title: Oleuropein hydrolysis in natural green olives: Importance of the endogenous enzymes.
abstract: The bitter taste of olives is mainly caused by the phenolic compound named oleuropein and the mechanism of its hydrolysis during the processing of natural green olives was studied. First, a rapid chemical hydrolysis of oleuropein takes place at a high temperature of 40°C and at a low pH value of 2.8, but the chemical hydrolysis of the bitter compound is slow at the common range of pH for these olives (3.8-4.2). However, decarboxymethyl elenolic acid linked to hydroxytyrosol and hydroxytyrosol have been found in a high concentration during the elaboration of natural green olives. When olives were heated at 90°C for 10min before brining, these compounds are not formed. Hence, the debittering process in natural green olives is due to the activity of β-glucosidase and esterase during the first months of storage and then a slow chemical hydrolysis of oleuropein happens throughout storage time.
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (IG-CSIC), Universidad Pablo de Olavide - Edificio 46, Ctra. de Utrera, km. 1, 41013 Seville, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Ramírez
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (IG-CSIC), Universidad Pablo de Olavide - Edificio 46, Ctra. de Utrera, km. 1, 41013 Seville, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Brenes
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (IG-CSIC), Universidad Pablo de Olavide - Edificio 46, Ctra. de Utrera, km. 1, 41013 Seville, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: García
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (IG-CSIC), Universidad Pablo de Olavide - Edificio 46, Ctra. de Utrera, km. 1, 41013 Seville, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Medina
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (IG-CSIC), Universidad Pablo de Olavide - Edificio 46, Ctra. de Utrera, km. 1, 41013 Seville, Spain. Electronic address: crb@cica.es.
authors.forename: Concepción
authors.initials: C
authors.lastname: Romero
mesh_terms: D004950:Esterases / Q000378:metabolism; D005511:Food Handling; D061353:Food Storage; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D057888:Iridoid Glucosides; D039823:Iridoids / Q000032:analysis*; D031658:Olea / Q000737:chemistry*; D010636:Phenols / Q000032:analysis; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives / Q000032:analysis; D011714:Pyrans / Q000032:analysis; D012492:Salts / Q000032:analysis; D013649:Taste; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D057888:Iridoid Glucosides; D039823:Iridoids; D010636:Phenols; D011714:Pyrans; D012492:Salts; C017082:brine; C005975:3,4-dihydroxyphenylethanol; C002769:oleuropein; C000352:elenolic acid; D004950:Esterases; D001617:beta-Glucosidase; D010626:Phenylethyl Alcohol
keywords: Chemical hydrolysis; Enzymatic hydrolysis; Natural table olives; Oleuropein