摘要：This paper focuses on the difference between the effect of heating and reheating on sunflower oil properties by using carbon dioxide laser and electrical heater. Two samples of sunflower oil were heated and reheated with carbon dioxide laser beaming up to 50°C, which takes 30 minutes; another two samples were heated and reheated up to 250°C using electrical heater in two minutes, along with an unheated control sample at ambient conditions. Chemical properties like acid value, free fatty acids, peroxide value, saponification value and ester value beside physical properties such as moisture, density, viscosity, refractive index and color measurements of sunflower oil were studied. Fourier transform infrared spectroscopy was used to differentiate between the chemical changes in the samples. The results demonstrate that when the same cooking oil is reheated, the chemical reactions enhance foaming, darkening of oil color, increased viscosity, and off-flavor. Hence, repeated heating of the oil can lead to degradation of the cooking oil, both chemically and physically. It was found that the long time of heating using laser rising temperature up to 50°C catalyzed chemical reactions that resulted in effects in the oil samples characteristics greater than the effects of the electrical heater in a few minutes with temperature 250°C.
