Olive oil mixtures. Part one: Decisional trees or how to verify the olive oil percentage in declared blends.

The commercialization of declared blends of olive oil and seed oil is something long approved by the European Union. There, the olive oil percentage must be at least 50% if the producer aims to advertise its presence on the front label, i.e., somewhere other than in the ingredients list. However, the Regulation did not propose any method to verify such proportion. For this purpose, we recommend the use of decisional trees, being the parameters under study those in which the greatest differences between olive and seed oils are shown: triacylglycerols, acyclic saturated hydrocarbons, free sterols, and tocopherols. In this way, to guarantee the presence of olive oil at 50%: i) palmitodiolein must be above 11-15%; ii) the ß/γ-tocopherol ratio must be below 2.4; iii) the alkane sum C21-C25 should be higher than 3.5-6%; and iv) the total sterol content cannot surpass 2400 mg/kg.

LC-MS phenolic profiling combined with multivariate analysis as an approach for the characterization of extra virgin olive oils of four rare Tunisian cultivars during ripening.

In this work, the phenolic composition of four rare cultivars grown under the same agronomical and environmental conditions was studied. This is to test the effects of cultivars and ripening index essentially on phenolic composition in olive oils as well as tocopherols composition, organoleptic profiling and oxidative properties. Furthermore, some agronomical traits were determined in which a general increase in the size of the fruit and oil contents were recorded for all cultivars. The phenolic fractions were identified and quantified using liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS) in multiple reaction monitoring mode (MRM). A total of 13 phenolic compounds belonging to different chemical families were determined. Qualitative and quantitative differences in phenolic composition were observed among cultivars and also among sampling times. On the contrary to the agronomical traits, a general decrease (p<0.05) of total phenolic compounds was observed during maturation. Likewise, a decrease in tocopherols concentrations and oxidative properties was observed.

Olive oil pilot-production assisted by pulsed electric field: impact on extraction yield, chemical parameters and sensory properties.

The impact of the use of pulsed electric field (PEF) technology on Arroniz olive oil production in terms of extraction yield and chemical and sensory quality has been studied at pilot scale in an industrial oil mill. The application of a PEF treatment (2 kV/cm; 11.25 kJ/kg) to the olive paste significantly increased the extraction yield by 13.3%, with respect to a control. Furthermore, olive oil obtained by PEF showed total phenolic content, total phytosterols and total tocopherols significantly higher than control (11.5%, 9.9% and 15.0%, respectively). The use of PEF had no negative effects on general chemical and sensory characteristics of the olive oil, maintaining the highest quality according to EU legal standards (EVOO; extra virgin olive oil). Therefore, PEF could be an appropriate technology to improve olive oil yield and produce EVOO enriched in human-health-related compounds, such as polyphenols, phytosterols and tocopherols.