14B-46

N. TIPSRISUKOND, I. U. GRUEN, A. D. Clarke, and L. N. Fernando. Department of Food Science, University of Missouri-Columbia, 122 Eckles Hall, Columbia, MO 65211-5200

Oxidative and hydrolytic reactions in lipids result in the formation of a variety of decomposition products. These products have significant effects on odor, flavor and other characteristics of a fat or oil. However, very few studies have compared the impact of controlled lipid degradation processes on chemical characteristics of fats or oils.

The objective of this study was to determine the percent free fatty acid (FFA), the volatiles and the FFA profiles in enzymatically or thermally degraded lard.

The percent FFA, volatile and FFA profiles of lipolysates of four different lipases (LipaseE5000, Microbial Lipase50, Pancreatic Lipase24, and Esterase/Lipase10X), as well as of thermally degraded lards (combinations of 100, 150, and 200ºC at 10, 60, and 360mins) were determined using titration, GC-MS and GC methods respectively.

Lipolysates were most efficiently produced using an invert emulsion technique with a 12.5% aqueous phase, an enzyme concentration of 1.5%, and a 12-hour incubation period. The optimal temperature was enzyme dependent (P<0.05). Titratable FFA of lipolysates ranged from 11.11 to 49.13%. LipaseE5000 generated the highest total FFA concentrations (P<0.05). Thermally degrading lard resulted in titratable FFA ranging from 33.16 to 119.02% with the highest titratable FFA achieved at 200ºC for 360 min (P<0.05). The predominant FFAs of lipolysates were C16:0 and C18:1, while the predominant FFA of thermally degraded lard was C18:1. Aldehydes, alcohols, esters, alkanes, and saturated-monocyclics were the major volatiles found in lipolysates, while the largest classes of volatiles of thermally degraded lard were alkanes, alkenes, aldehydes, enals, acids, branched alkanes, branched alkenes, and saturated-mono and -dicyclics.

Lipid or fat by-products from commercial slaughter operations are typically used to enhance the palatability of dried pet food. Liberated FFAs from fat or oil by lipid degradation processes might enable both pet and food industries to increase utilization of these by-products in flavor applications.