Potential impact of biopolymers (ε-polylysine and/or pectin) on gastrointestinal fate of foods: In vitro study

Food-grade biopolymers, such as proteins and polysaccharides, may impact the gastrointestinal fate of foods through various mechanisms. In this study, we examined the influence of ε-polylysine (an antimicrobial) and pectin (a thickening agent) on the behavior of a standard rodent diet (full-fat and fat-free) in a simulated gastrointestinal tract that included mouth, stomach, and small intestine phases. Powdered biopolymers were incorporated into the standard diet in either individual or complexed form. The presence of the biopolymers altered the microstructure and charge characteristics of the gastrointestinal contents. In particular, the presence of pectin appeared to increase the rate and extent of lipid digestion, which may have been due to its ability to inhibit protein aggregation. Our results do not support the hypothesis that polylysine inhibits lipid digestion, as has been reported previously. Overall, the results of this study may be useful for interpreting animal feeding studies of the influence of biopolymers on the gastrointestinal fate of foods.