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NUTRALYS(®) pea protein: characterization of in vitro gastric digestion and in vivo gastrointestinal peptide responses relevant to satiety.

Overduin J, Guérin-Deremaux L, Wils D, Lambers TT - Food Nutr Res (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Health, NIZO Food Research, Ede, The Netherlands; info@nizo.com.

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus

Time line of meal presentation and blood sampling. During meal-test sessions, test foods were consumed within 15 min by all rats. Blood samples were collected 10 min before food presentation and at multiple post-meal time points.
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Figure 0001: Time line of meal presentation and blood sampling. During meal-test sessions, test foods were consumed within 15 min by all rats. Blood samples were collected 10 min before food presentation and at multiple post-meal time points.

Mentions: In the weeks prior to experimental testing, the rats were trained to consume 10 g of the test foods within 8–15 min after presentation to ensure prompt and complete consumption of test foods during subsequent test sessions. Ten to 15 days before the start of test sessions, each animal received a surgically implanted chronic jugular-vein catheter under deep anesthesia. These catheters enable repeated blood sampling without skin puncturing, at reduced stress levels and at volumes sufficient to determine several hormones in parallel (23). A 10-day post-surgical recovery period was scheduled according to guidelines approved by the Wageningen University animal care and use committee, after which all animals had regained their pre-operative body weight. Starting at 4 days post-surgery, the rats received daily liquid meal presentations to verify and reinstate their prompt and rapid consumption of food. The experimental phase of this study proceeded according to a within-subject, repeated-measurement study design. Rats received the individual test foods in a quantity of 10 g (11 kcal) during weekly sessions (Fig. 1). The order of presentation of the different foods was balanced across rats. Before each of the three test sessions, rats were food deprived for 18 h to establish stable baseline hormone levels. During the meal sessions the animals were presented with a bowl containing one of the test foods. Blood was collected 10 min before food presentation (baseline sample), and at 20, 40, 60, 120, and 180 min thereafter. Because of occluding catheters, no blood could be collected from two animals, thus reducing the number of subjects to 10. Blood parameters were selected for their relevance as physiological signals mediating post-meal satiety. Blood sampling times were selected to obtain an adequate view of the meal-induced response within a 3-h time window. Blood glucose levels were analyzed using a portable glucose meter (Accu-Check; Roche, Indianapolis, IN). The remaining blood was transferred to EDTA-containing tubes with protease inhibitors aprotinin (0.6 TIU/ml of blood; Phoenix Europe GmbH, Karlsruhe, Germany) and dipeptidyl-peptidase inhibitor (2.5 µl; Millipore, Darmstadt, Germany). Blood tubes were immediately put on ice and centrifuged at 1,600 g and 4°C within 1 h after blood collection, to isolate the plasma which was stored immediately at −80°C until assaying. Plasma levels were determined of the gastrointestinal hormones ghrelin, CCK, GLP-1, and PYY. Ghrelin is produced primarily in the stomach; its plasma levels correlate with hunger and are suppressed after meals (24). CCK, historically, the first-described gastrointestinal satiation peptide, is released from I-cells in the duodenum and proximal jejunum in response to all macronutrients, but most prominently by fats and proteins (25). To moderate the blood volume taken from rats, CCK was measured only at baseline and 60 and 120 min time points only. GLP-1 and PYY are produced in the small and large intestines; their blood levels correlate with satiation and rise in response to the intestinal-luminal presence of meal-related digesta (25, 26). Acute PYY release may underlie satiation and elevated GLP-1 levels have been found in humans after high protein diets (27). With the exception of CCK, commercially available ELISA kits were used to determine plasma levels of endogenous peptides according to the standard directions from the manufacturer). Insulin was analyzed by kit 80-INSRTU-E01 (Alpco Diagnostics; lower detection limit [LDL]: 0.1 ng/ml). Plasma ghrelin was measured by kit EK-031-31, which detects total ghrelin, that is, the combined octanoylated (bioactive) and des-octanoylated forms (28) in rats (LDL: 0.12 ng/ml). CCK was measured by a selective RIA method developed at the laboratory of Dr. J.F. Rehfeld, Department Clinical Biochemistry, University of Copenhagen, Denmark. GLP-1 plasma levels were determined with RIA FEK-028-11 (LDL 27.6 pg/ml), which detects the main gastrointestinally secreted, bioactive form of GLP-1 (GLP-1 (7–36)-amide) as well as its primary, inactive, metabolite (GLP-1-(9–36) amide, a commonly used marker of GLP-1 secretion by virtue of its slightly longer half-life in plasma (29, 30). PYY was measured by kit FEK-059-03 (LDL 16.2 pg/ml), which detects PYY(1–36) and PYY(3–36), the two main circulating, bioactive forms in rats and other mammals (31).


NUTRALYS(®) pea protein: characterization of in vitro gastric digestion and in vivo gastrointestinal peptide responses relevant to satiety.

Overduin J, Guérin-Deremaux L, Wils D, Lambers TT - Food Nutr Res (2015)

Time line of meal presentation and blood sampling. During meal-test sessions, test foods were consumed within 15 min by all rats. Blood samples were collected 10 min before food presentation and at multiple post-meal time points.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400298&req=5

Figure 0001: Time line of meal presentation and blood sampling. During meal-test sessions, test foods were consumed within 15 min by all rats. Blood samples were collected 10 min before food presentation and at multiple post-meal time points.
Mentions: In the weeks prior to experimental testing, the rats were trained to consume 10 g of the test foods within 8–15 min after presentation to ensure prompt and complete consumption of test foods during subsequent test sessions. Ten to 15 days before the start of test sessions, each animal received a surgically implanted chronic jugular-vein catheter under deep anesthesia. These catheters enable repeated blood sampling without skin puncturing, at reduced stress levels and at volumes sufficient to determine several hormones in parallel (23). A 10-day post-surgical recovery period was scheduled according to guidelines approved by the Wageningen University animal care and use committee, after which all animals had regained their pre-operative body weight. Starting at 4 days post-surgery, the rats received daily liquid meal presentations to verify and reinstate their prompt and rapid consumption of food. The experimental phase of this study proceeded according to a within-subject, repeated-measurement study design. Rats received the individual test foods in a quantity of 10 g (11 kcal) during weekly sessions (Fig. 1). The order of presentation of the different foods was balanced across rats. Before each of the three test sessions, rats were food deprived for 18 h to establish stable baseline hormone levels. During the meal sessions the animals were presented with a bowl containing one of the test foods. Blood was collected 10 min before food presentation (baseline sample), and at 20, 40, 60, 120, and 180 min thereafter. Because of occluding catheters, no blood could be collected from two animals, thus reducing the number of subjects to 10. Blood parameters were selected for their relevance as physiological signals mediating post-meal satiety. Blood sampling times were selected to obtain an adequate view of the meal-induced response within a 3-h time window. Blood glucose levels were analyzed using a portable glucose meter (Accu-Check; Roche, Indianapolis, IN). The remaining blood was transferred to EDTA-containing tubes with protease inhibitors aprotinin (0.6 TIU/ml of blood; Phoenix Europe GmbH, Karlsruhe, Germany) and dipeptidyl-peptidase inhibitor (2.5 µl; Millipore, Darmstadt, Germany). Blood tubes were immediately put on ice and centrifuged at 1,600 g and 4°C within 1 h after blood collection, to isolate the plasma which was stored immediately at −80°C until assaying. Plasma levels were determined of the gastrointestinal hormones ghrelin, CCK, GLP-1, and PYY. Ghrelin is produced primarily in the stomach; its plasma levels correlate with hunger and are suppressed after meals (24). CCK, historically, the first-described gastrointestinal satiation peptide, is released from I-cells in the duodenum and proximal jejunum in response to all macronutrients, but most prominently by fats and proteins (25). To moderate the blood volume taken from rats, CCK was measured only at baseline and 60 and 120 min time points only. GLP-1 and PYY are produced in the small and large intestines; their blood levels correlate with satiation and rise in response to the intestinal-luminal presence of meal-related digesta (25, 26). Acute PYY release may underlie satiation and elevated GLP-1 levels have been found in humans after high protein diets (27). With the exception of CCK, commercially available ELISA kits were used to determine plasma levels of endogenous peptides according to the standard directions from the manufacturer). Insulin was analyzed by kit 80-INSRTU-E01 (Alpco Diagnostics; lower detection limit [LDL]: 0.1 ng/ml). Plasma ghrelin was measured by kit EK-031-31, which detects total ghrelin, that is, the combined octanoylated (bioactive) and des-octanoylated forms (28) in rats (LDL: 0.12 ng/ml). CCK was measured by a selective RIA method developed at the laboratory of Dr. J.F. Rehfeld, Department Clinical Biochemistry, University of Copenhagen, Denmark. GLP-1 plasma levels were determined with RIA FEK-028-11 (LDL 27.6 pg/ml), which detects the main gastrointestinally secreted, bioactive form of GLP-1 (GLP-1 (7–36)-amide) as well as its primary, inactive, metabolite (GLP-1-(9–36) amide, a commonly used marker of GLP-1 secretion by virtue of its slightly longer half-life in plasma (29, 30). PYY was measured by kit FEK-059-03 (LDL 16.2 pg/ml), which detects PYY(1–36) and PYY(3–36), the two main circulating, bioactive forms in rats and other mammals (31).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Health, NIZO Food Research, Ede, The Netherlands; info@nizo.com.

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus