title: Investigation into photostability of soybean oils by thermal lens spectroscopy.
abstract: Assessment of photochemical stability is essential for evaluating quality and the shelf life of vegetable oils, which are very important aspects of marketing and human health. Most of conventional methods used to investigate oxidative stability requires long time experimental procedures with high consumption of chemical inputs for the preparation or extraction of sample compounds. In this work we propose a time-resolved thermal lens method to analyze photostability of edible oils by quantitative measurement of photoreaction cross-section. An all-numerical routine is employed to solve a complex theoretical problem involving photochemical reaction, thermal lens effect, and mass diffusion during local laser excitation. The photostability of pure oil and oils with natural and synthetic antioxidants is investigated. The thermal lens results are compared with those obtained by conventional methods, and a complete set of physical properties of the samples is presented.
authors.affiliation: Departamento de Física, Universidade Estadual de Maringá, Maringá, PR 87020-900, Brazil.
authors.forename: E L
authors.initials: EL
authors.lastname: Savi
authors.affiliation: Departamento de Física, Universidade Estadual de Maringá, Maringá, PR 87020-900, Brazil.
authors.forename: L C
authors.initials: LC
authors.lastname: Malacarne
authors.affiliation: Departamento de Física, Universidade Estadual de Maringá, Maringá, PR 87020-900, Brazil.
authors.forename: M L
authors.initials: ML
authors.lastname: Baesso
authors.affiliation: Departamento de Agronomia, Universidade Estadual de Maringá, Maringá, PR 87020-900, Brazil.
authors.forename: P T M
authors.initials: PTM
authors.lastname: Pintro
authors.affiliation: Departamento de Agronomia, Universidade Estadual de Maringá, Maringá, PR 87020-900, Brazil.
authors.forename: C
authors.initials: C
authors.lastname: Croge
authors.affiliation: Energy, Mining and Environment Portfolio, National Research Council Canada, Vancouver, BC V6T-1W5, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Shen
authors.affiliation: Departamento de Física, Universidade Estadual de Maringá, Maringá, PR 87020-900, Brazil. Electronic address: astrathngc@pq.cnpq.br.
authors.forename: N G C
authors.initials: NGC
authors.lastname: Astrath
mesh_terms: D007909:Lenses; D008027:Light; D010084:Oxidation-Reduction; D012815:Signal Processing, Computer-Assisted; D013024:Soybean Oil; D013057:Spectrum Analysis / Q000379:methods*; D013696:Temperature
chemical_list: D013024:Soybean Oil
keywords: Molecular diffusion; Photoreaction; Photostability; Thermal lens