NUTRALYS® pea protein: characterization of in vitro gastric digestion and in vivo
gastrointestinal peptide responses relevant to satiety
Sammanfattning
Background: Pea protein (from Pisum sativum) is under consideration as a sustainable, satiety-
inducing food ingredient.
Objective: In the current study, pea-protein-induced physiological signals relevant to satiety were
characterized in vitro via gastric digestion kinetics and in vivo by monitoring post-meal
gastrointestinal hormonal responses in rats.
Design: Under in vitro simulated gastric conditions, the digestion of NUTRALYS® pea protein was
compared to that of two dairy proteins, slow-digestible casein and fast-digestible whey. In vivo, blood
glucose and gastrointestinal hormonal (insulin, ghrelin, cholecystokinin [CCK], glucagon-like peptide
1 [GLP-1], and peptide YY [PYY]) responses were monitored in nine male Wistar rats following
isocaloric (11 kcal) meals containing 35 energy% of either NUTRALYS® pea protein, whey protein, or
carbohydrate (non-protein).
Results: In vitro, pea protein transiently aggregated into particles, whereas casein formed a more
enduring protein network and whey protein remained dissolved. Pea-protein particle size ranged from
50 to 500 µm, well below the 2 mm threshold for gastric retention in humans. In vivo, pea-protein and
whey-protein meals induced comparable responses for CCK, GLP-1, and PYY, that is, the
anorexigenic hormones. Pea protein induced weaker initial, but equal 3-h integrated ghrelin and
insulin responses than whey protein, possibly due to the slower gastric breakdown of pea protein
observed in vitro. Two hours after meals, CCK levels were more elevated in the case of protein meals
compared to that of non-protein meals.
Conclusions: These results indicate that 1) pea protein transiently aggregates in the stomach and
has an intermediately fast intestinal bioavailability in between that of whey and casein; 2) pea-
protein- and dairy-protein-containing meals were comparably efficacious in triggering gastrointestinal
satiety signals.