Effects of temperature and storage time on the quality of alimentary animal fats

Experimental research were effectuated to establish the effect of storage time under refrigeration (+2oC) and freezing (-18oC) on the quality of three alimentary animal fats: pork lard, beef tallow and poultry fat. In assessing the various stages of oxidative changes, iodine value (IV), saponification value (SV), refractive index value (RIV), peroxide value (PV) and thiobarbituric acid reactive substances test (TBARS) were determined to identify and measure primary and secondary oxidation compounds, fatty acids profile and acidity value (AV) were determined for measuring the degree of lipolysis. All quality parameters, except iodine and refractive index values, increased during storage at both temperatures. Sample of fats stored at +2oC preserved acceptable characteristics for 90 days in the case of pork lard, 150 days in the case of beef tallow and 60 days in the case of poultry fat. PV of pork lard stored at -18oC increased from 1.52 to 12.87 during frozen storage for 210 days, while PV of poultry fat increased from 3.11 to 15.82; TBARS of pork lard increased from 1.26 to 11.80, while for poultry fat increased from 2.16 to 12.90 during frozen storage for 210 days. The total contents of monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids decreased significantly (P < 0.05) after 210 days of storage at +2oC for all fat samples. Acceptability tolerance was found to be 210 days for beef tallow, 150 days for pork lard and 120 days for poultry fat stored at -18oC.