Cholesterol esterase substantially enhances phytosterol ester bioaccessibility in a modified INFOGEST digestion model

Abstract

Standardization and of in vitro digestion models is crucial to obtain results that may be compared across laboratories. The INFOGEST network has published multiple iterations of a static in vitro digestion protocol. The protocol lacks cholesterol esterase (CE) activity during the intestinal phase, and few studies have evaluated its incorporation into the model. In the present study, the effect of additional CE on phytosterol ester (PSE) bioaccessibility in emulsions with different droplet sizes was evaluated. Different droplet sizes were obtained by utilizing different homogenization techniques to produce large (9.9 μm), medium (3.4 μm), and fine (1.3 μm) emulsions. Addition of CE resulted in an increase in PSE bioaccessibility for all emulsions. This change was emphasized in emulsions with smaller droplet sizes, with bioaccessibility of large (19.6%), medium (34.2%), and fine (40.8%) emulsions increasing 1.5, 2.2, and 2.1-fold. This finding provides evidence for the inclusion of CE into the INFOGEST protocol.

Keywords

• In vitro digestion
• Bioaccessibility
• Phytosterol esters
• Gas chromatography
• INFOGEST protocol