Kinetic and thermodynamic studies of tocored thermal degradation in lipid systems with various degrees of unsaturation. (15th April 2022)

• Record Type: Journal Article
• Authors: Zheng, Liyou; Guo, Hongyan; Xie, Liangliang; Korma, Sameh A.; Jin, Jun; Jin, Qingzhe; Cacciotti, Ilaria
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 160(2022)
• Publication Date: 2022-04-15
• Subjects: Tocopherol ortho-quinone -- Redshift -- Rancimat -- Degradation kinetics -- Thermodynamic analysis; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2022.113230
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: γ-Tocopherol-5, 6-quinone (tocored) is a crucial minor component of edible oils. It has been certified to endow oils with an orange-red color and antioxidant activity. The tocored performance in lipid systems when exposed to heat should be investigated. Thus, the kinetics and thermodynamics of tocored degradation in lipid systems with various degrees of unsaturation (methyl palmitate, MP; methyl oleate, MO; and methyl linoleate, ML) were studied over a temperature range of 90–120 °C. Tocored degradation probably followed zero-order kinetics, where the rate constant (3.22–24.59 and 23.18–299.2 mg kg −1 h −1 for MO and ML, respectively) significantly increased with increasing temperature ( p < 0.05). The activation energy ( E a ) values for the tocored degradation in MO and ML were 74.50 and 99.16 kJ mol −1, respectively. Considering the thermodynamic parameters (Δ H ++ >0, Δ S ++ <0, and Δ G ++ >0), the process both in MO and ML was endothermic and nonspontaneous. Above all, the kinetics and thermodynamics data extend the knowledge on the tocored stability in oily systems, which is of vital importance for further oil industrial processing. Graphical abstract: Image 1 Highlights: Tocored could endow oils with orange-red color and antioxidant activity. Solvent effect on the UV/Vis spectra of tocored was initially reported. Tocored thermal-degradation was investigated in lipid systems for the first time. Kinetic and thermodynamic studies on tocored degradation were performed. This study investigated the thermal degradation of tocopherol oxidant products.