The treatment with enzymes causes an increasing of all the substances of juice: total soluble solids, organic acids (measured as total acidity), proteins and polyphenols; in fact pectolytic enzymes are normally used to increase yields of extraction of plant tissues Results agree with literature data reporting that enzymatic hydrolysis of the cell walls increases the reducing sugars, soluble dry matter content, galacturonic acid content and titrable acidity of several fruit juices