title: Effect of zinc formulations, sodium chloride, and hydroxytyrosol on the growth/no-growth boundaries of table olive related yeasts.
abstract: This study uses a mathematical approach to assessing the inhibitory effect of Zn(2)(+)(0-10 mM, obtained from ZnCl2 and ZnSO4) in presence of NaCl (0-8%) and hydroxytyrosol (0-2588 mg/L), on a yeast cocktail formed by species Pichia galeiformis, Pichia kudriavzevii, Pichia manshurica and Candida thaimueangensis obtained from spoilt green olive packages. The logistic/probabilistic models were built in laboratory medium using a total of 1980 responses (1188 for NaCl and 792 for hydroxytyrosol). ZnCl2 showed significantly higher inhibitory effect than ZnSO4 in the presence of both NaCl (p < 0.033) and hydroxytyrosol (p < 0.009). NaCl did not interfere the effect of Zn(2)(+)while hydroxytyrosol, at high levels, had a slight antagonistic effect. According to models, Zn(2)(+)inhibits (p = 0.01) the yeast cocktail in the range 4.5-5.0 mM for ZnCl2, or 8.5-9.5 mM for ZnSO4. Therefore, this work confirms the fungicidal activity of zinc compounds (mainly ZnCl2) in synthetic medium, and also shows that the loss of zinc effectiveness in real green Spanish-style olive packaging is not due to the presence of NaCl or hydroxytyrosol, two of the most abundant chemical compounds in the product.
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (Agencia Estatal Consejo Superior de Investigaciones Científicas, CSIC), Campus Universitario Pablo de Olavide, Building 46, Ctra. Utrera, km 1, 41013 Seville, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Romero-Gil
authors.affiliation: AgroSevilla SCA, Paseo de Castellmadama s/n, 41590 La Roda de Andalucia, Seville, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Rejano-Zapata
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (Agencia Estatal Consejo Superior de Investigaciones Científicas, CSIC), Campus Universitario Pablo de Olavide, Building 46, Ctra. Utrera, km 1, 41013 Seville, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Garrido-Fernández
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (Agencia Estatal Consejo Superior de Investigaciones Científicas, CSIC), Campus Universitario Pablo de Olavide, Building 46, Ctra. Utrera, km 1, 41013 Seville, Spain. Electronic address: fnarroyo@cica.es.
authors.forename: F N
authors.initials: FN
authors.lastname: Arroyo-López
mesh_terms: D002175:Candida / Q000187:drug effects* / Q000254:growth & development; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D031658:Olea / Q000382:microbiology*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000494:pharmacology; D010843:Pichia / Q000187:drug effects* / Q000254:growth & development; D012965:Sodium Chloride / Q000494:pharmacology*; D015032:Zinc / Q000737:chemistry / Q000494:pharmacology*
chemical_list: C005975:3,4-dihydroxyphenylethanol; D012965:Sodium Chloride; D015032:Zinc; D010626:Phenylethyl Alcohol
keywords: Growth/no-growth interfaces; Hydroxytyrosol; Logistic regression; NaCl; Preservatives; Zinc interaction