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Lipoxygenase activity in olive ( Olea europaea ) fruit
Author(s) -
Salas Joaquín J.,
Willams Mark,
Harwood John L.,
Sánchez Juan
Publication year - 1999
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-999-0090-7
Subject(s) - lipoxygenase , olea , chemistry , linoleic acid , food science , biochemistry , aroma , linolenic acid , ripening , enzyme assay , polyunsaturated fatty acid , fatty acid , enzyme , botany , biology
The present work was designed to characterize lipoxygenase activity in olive fruit pulp, in order to determine its significance in the biosynthesis of virgin olive oil aroma. Lipoxygenase activity has been detected in particulate fractions of enzyme extracts from olive pulp subjected to differential centrifugation. The activity in different membrane fractions showed similar properties, with optimal pH in the range of 5.0–5.5 and a clear specificity for linolenic acid, which was oxidized at a rate double that of linoleic acid under the same reaction conditions. The enzyme preparations displayed very low activity with dilinoleoyl phosphatidylcholine, suggesting that olive lipoxygenase acts on nonesterified fatty acids. The enzyme showed regiospecificity for the Δ‐13‐position of both linoleic and linolenic acid, yielding 75–90% of Δ‐13‐fatty acid hydroperoxides. Olives showed the highest lipoxygenase activity about 15 wk after anthesis, with a steady decrease during the developmental and ripening periods. Olive lipoxygenase displayed properties that support its involvement in the biogenesis of six‐carbon volatile aldehydes, which are major constituents of the aroma of virgin olive oil, during the process of oil extraction.