This study aimed to investigate the gastric digestion behaviour of heat-treated enriched milk containing Coenzyme Q10-loaded emulsions with different interfacial compositions. Four enriched milk types were compared: pasteurized with a Tween 80 stabilised emulsion (PAST-TW80), or with a sodium caseinate-stabilised emulsion (PAST-NaCN), and UHT with a TW80-stabilised emulsion (UHT-TW80), or PAST with a NaCN-stabilised emulsion (UHT-NaCN)
all loaded with Coenzyme Q10. An in vitro dynamic gastric digestion model (Human Gastric Simulator) was utilized and the kinetics of milk coagulation and emptying of protein, lipid and Coenzyme Q10 were monitored. Adding NaCN-stabilised emulsion to heated milk led to a largely fragmented curd with signs of extensive droplets coalescence, disintegrating rapidly and accelerating protein and lipid release. Heated milk with TW80-stabilised emulsion produced a compact and closely integrated curd with limited coalescence, slowing nutrient emptying. UHT milk showed more curd fragmentation than PAST milk, regardless of emulsion type. The release profiles of Coenzyme Q10 were similar between UHT-TW80 and PAST-TW80 or between PAST-NaCN and UHT-NaCN, indicating the emulsion's interfacial composition as a key factor in controlling lipophilic bioactive release from the food matrix, regardless of heat treatment. These findings demonstrate that the emulsion's interfacial composition (NaCN vs TW80) and the heat treatment (PAST vs UHT) can be combined as a strategy to modulate milk coagulation kinetics and the rate of nutrient delivery to the small intestinal stage. This study provides insights into the development of functional milk products fortified with lipophilic bioactive compounds, as well as strategies for optimizing the controlled release of these compounds upon consumption.