Gastric emptying and nutrient absorption of pea protein products differing in heat treatment and texture: A randomized in vivo crossover trial and in vitro digestion study
Julia J.M. Roelofs, Elise J.M. van Eijnatten, Patteela Prathumars, Joris de Jong, Ron Wehrens, Diederik Esser, Anja E.M. Janssen, Paul A.M. Smeets
Abstract
Pea protein is an interesting alternative for animal-based proteins due to its good availability, low cost, and relatively balanced amino acid (AA) profile. Its digestibility may be affected by heat treatment and food texture. Our aim was to study in-vivo AA absorption kinetics and gastric behavior of pea protein products differing in heat treatment and texture and compare this with in-vitro digestion. We included fourteen males in this randomized crossover trial with three iso-caloric and iso-volumetric treatments: a 420-mL heated drink, 420-mL unheated drink and 105-g heated gel (semi-solid) consumed with 315 mL water, all containing 20 g pea protein. Gastric MRI scans were made until 90 min post-prandial. Blood samples were collected at baseline and up to five hours. All treatments were tested with an in-vitro digestion model (INFOGEST). Heat treatment did not alter AA absorption kinetics and gastric emptying. Time to maximum peak was delayed for the gel treatment (total AAs: 66.9 versus 48.0 min for both drinks, essential AAs: 75.4 versus 50.0 and 46.6 min for the drinks). For the gel treatment initial emptying was faster due to the rapid passage of water. In-vitro, the degree of hydrolysis was highest for the unheated drink in the gastric phase and for the gel treatment in the intestinal phase. In conclusion, heat treating pea protein products does not affect digestion. In contrast, texture of pea protein products can be altered to influence the rate of gastric emptying and AA absorption without affecting total AA absorption.