Regeneration of thermally polymerized frying oils with adsorbents

Two thermally polymerized palm oils used continuously for deep-fat frying of legume-based snacks for 30 and 36 h were treated with various adsorbents as such and in binary and quaternary blends, in an attempt to regenerate them. Activated charcoal powder (ACH), aluminum oxide (ALO), aluminum hydroxide (ALH), activated clay (ACL), celite (CE) and silica gel (SG), activated carbon (ACA), frypowder (FP), britesorb (BR) and magnesol (MA) were evaluated for their efficacy in regenerating the oils in terms of their effects on physicochemical parameters such as free fatty acids (FFA), total polar materials (TPM), p-anisidine value (p-AV), conjugated dienes, viscosity and colour. Binary and quaternary adsorbent treatments were better than single adsorbents in improving the overall quality of the oils studied. The efficacy of the best adsorbent blend was further evaluated in a highly polymerized cottonseed oil collected from a local eatery. Use of such adsorbents is recommended for small processing units in the unorganized sector, where such polymerized oil is generally discarded.