Improvement of keeping quality of edible fats by some commercially available tannins

Summary The literature on the use of tannins as antioxidants for fats is reviewed. A process is described for the improvement of the keeping quality of edible fats by treatment with tannin in which the tannin and/or tannin compound is removed by filtration. Data are presented for various types of animal and vegetable fats and oils which were treated with U.S.P. tannic acid by the process described. The process is particularly effective on lard and beef fats. Data are presented which show the effects of varying the temperature at which the treatment is made. A method for testing the effectiveness of removal of the tannin is described. The improvement value I_v, is introduced and is defined as the increase in keeping quality of a fat attributable to a process. It is analogous to the I_A value which is defined as the increase in induction period of a fat due to the addition of an antioxidant. A paper presented at the A.O.C.S. Fall Convention at Chicago, Nov. 7–9, 1945. Part of the data were presented at the Conference on Problems Related to Fat Deterioration in Foods under the auspices of Committee of Food Research, Research and Development Branch, Military Training Division, Office of the Quartermaster General in Washington in June 1945.