Effect of the blanching process and olive fruit temperature at milling on the biosynthesis of olive oil aroma

Abstract

Two sets of experiments were performed in order to study the origin of the modification of olive oil aroma during the industrial heat treatment of olive fruit. Data obtained suggest that both blanching of olive fruit and fruit temperature at milling affect the synthesis of volatile compounds, thus contributing independently to the modification of the aroma volatile profile of olive oil reported for the industrial thermal treatments of olive fruit. Increasing the fruit temperature at milling in the range 20–60 °C produces a decrease in the level of C6 and C5 compounds and a slight modification of the contents of esters. Blanching produced a decrease of the content of C5 compounds independently of the degree of fruit ripening, while esters contents remained unaffected. However, blanching showed to have different effects on the content of C6 compounds in the aroma of olive oil depending on the degree of fruit ripening. Biochemical aspects within the lipoxygenase pathway are discussed in order to explain the results obtained.