Characterization and Monitoring of the Oxidative Stability of Pork Grease

Abstract

the use of these waste materials is not always advantageous because they may be highly oxidized, generating rancid flavors and odors in feeds, which will negatively affect feed consumption and conversion [1], and in the production of biodiesel, since oxidation of the raw material interferes in the production process and impairs the quality of the final product [3].The main chemical changes that occur in fats and oils are triggered by the processes of auto-oxidation, polymerization, oxidation, and hydrolysis, which can be accelerated by heat, light (photo-oxidation) ionization reactions, and trace metals [4,5]. Heat increases the rate of the chemical reactions, breaking down more of the fatty acids into smaller compounds such as aldehydes and ketones. Transition metals, such as copper and iron, are effective promoters of radical reactions, reducing the activation energy of the oxidation reaction and increasing the rate of decomposition and formation of peroxides [5].Furthermore, during storage, the lipid fraction is gradually hydrolyzed by water or by natural lipolytic enzymes produced by bacterial and fungal contaminants. UV light can activate photosensitive compounds producing singlet states, forming additional peroxides [4,5].The oil composition (especially the fatty acid composition), the concentration of antioxidants, and the storage conditions (i.e., temperature, light, and oxygen) can have a significant effect on the quality of the oil during storage [6]. The changes are reflected by the acidity and oxidation indices. Increases in these indices are signs of additional lipid oxidation, which can impair the aroma, color, and flavor of oils [4,7].Thus, the objective of this study was the characterization of the fatty waste from pork cooking processes as well as the characterization of the oxidative stability and fatty acid composition during storage (first 150 days). AbstractThe purpose of this study was to characterize pork grease, an agroindustrial waste generated via food processing, and to monitor its oxidative stability during storage (150 days). The chemical parameters of the grease were assessed and fluorescence spectrometry was used to monitor its oxidation. The results indicated that the chemical parameters of the waste pork fat increased over time, indicating substantial deterioration and showing a significant difference (P < 0.05) after 60 days of storage. The fat contained 14 fatty different acids, and the polyunsaturated fatty acid component comprised 20.20 % of the total at time zero, although there was a significant difference (P < 0.05) after 90 days of storage. The fluorescence spectrometry intensity decreased over time, as did the polyunsaturated fatty acid content. The waste lard has potential as a raw material for the production of biodiesel, animal feed, and even food for human consumption if properly obtained and stored.