Determination of singlet oxygen quenching rate and mechanism of γ-oryzanol

• Published in: Heliyon Vol. 7; no. 5; p. e07065
• Main Authors: Sari, Yuli Perwita, Santoso, Umar, Supriyadi, Raharjo, Sri
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-05-2021; Elsevier
• Subjects: Nanoemulsion; Photooxidation; Rice bran oil; Singlet oxygen quenching; γ-Oryzanol; Photooxidation; Rice bran oil; Singlet oxygen quenching; Nanoemulsion; γ-Oryzanol
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2021.e07065

Photooxidation is one of the causes of quality deterioration in food. An antioxidant or singlet oxygen quencher is urgently needed to prevent photooxidation. γ-Oryzanol was recognized as a naturally present antioxidant in rice bran products. This research aimed to calculate the singlet oxygen quenching rate and its mechanism of γ-oryzanol to evaluate the potency of γ-oryzanol as singlet oxygen quencher. A series of linoleic acid (50 and 100 mM) or γ-oryzanol (0.7 and 1.5 mM) were prepared separately in ethanol: chloroform (96:4, v/v) containing 25 ppm of erythrosine. High-Performance Liquid Chromatography quantified the degradation of γ-oryzanol. Meanwhile, Gas Chromatography determined the changes in linoleic acid content during photooxidation. The singlet oxygen quenching rate was calculated by steady-state. The singlet oxygen quenching rate of γ-oryzanol was 3.04 × 106/M/s by physical and chemical quenching mechanism. Photooxidation caused the declined of γ-oryzanol by 0.1421 mM/h. Based on singlet oxygen quenching rate calculation, it suggests that γ-oryzanol can perform as a singlet oxygen quencher with slightly dominated by physical quenching mechanism (52.28%). The rest it performed via a chemical quenching mechanism.
Photooxidation, Singlet oxygen quenching, γ-Oryzanol, Rice bran oil, Nanoemulsion.