Mechanism of lipid metabolism regulation by soluble dietary fibre from micronized and non-micronized powders of lotus root nodes as revealed by their adsorption and activity inhibition of pancreatic lipase

Soluble dietary fibre (SDF) of micronized and non-micronized powders of lotus root nodes were investigated based on its adsorption and activity inhibition of pancreatic lipase (PL) by using circular dichroism, fluorescence spectroscopy and modification. Results showed that SDF2 (SDF from micronized powders of lotus root nodes) had stronger PL adsorption and enzyme activity inhibition than SDF1 (SDF from non-micronized powders of lotus root nodes). Specifically, SDF2 showed more binding sites than SDF1 in PL. There were hydrogen bonds and van der Waals interactions between SDF and PL, with Trp on PL probably serving as the main binding site. Carboxyl groups exhibited a stronger inhibition on PL by carboxymethyl and hydroxypropyl modification. The common mechanisms between SDF1 and SDF2 can be attributed to the combination between Trp and carboxyl groups, while the differences may be generated by the variations in structures or chemical groups induced by micronization. [Display omitted] •SDF2 had stronger adsorption and enzyme activity inhibition ability for PL.•The difference effect of SDF1 and SDF2 on PL may be generated by micronization.•PL inhibition by SDF was dependent on formation of PL-SDF complex.•PL-SDF complex may be combined by the interaction between Trp and carboxyl groups.