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Extra-virgin olive oil is basically used in food, but it can also be used as a source of high added-value components, such as oleocanthal and oleacein. Oleocanthal and oleacein are bioactive compounds with proven activities in the treatment of various diseases. By applying response surface methodology, oils of the Arbequina, Arbosana, and Koroneiki cultivars of super-intensive olive trees have been elaborated, under both irrigation and rainfed conditions. 289 oils have been obtained and 13 parameters per oil determined, which have been grouped into 221 models, that determine extraction performance, quality, and minor components of oils. The maximum extractable olive oil with the current technology is 89.0 ± 3.9%, with the rest remaining in the pomace. Oleacein is the component that most influences the antioxidant capacity of oils; its activity is 5.85 ± 0.33 µmol Trolox/mg. Irrigated Arbequina produces very aromatic oils. Rainfed Arbequina produces less aromatic (18.5 mg/kg of volatile) but with a higher content of phenolic compounds (514.4 mg/kg) oils. Koroneiki produces oils with a very high content of phenolic compounds but low in volatiles. For Koroneiki, the factors that maximize phenolic compounds are: rainfed crops, mill with 4.5 mm sieve, and malaxation at 40 °C for 30 min (1307.2 mg/kg of phenolic compounds, witch 500.0 mg/kg of oleacein, and 174.3 mg/kg of oleocanthal). A method to extract oleocanthal and oleacein from olive oils is proposed, as a way to develop new strategies to improve their functional properties.

In oil milling, in order to obtain high-quality oils without reducing the industrial yield, to the use of coadjuvants with a physical action and adequate operating conditions is necessary. The aim of this study was to evaluate the influence of talc addition during the malaxation stage in an oil mill on the resulting oil. Moreover, the oil obtained by talc treatment can be classified as extra virgin olive oil as this coadjuvant has a physical action. Talc increases the extraction efficacy by up to 2.35%, but retains 26.2% of its weight in oil; therefore, it is disadvantageous to use a dose higher than 0.75%. The volatile compound contents were increased in trials using lower doses of talc. In contrast, the quantity of the phenolic compounds was increased in trials using higher talc doses. In low doses, talc does not influence the content of antioxidants and volatile compounds.

The aim of this work is to obtain a balanced commercial virgin olive oil (VOO) using response surface methodology at an industrial level under continuous working conditions. Thus, a factorial design was developed with three factors: sieve size of the hammer mill, temperature, and malaxing time. Forty different responses were modulated, including extraction efficiency, but with special attention to phenolic and volatile compounds because they are responsible for the taste and aroma of VOO. The conditions for malaxing were 22 and 32 °C for 60 and 120 min using 5 and 6 mm sieve sizes. After modeling the responses, the highest extraction efficiency was obtained at 32 °C and 120 min; similar conditions were necessary to obtain the maximum contents of chlorophyll, carotenoid, and phenolic compounds, but the maximum content of volatile compounds was obtained at 22 °C. Therefore, it has also realized a combined optimization of total phenolics and total volatiles.

Three complete 23 factorial designs were developed in order to evaluate the effect of three physical acting coadjuvants on the extraction of virgin olive oil: talc, calcium carbonate and silica. Ranges of operating conditions were 0–2 % (w/w) for dosage of the coadjuvant, 20–60 °C for temperature and 20–60 min for time. Mathematical models and statistical analysis (ANOVA) were performed to evaluate the effects of these coadjuvants on oil yield, quality of virgin olive oil (acidity, peroxide index and UV absorption at 270 and 232 nm), natural pigments (chlorophylls and carotenoids) and natural antioxidants. In all cases, the oils obtained with coadjuvants were the same quality of those from non-treated olive paste. Therefore, all of them are producing a physical action. While improved oil extraction yields were achieved by using talc and calcium carbonate (1.1 and 1.0 kg oil per 100 kg olives), the use of silica resulted in an oil yield reduction (1.3 kg/100 kg olives). Concerning natural pigments and antioxidants, none of the studied coadjuvants modified the pigment content while that of the antioxidants increased slightly. All oils obtained with coadjuvants showed higher contents of polyphenols and tocopherols, which indicates increasing quality and nutraceutical level.

Industrial scale experiments were performed in an olive oil production factory to assess the effect of different physical acting coadjuvants on oil extraction and oil quality. Up to 120,000 kg olives were processed. Talc and calcium carbonate, with different particle sizes, were assayed at concentrations ranging from 0.3% to 1% by weight. Both coadjuvant types are food grade and are recognized as food additives by EU regulations (E-170 as calcium carbonate and E-553b as talc). Industrial trials were performed at room temperature with no added water, thus avoiding volatile compound loss and hydrosoluble compound content decrease. As a consequence, the obtained oils were more aromatic and their positive attributes more intense, in comparison to other olive oils produced in different operational conditions. In addition, energy requirements were decreased (releasing a lesser amount of carbon dioxide into the atmosphere) and water uptake was kept to a minimum. Results show that the use of coadjuvants improves the oil extraction yield. The extraction efficacy, defined as the percentage of initial oil that is extracted, increased by 2% by using carbonate in comparison to experiments performed without any coadjuvant, with 91.53% of oil content in the olives being extracted. For the same particle size, calcium carbonate was found to extract a greater oil amount than talc. For a single coadjuvant, the extraction yield decreased as the particle size increased. The best results, in terms of oil extraction yield, were obtained when using 0.3% calcium carbonate. Considering oil quality, no influence by either coadjuvant was detected as oil components remained unaltered during the extraction process. The sensorial evaluation gave the same result for all olive oils, no matter if a coadjuvant was used or not, indicating that these compounds only act physically on the oil extraction process.