape variety. The berries of Shiraz and Sultana bunches contained only low levels of monoterpene glycosides both on their own shoots or grafted onto Muscat shoots. The lack of difference between flavour compounds in grafted and nongrafted fruit indicate that aroma compounds are synthesised in the berries and that their presence is determined by the genotype of the grape bunch rather than by the genotype of the vine.

Effect of postharvest temperature on the muscat flavor and aroma volatile content in the berries of ‘Shine Muscat’ (Vitis labruscana Baily×V. vinifera L.)

“…Thus, there is a possibility that postharvest temperature may affect the hydrolysis of bound forms of linalool; as a result, the linalool content differed among the storage temperature. In addition, the content increased after the grapes were transferred from 0 C to 10 C. Alternatively, postharvest temperature may affect the biosynthesis of linalool, as recent studies have reported that the biosynthesis of linalool takes place in both the skin and the flesh of berries (Gholami et al, 1995;Luan and Wüst, 2002).…”

Origins of Grape and Wine Aroma. Part 1. Chemical Components and Viticultural Impacts

“…This is of particular interest since all anthocyanin glycosides are found as monoglycosides in V. vinifera (Ribéreau-Gayon 1974), suggesting that aroma compound glycosylation occurs via specific pathways separate from those which glycosylate anthocyanins. In addition, glycoconjugated terpenes and norisoprenoids in the grape are synthesized independently of those produced in the leaves in Shiraz and Muscat of Alexandria (Gholami et al 1995, Günata et al 2002, indicating that glycosylated aroma precursors are synthesized de novo and not translocated to the fruit from other plant tissues.…”

Glycosidically Bound Volatile Aroma Compounds in Grapes and Wine: A Review

“…To test the theory of glycoside translocation, Gholami and colleagues studied two grape varieties, a terpenic variety, Muscat of Alexandria, and a non-terpenic variety, Syrah (Gholami et al 1995). Muscat inflorescence clusters were grafted to Syrah vines and vice versa.…”