Comparative Evaluation of Regenerative Capacity of Different Adsorbents and Filters for Degraded Frying Oil

Abstract

The quality of degraded frying oil using Magnasol and Filtrite adsorbents was evaluated. Level of adsorbents (1%, 2% and 3%), treatment duration (2min, 5min and 8min) and temperature (60°C and 160°C) were the processing variables considered. The maximum improvement was up to an extent of 7.0% to 8.8%, 15.2% to 18%, 11.7% to 14.6% and 4.5% to 5.9% for capacitance (C), viscosity (μ), photometric colour index (PCI) and free fatty acids (FFAs), respectively. Specific gravity (γ) and colour parameters (L*, a*, b* and ΔE*) showed no significant difference due to treatments. The interaction of temperature and adsorbent level showed a more pronounced effect. The use of an adsorbent with different filters in a device, used at the food service establishment to filter oil under high-pressure, improved oil quality except for FFAs. The maximum reduction in C, γ, PCI and FFAs varied between 5.1% to 42.6%, 7.4% to 33.3%, 7.8% to 62.7% and 0.5% to 4.4%, respectively, depending upon filtration treatment. Colour parameters and γ were not affected. Polishing of oil by circulating it through the device for up to 30min also provided improvement in γ, C, μ, PCI and FFAs in the ranges of 0.18–0.40%, 19.3–27.2%, 16.0–23.7%, 28.7–42.9% and 1.1–2.2%, respectively. The combination of active and passive filtration systems has good prospects for oil quality improvement.

Keywords

frying oils adsorbents oil quality filtration colour viscosity capacitance

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