Improving olive oil quality using CO ₂ evolved from olive pastes during processing

Abstract

The effect of blanketing with CO 2 , naturally evolved during malaxation of olive pastes, on the quality of virgin olive oil was investigated at lab-scale. The O 2 depletion was monitored along with CO 2 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 O 2 concentration as afforded by CO 2 blanketing. The quality of olive oils obtained at different time intervals was monitored by total acidity, peroxide value (PV), specific extinction coefficients K 232 and K 270 , total chlorophyll and total hydrophilic phenols, and HPLC hydrophilic phenols profile. A rapid decrease in oxygen concentration and a simultaneous increase in CO 2 concentration were recorded, confirming the accelerated respiration. The oil produced in SC showed a lower PV and K 232 coefficient and a higher chlorophyll (10-17 mg/kg) and hydrophilic phenols (110 mg/kg) concentration. No differences in total acidity and K 270 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.

Technological Aspects of Olive Oil Production

“…Furthermore, the natural increase of an inert gas of this respiration catabolite, such as CO2, released during malaxation after the destruction of the olive cell, may be combined with the use of nitrogen or argon to reduce the O2 contact with the olive pastes during malaxation (Parenti et al 2006a(Parenti et al , 2006bServili et al, 2008).…”

“…In fact, if the malaxer is filled with crushed paste during the process, the olive tissues of pastes naturally release carbon dioxide (CO2) (Weichmann, 1987), whereas the limited amount of oxygen they adsorb during the crushing process will be consumed rapidly by endogenous enzyme activities. As a consequence, the malaxer head space will be naturally saturated by an inert gas, such as carbon dioxide (Servili et al, 2003a;Parenti et al, 2006aParenti et al, , 2006bServili et al, 2008).…”

Improving olive oil quality with double protection: Destoning and malaxation in nitrogen atmosphere

“…This favours the reduction of O 2 level in the paste which promotes the hydrophilic phenol content in the olive paste and VOO [4,5]. The concentration of phenolic compounds is strongly affected by several endogenous enzymes present in the olive drupes such as polyphenoloxidase (PPO), peroxidase (POD) and lipoxygenase (LPO) that are activated during processing [6][7][8]. Inhibition of PPO and POD, which catalyze the oxidation of phenolic compounds during malaxation, increases the concentration of hydrophilic phenols in olive paste and VOO [4,5,9,10].…”

The freezing process helps to preserve the quality of extra virgin olive oil over time: A case study up to 18months

“…The phenolic content in EVOOs is, in turn, strongly affected by several factors, such as the cultivar and the ripening stage (Kalua, Allen, Bedgood, Bishop, & Prenzler, 2005), the milling process (Amirante et al, 2002;Salvador, Arand, Gomez-Alonso, & Fregapane, 2003;, the presence of CO 2 during malaxation (Parenti, Spugnoli, Masella, Calamai, & Pantani, 2006), the olive stoning before milling (Mulinacci et al, 2005;Servili et al, 2007). To date, the phenolic compounds are recognized of paramount importance for the EVOOs quality and conservation because of their antioxidant properties (Bendini et al, 2007;Servili et al, 2004).…”