title: Effects, quenching mechanisms, and kinetics of water soluble compounds in riboflavin photosensitized oxidation of milk.
abstract: To protect the nutrient and flavor stability of milk under light, the effects of 0, 0.01, 0.03, and 0.05 M 1,4-diazabicyclo[2,2,2]octane (DABCO) and 2,5-dimethylfuran (DMF) on the riboflavin photosensitized oxidation of milk were studied. The oxidation of milk was studied by measuring the headspace oxygen in sample bottles after 3 h of light exposure at 3000 lux. As the concentration of DABCO and DMF, which are water soluble compounds, increased in the sample from 0, 0.01, and 0.03 to 0.05 M, the depleted headspace oxygen content significantly decreased (P < 0.05). Steady state kinetic studies of singlet oxygen oxidation showed that the antioxidant activity of DABCO and DMF was due to singlet oxygen quenching. The reaction rate constant of singlet oxygen with milk fat was 8.1 x 10(5) M(-1) s(-1). Total singlet oxygen quenching rates of DABCO and DMF were 1.5 x 10(7) and 2.6 x 10(7) M(-1) s(-1), respectively. DABCO and DMF could be used to slow the reaction between singlet oxygen and milk components to protect nutrients, especially riboflavin, and to improve the oxidative stability of milk fat during storage or processing under light.
authors.affiliation: Department of Food Science and Technology, The Ohio State University, Columbus, 43210, USA.
authors.forename: Dondeena G
authors.initials: DG
authors.lastname: Bradley
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: David B
authors.initials: DB
authors.lastname: Min
mesh_terms: D000818:Animals; D005663:Furans / Q000494:pharmacology; D007700:Kinetics; D008027:Light; D008892:Milk / Q000737:chemistry*; D010084:Oxidation-Reduction; D010879:Piperazines / Q000494:pharmacology; D011837:Radiation-Protective Agents / Q000494:pharmacology; D012256:Riboflavin / Q000737:chemistry / Q000528:radiation effects*; D026082:Singlet Oxygen / Q000737:chemistry; D012995:Solubility; D014867:Water
chemical_list: D005663:Furans; D010879:Piperazines; D011837:Radiation-Protective Agents; D014867:Water; D026082:Singlet Oxygen; C037555:2,5-dimethylfuran; D012256:Riboflavin; C007306:triethylenediamine