COMPOSITIONAL AND THERMAL CHARACTERIZATION OF GENUINE AND RANDOMIZED LARD - A COMPARATIVE-STUDY

Composition and thermal characterization of genuine and randomized lar d were investigated comparatively in an attempt to find common merits that assess lard detection. The investigation included compositional a nd positional distribution of fatty acids, triacylglycerol profiling b y gas chromatography (CC) and reversed-phase high-performance liquid c hromatography (RP-HPLC), as well as thermal behavior by differential s canning calorimetry (DSC) of both samples. Individual and total satura ted and unsaturated fatty acid composition in total fats of both genui ne and randomized lard were identical. On the other hand, the results of pancreatic lipolysis/GC analysis showed that the average percent pa lmitic acid [PAEF(%)] and myristic acid [MAEF(%)] enrichment factors o f genuine (280 and 270) and randomized lard (110 and 98) were quite di fferent. Thus, application of PAEF to detect randomized lard is of no value. However, normalization of fatty acid distribution by randomizat ion in 2-monoacylglycerols made the individual and total saturated and unsaturated fatty acids almost identical to that of total fat and neu tral triacylglycerols (TC) of lard. TC compositional analysis by GC re vealed that both genuine and randomized lard had six dominant TG (C-46 , C-48, C-50, C-52, C-54, and C-56) With quite different concentration s. TC with C-52 represent the major constituent of genuine and randomi zed lard. TC profiling of samples was also carried out by RP-HPLC with a refractive index detector. The same peaks were eluted in both sampl es, but the area % of major peaks changed due to randomization. 2-Palm itooleostearin (SPO) was found in high proportion in lard. However, th e ratios of SPO to 2-palmitooleolinolein of both genuine and randomize d lard are close (0.6 +/- 0.05) and significantly distinguishable from that of beef (4.24), mutton (6.17), chicken (0.21), and turkey (0.14) fats. The DSC thermogram and thermodynamics of phase transitions of b oth samples were quite different and do not reveal common characterist ic(s) that could be used for immediate detection of lard substances in fat admixtures.