Abstract :
[en] Dietary lipids are incorporated in food products under different types of structures, e.g., as dispersed lipid droplets (in oil -in -water emulsions, like creams) or as a continuous lipid phase (in water -in -oil emulsions, like butter for example). The crystallization, melting behavior and polymorphic stability
of fats are determined by the behavior of the TAGs they contain. In clinical studies, there is a need to add some 13C TAGs as tracers to the ingested fats in order to track their metabolic fate. However, this procedure could modify the physicochemical properties of the fat. The present study was conducted in the framework of a clinical trial aiming at highlighting the effect of the physical structure of a fat (droplets in 0/W emulsion or bulk) in a meal on the absorption, chylomicron transport and further metabolic handling of dietary fatty acids (1). We therefore monitored the thermal and polymorphic behavior of anhydrous milk fat (AMF) enriched in tracers (a mixture of tripalmitin, triolein and tricaprylin; at 2 different concentrations: 1.5 and 5.7 wt%) using DSC and XRD and further compared it to the native AMF. The addition of 13C TAGs modified the AMF melting profile, especially at high concentration. The enriched AMF was completely melted at around 37°C, i.e.
close to the body temperature. However, under some conditions, the AMF enriched in high 13C
TAGs concentration remained crystallized at 37°C. Similar trends were observed in both systems (bulk vs emulsified). Moreover, AMF polymorphic behavior was also modified upon tracer addition. While only β’ form was observed in the native AMF, the 13 -form was detected in the AMF containing high 13C TAGs concentration. Importantly, low concentration of tracers should not have high
impact on human digestive physiology. However more attention should be paid to physicochemical structure when high concentrations are added.
(1) Vors et al. 2013. Modulating absorption and postprandial handling of dietary fatty acids by structuring fat in the meal: a randomized cross -over clinical trial. Am J Clin Nutr, 97(1): 23-36.
