Title
Lipid digestion of protein stabilized emulsions investigated in a dynamic in vitro gastro-intestinal model system
Author
Helbig, A.
Silletti, E.
van Aken, G.A.
Oosterveld, A.
Minekus, M.
Hamer, R.J.
Gruppen, H.
Publication year
2013
Abstract
This study investigated the effect of gastric passage of protein stabilized emulsions, i.e., whey protein isolate (WPI) and lysozyme, under dynamic in vitro conditions on both the gastric and intestinal lipolysis. Emulsions were prepared at neutral pH to enable an opposite surface charge. Experiments were performed in a multi-compartmental digestion model (TNO Gastro-Intestinal Model) including a gastric compartment simulating in vivo conditions, i.e., gradual acidification, mixing, lipolysis and proteolysis. Under gastric conditions, lysozyme-stabilized emulsions remained macroscopically homogenous, whereas WPI-stabilized emulsions separated into a cream and serum layer. Microscopy revealed flocculation of both emulsions, but larger particles were found for the initial negatively charged WPI-stabilized emulsions compared to the positively charged lysozyme-stabilized emulsions. This suggested that creaming was due to larger flocs formation caused by a change from net negative to net neutral charge as an effect of the gradual decreasing pH. Analysis of lipid composition, i.e., free fatty acids (FFA), monoglycerides, diglycerides (DG) and triglycerides revealed mainly FFA and DG in the gastric compartment. As a result of creaming, the entry of lipids into the small intestinal part was delayed for WPI-stabilized emulsions. However, the total amount of FFA released at the end of the experiment was similar for both emulsions. Our results show, that the charge differences affected the creaming behavior, but not the lipase activity, on the two studied emulsions. © 2012 Springer Science+Business Media New York.
Subject
Life
PHS - Pharmacokinetics & Human Studies (tot 2013 daarna KFP)
EELS - Earth, Environmental and Life Sciences
Biomedical Innovation
Healthy Living
Creaming
Fat digestion
Gastric lipolysis
In vitro digestion model
Intestinal lipolysis
Protein emulsion
Satiety from fat
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DOI
https://doi.org/10.1007/s13228-012-0029-6
TNO identifier
487302
ISSN
1869-1978
Source
Food Digestion, 4 (2-3), 58-68
Document type
article