Robert Cordonnier

Sequential enzymic hydrolysis of potentially aromatic glycosides from grape

Abstract The mechanism of action of α- l -arabinofuranosidase, α- l -rhamnopyranosidase, and β- d -glucopyranosidase on p -nitrophenyl and grape monoterpenyl disaccharide-glycosides has been studied. First, the (1→6) linkage is cleaved by either α- l -arabinofuranosidase or α- l -rhamnosidase, and arabinose, rhamnose, and the corresponding monoterpenyl β- d -glucosides are released. Subsequently, liberation of monoterpenol takes place after action of β- d -glucosidase. The possible use of these glycosidases for the enhancement of the aroma of grape juice and derived beverages is emphasised.

Changes in free and bound fractions of aromatic components in vine leaves during development of muscat grapes

Abstract Some aroma components of the grape Vitis vinifera cv Muscat of Alexandria (free and glycosidically bound terpenols, benzyl and 2-phenyl ethyl alcohols) were studied in vine leaves during the period of development and maturation of the fruit. These components seem to be synthesized in the leaf blade. The leaf stalk was characterized by high levels of terpenols, particularly free ones such as geraniol and citronellol.