Improvement of phenolic compound content in virgin olive oils by using enzymes during malaxation

The effect of enzyme addition to the olive paste on the phenolic compositio n of virgin olive oil has been studied. The experiments were carried out wi th both Picual and Arbequina cultivars, using the continuous two-phase extr action system at industrial scale and for three consecutive seasons. Phenol ic compounds, in particular orthodiphenols, increased their concentration i n oils when enzymes were added to the olive paste before the malaxation sta ge. Among non-orthodiphenols, the lignans 1-acetoxypinoresinol and pinoresi nol slightly increased their concentration. In general, the positive effect of enzymes was more marked for Arbequina than for the Picual cultivar. The peroxide index and "Rancimat" stability of oils were also positively affec ted when using enzymes. Besides, wash waters from the vertical centrifuge s howed a higher concentration of phenolics when the pastes were treated with enzymes. Therefore, the use of enzymatic formulations during the extractio n process of olive oil may not only increase the oil yield but also the nut ritional quality of the oil. (C) 2001 Elsevier Science Ltd. All rights rese rved.