title: Reduction of oil bitterness by heating of olive (Olea europaea) fruits.
abstract: Olives (Olea europaea) of the Manzanilla and Verdial varieties, harvested at the green mature stage of ripening, were heated at 30, 40, 45, and 50 degrees C during 24 h and at 40 degrees C during 24, 48, and 72 h, respectively. Just after treatments, oils were physically extracted from the olives. Olive heating promotes a reduction of oil bitterness in direct relationship to the time and temperature used. Fruit heating at < or =40 degrees C during 24 h did not produce significant changes of acidity, UV absorption, peroxide index, panel test score, or oxidative stability of the obtained oils. Both longer treatments at 40 degrees C and heating at >40 degrees C yielded oils with less oxidative stability. Oils obtained from olives heated at > or =40 degrees C showed higher concentrations of chlorophylls and carotenes. For each olive variety, a good correlation between oil bitterness and content of hydroxytyrosol secoiridoid derivatives was found.
authors.affiliation: Instituto de la Grasa (CSIC), Departamento de Fisiología y Tecnología de Productos Vegetales, Avenida Padre García Tejero 4, 41012 Sevilla, Spain. jmgarcia@cica.es
authors.forename: J M
authors.initials: JM
authors.lastname: García
authors.forename: K
authors.initials: K
authors.lastname: Yousfi
authors.forename: R
authors.initials: R
authors.lastname: Mateos
authors.forename: M
authors.initials: M
authors.lastname: Olmo
authors.forename: A
authors.initials: A
authors.lastname: Cert
mesh_terms: D005511:Food Handling / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010938:Plant Oils / Q000737:chemistry*; D013649:Taste; D013696:Temperature; D013997:Time Factors
chemical_list: D000069463:Olive Oil; D010938:Plant Oils