Development of a protein food based on texturized wheat proteins, with high protein digestibility and improved lysine content.

The development of plant-based protein foods may facilitate the decrease in animal product consumption in western countries. Wheat proteins, as a starch coproduct, are available in large amounts and are good candidates for this development. We investigated the effect of a new texturing process on wheat protein digestibility and implemented strategies aimed at enhancing the lysine content of the product developed. Protein true ileal digestibility (TID) was determined in minipigs. In a preliminary experiment, the TID of wheat protein (WP), texturized wheat protein (TWP), TWP enriched with free lysine (TWP-L), or with chickpea flour (TWP-CP) was measured and compared to beef meat proteins. In the main experiment, minipigs (n = 6) were fed a dish (blanquette type) containing 40 g of protein in the form of TWP-CP, TWP-CP enriched with free lysine TWP-CP+L, chicken filet, or texturized soy, together with quinoa (18.5 g of protein) in order to improve meal supply of lysine. Wheat protein texturing did not affect total amino acid TID (96.8 % for TWP vs 95.3 % for WP), which was not different from that of beef meat (95.8 %). Chickpea addition did not affect protein TID (96.5 % for TWP-CP vs 96.8 % for TWP). The Digestible Indispensable Amino Acid Score for adults of the dish combining TWP-CP+L with quinoa was 91, whereas it was 110 and 111 for the dishes containing chicken filet or texturized soy. The above results show that, by optimizing lysine content through the formulation of the product, wheat protein texturization can enable the development of protein-rich products of nutritional quality compatible with quality protein intake in the context of a complete meal.

Despite similar clinical features metabolomics reveals distinct signatures in insulin resistant and progressively obese minipigs

Obesity is a major contributor to the silent and progressive development of type 2 diabetes (T2D) whose prevention could be improved if individuals at risk were identified earlier. Our aim is to identify early phenotypes that precede T2D in diet-induced obese minipigs. We fed four groups of minipigs (n = 5–10) either normal-fat or high-fat high-sugar diet during 2, 4, or 6 months. Morphometric features were recorded, and metabolomics and clinical parameters were assessed on fasting plasma samples. Multivariate statistical analysis on 46 morphometrical and clinical parameters allowed to differentiate 4 distinct phenotypes: NFC (control group) and three others (HF2M, HF4M, HF6M) corresponding to the different stages of the obesity progression. Compared to NFC, we observed a rapid progression of body weight and fat mass (4-, 7-, and tenfold) in obese phenotypes. Insulin resistance (IR; 2.5-fold increase of HOMA-IR) and mild dyslipidemia (1.2- and twofold increase in total cholesterol and HDL) were already present in the HF2M and remained stable in HF4M and HF6M. Plasma metabolome revealed subtle changes of 23 metabolites among the obese groups, including a progressive switch in energy metabolism from amino acids to lipids, and a transient increase in de novo lipogenesis and TCA-related metabolites in HF2M. Low anti-oxidative capacities and anti-inflammatory response metabolites were found in the HF4M, and a perturbed hexose metabolism was observed in HF6M. Overall, we show that IR and progressively obese minipigs reveal phenotype-specific metabolomic signatures for which some of the identified metabolites could be considered as potential biomarkers of early progression to TD2. (AU)

Casein structures differently affect postprandial amino acid delivery through their intra-gastric clotting properties.

We aimed to assess if casein structure affects its digestion and its subsequent amino acid delivery kinetic. Higher nitrogen levels were recovered in dialysates after in vitro digestions of sodium caseinate (SC, formed of small aggregates) compared to micellar casein (MC, native form of casein) and calcium caseinate (CC, intermediate structure). Likewise, plasma indispensable amino-acid concentration peak was higher after SC compared to MC or CC ingestion in healthy volunteers in a randomized, double blind, cross-over study. In pigs, gamma-scintigraphy using labelled meals revealed that SC was mainly localized in the proximal part of the stomach whereas MC was distributed in the whole gastric cavity. Caseins were found in both solid and liquid phases and partly hydrolyzed casein in the solid phase shortly after SC drink ingestion. These data support the concept of slow (MC) and rapid (SC) casein depending of casein structure, likely due to their intra-gastric clotting properties.

Compared with Milk Protein, a Wheat and Pea Protein Blend Reduces High-Fat, High-Sucrose Induced Metabolic Dysregulations while Similarly Supporting Tissue Protein Anabolism in Rats.

BACKGROUND: Plant proteins (PPs) have been associated with better cardiovascular health than animal proteins (APs) in epidemiological studies. However, the underlying metabolic mechanisms remain mostly unknown. OBJECTIVES: Using a combination of cutting-edge isotopic methods, we aimed to better characterize the differences in protein and energy metabolisms induced by dietary protein sources (PP compared with AP) in a prudent or western dietary context. METHODS: Male Wistar rats (n = 44, 8 wk old) were fed for 4.5 mo with isoproteic diets differing in their protein isolate sources, either AP (100% milk) or PP (50%:50% pea: wheat) and being normal (NFS) or high (HFS) in sucrose (6% or 15% kcal) and saturated fat (7% or 20% kcal), respectively. We measured body weight and composition, hepatic enzyme activities and lipid content, and plasma metabolites. In the intestine, liver, adipose tissues, and skeletal muscles, we concomitantly assessed the extent of amino acid (AA) trafficking using a 15N natural abundance method, the rates of macronutrient routing to dispensable AA using a 13C natural abundance method, and the metabolic fluxes of protein synthesis (PS) and de novo lipogenesis using a 2H labeling method. Data were analyzed using ANOVA and Mixed models. RESULTS: At the whole-body level, PP limited HFS-induced insulin resistance (-27% in HOMA-IR between HFS groups, P < 0.05). In the liver, PP induced lower lipid content (-17%, P < 0.01) and de novo lipogenesis (-24%, P < 0.05). In the different tissues studied, PP induced higher AA transamination accompanied by higher routings of dietary carbohydrates and lipids toward dispensable AA synthesis by glycolysis and ß-oxidation, resulting in similar tissue PS and protein mass. CONCLUSIONS: In growing rats, compared with AP, a balanced blend of PP similarly supports protein anabolism while better limiting whole-body and tissue metabolic dysregulations through mechanisms related to their less optimal AA profile for direct channeling to PS.

Plant Protein Can Be as Efficient as Milk Protein to Maintain Fat Free Mass in Old Rats, Even When Fat and Sugar Intakes Are High.

BACKGROUND: Alternative, sustainable, and adequate sources of protein must be found to meet global demand. OBJECTIVES: Our aim was to assess the effect of a plant protein blend with a good balance of indispensable amino acids and high contents of leucine, arginine, and cysteine on the maintenance of muscle protein mass and function during aging in comparison to milk proteins and to determine if this effect varied according to the quality of the background diet. METHODS: Old male Wistar rats (n = 96, 18 mo old) were randomly allocated for 4 mo to 1 of 4 diets, differing according to protein source (milk or plant protein blend) and energy content (standard, 3.6 kcal/g, with starch, or high, 4.9 kcal/g, with saturated fat and sucrose). We measured: every 2 mo, body composition and plasma biochemistry; before and after 4 mo, muscle functionality; after 4 mo, in vivo muscle protein synthesis (flooding dose of L-[1-13C]-valine) and muscle, liver, and heart weights. Two-factor ANOVA and repeated measures 2-factor ANOVA were conducted. RESULTS: There was no difference between protein type on the maintenance during aging of lean body mass, muscle mass, and muscle functionality. The high-energy diet significantly increased body fat (+47%) and heart weight (+8%) compared to the standard energy diet but had no effect on fasting plasma glucose and insulin. Muscle protein synthesis was significantly stimulated by feeding to the same extent in all groups (+13%). CONCLUSIONS: Since high-energy diets had little impact on insulin sensitivity and related metabolism, we could not test the hypothesis that in situations of higher insulin resistance, our plant protein blend may be better than milk protein. However, this rat study offers significant proof of concept from the nutritional standpoint that appropriately blended plant proteins can have high nutritional value even in demanding situations such as aging protein metabolism.

Targeting the gut to prevent and counteract metabolic disorders and pathologies during aging.

Impairment of gut function is one of the explanatory mechanisms of health status decline in elderly population. These impairments involve a decline in gut digestive physiology, metabolism and immune status, and associated to that, changes in composition and function of the microbiota it harbors. Continuous deteriorations are generally associated with the development of systemic dysregulations and ultimately pathologies that can worsen the initial health status of individuals. All these alterations observed at the gut level can then constitute a wide range of potential targets for development of nutritional strategies that can impact gut tissue or associated microbiota pattern. This can be key, in a preventive manner, to limit gut functionality decline, or in a curative way to help maintaining optimum nutrients bioavailability in a context on increased requirements, as frequently observed in pathological situations. The aim of this review is to give an overview on the alterations that can occur in the gut during aging and lead to the development of altered function in other tissues and organs, ultimately leading to the development of pathologies. Subsequently is discussed how nutritional strategies that target gut tissue and gut microbiota can help to avoid or delay the occurrence of aging-related pathologies.

Despite similar clinical features metabolomics reveals distinct signatures in insulin resistant and progressively obese minipigs.

Obesity is a major contributor to the silent and progressive development of type 2 diabetes (T2D) whose prevention could be improved if individuals at risk were identified earlier. Our aim is to identify early phenotypes that precede T2D in diet-induced obese minipigs. We fed four groups of minipigs (n = 5-10) either normal-fat or high-fat high-sugar diet during 2, 4, or 6 months. Morphometric features were recorded, and metabolomics and clinical parameters were assessed on fasting plasma samples. Multivariate statistical analysis on 46 morphometrical and clinical parameters allowed to differentiate 4 distinct phenotypes: NFC (control group) and three others (HF2M, HF4M, HF6M) corresponding to the different stages of the obesity progression. Compared to NFC, we observed a rapid progression of body weight and fat mass (4-, 7-, and tenfold) in obese phenotypes. Insulin resistance (IR; 2.5-fold increase of HOMA-IR) and mild dyslipidemia (1.2- and twofold increase in total cholesterol and HDL) were already present in the HF2M and remained stable in HF4M and HF6M. Plasma metabolome revealed subtle changes of 23 metabolites among the obese groups, including a progressive switch in energy metabolism from amino acids to lipids, and a transient increase in de novo lipogenesis and TCA-related metabolites in HF2M. Low anti-oxidative capacities and anti-inflammatory response metabolites were found in the HF4M, and a perturbed hexose metabolism was observed in HF6M. Overall, we show that IR and progressively obese minipigs reveal phenotype-specific metabolomic signatures for which some of the identified metabolites could be considered as potential biomarkers of early progression to TD2.

Lysine and homoarginine are closely interrelated metabolites in the rat.

L-Lysine (Lys) and L-arginine (Arg), but not L-homoarginine (hArg), are proteinogenic amino acids. In healthy humans, oral administration of hArg increased the plasma concentration of Lys, suggesting Lys as a metabolite of hArg. In humans and animals, hArg is biosynthesized from Arg and Lys by arginine:glycine amidinotransferase (AGAT). In vitro, recombinant human arginase and bovine liver arginase I hydrolyzed hArg to Lys, suggesting Lys as a metabolite of hArg. The aim of the present study was to investigate whether changes in blood concentrations of hArg and Lys in old rats fed for 4 months with varied controlled experimental diets could suggest interconversion of these amino acids. Blood samples (n = 253) were taken before (T0) and after 2 months (T2) and 4 months (T4) of the experiment. Plasma concentrations of Lys and hArg were determined by gas chromatography-mass spectrometry. The plasma hArg concentration markedly correlated with the plasma Lys concentration at all timepoints (r ≥ 0.7, P < 0.0001). Further analysis demonstrated that hArg and Lys are closely and specifically associated independently of experimental time/rat age and diet, suggesting that hArg and Lys are mutual metabolites in old rats. Based on the plasma concentration changes, the median yield of hArg from Lys was determined to be 0.17% at T0 and each 0.27% at T2 and T4. With a circulating concentration of about 3 µM, hArg a major metabolite of Lys in healthy humans. hArg supplementation is currently investigated as a cardioprotective means to improve impaired hArg synthesis. Present knowledge suggests that Lys rather than hArg supplementation may be even more favorable.

Approximately Half of Total Protein Intake by Adults Must be Animal-Based to Meet Nonprotein, Nutrient-Based Recommendations, With Variations Due to Age and Sex.

BACKGROUND: Shifting towards a more plant-based diet, as promoted in Western countries, will reduce the animal protein contribution to total proteins. Such a reduction may not only impair protein adequacy, but also the adequacy in other nutrients. OBJECTIVES: We determined, for different adult subpopulations, the minimum total protein levels and the minimum animal protein contributions to total proteins that are compatible with the fulfillment of all nonprotein nutrient-based recommendations. METHODS: Mean nutritional contents and mean diet costs were estimated using a French, cross-sectional, representative survey for 5 French subpopulations: 1) women < 50 y; 2) women 50-64 y; 3) women ≥ 65 y; 4) men < 65 y; and 5) men ≥ 65 y. For each subpopulation, linear programming optimization was used to assess the minimum protein level (model set #1) and the minimum animal protein contribution to total proteins (model set #2) that are compatible with the fulfillment of all nutrient-based recommendations (except proteins, for which levels were analyzed as outputs). Total diet costs were not allowed to increase. Eating habits were considered in model set #2 only. RESULTS: The minimum amount of protein that was theoretically compatible with the fulfillment of nutrient-based recommendations (model set #1) was below the minimum recommended protein intake for all subpopulations except women < 50 y. In model set #2, for women and men ≥ 65 y, decreasing animal protein contributions to total proteins below 55% and 60%, respectively, led to protein levels below recommended levels. For the other subpopulations (women < 50 y, women 50-64 y, and men < 65 y), the lowest animal protein contributions to total proteins compatible with a nutritionally adequate diet (including protein adequacy) were 55%, 50%, and 45%, respectively. CONCLUSIONS: This study provides factual information about the animal protein contributions to total proteins compatible with meeting all nutrient-based recommendations at no additional cost, and shows that they vary between 45% and 60% depending on the group of adults considered.

A Mix of Dietary Fibres Changes Interorgan Nutrients Exchanges and Muscle-Adipose Energy Handling in Overfed Mini-Pigs.

This study evaluates the capacity of a bread enriched with fermentable dietary fibres to modulate the metabolism and nutrients handling between tissues, gut and peripheral, in a context of overfeeding. Net fluxes of glucose, lactate, urea, short chain fatty acids (SCFA), and amino acids were recorded in control and overfed female mini-pigs supplemented or not with fibre-enriched bread. SCFA in fecal water and gene expressions, but not protein levels or metabolic fluxes, were measured in muscle, adipose tissue, and intestine. Fibre supplementation increased the potential for fatty acid oxidation and mitochondrial activity in muscle (acox, ucp2, sdha and cpt1-m, p < 0.05) as well as main regulatory transcription factors of metabolic activity such as pparα, pgc-1α and nrf2. All these features were associated with a reduced muscle fibre cross sectional area, resembling to controls (i.e., lean phenotype). SCFA may be direct inducers of these cross-talk alterations, as their feces content (+52%, p = 0.05) was increased in fibre-supplemented mini-pigs. The SCFA effects could be mediated at the gut level by an increased production of incretins (increased gcg mRNA, p < 0.05) and an up-regulation of SCFA receptors (increased gpr41 mRNA, p < 0.01). Hence, consumption of supplemented bread with fermentable fibres can be an appropriate strategy to activate muscle energy catabolism and limit the establishment of an obese phenotype.

A Scoping Review: Metabolomics Signatures Associated with Animal and Plant Protein Intake and Their Potential Relation with Cardiometabolic Risk.

The dietary shift from animal protein (AP) to plant protein (PP) sources is encouraged for both environmental and health reasons. For instance, PPs are associated with lower cardiovascular and diabetes risks compared with APs, although the underlying mechanisms mostly remain unknown. Metabolomics is a valuable tool for globally and mechanistically characterizing the impact of AP and PP intake, given its unique ability to provide integrated signatures and specific biomarkers of metabolic effects through a comprehensive snapshot of metabolic status. This scoping review is aimed at gathering and analyzing the available metabolomics data associated with PP- and AP-rich diets, and discusses the metabolic effects underlying these metabolomics signatures and their potential implication for cardiometabolic health. We selected 24 human studies comparing the urine, plasma, or serum metabolomes associated with diets with contrasted AP and PP intakes. Among the 439 metabolites reported in those studies as able to discriminate AP- and PP-rich diets, 46 were considered to provide a robust level of evidence, according to a scoring system, especially amino acids (AAs) and AA-related products. Branched-chain amino acids, aromatic amino acids (AAAs), glutamate, short-chain acylcarnitines, and trimethylamine-N-oxide, which are known to be related to an increased cardiometabolic risk, were associated with AP-rich diets, whereas glycine (rather related to a reduced risk) was associated with PP-rich diets. Tricarboxylic acid (TCA) cycle intermediates and products from gut microbiota AAA degradation were also often reported, but the direction of their associations differed across studies. Overall, AP- and PP-rich diets result in different metabolomics signatures, with several metabolites being plausible candidates to explain some of their differential associations with cardiometabolic risk. Additional studies specifically focusing on protein type, with rigorous intake control, are needed to better characterize the associated metabolic phenotypes and understand how they could mediate differential AP and PP effects on cardiometabolic risk.

True ileal amino acid digestibility and digestible indispensable amino acid scores (DIAASs) of plant-based protein foods.

Plant-based protein foods are increasingly common, but data on their nutritional protein quality are scarce. This study evaluated it for seitan (wheat-based food), tofu (soya-based food), soya milk, and a pea emulsion. The true ileal digestibility (TID) of their amino acids was determined in minipigs, to calculate the digestible indispensable amino acid score (DIAAS). The TID of the proteins was high and not significantly different between the foods tested: 97% for seitan, 95% for tofu, 92% for soya milk and 94% for pea emulsion. There were only minor differences in individual amino acid TIDs. DIAAS ranking was thus essentially driven by the amino acid composition of the food: soya-based food > pea emulsion > seitan. Nevertheless, the lower TID of sulphur-containing amino acids in tofu than in soya milk induced a significant decrease in DIAAS (from 117% to 97%), highlighting the importance of the matrix effect on nutritional protein quality.

Food matrix structure (from Biscuit to Custard) has an impact on folate bioavailability in healthy volunteers.

PURPOSE: We examined the impact of matrix food structure on post-prandial folate bioavailability (and other macronutrients) in human volunteers using a randomized, controlled, crossover experimental design. METHODS: Twelve healthy male volunteers (22.6 ± 0.4 years old) were offered four food models (differing in matrix structure: Custard, Pudding, Sponge cake and Biscuit) to which 1 mg of folic acid was added, according to a randomized, controlled, crossover experimental design. Plasma folates, glucose, insulin, alpha amino nitrogen and triglycerides were measured over the post-prandial period (from T0 to T480 min). RESULTS: Food matrix structure was capable of altering folate plasma availability. The highest folate availability was observed for pudding and to a lesser extent Sponge cake whereas the lowest was for the two matrices presenting extreme rheological properties: Custard (liquid) (P < 0.05 total AUC) and to a lesser extent Biscuit (hard solid) (P < 0.05, AUC 180 min). The analysis of plasma kinetics of appearance of other nutrients/metabolites helps to understand/explain the lower bioavailability of folates in Custard and Biscuit. CONCLUSION: A least overall efficient bio-accessibility of all macronutrients and folic acid is observed in the gut lumen for Biscuit (delayed/incomplete destructuration of biscuit along the digestive tract). On the contrary, the lower folic acid absorption observed with custard does not fit with the rapid plasma appearance of other nutrients and should require further investigation.

Combining Plant Proteins to Achieve Amino Acid Profiles Adapted to Various Nutritional Objectives-An Exploratory Analysis Using Linear Programming.

Although plant proteins are often considered to have less nutritional quality because of their suboptimal amino acid (AA) content, the wide variety of their sources, both conventional and emerging, suggests potential opportunities from complementarity between food sources. This study therefore aimed to explore whether, and to what extent, combinations of protein ingredients could reproduce an AA profile set as a nutritional objective, and to identify theoretical solutions and limitations. We collected compositional data on protein ingredients and raw plant foods (n = 151), and then ran several series of linear optimization to identify protein ingredient mixes that maximized the content in indispensable AA and reproduced various objective profiles: a "balanced profile," based on AA requirements for adults; "animal profiles" corresponding to conventional animal protein compositions, and a "cardioprotective profile," which has been associated with a lower cardiovascular risk. We assumed a very good digestibility of plant protein isolates. As expected, obtaining a balanced profile was obvious, but we also identified numerous plant protein mixtures that met demanding AA profiles. Only for particularly demanding profiles, such as mimicking a particular animal protein, did solutions require the use of protein fractions from more specific sources such as pea or canola. Optimal plant blends could mimic animal proteins such as egg white, cow milk, chicken, whey or casein with a similarity reaching 94.2, 98.8, 86.4, 92.4, and 98.0%, respectively. The limiting constraints were mainly isoleucine, lysine, and histidine target contents. These different solutions offer potential for the formulation of mixtures adapted to specific populations or the design of plant-based substitutes. Some ingredients are not commercially available but they could be developed.

Food-dependent set-up of the DiDGI® dynamic in vitro system: Correlation with the porcine model for protein digestion of soya-based food.

The present study compared in vivo protein digestion in a miniature pig model with the dynamic in vitro system DiDGI®, using three digestive compartments (stomach, duodenum, and jejunum + ileum). Two soya-based meals-commercial soya milk and tofu-were studied, each with the same macronutrient content but different macrostructures. Our aim was to first deduce from the in vivo experiments in pigs key digestive parameters such as gastric pH, stomach emptying kinetics, and intestinal transit time, in order to design a relevant set-up for the dynamic in vitro system. Then, we compared digestive samples collected at fixed sampling times from both in vivo and in vitro models regarding different values related to proteolysis. We observed similar evolutions of gastric peptide distribution and duodenal proteolysis between models. Overall, apparent ileal digestibility of nitrogen was similar in vitro and in vivo and the differences between the two meals were conserved between models.

Important determinants to take into account to optimize protein nutrition in the elderly: solutions to a complex equation.

During ageing, skeletal muscle develops anabolic resistance towards the stimulation of protein synthesis induced by dietary amino acids. The stimulation of muscle protein synthesis after food intake remains insufficient, even with a protein intake recommended for healthy adults. This alteration is one of the mechanisms known to be responsible for the decrease of muscle mass and function during ageing, namely sarcopenia. Increasing dietary protein intake above the current RDA(0⋅83 g/kg/d) has been strongly suggested to overcome the anabolic resistance observed. It is also specified that the dietary protein ingested should be of good quality. A protein of good quality is a protein whose amino acid (AA) composition covers the requirement of each AA when ingested at the RDA. However, the biological value of proteins may vary among dietary sources in which AA composition could be unbalanced. In the present review, we suggest that the quality of a dietary protein is also related to several other determinants. These determinants include the speed of digestion of dietary proteins, the presence of specific AA, the food matrix in which the dietary proteins are included, the processes involved in the production of food products (milk gelation and cooking temperature), the energy supply and its nature, and the interaction between nutrients before ingestion. Particular attention is given to plant proteins for nutrition of the elderly. Finally, the timing of protein intake and its association with the desynchronized intake of energetic nutrients are discussed.

Postprandial NMR-Based Metabolic Exchanges Reflect Impaired Phenotypic Flexibility across Splanchnic Organs in the Obese Yucatan Mini-Pig.

The postprandial period represents one of the most challenging phenomena in whole-body metabolism, and it can be used as a unique window to evaluate the phenotypic flexibility of an individual in response to a given meal, which can be done by measuring the resilience of the metabolome. However, this exploration of the metabolism has never been applied to the arteriovenous (AV) exploration of organs metabolism. Here, we applied an AV metabolomics strategy to evaluate the postprandial flexibility across the liver and the intestine of mini-pigs subjected to a high fat-high sucrose (HFHS) diet for 2 months. We identified for the first time a postprandial signature associated to the insulin resistance and obesity outcomes, and we showed that the splanchnic postprandial metabolome was considerably affected by the meal and the obesity condition. Most of the changes induced by obesity were observed in the exchanges across the liver, where the metabolism was reorganized to maintain whole body glucose homeostasis by routing glucose formed de novo from a large variety of substrates into glycogen. Furthermore, metabolites related to lipid handling and energy metabolism showed a blunted postprandial response in the obese animals across organs. Finally, some of our results reflect a loss of flexibility in response to the HFHS meal challenge in unsuspected metabolic pathways that must be further explored as potential new events involved in early obesity and the onset of insulin resistance.

Effects of the apple matrix on the postprandial bioavailability of flavan-3-ols and nutrigenomic response of apple polyphenols in minipigs challenged with a high fat meal.

Food matrix interactions with polyphenols can affect their bioavailability and as a consequence may modulate their biological effects. The aim of this study was to determine if the matrix and its processing would modulate the bioavailability and the postprandial nutrigenomic response to a dietary inflammatory stress of apple flavan-3-ol monomers. We carried out an acute randomized controlled study in minipigs challenged with a high fat meal (HFM) supplemented with raw fruit, puree, or apple phenolic extract with matched content of flavan-3-ol monomers. Fasting and postprandial blood samples were collected over 3 h to quantify flavan-3-ol monomers in sera by UPLC-Q-TOF/MS and to isolate peripheral blood mononuclear cells (PBMCs) for assessing the changes in the gene expression profile using a microarray analysis. When compared to the extract-supplemented meal, the peak of the total flavan-3-ol concentration was reduced by half with both raw apple and puree supplements. The apple matrices also affected the gene expression profile as revealed by the Principal Component Analysis of the microarray data from PBMCs which discriminated the supplementation of HFM with the polyphenol extract from those with raw apples or puree. A total of 309 genes were identified as differentially expressed by the apple-derived products compared to HFM, with 63% modulated only in the presence of the food matrix (apple and puree). The number of differentially modulated genes was higher with the puree (246) than with the unprocessed apple (182). Pathway enrichment analyses revealed that genes affected by the apple-derived products control inflammation and leukocyte transendothelial migration both involved in the onset of atherosclerotic processes. Overall, this study showed that the two apple matrices reduce the postprandial serum concentration of flavon-3-ols whereas they increase the nutrigenomic response of PBMCs. The biological processes identified as modulated by the apple products suggest an attenuation of the transient pro-inflammatory response induced by a HFM. The differences observed between the nutrigenomic responses support that the apple matrix and its processing affect the nutrigenomic response, probably by increasing the bioavailability of other apple phytochemicals. To conclude, this study raises awareness for considering the impact of the food matrix and its processing on the biological response of polyphenols in nutritional studies.

Temporal changes in postprandial intragastric pH: Comparing measurement methods, food structure effects, and kinetic modelling.

Intragastric pH greatly affects food disintegration and the release of nutrients in the gut. Here, the behaviour of two liquid meals (soymilk, pea emulsion) and two solid meals (tofu, seitan) was tested in miniature pigs fitted with gastric cannula. For 5 h, intragastric pH was recorded using one of three methods: ex vivo measurements of chyme samples, in situ measurements using pH catheters, or in situ measurements using wireless pH capsules, both inserted through a pig's cannula. The pH values obtained with the two in situ methods were highly correlated. The liquid and solid foods yielded distinct pH kinetics. For the solids, pH simply decreased exponentially. For the liquids, pH increased rapidly and then plateaued for 2 h before dropping Food macrostructure and, to a lesser extent, food buffering capacity clearly had an impact on intragastric pH. We modelled changes in intragastric pH over time with food-dependent nonlinear equations.