Mechanisms
of Degradation of the Natural High-Potency
Sweetener (2<i>R</i>,4<i>R</i>)‑Monatin
in Mock Beverage Solutions
- Publication date
- Publisher
Abstract
The
sodium, potassium, or mixed sodium/potassium salt of the naturally
occurring high-potency sweetener (2<i>R</i>,4<i>R</i>)-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 (<sup>1</sup>O<sub>2</sub>), free radicals, and
peroxides (both H<sub>2</sub>O<sub>2</sub> 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 <sup>1</sup>O<sub>2</sub> support the proposed
photodegradation pathways
