Improving olive oil quality using CO2 evolved from olive pastes during processing

University of Florence, Florens, Tuscany, Italy
European Journal of Lipid Science and Technology (Impact Factor: 1.81). 11/2006; 108(11):904 - 912. DOI: 10.1002/ejlt.200600182


The effect of blanketing with CO2, naturally evolved during malaxation of olive pastes, on the quality of virgin olive oil was investigated at lab-scale. The O2 depletion was monitored along with CO2 emission to confirm the previously hypothesized accelerated respiration. Malaxation experiments were conducted for 180 min both in sealed (SC) and in the traditional open-to-air conditions to ascertain whether the oil quality was affected by O2 concentration as afforded by CO2 blanketing. The quality of olive oils obtained at different time intervals was monitored by total acidity, peroxide value (PV), specific extinction coefficients K232 and K270, total chlorophyll and total hydrophilic phenols, and HPLC hydrophilic phenols profile. A rapid decrease in oxygen concentration and a simultaneous increase in CO2 concentration were recorded, confirming the accelerated respiration. The oil produced in SC showed a lower PV and K232 coefficient and a higher chlorophyll (10–17 mg/kg) and hydrophilic phenols (110 mg/kg) concentration. No differences in total acidity and K270 coefficient were observed. The hydrophilic phenols profile indicated that, at least for the Frantoio cultivar and an advanced ripeness state, the maximal extraction is generally achieved already after 20 min. Most of the individual hydrophilic phenols have higher concentrations (up to 50%) in SC.

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    • "In the reality, the malaxation under inert gas is not widely widespread due to the high cost of nitrogen and argon that cannot be ignored (Clodoveo, 2013a). In fact, in order to address this problem, Parenti et al. (2006) suggested to profit by the phenomenon of CO2 emission coupled with the O2 depletion during malaxation under sealed conditions. The last evolution is represented by malaxer equipped with sensors, which are able to measure the temperature of the olive paste and the oxygen concentration in the headspace and inside the olive paste (Amirante et al., 2008; Amirante et al., 2012a). "
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    ABSTRACT: The sensory and health properties of virgin olive oil (VOO) are highly related to its volatile and phenolic composition. Oxygen control in the pastes during malaxation may be a new technological parameter to regulate enzymatic activities, such as polyphenoloxidase, peroxidase, and lipoxygenase, which affect the phenolic and volatile composition of VOO. In this work, we monitored CO2 and O2 concentrations during industrial-scale olive paste malaxation with various initial O2 concentrations within the malaxer headspace. Results show that the O2 concentration in the malaxer headspace did not affect CO2 production during processing, whereas a strong influence was observed on the changes of the phenolic composition of olive pastes and VOOs, with high correlation coefficient for the total phenols (R = 0.94), especially for oleuropein and demethyloleuropein derivatives (R = 0.81). In contrast, aroma production during malaxation was minimally affected by the O2 concentration in the malaxer headspace.
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