Physiological comparability of the harmonized INFOGEST in vitro digestion method to in vivo pig digestion. (December 2017)

• Record Type: Journal Article
• Authors: Egger, Lotti; Schlegel, Patrick; Baumann, Christian; Stoffers, Helena; Guggisberg, Dominik; Brügger, Cédric; Dürr, Desirée; Stoll, Peter; Vergères, Guy; Portmann, Reto
• Is Part Of: Food research international. Volume 102(2017)
• Page Start: 567
• Page End: 574
• Publication Date: 2017-12
• Subjects: FAA free amino acids -- IVD in vitro digestion -- SMP skim milk powder; In vitro - in vivo digestion -- Dairy proteins -- Peptides -- Mass spectrometry -- Harmonized IVD protocol; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2017.09.047
• Languages: English
• ISSNs: 0963-9969

Abstract

Abstract: Recently, a static in vitro digestion (IVD) protocol was published by Minekus and coworkers (Minekus et al., 2014) within the COST INFOGEST network. The protocol, concentrating on physiological enzyme activities had the main goal to improve the comparability of experimental data between labs. The protocol was validated in several inter-laboratory studies using skim milk powder (SMP) and indeed demonstrated improved harmonization compared with previous experiments with individual IVD protocols (Egger et al., 2016). Although the enzyme activities and salt concentrations of the harmonized protocol are based on available human in vivo data, confirmation of the protocol's physiological relevance has been lacking until now. The main goal of the study was therefore to compare the harmonized IVD protocol with data from in vivo digestion. Towards this aim, an in vivo pig experiment with the same SMP as used for the validation of the IVD protocol was performed followed by a comparison of protein hydrolysis between in vivo and in vitro results. Protein hydrolysis at different levels was analyzed with gel electrophoresis, mass spectrometry, high performance liquid chromatography, and spectrophotometric o-phthaldialdehyde determination of free amino acids. Principle component analysis was used for graphical data comparison. Milk proteins detected after gastric IVD corresponded to gastric and duodenal in vivo samples and intestinal IVD samples corresponded to distal jejunal in vivo samples. Peptides identified after the gastric phase of IVD, correlated with in vivo gastric samples (r = 0.8) and intestinal IVD peptides correlated best with in vivo samples collected from the median jejunum (r = 0.57). Free amino acids were in both systems mainly released during the intestinal phase of digestion. Protein hydrolysis in the harmonized IVD was similar to in vivo protein hydrolysis in pigs at the gastric and intestinal endpoints. Therefore, the harmonized static in vitro protocol is suited to study protein hydrolysis at these endpoints. Graphical abstract: Highlights: Resistance of lactoglobulin in the gastric step and no intact caseins visible in the intestinal phases in both systems. Peptide patterns of digested SMP were similar between in vitro and in vivo digestion at the gastric and intestinal endpoints. In vivo as well as in vitro free amino acids are mainly released during the intestinal phase of digestion.