Enhancing lipid digestion and absorption rate: The role of whey protein isolate short fibrils in emulsions

Abstract

Lipid serve as a crucial energy source during prolonged endurance exercise, and whey protein isolate (WPI) is commonly applied in food emulsions to modulate lipid digestibility. Herein, we prepared WPI short fibrils, <400 nm in length, to stabilize emulsion and increase lipid digestion and absorption rates. Specifically, a 2 % (w/v) WPI solution was adjusted to pH 2 and heated at 90 °C for 6 h to produce long fibrils, followed by 168 h of shear force treatment to obtain short fibrils. Compared to native WPI and long fibrils, short fibrils exhibited smaller molecular weight and higher surface hydrophobicity. Both short and long fibrils showed no cytotoxic effects on BRL and HEK-293 cells. Emulsions stabilized by short fibrils displayed excellent emulsifying capacity and stability, along with favorable dispersion during in vitro digestion. Importantly, the short fibrils emulsion improved in vitro digestion rate of lipids and promoted the rapid lipid absorption in vivo. These findings suggest that modifying protein fibrils around oil droplets can modulate lipid digestibility, with short fibrils offering potential to improve lipid absorption in functional foods tailored for personalized nutrition in extreme endurance exercise.