RESUMO
PURPOSE: The objective was to investigate the metabolic fate of phytosteryl/-stanyl fatty acid and ferulic acid esters upon consumption by healthy humans. METHODS: A capillary gas chromatographic methodology was employed to follow a randomized, single-blind three group crossover clinical trial and to quantify simultaneously individual intact esters, liberated phytosterols/-stanols and their metabolites in feces. Skimmed milk drinking yogurts enriched with complex mixtures of phytosteryl/-stanyl fatty acid esters and ferulates, respectively, were employed as food carriers. RESULTS: On average, 73 % of total plant stanyl fatty acid esters and 80 % of total plant steryl fatty acid esters were hydrolyzed. Among the individuals, the hydrolysis rates ranged from 40 to 96 %. In addition, there were subject-dependent discrepancies between the amounts of phytosterols/-stanols actually determined in the feces and the calculated hydrolysis rates. On average, 69 % of the amounts of sterols/stanols expected from the amounts of remaining intact esters were found. CONCLUSIONS: The study revealed large interindividual variability regarding the recoveries of dietary phytosteryl/-stanyl esters upon gastrointestinal passage in healthy humans. Nevertheless, there was a significant impact of the acid moiety (oleate=linoleate=linolenate>eicosanoate>palmitate>ferulate) on the hydrolysis rates; the influence of the phytosterol/-stanol moiety was less pronounced.
Assuntos
Colesterol/análogos & derivados , Ácidos Cumáricos/metabolismo , Dieta , Digestão , Ácidos Graxos/metabolismo , Fezes/química , Fitosteróis/metabolismo , Sitosteroides/metabolismo , Adulto , Anticolesterolemiantes/administração & dosagem , Anticolesterolemiantes/análise , Anticolesterolemiantes/química , Anticolesterolemiantes/metabolismo , Bebidas , Colesterol/administração & dosagem , Colesterol/análise , Colesterol/química , Colesterol/metabolismo , Ácidos Cumáricos/administração & dosagem , Ácidos Cumáricos/análise , Ácidos Cumáricos/química , Estudos Cross-Over , Dieta com Restrição de Gorduras , Esterificação , Ácidos Graxos/administração & dosagem , Ácidos Graxos/análise , Ácidos Graxos/química , Alimentos Formulados , Humanos , Hidrólise , Masculino , Fitosteróis/administração & dosagem , Fitosteróis/análise , Fitosteróis/química , Método Simples-Cego , Sitosteroides/administração & dosagem , Sitosteroides/análise , Sitosteroides/química , Iogurte , Adulto JovemRESUMO
Approaches for the capillary gas chromatographic (GC) based analysis of intact plant stanyl esters in enriched foods were developed. Reference compounds were synthesized by enzyme-catalyzed transesterifications. Their identities were confirmed by means of mass spectrometry. Using a medium polar trifluoropropylmethyl polysiloxane stationary phase, long-chain plant stanyl esters could be separated according to their stanol moieties and their fatty acid chains. Thermal degradation during GC analysis was compensated by determining response factors; calibrations were performed for ten individual plant stanyl esters. For the analysis of low-fat products (skimmed milk drinking yogurts), the GC separation was combined with a "fast extraction" under acidic conditions. For fat-based foods (margarines), online coupled LC-GC offered an elegant and efficient way to avoid time-consuming sample preparation steps. The robust and rapid methods allow conclusions on both, the stanol profiles and the fatty acid moieties, and thus provide a basis for the authentication of this type of functional food ingredients.