Effect of Storage Prior to Rendering on Quality of Fowl Leaf Fat

Abstract The purpose of the study was to determine the effect of storage conditions prior to rendering on the chemical, microbial and flavor changes that occur in fowl leaf fat. Fresh fat obtained from a commercial processor on two different days was stored unrendered at −17.8°, −6.7°, −3.9°, −1.1° or 4.4° C. Periodically during storage samples were removed and assayed for total plate count and total lipolytic count, then rendered, and assayed for peroxide value (P.V.) and free fatty acids (F.F.A.). Storage was terminated when fat was judged unacceptable by published guidelines for P.V. and/or F.F.A. Flavor changes were evaluated by a sensory panel. Oxidative changes were also determined for fat stored in the rendered form. The rates of oxidative and hydrolytic rancidity and of microbial growth were temperature-dependent. Only for fat stored unrendered at 4.4° C. did the fat become unacceptable as judged by both parameters for acceptability (P.V. and F.F.A.). At lower storage temperatures fat became unacceptable due to P.V., with F.F.A., values still within acceptable limits. Fat stored in the rendered form was found to be more stable to oxidation as judged by P.V. Although P.V. for the fat stored unrendered at −17.8° C. did not increase during storage, a sensory panel was able to detect slight off-flavor after 24 weeks. A significant (P