Thermal Diffusivity Measurements in Edible Oils using Transient Thermal Lens

Abstract

Time resolved thermal lens (TL) spectrometry is applied to the study of the thermal diffusivity of edible oils such as olive, and refined and thermally treated avocado oils. A two laser mismatched-mode experimental configuration was used, with a He-Ne laser as a probe beam and an Ar + laser as the excitation one. The characteristic time constant of the transient thermal lens was obtained by fitting the experimental data to the theoretical expression for a transient thermal lens. The results showed that virgin olive oil has a higher thermal diffusivity than for refined and thermally treated avocado oils. This measured thermal property may contribute to a better understanding of the quality of edible oils, which is very important in the food industry. The thermal diffusivity results for virgin olive oil, obtained from this technique, agree with those reported in the literature.

Thermal Diffusivity of Palm Olein and Compounds Containing β-carotene

“…The experimental values for the parameter θ < 0.3 are emphasized. The thermal diffusivities measured in this work have the same order of magnitude as many other vegetable oils previously measured [7,8,17]. Figure 3 shows the thermal diffusivities as a function of the concentration of β-carotene in the solution with palm olein.…”

“…The best fit of the theoretical function for the LT signal of the laser probe in the photodetector results in a thermal diffusivity D = 11.9× 10 −4 cm 2 · s −1 , which is the same order as other vegetable oils reported in the literature [7,8,17]. An exponential enhancement in the thermal diffusivity was observed when the concentration of β-carotene in the samples was increased.…”

“…The temporal evolution of the on-axis probe beam intensity is measured in the far field using a circular aperture in front of a photodiode. The TL technique has also been used successfully to measure the thermal diffusivity of organic solvents [6], edible commercial oils [7], and biodiesel oils [8].…”

Monitoring the Thermal Parameters of Different Edible Oils by Using Thermal Lens Spectrometry

“…A schematic diagram of the TLS experimental setup and theoretical model for a continuous-wave (CW) laser-induced mode mismatched dual-beam TLS is described in Refs. [2] and [4]. In the dual-beam thermal lens measurements, a sample is placed in a TEM 00 Gaussian laser beam Fig.…”

“…In this paper the authors were focused on optical properties and photochemical reactions studied by thermal lens spectrometry, where the laser power was changed to study the photosensitivity of the samples. Also, in previous research we studied some samples of avocado oils [4]. These samples were subjected to different temperatures in order to study the degradation of this oil by means of their thermal diffusivity.…”