Lipoxygenase Activities in Ripening Olive Fruit Tissue

Abstract

Extracts of ripening olive fruits (Olea europaea L. cv. Kalamata) ‐were analyzed for the presence of lipoxygenase activity and for the content of phenolic compounds, which are lipoxygenase inhibitors. Two distinct lipoxygenase activities were identified by their pH optima and sensitivity to the inhibitor nordihydroguaiaretic acid (NDGA). Both activities were low during early ripening stages, and increased sharply between 57 and 94 days postanthesis, reaching a plateau at about 120 days. The content of phenolic compounds, mainly oleuropein, changed in the opposite way, suggesting their involvement in the regulation of the two lipoxygenase activities during the olive fruit development. The two lipoxygenase activities could have a role in fruit maturation and senescence.

Virgin Olive Oil Phenols, Fatty Acid Composition and Sensory Profile: Can Cultivar Overpower Environmental and Ripening Effect?

“…Concentration of the C6 and C5 volatile substances decreases with ripening [ 77 ], as result of the enzymes’ activity reduction with ripening, and are highly correlated with fruitiness [ 37 , 78 ]. The development of these substances is associated with the content of PUFA, as they are a substrate of lipoxygenase, while phenolic substances are inhibitors of the same enzymes [ 79 ]. The most probable reason for lower fruitiness in the first harvest periods of Leccino (oils from unripe fruit) ( Figure 4 ), lies in the different activity of the enzymes, the availability of the substrate and the presence of inhibitors.…”

Oil accumulation kinetic along ripening in four olive cultivars varying for fruit size

“…Several works reported oil accumulation during olive ripening phases for cultivars from Spain, Portugal, Greek and Italy [6][7][8][9]. However, these kinds of works deal usually to study fruit changes either for ultrastructure [10], enzyme expression studies such as lipoxygenases [9] or oleosines [8], and compounds accumulation such as phenols [6], triterpenoids [11] and crop load [12]. The common agronomic parameter that varied in most experiments is watering.…”

Pectic polysaccharides are attacked by hydroxyl radicals in ripening fruit: evidence from a fluorescent fingerprinting method

“…chlorophyll loss and membrane permeabilization) occurring in a ripening fruit and in a leaf or petal approaching abscission. Lipoxygenases, which often increase during ripening ( Ealing, 1994 ; de Gregorio et al. , 2000 ), generate hydroperoxide groups (>CH–OOH) in unsaturated fatty acid residues, accompanied by the formation of reactive oxygen species (ROS).…”