| Pectin depolymerization during fruit ripening has been shown to be largely due to pectinolytic enzymes, including polygalacturonases (E.C. 3.2.1.15) and pectinmethylesterases (E.C. 3.2.1.11). Studies have shown that these enzymes are not the primary determinants of softening, although participation in texture changes during the late stages of ripening seems evident. Pectin depolymerization differs significantly between various fruit types, notably avocado and tomato, even though levels of extractable PG activity in these fruits are similar. Collective evidence indicates that the activities of some cell wall enzymes are restricted in vivo, with maximum hydrolytic potential expressed only in response to tissue disruption or wounding. In contrast, other... |
