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 5 h. 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.

Correction for 'Gastric coagulation and postprandial amino acid absorption of milk is affected by mineral composition: a randomized crossover trial' by Elise J. M. van Eijnatten et al., Food Funct., 2024, 15, 3098-3107, https://doi.org/10.1039/D3FO04063A.

Background: During breastfeeding the macronutrient composition of breastmilk changes gradually from relatively low-fat (foremilk) to relatively high-fat (hindmilk), initially exposing the gastrointestinal tract to a relatively low fat concentration. In contrast, infant formulae (IF) are homogenous. Mild processing and addition of milk fat globule membrane (MFGM) may impact gastric emulsion instability, potentially impacting the phased release of nutrients as observed during breastfeeding. Objective: To assess gastric emulsion stability, gastric emptying, and the postprandial plasma metabolome of an experimental minimally processed IF (EF) with an altered fat-globule interface and a control IF (CF). Methods: Twenty healthy males participated in this double-blind randomized crossover trial. Gastric MRI scans and blood samples were obtained before and after consumption of 600 ml CF or EF over a 2-h period. Outcomes included gastric top layer formation, total gastric volume, and blood parameters (free fatty acids (FFA), insulin, glucose, and nuclear magnetic resonance (NMR-)metabolomics). Results: EF showed an earlier onset (13.4 min, p = 0.017), smaller maximum volume (49.0 ml, p = 0.033), and a shorter time to maximum top layer volume (13.9 min, p = 0.022), but similar AUC (p = 0.915) compared to CF. Total gastric volume did not show a treatment*time effect. Insulin concentrations were lower for EF. FFA and glucose did not differ. EF yielded higher serum concentrations of phospholipid- and cholesterol-related metabolites. Conclusion: An EF displayed faster gastric creaming than a CF, thereby potentially better mimicking the behavior of breastmilk which leads to phased release of nutrients into the intestine. Overall physiological benefits of this difference in gastric behavior remain to be studied further in infants.

2AbstractBackgroundGastric fluid plays a key role in food digestion and drug dissolution, therefore, the amount of gastric fluid present in a fasted state may influence subsequent digestion and drug delivery. We aimed to describe intra- and interindividual variation in fasted gastric content volume (FGCV) and to determine the association with age, sex, and body size characteristics.MethodsData from 24 MRI studies measuring FGCV in healthy, mostly young individuals after an overnight fast were pooled. Analysis included 366 participants with a total of 870 measurements. Linear mixed model analysis was performed to calculate intra- and interindividual variability and to assess the effects of age, sex, weight, height, weight*height as a proxy for body size, and body mass index (BMI).ResultsFGCV ranged from 0 to 156 mL, with a mean (± SD) value of 33 ± 25 mL. The overall coefficient of variation within the study population was 75.6%, interindividual SD was 15 mL, and the intraindividual SD was 19 mL. Age, weight, height, weight*height, and BMI had no effect on FGCV. Women had lower volumes compared to men (MD: -6 mL), when corrected for the aforementioned factors.ConclusionFGCV is highly variable, with higher intraindividual compared to interindividual variability, indicating that FGCV is subject to day-to-day and within-day variation and is not a stable personal characteristic. This highlights the importance of considering FGCV when studying digestion and drug dissolution. Exact implications remain to be studied.GRAPHICAL ABSTRACTKEY POINTSFasted gastric content volume is highly variable, both within an individual and between individuals, and should range between 0 and 138 mL in healthy young individuals.Women have lower fasted gastric content volume compared to men; age, body weight and body size were not associated with differences in fasted gastric content volume.Fasted gastric content volume can impact both digestion and drug dissolution, although exact implications of the observed variations remain to be studied.

ABSTRACT Background In vitro studies suggest that casein coagulation of milk is influenced by its mineral composition, and may therefore affect the dynamics of protein digestion, gastric emptying and appearance of amino acids (AA) in the blood, but this remains to be confirmed in vivo . Objective This study aimed to compare gastrointestinal digestion between two milks with the same total calcium content but different casein mineralization (CM). Design Fifteen males (age 30.9±13.8 y, BMI 22.5±2.2 kg/m2) participated in this randomized cross-over study with two treatments. Participants underwent gastric magnetic resonance imaging (MRI) scans at baseline and every 10 min up to 90 min after consumption of 600 ml milk with low or high CM. Blood samples were taken at baseline and up to 5 hours postprandially. Primary outcomes were postprandial plasma AA concentrations and gastric emptying rate. Secondary outcomes were postprandial glucose and insulin levels, gastric coagulation as estimated by image texture metrics, and appetite ratings. Results Gastric content volume over time was similar for both treatments. However, gastric content image analysis suggested that the liquid fraction emptied quicker in the high CM milk, while the coagulum emptied slower. Relative to high CM, low CM showed earlier appearance of AAs that are more dominant in casein, such as proline (MD 4.18 µmol/L, 95%CI [2.38-5.98], p<0.001), while there was no difference in appearance of AAs that are more dominant in whey protein, such as leucine. The image texture metrics homogeneity and busyness differed significantly between treatments (MD 0.007, 95%CI [0.001, 0.012], p=0.022; MD 0.005, 95%CI [0.001, 0.010], p=0.012) likely because of a reduced coagulation in the low CM milk. Conclusions Mineral composition of milk can influence postprandial serum AA kinetics, likely due to differences in coagulation dynamics.

Background During breastfeeding the macronutrient composition of breastmilk changes gradually from relatively low-fat (foremilk) to relatively high-fat (hindmilk), initially exposing the gastrointestinal tract to a relatively low fat concentration. In contrast, infant formulae (IF) are homogenous. Mild processing and addition of milk fat globule membrane (MFGM) may impact gastric emulsion instability, potentially impacting the phased release of nutrients as observed during breastfeeding. Objective To assess gastric emulsion stability, gastric emptying, and the postprandial plasma metabolome of an experimental minimally processed IF (EF) with an altered fat-globule interface and a control IF (CF). Methods Twenty healthy males participated in this double-blind randomized crossover trial. Gastric MRI scans and blood samples were obtained before and after consumption of 600 ml CF or EF over a 2-h period. Outcomes included gastric top layer formation, total gastric volume, and blood parameters (FFA, insulin, glucose, and NMR-metabolomics). Results EF showed an earlier onset (13.4 min, p=0.017), smaller maximum volume (49.0 ml, p= 0.033), and a shorter time to maximum top layer volume (13.9 min, p=0.022), but similar AUC (p=0.915) compared to CF. Total gastric volume did not show a treatment*time effect. Insulin concentrations were lower for EF. FFA and glucose did not differ. EF yielded higher serum concentrations of phospholipid-and cholesterol-related metabolites. Conclusion An EF displayed faster gastric creaming than a CF, thereby potentially better mimicking the behavior of breastmilk which leads to phased release of nutrients into the intestine. Overall physiological benefits of this difference in gastric behavior remain to be studied further in infants.

AbstractBackgroundPea 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.ObjectivesTo studyin-vivoAA absorption kinetics and gastric behavior of pea protein products differing in heat treatment and texture and compare this within-vitrodigestion.DesignFourteen males participated in a randomized crossover trial. Iso-caloric and iso-volumetric treatments were 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 minutes post-prandial. Blood samples were collected at baseline and up to five hours. All treatments were tested with anin-vitrodigestion model (INFOGEST).ResultsHeat 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.ConclusionHeat 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.