Postharvest Heat Treatment for Olive Oil Debittering at the Industrial Scale

To enhance the debittering of olive oil, 500-kg olive fruit (Olea europaea L.) samples in duplicate from different olive cultivars and orchard locations in Spain (Manzanilla olive fruits from Villarrasa during the 2002/2003, 2004/2005 and 2005/2006 seasons, or from Dos Hermanas during the 2004/2005 and 2005/2006 seasons, Picual olive fruits from Cabra during the 2004/2005 season and Verdial olives from Villarrasa during the 2004/2005 and 2005/2006 seasons) were treated by dipping in hot water under different conditions (50–68 °C for 3 or 5 min), which had been previously determined based on laboratory-scale experiments, and subsequently processed for virgin olive oil extraction. Heat treatment produced a change in the intensity of the oil bitterness in all cases, increased the pigment content, decreased stability and reduced the sensory freshness of the oil. Although heat treatment reduced the phenolic content of the oil, this effect was not uniform among the different phenolic compounds and depended on the crop season and olive variety. Therefore, the determination of debittering conditions will require a series of preliminary laboratory-scale experiments.