Regeneration of Spent Cooking Fat and Oil by the use of Chitosan-gel Beads Including Activated Carbon and Alkali

Abstract
If it is possible to regenerate spent cooking fat and oil back to a grade which is utilizable as food, the discharge of the former could be decreased, leading to the protection of resources and the environment. Therefore, chitosan-gel beads containing activated carbon and alkali, which have been developed on the purpose of regenerating spent fat and oil, were used in regeneration treatment experiments that were conducted for many materials originating from various sources.
As a result, by means of very simple treatments, acid value (AV), which is an index of the deterioration of fat and oil, decreased, and the reduction of discoloration and odor was observed. Furthermore, it turned out that the change of water content, POV (peroxide value) and IV (iodine value) was small, and therefore this method was suitable as a method of regenerating spent cooking fat and oil on a small scale, such as in household use.
For the purpose of increasing the treatment efficiency, research on the preparation and reaction conditions of the chitosan-gel beads was conducted. Crushing the chitosan-gel beads and/or keeping the moisture content in the range of 50-65% were suitable methods. Further, the reaction rate was increased by warming and/or stirring. The same effect was also observed when agar was used instead of chitosan, i.e., in the case of agar-gel beads containing activated carbon and alkali.

Key words: spent cooking fat and oil, acid value, peroxide value, chitosan, agar