Effects of heat-treatments of olive fruit on pigment composition of virgin olive oil

The effects of heat-treatments of olive fruits on olive oil colour were investigated by quantification of the main pigments present in virgin olive oil. Contents of lutein and β-carotene increased as a consequence of heat-treatments. Lutein content increased at least 2.2-fold compared to control olive oil. β-Carotene contents also increased due to heat-treatments although not as much as lutein contents. Chlorophyllic compounds, such as chlorophylls a and b and pheophytins a and b, also increased significantly. Thus, chlorophyll a contents increased in a range of 2.0 to 7.7-fold compared to the amount found in control olive oil, while pheophytin a contents did so over a wider range (1.4 to 17.5-fold). The temperature of fruits when entering the crusher is the only factor responsible for this effect. The involvement of LOX activity in pigment degradation is considered.