Data underlying the publication: Unifying lipolysis under INFOGEST conditions by total surface area and coalescence

Lipids are crucial for human health, but excessive or rapid lipid digestion can lead to metabolic disorders such as obesity, hyperglycaemia, and hyperlipidaemia. Controlling the rate and extent of lipid digestion is therefore key in nutritional and functional food design. In vivo digestion studies provide realistic insights but are limited by ethical, practical, and cost concerns. Consequently, standardized in vitro digestion protocols such as INFOGEST 2.0 (2019) are widely used to simulate gastrointestinal conditions and assess lipid hydrolysis through free fatty acid (FFA) release. However, the static INFOGEST model does not explicitly account for interfacial area, which is critical since lipolysis occurs at the oil–water interface. Factors such as oil volume fraction, droplet size, and coalescence directly influence this available surface area and therefore the kinetics of lipid digestion. Previous studies have independently reported that smaller droplets enhance lipolysis, while excessive oil or coalescence reduce it, but a unified quantitative description is still missing. The current study aims to quantitatively describe intestinal lipolysis by integrating total surface area effects with kinetic modeling. It systematically varies oil amount and droplet size under INFOGEST conditions, while incorporating droplet coalescence dynamics. Lipolysis (FFA release) is predicted using a surface area-normalized reaction rate constant and a first-order coalescence model, providing a mechanistic understanding of how emulsion stability governs lipid digestion.