Macromolecular properties governing the impact of charged polysaccharides on bioaccessibility of bioactive peptides and bioactive lipophilic nutraceuticals

Edible polysaccharides are natural biopolymers, accepted as food additives, that can be utilized to rationally design the digestive fate of colloidal systems. This talk will overview how the macromolecular of charged polysaccharides delineate beneficial and deleterious effects on the digestive fate of protein-based systems. First, we will overview two studies1,2 on the deleterious effect of carrageenan (CGN) on digestive proteolysis, bioaccessibility of bioactive peptides and the colon microbiome. Zeta potential, indicative of biopolymer charge, will be shown to explain the impact of different CGN preparations on the bioaccessibility of bioactive peptides generated from dairy proteins during digestion in children and adults2. This link will also be shown to be linked to adverse effects on the colon microbiome based on faecal batch cultures of freshly collected human feces (from 10 healthy individuals, age 25.7±4.2) and Illumina Miseq 16S rRNA sequencing that indicate a marked increase in the Firmicutes/Bacteroidetes ratio and reduced microbiota richness (Chao1 index) and evenness (Shannon index); again, linked to CGN sulphation. Second, we will describe alpha-lactalbumin (ALA) as a delivery platform for capsaicin (CAP), a bioactive nutraceutical from chili peppers3 and the use of charged polysaccharides to manipulate the digestive fate of the system. ITC, in silico docking models, HPLC and light scattering colloidal characterizations will elucidate the varying encapsulation and colloidal properties of the system. Moreover, findings from dynamic in vitro digestion models will underpin electrostatic biopolymer interactions between ALA and alginate or chitosan as detrimental to the controlled released of CAP in the mouth, stomach and small intestine but without adversely affecting the digestive proteolysis of ALA, as affirmed by proteomic analysis. Altogether, this talk underpins polysaccharide charge as a strong determinant for possible anti-nutritional effects and concomitant opportunities to control the delivery of lipophilic nutraceuticals.

References

1. David, et al, (2020). Food Res. Int. 130, 108964 .

2. David, et al (2020). Foods 9, 1253.

3. Romano, et al (2021). Food Chem. 352, 129306.