Rectified Concentrate Must (RCM) from grapes is a mix of glucose and f
ructose in almost equal proportions. A substantial increase in the pro
portion of fructose with respect to glucose by using enzymes is propos
ed in this work. Glucose is converted enzymatically into gluconic acid
. Soluble glucose-oxidase catalase is used. A 97% fructose sirup is ob
tained. Sweetening power of High Fructose Rectified Concentrate Must (
HFRCM) is 30% higher than regular RCM. Relationship between glucose co
ncentration, enzyme concentration, H2O2 supply and air supply are stud
ied.