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.Peer reviewe

Relation Between Oxidative Stability and Composition in Argentinian Olive Oils

The relation between oxidative stability and composition in 58 virgin olive oils from different cultivars and Argentinian regions was studied over four harvest years. The oxidative stability of the oils was assessed using the OSI index (110 °C, 20 L/h air flow). A multiple linear regression model is proposed using OSI values as the dependent variable (multiple R = 0.933, p = 1 x 10-15), with positive contributions of the independent variables: fatty acid composition [oleic acid/(linoleic acid ? linolenic acid), 55.3%, p = 1 x 10-15], total polyphenols (24.1%, p = 1.8 x 10-9), carotenes (4.8%, p = 6.1 x 10-5), β-toco- pherol (1.9%, 6.0 x 10-3) and other compounds (13.9%). Highly significant correlation was observed between oxidative stability indexes estimated by the compositional model and those experimentally determined by Rancimat method (b = 0.981, R = 0.924). Chlorophylls and Δ-5- avenasterol contributions to the model were non-significant when variables related with fatty acids and polyphenols were included. The results suggest that the fatty acid composition and the polyphenol content are the main factors that affect the oxidative stability of olive oils. The proposed model allows the estimation of the oxidative stability in olive oils independently of the cultivar. The model was obtained also taking into account samples that lie ossut of the international legal limits in some compositional values due to natural variations.Fil: Ceci, Liliana Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Carelli Albarracin, Amalia Antonia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin