Pectinesterase and polygalacturonase in changes of pectic matter in olives (cv. Hojiblanca) intended for milling

Abstract

AbstractVirgin olive oil is a highly valued product, and it is important to optimize extraction yield. The pectic composition and the related enzymatic activities, present in the raw material, are variables that may affect that process. The pectinolytic activities producing modifications in the pectic matter of olive fruits (variety Hojiblanca) during ripening and the associated changes in texture were studied. Pectinesterase (PE) activity increased with ripeness until reaching a peak when anthocyanin synthesis in the fruit became marked (turning color stage). From then on, it decreased. In contrast, polygalacturonase (PG) activity in the ripe‐green fruit decreased sharply when anthocyanin formation began (small reddish spots stage) and then increased, reaching a maximum in the ripe‐black fruit. Parallel changes were noted in the texture and pectic content of the olives, related to endo‐ and exo‐PG enzymatic activities, together with a decrease in the degree of esterification of the pectic matter, which could be associated with PE action. The distribution of the pectic fractions in the raw material and the changes in them during the olive oil extraction process showed the role of PE and PG in the fruits that was related to the yield of extracted oil.