Use of Natural Microtalcs during the Virgin Olive Oil Production Process to Increase Its Content in Antioxidant Compounds

Abstract

During the olive oil production process, certain olive varieties, such as ‘Hojiblanca’ and ‘Picual’, create pastes from which it is difficult to separate the oil, resulting in low extraction yields. To improve oil extraction, one alternative is the addition of natural microtalcs (NMT). In the present study, a NMT of great purity (CaCO3 concentration less than 6 wt.%) and small average particle size (ϕ ≤ 2.1 µm) was added in the malaxation stage on an industrial scale at two olive mills. In one of them and using ‘Hojiblanca’ olives, the performance of the high-purity NMT was compared with that of a traditional NMT, while in the other, the effect of its dosage in the quality of ‘Picual’ oils was assessed. The performance of the high-purity NMT was evaluated in terms of industrial oil yield, extractability index, quality parameters and oxidative stability of the resulting oils. The addition of the high-purity NMT not only increased the extraction yields but also improved the quality of the virgin olive oils, especially in relation to antioxidant compounds (tocopherols and phenolic compounds). Increases of 10.4% in phenolic compounds and of 21.5% in the tocopherols were found, thus enhancing the oxidative stability of the oils.

Exploring the relevance of the type of horizontal separator to optimize the extraction efficacy for the Arbequina variety

“…Its production is exclusively by physical–mechanical procedures or at least with the addition of specific adjuvants, which often leads to difficulties in reaching a sufficiently good extraction efficiency ( Caponio et al., 2016 ; Khaleghi et al., 2023 ; Tamborrino et al., 2023 ). Although new processing technologies, such as the application of heat exchangers, ultrasound, pulsed electric field, microwaves, and vacuum technology, can improve oil extraction, it is always important to consider the interaction between the characteristics of the olives and the extraction device ( Taticchi et al., 2013 ; Gila et al., 2015 ; Pérez et al., 2021 ; Sánchez et al., 2022 ; Khaleghi et al., 2023 ; Nardella et al., 2023 ).…”