Monovarietal olive oils fortified with carotenoids: Physicochemical and sensory trends and taste sensor evaluation

Abstract

This study evaluated the effects of lutein or -carotene incorporation (0.1mg/ml) on the quality, sensory attributes and stability of Arbequina, Picual or Royal monovarietal extra virgin olive oils. The fortification significantly decreased (p value<0.05) the chemical quality of the fortified oils (peroxide values: +3% to +34%; extinction coefficients: +4% to +55%). The negative impact was higher on Arbequina oil, followed by Royal and Picual oils, especially in lutein fortified oils. Nevertheless, all fortified oils fulfilled the legal thresholds required by extra virgin category. Compared with the unfortified ones, fortified oils showed significantly lower (p value<0.05) stability and total phenol content (6% and 12%, respectively). The fortification changed the oils' green color into a yellowish-orange color. Bitterness, pungency and sweetness varied significantly (p value<0.05) with the type of monovarietal olive oil. Bitter and pungent intensities increased in Arbequina and Picual fortified oils (+29% to +191%, especially for the former) and decreased in Royal fortified oils (42% and 62%, respectively). The fortification increased the sweetness of Picual and Royal oils (+109% and +10%), but decreased in Arbequina oils (74%). The physicochemical-sensory changes induced by the fortification allowed a clear differentiation of the monovarietal oils and, for each oil cultivar, by fortification agent. The use of an electronic tongue further confirmed the fortification impact at the phenolic and sensory levels, allowing the discrimination of unfortified and fortified oils and the quantification of oils' bitterness, pungency or sweetness and, in a less extent, the total phenols contents.