Protein Ingredient Quality within Infant Formulas Impacts Plasma Amino Acid Concentrations in Neonatal Minipiglets.

BACKGROUND: Infant formulas (IFs), the only adequate substitute to human milk, are complex matrices that require numerous ingredients and processing steps that may impact protein digestion and subsequent amino acid (AA) absorption. OBJECTIVES: The objective was to understand the impact of the protein ingredient quality within IFs on postprandial plasma AA profiles. METHODS: Four isonitrogenous and isocaloric IFs were produced at a semi-industrial scale using whey proteins from different origins (cheese compared with ideal whey) and denaturation levels (IF-A, -B, -C), and caseins with different supramolecular organizations (IF-C, -D). Ten Yucatan minipiglets (12- to 27-d-old) were used as a human infant model and received each IF for 3 d according to a Williams Latin square followed by a 2-d wash-out period. Jugular plasma was regularly sampled from 10 min preprandial to 4 h postprandial on the third day to measure free AAs, urea, insulin, and glucose concentrations. Data were statistically analyzed using a mixed linear model with diet (IFs), time, and sex as fixed factors and piglet as random factor. RESULTS: IFs made with cheese whey (IF-A and -B) elicited significantly higher plasma total and essential AA concentrations than IFs made with ideal whey (IF-C and -D), regardless of the pre- and postprandial times. Most of the differences observed postprandially were explained by AA homeostasis modifications. IFs based on cheese whey induced an increased plasma concentration of Thr due to both a higher Thr content in these IFs and a Thr-limiting degrading capability in piglets. The use of a nonmicellar casein ingredient led to reduced plasma content of AA catabolism markers (IF-D compared with IF-C). CONCLUSIONS: Overall, our results highlight the importance of the protein ingredient quality (composition and structure) within IFs on neonatal plasma AA profiles, which may further impact infant protein metabolism.

Minimal processed infant formula vs. conventional shows comparable protein quality and increased postprandial plasma amino acid kinetics in rats.

During industrial processing, heat treatments applied to infant formulas may affect protein digestion. Recently, innovative processing routes have been developed to produce minimally heat-processed infant formula. Our objective was to compare the in vivo protein digestion kinetics and protein quality of a minimally processed (T−) and a heat-treated (T+++) infant formula. Sixty-eight male Wistar rats (21 d) were fed with either a diet containing 40 % T− (n 30) or T+++ (n 30), or a milk protein control diet (n 8) during 2 weeks. T− and T+++ rats were then sequentially euthanised 0, 1, 2, 3 or 6 h (n 6/time point) after ingestion of a meal containing their experimental diet. Control rats were euthanised 6 h after ingestion of a protein-free meal to determine nitrogen and amino acid endogenous losses. Nitrogen and amino acid true caecal digestibility was high for both T− and T+++ diets (> 90 %), but a tendency towards higher nitrogen digestibility was observed for the T− diet (96·6 ± 3·1 %) compared with the T+++ diet (91·9 ± 5·4 %, P = 0·0891). This slightly increased digestibility led to a greater increase in total amino acid concentration in plasma after ingestion of the T− diet (P = 0·0010). Comparable protein quality between the two infant formulas was found with a digestible indispensable amino acid score of 0·8. In conclusion, this study showed that minimal processing routes to produce native infant formula do not modify protein quality but tend to enhance its true nitrogen digestibility and increase postprandial plasma amino acid kinetics in rats.

Nutritional quality of proteins from two beef co-products as determined in the growing pig.

The increasing demand for food and especially proteins leads to the search for alternative protein sources. Meat co-products, which are available but little used in human food, provide a potential solution to this challenge. The present study aimed to evaluate the nutritional quality of two beef protein ingredients (greasy greaves recovered proteins (GGRP) and water recovered proteins (WRP)), both co-products of the fat rendering process. Their true ileal digestibility (TID), digestible indispensable amino acid score (DIAAS) and kinetics of plasma amino acids (AA) were measured in ten growing pigs, each fed the two co-products and a protein-free diet. Titanium dioxide was used as an indigestible marker. Digesta samples were collected for 9 h after meal ingestion, and blood samples were collected at ten time points during the same period. Total nitrogen (N) and AA contents were determined. Data were statistically analysed using linear mixed models. The TID of total N was not different between WRP and GGRP (81-84 %, P > 0·05). The first-limiting AA was Trp for both ingredients, with a DIAAS much higher for GGRP than for WRP (74 and 10 % for adults, respectively; P < 0·001). Postprandial plasma AA concentration peaked earlier for WRP (3 h) than for GGRP (5 h). Plasma concentrations of total and essential AA were higher (P < 0·001) with GGRP diet than WRP diet. Overall, GGRP has a nutritional quality suitable to meet the needs of adults for AA, while WRP needs to be supplemented with other protein sources to fulfil the dietary requirements.

Impact of a minimally processing route for the production of infant formulas on their sensory properties.

Infant formulas (IFs), the sole adequate substitute to human milk, undergo several thermal treatments during production that can damage milk proteins and promote the formation of Maillard reaction products, modifying nutritional and sensory properties. The aim of this study was to determine the impact of a minimally processing route based on membrane filtration associated with different levels of heat treatment, on the odor, taste, texture and color attributes of IFs, then to compare with those of commercial milks. Three experimental IFs (produced with membrane filtration associated with low - T-, medium - T+, or high thermal treatments - T+++) were evaluated. Triangular tests conducted with a panel of 50 adults highlighted clear disparities between all the IFs. The same panel applied the Check-All-That-Apply method to evaluate the IFs: the range of variability between T- and T+++ was similar to that between the 2 commercial IFs, and the sensory characteristics of the experimental IFs were not far from the commercial brands for flavor and texture attributes. Analysis performed on the citation frequencies for each descriptor differentiated T-/T+ from T+++, but all the experimental IFs were described with positive sensory characteristics, unlike one commercial IF. Volatile organic compounds (VOCs) content of IFs with low and high thermal treatments were analyzed. Forty VOCs were identified by gas chromatography-mass spectrometry. T- contained a higher quantity of VOCs than T+++, except for benzaldehyde (Maillard reaction product), and aldehydes (oxidation-related products) were the most represented compounds. In conclusion, the processing was associated with sensory differences among IFs, but no marked difference in flavors was found according to CATA and physicochemical analysis. Additionally, no unpleasant sensory descriptors were noted. This shows that the minimally processed route leads to IFs that could fit well within the market from a sensory point of view.

Ileal Digestibility of Nitrogen and Amino Acids in Human Milk and an Infant Formula as Determined in Neonatal Minipiglets.

BACKGROUND: Infant formula (IF) has to provide at least the same amount of amino acids (AAs) as human milk (HM). AA digestibility in HM and IF was not studied extensively, with no data available for tryptophan digestibility. OBJECTIVES: The present study aimed to measure the true ileal digestibility (TID) of total nitrogen and AAs in HM and IF to estimate AA bioavailability using Yucatan mini-piglets as an infant model. METHODS: Twenty-four 19-day-old piglets (males and females) received either HM or IF for 6 days or a protein-free diet for 3 days, with cobalt-EDTA as an indigestible marker. Diets were fed hourly over 6 h before euthanasia and digesta collection. Total N, AA, and marker contents in diets and digesta were measured to determine the TID. Unidimensional statistical analyses were conducted. RESULTS: Dietary N content was not different between HM and IF, while true protein was lower in HM (-4 g/L) due to a 7-fold higher non-protein N content in HM. The TID of total N was lower (P < 0.001) for HM (91.3 ± 1.24%) than for IF (98.0 ± 0.810%), while the TID of amino acid nitrogen (AAN) was not different (average of 97.4 ± 0.655%, P = 0.272). HM and IF had similar (P > 0.05) TID for most of the AAs including tryptophan (96.7 ± 0.950%, P = 0.079), except for some AAs (lysine, phenylalanine, threonine, valine, alanine, proline, and serine), with small significant difference (P < 0.05). The first limiting AA was the aromatic AAs, and the digestible indispensable AA score (DIAAS) was higher for HM (DIAASHM = 101) than for IF (DIAASIF = 83). CONCLUSION: HM, compared to IF, had a lower TID for total N only, whereas the TID of AAN and most AAs, including Trp, was high and similar. A larger proportion of non-protein N is transferred to the microbiota with HM, which is of physiological relevance, although this fraction is poorly considered for IF manufacturing.

Relationship between sensory liking for fat, sweet or salt and cardiometabolic diseases: mediating effects of diet and weight status.

PURPOSE: Previous works have been suggested that individual sensory liking is a predictor of dietary intake and weight status, and may consequently influence development of cardiometabolic diseases (CMDs). We investigated the association between sensory liking for fat-and-salt, fat-and-sweet, sweet or salt and the onset of hypertension, diabetes and cardiovascular diseases (CVDs) over 6 years in adults, and the mediating effects of dietary intake and body mass index (BMI). METHODS: We examined the CMDs risk among 41,332 (for CVD and diabetes) and 37,936 (for hypertension) French adults (NutriNet-Santé cohort). Liking scores, individual characteristics, diet and anthropometry were assessed at baseline using questionnaires. Health events were collected during 6 years. Associations between sensory liking and CMDs risk, and the mediating effect of diet and BMI, were assessed using Cox proportional hazards models. RESULTS: Sensory liking for fat-and-salt was associated with an increased risk of diabetes, hypertension and CVD [hazard ratios (HR) for 1-point increment of the sensory score: HR 1.30 (95% CI 1.18, 1.43), HR 1.08 (1.04, 1.13) and HR 1.10 (1.02, 1.19), respectively]. BMI and dietary intake both explained 93%, 98% and 70%, of the overall variation of liking for fat-and-salt liking in diabetes, hypertension and CVD, respectively. Liking for fat-and-sweet and liking for salt were also associated with an increased risk of diabetes [HR 1.09 (1.01, 1.17) and HR 1.09 (1.01, 1.18), respectively], whereas liking for sweet was associated with a decreased risk [HR 0.76 (0.69, 0.84)]. CONCLUSIONS: Higher liking for fat-and-salt is significantly associated with CMDs risk, largely explained by dietary intake and BMI. Our findings may help to guide effective targeted measures in prevention.

Impact of human milk pasteurization on the kinetics of peptide release during in vitro dynamic term newborn digestion.

Holder pasteurization (62.5°C, 30 min) ensures sanitary quality of donor's human milk but also denatures beneficial proteins. Understanding whether this further impacts the kinetics of peptide release during gastrointestinal digestion of human milk was the aim of the present paper. Mature raw (RHM) or pasteurized (PHM) human milk were digested (RHM, n = 2; PHM, n = 3) by an in vitro dynamic system (term stage). Label-free quantitative peptidomics was performed on milk and digesta (ten time points). Ascending hierarchical clustering was conducted on "Pasteurization × Digestion time" interaction coefficients. Preproteolysis occurred in human milk (159 unique peptides; RHM: 91, PHM: 151), mostly on ß-casein (88% of the endogenous peptides). The predicted cleavage number increased with pasteurization, potentially through plasmin activation (plasmin cleavages: RHM, 53; PHM, 76). During digestion, eight clusters resumed 1054 peptides from RHM and PHM, originating for 49% of them from ß-casein. For seven clusters (57% of peptides), the kinetics of peptide release differed between RHM and PHM. The parent protein was significantly linked to the clustering (p-value = 1.4 E-09), with ß-casein and lactoferrin associated to clusters in an opposite manner. Pasteurization impacted selectively gastric and intestinal kinetics of peptide release in term newborns, which may have further nutritional consequences.

Associations between liking for fat, sweet or salt and obesity risk in French adults: a prospective cohort study.

BACKGROUND: Individual sensory liking appears to be an important determinant of dietary intake and may consequently influence weight status. Cross-sectional studies have shown positive association between fat liking and weight status and equivocal results regarding salt and sweet liking. Moreover, the contribution of dietary intake to explain this relationship has not been studied yet. We investigated the prospective association between sensory liking for fat, sweet or salt and the onset of obesity over 5 years in adults, and the mediating effect of dietary intake. METHODS: We prospectively examine the risk of obesity among 24,776 French adults participating in the NutriNet-Santé cohort study. Liking scores and dietary data were assessed at baseline using a validated web-based questionnaire and 24 h records, respectively. Self-reported anthropometric data were collected using web-based questionnaire, each year during 5 years. Associations between quartiles of liking for fat, sweet or salt and obesity risk, and the mediating effect of diet were assessed by multivariate Cox proportional hazards models stratified by gender, adjusted for sociodemographic and lifestyle factors. RESULTS: In both genders, sensory liking for fat was associated with an increased risk of obesity (hazard ratios for quartile 4 compared to quartile 1, men: HR(Q4vs.Q1) = 2.39 (95% CI 1.39,4.11) P-trend = 0.0005, women: HR(Q4vs.Q1) = 2.02 (1.51,2.71) P-trend = <0.0001). Dietary intake explained 32% in men and 52% in women of the overall variation of liking for fat in obesity. Sensory liking for sweet was associated with a decreased risk of obesity (men: HR(Q4vs.Q1) = 0.51 (0.31,0.83) P-trend = 0.01, women: HR(Q4vs.Q1) = 0.72 (0.54,0.96) P-trend = 0.035). No significant association between salt liking and the risk of obesity was found. CONCLUSIONS: Unlike sweet and salt liking, higher liking for fat appears to be a major risk factor of obesity, largely explained by dietary intake. Our findings emphasize the need to centrally position sensory liking in obesity prevention.

Sociodemographic, psychological, and lifestyle characteristics are associated with a liking for salty and sweet tastes in French adults.

BACKGROUND: Various studies have shown that sensory liking influences dietary behavior and that individual characteristics are related to food intake and weight status, but little is known about individual profiles associated with salt and sweet liking. OBJECTIVE: The aim of the present study was to investigate the association between a liking for salty and sweet tastes (i.e., a liking for foods rich in salt or sugar and preferred amounts of salt or sugar seasoning in foods) and sociodemographic, psychological, and lifestyle characteristics in a large sample. METHODS: Individual factors and liking scores were collected by validated questionnaires from 37,181 French adults participating in the NutriNet-Santé study, a large web-based observational cohort launched in 2009 that studies relations between nutrition and health. The associations were assessed by multivariable multinomial logistic regression models adjusted for socioeconomic, anthropometric, and health variables. RESULTS: In both genders, with increasing age, individuals were more likely to have a high salt liking (men, OR: 1.24; 95% CI: 1.18, 1.30; women, OR: 1.14, 95% CI: 1.09, 1.19), whereas they were less likely to have a strong sweet liking (men, OR: 0.87; 95% CI: 0.83, 0.91; women, OR: 0.66; 95% CI: 0.64, 0.68). Current smokers (men, OR: 2.30; 95% CI: 1.90, 2.78; women, OR: 1.50; 95% CI: 1.36, 1.66) and heavy drinkers (men, OR: 2.92; 95% CI: 2.37, 3.58; women, OR: 2.57, 95% CI: 2.22, 2.98) were more likely to like salt than nonsmokers and alcohol abstainers. Regarding the sweet taste, women smokers were less likely to like sweets (OR: 0.80; 95% CI: 0.72, 0.89). Highly uncontrolled eaters [men, OR: 2.39; 95% CI: 2.04, 2.80; women, OR: 2.22; 95% CI: 1.99, 2.47) and highly emotional women (OR: 1.35; 95% CI: 1.18, 1.55) were more likely to have a high liking for sweets than slightly uncontrolled eaters and nonemotional eaters, whereas those with high cognitive restraint (men, OR: 0.39; 95% CI: 0.33, 0.46; women, OR: 0.55; 95% CI: 0.50, 0.60) and former weight-loss dieters (men, OR: 0.60; 95% CI: 0.52, 0.70; women, OR: 0.68; 95% CI: 0.62, 0.73) were less likely to have a strong sweet liking compared with those with low cognitive restraint and never-dieters. CONCLUSION: An unhealthy lifestyle that includes smoking and alcohol consumption may influence salt liking, and eating behavior may have an impact on sweet liking. Further research is needed to study the influence of individual factors and sensory liking on dietary intake and weight status. This study was registered at the European Clinical Trials Database as 2013-000929-31.

Liking for fat is associated with sociodemographic, psychological, lifestyle and health characteristics.

Sensory liking influences dietary behaviour, but little is known about specifically associated individual profiles. The aim of the present study was to investigate the associations between liking for fat-and-salt and fat-and-sweet sensations and sociodemographic, economic, psychological, lifestyle and health characteristics in a large sample. Individual characteristics and liking scores were collected by a questionnaire among 37,181 French adults. Liking scores were constructed using a validated preference questionnaire. Multinomial logistic regression models were used to assess the associations between liking levels and individual characteristics. In both sexes, subjects belonging to low-level occupational categories (OR 1·39, 95% CI 1·16, 1·67 in men; OR 1·28, 95% CI 1·16, 1·41 in women), highly uncontrolled eaters (men: OR 2·90, 95% CI 2·60, 3·23; women: OR 2·73, 95% CI 2·27, 3·30) and obese subjects (men: OR 1·45, 95% CI 1·14, 1·84; women: OR 1·47, 95% CI 1·29, 1·68) were more likely to have a strong liking for the fat-and-sweet sensation, whereas older individuals (men: OR 0·13, 95% CI 0·10, 0·16; women: OR 0·11, 95% CI 0·09, 0·14) and highly cognitive restrainers (men: OR 0·52, 95% CI 0·44, 0·63; women: OR 0·60, 95% CI 0·55, 0·66) were less likely to have a strong liking. Regarding liking for the fat-and-salt sensation, the same associations were found and specific relationships were also highlighted: current smokers and heavy drinkers were more likely to strongly prefer the fat-and-salt sensation compared with non-smokers and abstainers or irregular alcohol consumers. The relationship between individual characteristics and a liking for fat sensation provides new and original information that may be useful for a better understanding of the associations between sensory liking and individual behaviour.

Association between intake of nutrients and food groups and liking for fat (The Nutrinet-Santé Study).

Apart from the established association between liking for fat and fat intake, little is known about the association between liking for fat and intake of specific nutrients or food groups. We investigated the association between dietary intake and liking for fat, fat-and-sweet and fat-and-salt. Liking scores were constructed using a validated preference questionnaire administered to 41,595 French adults participating in the Nutrinet-Santé study. Dietary data were collected using web-based 24 h records. Relationships between liking and dietary intake were assessed using linear regression adjusted for age and energy intake. Results are expressed in percentage difference of intake between individuals with low liking and those with high liking. Compared with participants with low liking for fat, individuals with a strong liking for fat had higher intakes of total energy (+10.1% in women (W); +8.4% in men (M)), fats (W: +7.3%; M: +10.0%), saturated fats (W: +10.8%; M+15.4%), meat (W: +13.0%; M: +12.6%), butter (W: +34.0%; M: +48.1%), sweetened cream desserts (W: +14.8%; M: +21.1%) and croissant-like pastries (W: +27.2%; M: +36.9). They also consumed lower quantities of omega-3 fatty acids (W: -6.2%;M: -6.0%), fiber (W: -16.4%; M: -18.9%), fruits (W: -28.8%; M: -29.5%), vegetables (W: -16.4%; M: -19.7%) and yogurt (W: -12.1%; M: -14.8%). Participants with high liking for fat-and-salt had higher intakes of total energy, sodium and alcoholic beverages and lower consumption of total and simple carbohydrates and fruit and vegetables than persons with high liking for fat-and-sweet. Our study contributes to the understanding of liking as a determinant of dietary intake. It highlighted that increased liking for fat, especially fat-and-salt liking, was associated with a lower intake of healthy foods, such as fruit and vegetables.

Amino acid requirements of the infant: the amino acid composition of human breast milk.

The recommended amino acid requirements of the infant are based on the amino acid composition of mature human breast milk. The amino acid composition of breast milk is usually determined following either acid or alkaline (for tryptophan) hydrolysis. For accuracy, however, the known effect of hydrolysis time on amino acid composition should be accounted for. Also, ideally the amino acid composition of breast milk should be given in units of digested (assumed to be absorbed) amino acids. A review of the literature is presented which gives mean total amino acid concentrations in mature human milk (n = 26 studies), mean hydrolysis correction factors (n = 3 studies) and mean true ileal amino acid digestibility coefficients (n = 3 studies, suckling piglet). There were differences between the estimates of amino acid concentration corrected for hydrolysis time and digestibility, and current FAO (2013) recommendations that were not corrected for these factors. The values based on the published literature up until 2023 (mg/g true protein) corrected for hydrolysis time and digestibility gave higher values (more than 16% higher) for leucine, lysine and threonine, and considerably higher values (greater than 30%) for histidine and tryptophan. Current recommendations may need revision.

The use of 15N-labelled protein to account for the endogenous nitrogen contribution to in vitro protein digestibility measurement.

Protein digestibility, a key indicator of dietary protein quality for human nutrition, can be estimated using an in vitro digestion model, however its definition and determination remain variable across studies. The present study aimed to determine the contribution of the endogenous nitrogen (N) to the plant and animal protein digestibility values obtained in vitro. 15N-labelled gluten and caseins (4, 8 and 16 % of the model meal) were used to differentiate dietary and endogenous N and were digested using the INFOGEST in vitro digestion model with no oral phase. The dietary and endogenous N were measured before and during digestion after centrifugation and 10 kDa ultrafiltration. The proteolysis degree was measured by the OPA method. The endogenous and dietary N were determined by elemental analyser coupled with isotopic ratio mass spectrometry. Apparent and true digestibility were determined and values of 135, 92 and 71 % for apparent vs. 78, 69, 60 % for true digestibility were obtained for 4, 8 and 16 % dietary protein level, respectively, with a significant effect of protein level. Differences between apparent and true digestibility pointed out the important contribution of the endogenous nitrogen. Our results showed that 40 % of the N below 10 kDa, i.e., the digestible fraction, were from endogenous origin (i.e. from the pancreatin) and was even present before digestion. An average value of 27 % for pancreatin N autolysis was estimated independently of the protein levels or sources. The use of 15N-labelled protein to evaluate in vitro protein digestibility highlighted the important contribution of the endogenous N, in particular when low dietary protein solution (4 %) are digested. This gives new keys to overcome drawbacks of in vitro models for determining protein digestibility.

Protein ingredient quality of infant formulas impacts their structure and kinetics of proteolysis under in vitro dynamic digestion.

Infant formula (IF) is a complex matrix requiring numerous ingredients and processing steps. The objective was to understand how the quality of protein ingredients impacts IF structure and, in turn, their kinetics of digestion. Four powdered IFs (A/B/C/D), based on commercial whey protein (WP) ingredients, with different protein denaturation levels and composition (A/B/C), and on caseins with different supramolecular organisations (C/D), were produced at a semi-industrial level after homogenization and spray-drying. Once reconstituted in water (13 %, wt/wt), the IF microstructure was analysed with asymmetrical flow field-flow fractionation coupled with multi-angle light scattering and differential refractometer, transmission electron microscopy and electrophoresis. The rehydrated IFs were subjected to simulated infant in vitro dynamic digestion (DIDGI®). Digesta were regularly sampled to follow structural changes (confocal microscopy, laser-light scattering) and proteolysis (OPA, SDS-PAGE, LC-MS/MS, cation-exchange chromatography). Before digestion, different microstructures were observed among IFs. IF-A, characterized by more denatured WPs, presented star-shaped mixed aggregates, with protein aggregates bounded to casein micelles, themselves adsorbed at the fat droplet interface. Non-micellar caseins, brought by non-micellar casein powder (IF-D) underwent rearrangement and aggregation at the interface of flocculated fat droplets, leading to a largely different microstructure of IF emulsion, with large aggregates of lipids and proteins. During digestion, IF-A more digested (degree of proteolysis + 16 %) at 180 min of intestinal phase than IF-C/D. The modification of the supramolecular organisation of caseins implied different kinetics of peptide release derived from caseins during the gastric phase (more abundant at G80 for IF-D). Bioactive peptide release kinetics were also different during digestion with IF-C presenting a maximal abundance for a large proportion of them. Overall, the present study highlights the importance of the structure and composition of the protein ingredients (WPs and caseins) selected for IF formulation on the final IF structure and, in turn, on proteolysis. Whether it has some physiological consequences remains to be investigated.

Animal models for determining amino acid digestibility in humans - a review.

Animal models have been commonly used for determining amino acid digestibility in humans. This allows digestibility assays to be undertaken more efficiently than those undertaken using humans directly. The laboratory rat, usually considered as a suitable animal model, has been widely used, especially as the rat is easy to raise and relatively inexpensive to house. Although more technically demanding, the pig has also been promoted as a useful model for human nutrition studies. It may be a better model than the rat, as it is a meal eater, its upper digestive tract is anatomically and physiologically closer to that of humans and it eats most foods consumed by humans. Amino acid digestibility may be determined either at the faecal or the ileal level, the latter being considered the most accurate. This contribution evaluates the suitability of the rat and pig as animal models for assessing ileal and faecal amino acid digestibility in humans. The drawbacks and advantages of using these animal models are discussed. The review is based mainly on results from controlled studies comparing both species; however, as the number of these studies is limited, data from indirect comparisons also provide insight.

Manufacture of Whey Protein Hydrolysates Using Plant Enzymes: Effect of Processing Conditions and Simulated Gastrointestinal Digestion on Angiotensin-I-Converting Enzyme (ACE) Inhibitory Activity.

Hydrolysis of proteins leads to the release of bioactive peptides with positive impact on human health. Peptides exhibiting antihypertensive properties (i.e., inhibition of angiotensin-I-converting enzyme) are commonly found in whey protein hydrolysates made with enzymes of animal, plant or microbial origin. However, bioactive properties can be influenced by processing conditions and gastrointestinal digestion. In this study, we evaluated the impact of three plant enzymes (papain, bromelain and ficin) in the manufacture of whey protein hydrolysates with varying level of pH, enzyme-to-substrate ratio and time of hydrolysis, based on a central composite design, to determine the degree of hydrolysis and antihypertensive properties. Hydrolysates made on laboratory scales showed great variation in the type of enzyme used, their concentrations and the pH level of hydrolysis. However, low degrees of hydrolysis in papain and bromelain treatments were associated with increased antihypertensive properties, when compared to ficin. Simulated gastrointestinal digestion performed for selected hydrolysates showed an increase in antihypertensive properties of hydrolysates made with papain and bromelain, which was probably caused by further release of peptides. Several peptides with reported antihypertensive properties were found in all treatments. These results suggest plant enzymes used in this study can be suitable candidates to develop ingredients with bioactive properties.

Supplementing human milk with a donkey or bovine milk derived fortifier: Consequences on proteolysis, lipolysis and particle structure under in vitro dynamic digestion.

Fortification of human milk (HM) is often necessary to meet the nutritional requirements of preterm infants. This study sought to establish whether HM supplemented with an experimental donkey milk-derived fortifier (DMF) or a commercial bovine milk-derived fortifier (BMF) affected digestion, using an in vitro dynamic system at the preterm stage. Particle size in gastric phase was higher in DMF than in BMF, due to protein aggregates surrounding lipid globules. Before digestion, BMF, with its extensively hydrolysed proteins, had a higher degree of proteolysis (30%) than DMF (11%), which contained intact proteins. After digestion, this difference was reduced concomitantly to a similar net degree of proteolysis (33%). DMF, with a higher proportion of ω3, resulted in a lower ω6/ω3 free PUFA ratio than BMF throughout digestion, although the final degree of lipolysis was similar (54%). In summary, DMF could represent a better source of proteins and lipids for the preterm infant.

Simulated dynamic digestion reveals different peptide releases from human milk processed by means of holder or high temperature-short time pasteurization.

High Temperature-Short Time (HTST) pasteurization was proposed as an alternative to Holder pasteurization (HOP) to increase the retention of specific human milk (HM) bioactive proteins. The present study explored whether HTST and HOP differently affect peptide release during simulated preterm infant gastrointestinal digestion. Raw (RHM), HOP- and HTST- pasteurized HM were digested using an in vitro dynamic system, and the identified peptides were analyzed by mass spectrometry and multivariate statistics. Before digestion, 158 peptides were identified in either RHM, HTST- or HOP- HM, mostly (84.4%) originating from ß-casein (CASB). During gastric digestion, HOP-HM presented a greater number and more abundant specific CASB peptides. A delayed release of peptides was observed in RHM during the intestinal phase, with respect to both pasteurized HM. Although limited to gastric digestion, the HM peptidomic profile differed according to the pasteurization type, and the pattern of the HTST peptides showed a greater similarity with RHM.

Infant nutrition affects the microbiota-gut-brain axis: Comparison of human milk vs. infant formula feeding in the piglet model.

Early nutrition plays a dominant role in infant development and health. It is now understood that the infant diet impacts the gut microbiota and its relationship with gut function and brain development. However, its impact on the microbiota-gut-brain axis has not been studied in an integrative way. The objective here was to evaluate the effects of human milk (HM) or cow's milk based infant formula (IF) on the relationships between gut microbiota and the collective host intestinal-brain axis. Eighteen 10-day-old Yucatan mini-piglets were fed with HM or IF. Intestinal and fecal microbiota composition, intestinal phenotypic parameters, and the expression of genes involved in several gut and brain functions were determined. Unidimensional analyses were performed, followed by multifactorial analyses to evaluate the relationships among all the variables across the microbiota-gut-brain axis. Compared to IF, HM decreased the α-diversity of colonic and fecal microbiota and modified their composition. Piglets fed HM had a significantly higher ileal and colonic paracellular permeability assessed by ex vivo analysis, a lower expression of genes encoding tight junction proteins, and a higher expression of genes encoding pro-inflammatory and anti-inflammatory immune activity. In addition, the expression of genes involved in endocrine function, tryptophan metabolism and nutrient transport was modified mostly in the colon. These diet-induced intestinal modifications were associated with changes in the brain tissue expression of genes encoding the blood-brain barrier, endocrine function and short chain fatty acid receptors, mostly in hypothalamic and striatal areas. The integrative approach underlined specific groups of bacteria (Veillonellaceae, Enterobacteriaceae, Lachnospiraceae, Rikenellaceae, and Prevotellaceae) associated with changes in the gut-brain axis. There is a clear influence of the infant diet, even over a short dietary intervention period, on establishment of the microbiota-gut-brain axis.

Addition of Dairy Lipids and Probiotic Lactobacillus fermentum in Infant Formulas Modulates Proteolysis and Lipolysis With Moderate Consequences on Gut Physiology and Metabolism in Yucatan Piglets.

Breast milk is the gold standard in neonatal nutrition, but most infants are fed infant formulas in which lipids are usually of plant origin. The addition of dairy lipids and/or milk fat globule membrane extracts in formulas improves their composition with beneficial consequences on protein and lipid digestion. The probiotic Lactobacillus fermentum (Lf) was reported to reduce transit time in rat pups, which may also improve digestion. This study aimed to investigate the effects of the addition of dairy lipids in formulas, with or without Lf, on protein and lipid digestion and on gut physiology and metabolism. Piglets were suckled from postnatal days 2 to 28, with formulas containing either plant lipids (PL), a half-half mixture of plant and dairy lipids (DL), or this mixture supplemented with Lf (DL+Lf). At day 28, piglets were euthanized 90 min after their last feeding. Microstructure of digesta did not differ among formulas. Gastric proteolysis was increased (P < 0.01) in DL and DL+Lf (21.9 ± 2.1 and 22.6 ± 1.3%, respectively) compared with PL (17.3 ± 0.6%) and the residual proportion of gastric intact caseins decreased (p < 0.01) in DL+Lf (5.4 ± 2.5%) compared with PL and DL (10.6 ± 3.1% and 21.8 ± 6.8%, respectively). Peptide diversity in ileum and colon digesta was lower in PL compared to DL and DL+Lf. DL and DL+Lf displayed an increased (p < 0.01) proportion of diacylglycerol/cholesterol in jejunum and ileum digesta compared to PL and tended (p = 0.07) to have lower triglyceride/total lipid ratio in ileum DL+Lf (0.019 ± 0.003) as compared to PL (0.045 ± 0.011). The percentage of endocrine tissue and the number of islets in the pancreas were decreased (p < 0.05) in DL+Lf compared with DL. DL+Lf displayed a beneficial effect on host defenses [increased goblet cell density in jejunum (p < 0.05)] and a trophic effect [increased duodenal (p = 0.09) and jejunal (p < 0.05) weights]. Altogether, our results demonstrate that the addition of dairy lipids and probiotic Lf in infant formula modulated protein and lipid digestion, with consequences on lipid profile and with beneficial, although moderate, physiological effects.