AROMA OF VIRGIN OLIVE OIL - BIOGENESIS OF THE GREEN ODOR NOTES

The enzymes acylhydrolase, lipoxygenase, and fatty acid hydroperoxide lyase were found in cell-free extract of olive fruit. Triacylglycerols and phospholipids are hydrolyzed to free fatty acid, mainly polyunsat urated, by acylhydrolase. From linoleic and linolenic acids 9- and 13- hydroperoxides were formed by lipoxygenase. The lyase cleaves the 13-h ydroperoxides of linoleic and linolenic acids to form the volatile ald ehydes hexanal and cis-3-hexenal, respectively; the enzyme does not ac t on 9-hydroperoxides of these acids. Incubation of ripe olive fruit t issue disks resulted in biological conversion of hexanal and trans-2-h exenal to corresponding alcohols. Hexyl alcohols were converted to the ir acetate esters during the incubation with olive fruit tissue. A seq uential enzymatic pathway for the formation of green odor compounds in virgin olive oil is proposed.