Infant milk formulas: effect of heat treatments on the protein physicochemical properties and the nutritional quality

Infant milk formulas: effect of heat treatments on the protein physicochemical properties and the nutritional quality. STLOpenday

Kinetics of heat-induced denaturation of whey proteins and characterization of protein aggregates in model infant formulas

In 2018, about 60% of world’s newborns received cow milk-based infant formulas (IF) instead of human milk (UNICEF). The process of manufacturing IF involves heat treatments altering the physicochemical properties of milk components, especially whey proteins (WP), and so the rheological properties of IF. The objective of the study was to investigate the impacts of thermal treatments on the denaturation of WP of IF, particularly for those mimicking the protein profile of human milk, and to characterize the heat-induced protein structures.Three model IF were produced with a caseins:WP ratio of 40:60 at 1.3% and 5.5% of total proteins, i.e. the protein contents at which are applied heat treatments during the manufacture of liquid or powder IF, respectively. Skimmed milk was mixed with a WP isolate, a mix of WP isolate and purified lactoferrin or a mix of both purified lactoferrin and α-lactalbumin in proportion similar to that in human milk. The kinetic of heat-induced denaturation of each WP was investigated between 67.5°C and 80°C by RP-HPLC. The heat-induced protein structures were studied by dynamic light scattering, electrophoresis and asymmetric flow field flow fractionation coupled with MALLS.The results revealed that the extent of denaturation of WP depended on the protein content and the nature of the WP within the IF. IF at 5.5% of proteins and containing β-lactoglobulin gelled for longer heating time at 80°C. At similar rate of total WP denaturation at 67.5°C and 80°C, the protein composition of the heat-induced aggregates changed between formulas, protein concentrations and heating temperatures but disulfide bonds were the main intermolecular links. The aggregates were larger and of fractal shape (dfapp=2.1) in formulas at 5.5% proteins whereas they were of spherical shape (dfapp=2.9) in formulas at 1.3% proteins.These results will give to industrials reliable data on the protein structures formed during the heat treatments of IF. The impact on digestibility will be subsequently investigated

The Epidemiology and Outcome of Biliary Atresia: Saudi Arabian National Study (2000–2018)

BackgroundThe epidemiology and outcomes of biliary atresia (BA) have been well-documented in national cohorts from two main ethnicities, namely, the Asian Orientals and Caucasians, with incidence ranging from 1 in 5,000 to 1 in 9,000 live births in East Asia and 1 in 15,000 to 19,000 live births in Europe and North America.ObjectiveWe report the first nationwide BA study outside North America, Europe, and East Asia to describe the epidemiology and outcomes of BA in Saudi Arabia.MethodsA national database of BA cases diagnosed between 2000 and 2018 was analyzed. We assessed clearance of jaundice (bilirubin <20 μmol/L) in all cases that underwent Kasai portoenterostomy (KPE). We then estimated survival using the Kaplan–Meier method with endpoints of liver transplantation (LT), death, or survival with native liver (SNL).ResultsBA was diagnosed in 204 infants (106 females; 10% pre-term). The incidence of BA was 1 in 44,365, or 2.254 in 100,000 live births (range, 0.5–4 in 100,000). Polysplenia was diagnosed in 22 cases (11%). The median age at referral was 65 days. A total of 146 children (71.5%) underwent KPE at a median age of 70 days. Clearance of jaundice was achieved in 66 of the 146 (45%) infants. The 10-year SNL after KPE was 25.5%, and the overall 10-year estimated survival was 72.5%. The Kaplan–Meier survival curves for patients undergoing KPE at the age of <60, 61–90, and >90 days showed a SNL rate at 51.6, 33, and 12.5%, respectively, at 5 years (P < 0.001). The 2-, 5-, and 10-year post-LT survival rates were 92.5, 90.6, and 90%, respectively. Undergoing an initial KPE did not impact negatively on the overall LT survival rate when compared to BA cases that underwent primary LT (P = 0.88).ConclusionThe incidence rate of BA in Saudi Arabia is lower than the incidence reported elsewhere. Late referral of BA cases remains a problem in Saudi Arabia; as a result, the SNL rate was lower than reported by other national registries. Hence, national policies devoted to timely referral and earlier age at KPE are needed

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Model infant milk formulas : relationship between protein structures and digestive behaviour

Les traitements thermiques appliqués pendant la fabrication des préparations pour nourrissons (PPNs) peuvent altérer les structures des protéines et donc leur comportement au cours de la digestion. L'objectif de ce projet de thèse était d'étudier la relation entre la structure des protéines au sein de PPNs modèles et leur comportement au cours de leur digestion in vitro.Trois PPNs modèles ont été développées, se différenciant par leur profil en protéines du lactosérum (PS) afin de se rapprocher du profil protéique du lait maternel. Les PPNs, avec différentes teneurs en matière sèche et donc concentration protéique (1.3% ou 5.5%), ont été traitées thermiquement entre 67.5°C et 80°C. La cinétique de dénaturation thermique des PS a été étudiée puis les structures protéiques générées ont été caractérisées pour un même taux de dénaturation des PS (65%).La cinétique de digestion protéique a été évaluée en digestion in vitro statique puis dynamique, simulant les conditions physiologiques du nourrisson.Les résultats ont montré que la cinétique de dénaturation des PS était ralentie pour la PPN proche du lait maternel, de par l’absence de ß-LG et ce indépendamment de la teneur en matière sèche. Pour un même taux de dénaturation des PS, la structure protéique des PPNs variait selon la composition protéique des PPNs, leur teneur en matière sèche et les conditions thermiques, ce qui, in fine, impactait le devenir des protéines au cours de la digestion in vitro.La structure des protéines pourrait donc être un levier pour l’optimisation des PPNs. Ces résultats doivent être complétés par l'évaluation de l'impact physiologique de ces différentes structures.The heat treatments applied during the manufacture of infant milk formulas (IMFs) may alter the protein structures and so their behaviour during digestion. The aim of this PhD project was to study the relationship between protein structure within model IMFs and their behaviour during in vitro digestion.Three model IMFs were formulated, differing only in their whey protein (WP) profile to be as close as possible to the protein profile of human milk. The IMFs, with different dry matter contents and therefore protein concentration (1.3% or 5.5%), were heat-treated between 67.5°C and 80°C. The kinetics of heat-induced WP denaturation were studied, then the protein structures generated were characterised for an identical extent of WP denaturation (65%). The kinetics of protein hydrolysis were evaluated using static then dynamic in vitro digestion methods at the infant stage.The results showed that the denaturation kinetics of WPs were slowed down for IMF close to human milk, due to the absence of ß-LG, regardless of the dry matter content. For an identical extent of WP denaturation, the heat-induced protein structures varied according to the protein profile, the dry matter of IMFs, and the heating conditions, which ultimately impacted the protein behaviour during in vitro digestion.The protein structure could therefore be a lever for the IMF optimisation. These results must be complemented by the evaluation of the physiological impact of these different structures

Formules infantiles modèles : Relation entre structures protéiques et comportement en digestion Modification du profil protéique, de la teneur en matière sèche et de la température de traitement

The heat treatments applied during the manufacture of infant milk formulas (IMFs) may alter the protein structures and so their behaviour during digestion. The aim of this PhD project was to study the relationship between protein structure within model IMFs and their behaviour during in vitro digestion.Three model IMFs were formulated, differing only in their whey protein (WP) profile to be as close as possible to the protein profile of human milk. The IMFs, with different dry matter contents and therefore protein concentration (1.3% or 5.5%), were heat-treated between 67.5°C and 80°C. The kinetics of heat-induced WP denaturation were studied, then the protein structures generated were characterised for an identical extent of WP denaturation (65%). The kinetics of protein hydrolysis were evaluated using static then dynamic in vitro digestion methods at the infant stage.The results showed that the denaturation kinetics of WPs were slowed down for IMF close to human milk due to the absence of β-LG, regardless of the dry matter content. For an identical extent of WP denaturation, the heat-induced protein structures varied according to the protein profile, the dry matter of IMFs, and the heating conditions, which ultimately impacted the protein behaviour during in vitro digestion.The protein structure could therefore be a lever for the IMF optimisation. These results must be complemented by the evaluation of the physiological impact of these different structures.Les traitements thermiques appliqués pendant la fabrication des préparations pour nourrissons (PPNs) peuvent altérer les structures des protéines et donc leur comportement au cours de la digestion. L'objectif de ce projet de thèse était d'étudier la relation entre la structure des protéines au sein de PPNs modèles et leur comportement au cours de leur digestion in vitro.Trois PPNs modèles ont été développées, se différenciant par leur profil en protéines du lactosérum (PS) afin de se rapprocher du profil protéique du lait maternel. Les PPNs, avec différentes teneurs en matière sèche et donc concentration protéique (1.3% ou 5.5%), ont été traitées thermiquement entre 67.5°C et 80°C. La cinétique de dénaturation thermique des PS a été étudiée puis les structures protéiques générées ont été caractérisées pour un même taux de dénaturation des PS (65%). La cinétique de digestion protéique a été évaluée en digestion in vitro statique puis dynamique, simulant les conditions physiologiques du nourrisson.Les résultats ont montré que la cinétique de dénaturation des PS était ralentie pour la PPN proche du lait maternel de par l’absence de β-LG, et ce indépendamment de la teneur en matière sèche. Pour un même taux de dénaturation des PS, la structure protéique des PPNs variait selon la composition protéique des PPNs, leur teneur en matière sèche et les conditions thermiques, ce qui, in fine, impactait le devenir des protéines au cours de la digestion in vitro.La structure des protéines pourrait donc être un levier pour l’optimisation des PPNs. Ces résultats doivent être complétés par l’évaluation de l’impact physiologique de ces différentes structures

Formules infantiles modèles : relation entre structures protéiques et comportement en digestion

The heat treatments applied during the manufacture of infant milk formulas (IMFs) may alter the protein structures and so their behaviour during digestion. The aim of this PhD project was to study the relationship between protein structure within model IMFs and their behaviour during in vitro digestion.Three model IMFs were formulated, differing only in their whey protein (WP) profile to be as close as possible to the protein profile of human milk. The IMFs, with different dry matter contents and therefore protein concentration (1.3% or 5.5%), were heat-treated between 67.5°C and 80°C. The kinetics of heat-induced WP denaturation were studied, then the protein structures generated were characterised for an identical extent of WP denaturation (65%). The kinetics of protein hydrolysis were evaluated using static then dynamic in vitro digestion methods at the infant stage.The results showed that the denaturation kinetics of WPs were slowed down for IMF close to human milk, due to the absence of ß-LG, regardless of the dry matter content. For an identical extent of WP denaturation, the heat-induced protein structures varied according to the protein profile, the dry matter of IMFs, and the heating conditions, which ultimately impacted the protein behaviour during in vitro digestion.The protein structure could therefore be a lever for the IMF optimisation. These results must be complemented by the evaluation of the physiological impact of these different structures.Les traitements thermiques appliqués pendant la fabrication des préparations pour nourrissons (PPNs) peuvent altérer les structures des protéines et donc leur comportement au cours de la digestion. L'objectif de ce projet de thèse était d'étudier la relation entre la structure des protéines au sein de PPNs modèles et leur comportement au cours de leur digestion in vitro.Trois PPNs modèles ont été développées, se différenciant par leur profil en protéines du lactosérum (PS) afin de se rapprocher du profil protéique du lait maternel. Les PPNs, avec différentes teneurs en matière sèche et donc concentration protéique (1.3% ou 5.5%), ont été traitées thermiquement entre 67.5°C et 80°C. La cinétique de dénaturation thermique des PS a été étudiée puis les structures protéiques générées ont été caractérisées pour un même taux de dénaturation des PS (65%).La cinétique de digestion protéique a été évaluée en digestion in vitro statique puis dynamique, simulant les conditions physiologiques du nourrisson.Les résultats ont montré que la cinétique de dénaturation des PS était ralentie pour la PPN proche du lait maternel, de par l’absence de ß-LG et ce indépendamment de la teneur en matière sèche. Pour un même taux de dénaturation des PS, la structure protéique des PPNs variait selon la composition protéique des PPNs, leur teneur en matière sèche et les conditions thermiques, ce qui, in fine, impactait le devenir des protéines au cours de la digestion in vitro.La structure des protéines pourrait donc être un levier pour l’optimisation des PPNs. Ces résultats doivent être complétés par l'évaluation de l'impact physiologique de ces différentes structures

20th International Symposium on Field- and Flow-Based Separations

Milk contains two types of proteins: Caseins and whey proteins. There are four caseins: α/β/γ/κ caseins that formed micelles in milk. Whey proteins are globular proteins between 12 and 200 kDa: α-lactalbumin; β-lactoglobulin; Serum albumin; Immunoglobulin and Lactoferrin. Industrials fractionate milk to produce whey protein and casein isolate to make ingredients for the formulation of dairy products. Whey protein isolate can be heated to functionalize or pasteurize them. The objective of these three studies are to characterize the isolates of whey proteins and the impact of heating treatment on whey protein fractions and formulations using different FFF techniques: Asymmetrical-FFF; 2D AsFlFFF-RPLC and Centrifugal-FFF Whey protein isolate heated at high temperature were studied by Centrifugal-FFF coupled with MALS and RI. Aggregates with the lowest density and size elute in the void peak and represent 51% of the mass fraction. For the bigger one, there are two populations: one smaller than 1 micrometer and one higher, up to 4.5 micrometers. For size determination, the biggest population fractionated has been collected and analyzed by DLS in batch. Infant milk formulation without fat was investigated by Asymmetrical Flow FFF coupled with MALS; QELS and RI. The formulation contains bovine milk and isolate whey protein fractions. The technique separates the non-aggregated whey protein to the casein micelles. The addition of lactoferrin partially disintegrated the casein micelles. The formulations are heated at 67.5°C or 80°C. Native whey protein content decreases with the heat treatment, leading to their aggregation on with the casein micelles. The phenomena depend on the temperature and protein composition. At 80°C, shape ratio Rg/Rh of casein micelles increase with the temperature when the formulation is enriched in lactoferrin. The Rg and Rh decrease when the formulation is enriched in α-lactalbumin and lactoferrin. Transmission Electronic Microscopy are correlated with these results. At 80°C, whey protein aggregates are fixed outside the micelle for the first formulation and they are fixed inside the micelles for the second formulation. Whey protein isolate contains few quantities of caseins. The second objective of this study is to identify the presence of trace of caseins in whey protein isolate using 2D AsFlFFF-RP-HPLC. This technique allows to separate proteins by their size and by their polarity. A whey protein standard mix is studied: α-lactalbumin, β-lactoglobulin A and B, BSA, and 3 caseins. A 2D map is obtained with all separated proteins

Modification of protein structures by altering the whey protein profile and heat treatment affects in vitro static digestion of model infant milk formulas

International audienceHeat treatments induce changes in the protein structure in infant milk formulas (IMFs). The present study aims to investigate whether these structural modifications affect protein digestion. Model IMFs (1.3% proteins), with a bovine or a human whey protein profile, were unheated or heated at 67.5°C or 80°C to reach 65% of denaturation, resulting in six protein structures. IMFs were submitted to in vitro static gastro-intestinal digestion simulating infant conditions. During digestion, laser light scattering was performed to analyze IMF destabilization and SDS-PAGE, OPA assay and cation exchange chromatography were used to monitor proteolysis. Results showed that, during gastric digestion, α-lactalbumin and β-lactoglobulin were resistant to hydrolysis in a similar manner for all protein structures within IMFs (p > 0.05), while the heat-induced denaturation of lactoferrin significantly increased its susceptibility to hydrolysis. Casein hydrolysis was enhanced when the native casein micelle structure was modified, i.e. partially disintegrated in the presence of lactoferrin or covered by heat-denatured whey proteins. The IMF destabilization at the end of the gastric digestion varied with protein structures, with larger particle size for IMF containing native casein micelles. During intestinal digestion, the kinetics of protein hydrolysis varied with the IMF protein structures, particularly for IMFs containing denatured lactoferrin, exhibiting higher proteolysis degree (67.5°C and 80°C vs. unheated) and essential amino acid bioaccessibility (67.5°C vs. unheated). Overall, the protein structures, generated by modulating the whey protein profile and the heating conditions , impacted the IMF destabilization during the gastric phase and the proteolysis during the entire simulated infant digestion