Impact of fat content on the modulation of viscosity, microstructure and enzymatic hydrolysis of UHT milk during simulated gastrointestinal digestion

Digestion of ultra-high temperature milk with different levels of fat content was examined in vitro under semi-dynamic conditions with real-time measurements of viscosity. All milk viscosity increased during the gastric phase despite digestive fluid dilution due to protein aggregation. Higher fat formulations presented greater viscosity and denser microstructure with larger mean droplet size. It experienced faster proteolysis and lipolysis throughout digestion with 524 mu mol free fatty acids released compared with semi-skimmed milk (467 mu mol), but had lower conversion of triglycerides at the intestinal phase terminus. This study has provided a rheological understanding of the dynamics of UHT milk digestion as impacted by fat content.

Automated summary

This study examines the digestion of ultra-high temperature milk with different levels of fat content and determines its impact on viscosity and microstructure. Higher fat formulations result in increased viscosity and larger droplet size, with faster release of free fatty acids during digestion. However, these formulations show lower conversion of triglycerides at the end of the intestinal phase.