The presence of tallow in lard is not easy to determine, due to the similarity of thecomposition of these two animal fats, which differ mainly in the distribution offatty acids (FA) in the three positions of the glycerol molecule. The determination ofthe composition of the triacylglycerol (TAG) fraction of lard, tallow, and their mixtureswas investigated by HPLC in combination with atmospheric pressure chemicalionization mass spectrometry (APCI-MS). The presence of tallow in lard was determinedthrough the study of the sn-POP/sn-PPO ratio by multidimensional HPLC. The offlinebidimensional system was attained through the coupling of non-aqueous reversedphase (NARP)-HPLC and silver ion (Ag)-HPLC. The primary column eluate wasfractionated and the fraction containing POP/PPO isomers was injected onto thesecondary column, allowing the separation of positional isomers, unresolved in thefirst dimension. Peak assignment was carried out by combining retention data withAPCI-MS spectral information. The fatty acid distribution along the glycerol backbone,determined by Ag-HPLC, was confirmed through diglyceride ion ratios derivedfrom APCI-MS analysis. Method validation was carried out in preliminary applicationson standard TAGs. The analytical results obtained show that even a 5% additionof tallow to lard modifies the distribution of positional isomers.
Determination of beef tallow in lard through a multidimensional off-line non aqueous reversed phase-argentation LC method coupled to mass spectrometry
Fazio A.;
2006-01-01
Abstract
The presence of tallow in lard is not easy to determine, due to the similarity of thecomposition of these two animal fats, which differ mainly in the distribution offatty acids (FA) in the three positions of the glycerol molecule. The determination ofthe composition of the triacylglycerol (TAG) fraction of lard, tallow, and their mixtureswas investigated by HPLC in combination with atmospheric pressure chemicalionization mass spectrometry (APCI-MS). The presence of tallow in lard was determinedthrough the study of the sn-POP/sn-PPO ratio by multidimensional HPLC. The offlinebidimensional system was attained through the coupling of non-aqueous reversedphase (NARP)-HPLC and silver ion (Ag)-HPLC. The primary column eluate wasfractionated and the fraction containing POP/PPO isomers was injected onto thesecondary column, allowing the separation of positional isomers, unresolved in thefirst dimension. Peak assignment was carried out by combining retention data withAPCI-MS spectral information. The fatty acid distribution along the glycerol backbone,determined by Ag-HPLC, was confirmed through diglyceride ion ratios derivedfrom APCI-MS analysis. Method validation was carried out in preliminary applicationson standard TAGs. The analytical results obtained show that even a 5% additionof tallow to lard modifies the distribution of positional isomers.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
