Inhibition of starch digestion: The role of hydrophobic domain of both α-amylase and substrates.

The physicochemical mechanism of starch digestion is very complicated since it may be affected by the non-valence interactions of the amylase inhibitor with the substrate or the enzyme. The role of hydrophobic interaction in the process of starch digestion is not clear. In this study, pluronics (PLs) with different hydrophobicity were used as model amphiphilic compounds to study their inhibition on starch digestion using multi-spectroscopic methods. The results showed that the hydrophobic nature of PLs changed starch structure, but it had a greater effect on the structure of α-amylase by exposing more tryptophan residues and increasing α-helix and ß-sheet contents. Further investigation by using different chain-length fatty acids confirmed the results. The finding in this study is informative to design and fabricate α-amylase inhibitors for controlling starch digestion at the molecular level.

Synergistic interaction between exogenous and endogenous emulsifiers and its impact on in vitro digestion of lipid in crowded medium.

Control of lipid digestibility by various food components has received great attention in recent decades. However, there is limited literature on investigating the synergistic effect of exogenous emulsifiers and endogenous sodium cholate (SC) on lipid digestion in a simulated physiological crowded medium. In this work, the synergistic interaction of Tween80 and SC according to the regular solution theory, and the hydrolysis of lipid emulsions containing tricaprylin, glyceryltrioleate or soybean oil in crowding medium was studied. The results show that emulsions stabilized by a combination of Tween80 and SC showed higher digestion rate and transformation than those with Tween80 or SC. The digestion rate could be increased by polyethylene glycols (PEGn) with varying crowding degree. The denaturation temperature of the lipase was increased in macromolecular crowded medium. This work allows for better understanding of the interaction between the amphiphiles and the macromolecular crowding effect on lipase digestion in the physiological environment.