title: Mechanisms of degradation of the natural high-potency sweetener (2R,4R)-monatin in mock beverage solutions.
abstract: The sodium, potassium, or mixed sodium/potassium salt of the naturally occurring high-potency sweetener (2R,4R)-monatin, also known by the common name arruva, degrades over time in model beverage solutions in the presence of light. By use of UHPLC, LC-MS/MS, and peroxide assays, it has been demonstrated that degradation is accelerated by UV/visible light and the presence of trace metal ions. Data are presented that are consistent with a role for singlet oxygen (¹O₂), free radicals, and peroxides (both H₂O₂ and organic peroxides) in monatin oxidation. Separation of degradation products by UHPLC/HPLC or LC-MS/MS provided evidence for the formation of hydroxylated and peroxide species formed on the indole ring (mass increases 16 and 32, respectively) as well as multiple ring and side-chain oxidation and scission products. Model oxidation systems using the photosensitizer Rose Bengal as a source of ¹O₂ support the proposed photodegradation pathways.
authors.affiliation: The Heart Research Institute, 7 Eliza Street, Newtown, New South Wales 2042, Australia.
authors.forename: Corin
authors.initials: C
authors.lastname: Storkey
authors.forename: David I
authors.initials: DI
authors.lastname: Pattison
authors.forename: Dan S
authors.initials: DS
authors.lastname: Gaspard
authors.forename: Erik D
authors.initials: ED
authors.lastname: Hagestuen
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Davies
mesh_terms: D001628:Beverages / Q000032:analysis*; D018698:Glutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D007211:Indoles / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction / Q000528:radiation effects; D010782:Photolysis; D013237:Stereoisomerism; D013549:Sweetening Agents / Q000737:chemistry*
chemical_list: C414924:4-hydroxy-4-(indol-3-ylmethyl)glutamic acid; D007211:Indoles; D013549:Sweetening Agents; D018698:Glutamic Acid