Enzymatic enhancement of the free monoterpenol content of a Portuguese wine from a single, native grape variety; ?Trajadura?

Abstract

Three important monoterpene aroma releasing activities contained in an Aspergillus niger preparation were investigated for effects of pH, alcohol, Se, temperature and concentration of glucose. Application of the enzyme preparation during microvinification or wine maturation of a Portuguese white wine from "Trajadura" grapes, increased monoterpene content roughly 2-fold and 3-fold respectively . ABBREVIATIONS a-L-mf -a:L-arabinofuranosidase ; a-L-rhap -a-L-rhamnopyranosidase ; #%D-glup -& Dglucopyranosidase ; pnp -p-nitrophenyl.

Aroma Changes during Black Currant (Ribes nigrum L.) Nectar Processing

“…It might be expected that terpenoids would be liberated from their glucoside precursors by the action of β-glucosidase during the enzyme treatment, but this reaction does not occur in black currant nectar. The explanation is that β-glucosidase activity is totally inhibited by the glucose and fructose from the berries (Canal-Llauberes, 1993;Rogerson, 1995).…”

Flavour enhancement through the enzymatic hydrolysis of glycosidic aroma precursors in juices and wine beverages: a review

“…[6][7][8][9] Acid hydrolysis occurs quite slowly in winemaking conditions and is closely dependent on the pH, temperature and structure of the aglycone moiety. Glycosides also may be hydrolysed by the action of β-glucoside glucohydrolases, commonly known as β-glucosidases.…”

β-Glucosidase from the Grape Native YeastDebaryomyces vanrijiae: Purification, Characterization, and Its Effect on Monoterpene Content of a Muscat Grape Juice

“…Beside volatile aroma compounds, grape berries and several fruits contain different aroma precursors. Among them, glycosidic precursors represent an important aroma source (Gunata et al, 1985;Bayonove et al, 1992;Rogerson et al, 1995;Winterhalter and Skouruomounis, 1997). Indeed a main proportion of potent flavorants, monoterpenes, shikimate-derived compounds, and C 13 -norisoprenoids in grapes is linked to the sugars consisting of β-D-glucosides or diglycosides (Williams et al, 1982;Voirin et al 1992;Gunata et al, 1985;Baumes et al, 1994).…”