Plasma sphingomyelins and carnitine esters of infants consuming whole goat or cow milk-based infant formulas or human milk.

BACKGROUND: Infant formulas are typically manufactured using skimmed milk, whey proteins, and vegetable oils, which excludes milk fat globule membranes (MFGM). MFGM contains polar lipids including sphingomyelin (SM). OBJECTIVE: Comparison of infant plasma SM and acylcarnitine species between infants who are breastfed or receiving infant formulas with different fat sources. METHODS: In this explorative study we focused on SM and acylcarnitine species concentrations measured in plasma samples from the TIGGA study (ACTRN12608000047392), where infants were randomized to receive either a cow milk-based infant formula (CIF) with vegetable oils only or a goat milk-based infant formula (GIF) with a goat milk fat (including MFGM) and plant oil mixture at least up to the age of 4 months. Breastfed infants were followed as a reference group. Using tandem mass spectrometry, SM species in the study formulas and SM and acylcarnitine species in plasma samples collected at the age of four months were analyzed. RESULTS: Total SM concentrations (around 42 µmol/L) and patterns of SM species were similar in both formulas. The total plasma SM concentrations were not different between the formula groups, but were 15 % (CIF) and 21% (GIF) lower in the formula groups than in the breast fed group. Between the formula groups, differences in SM species were statistically significant but small. Total carnitine and major (acyl) carnitine species were not different between the groups. CONCLUSIONS: The higher total SM concentration in breastfed than in formula-fed infants might be related to a higher SM content in human milk, differences in cholesterol metabolism, dietary fatty acid intake or other factors not yet identified. SM and acylcarnitine species composition in plasma is not closely related to the formula fatty acid composition. CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE WHERE IT WAS OBTAINED: ACTRN12608000047392 https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=82514&isReview=true.

Comment on Jankiewicz et al. The Effect of Goat-Milk-Based Infant Formulas on Growth and Safety Parameters: A Systematic Review and Meta-Analysis. Nutrients 2023, 15, 2110.

We have read the article entitled "The effect of goat-milk-based infant formulas on growth and safety parameters: a systematic review and meta-analysis" by Jankiewicz et al [...].

Whole Goat Milk-Based Formula versus Whey-Based Cow Milk Formula: What Formula Do Infants Enjoy More?-A Feasibility, Double-Blind, Randomized Controlled Trial.

(1) Background: While goat milk formula (GMF) is an alternative to cow milk formula (CMF), infants' preferences for one over the other have not been formally assessed. Specifically, our aim in this study was to determine whether infants experience fewer feeding behavior problems with whole milk-based GMF than with conventional whey-based CMF. (2) Methods: This was a multicenter, double-blind, randomized controlled trial with two-arm parallel assignment conducted in six pediatricians' offices in or near Paris, France, between June 2018 and 31 December 2021. Overall, 64 healthy infants (≤4 months old), predominantly formula-fed, were randomly assigned to either the whole milk-based GMF (n = 33) or whey-based CMF (n = 31) arm. Parents completed the Baby Eating Behavior Questionnaire (BEBQ) and the modified QUALIN questionnaire to evaluate infant feeding behavior and quality of life (psychomotor and socioemotional development), respectively, at inclusion (1 to 5 days before milk delivery) and the final visit (day 28 ± 3 after milk delivery). Informed consent was obtained for all recruited patients, and an ethical committee approved the study. (3) Results: Changes in BEBQ Enjoyment of Food and Slowness in Eating subscale scores from inclusion to final visit did not differ between arms. However, there were significant improvements in subscale scores for Food Responsiveness (GMF: 0.15 ± 1; CMF: -0.48 ± 0.81; p = 0.010) and General Appetite (GMF: 0.26 ± 1.2; CMF: -0.48 ± 0.88; p = 0.012), and modified QUALIN (GMF: 4.6 ± 9.4; CMF: -0.40 ± 7.6; p = 0.03) scores in favor of the GMF group. (4) Conclusions: In this double-blind, randomized controlled trial, GMF-fed infants exhibited a greater general appetite than CMF-fed infants, possibly due to differences in the composition of these formulas (i.e., protein and lipid profiles). In addition, GMF-fed infants enjoyed a better quality of life. There was no difference in food enjoyment between groups. These findings suggest that whole-milk-based GMF could be an attractive alternative to whey-based CMF. Clinical trial registration: NCT03488758 (clinicaltrials.gov).

Effects of infant feeding with goat milk formula or cow milk formula on atopic dermatitis: protocol of the randomised controlled Goat Infant Formula Feeding and Eczema (GIraFFE) trial.

INTRODUCTION: Atopic dermatitis (AD) is a chronic, inflammatory skin condition significantly affecting quality of life. A small randomised trial showed an approximately one-third lower incidence of AD in goat milk formula-fed compared with cow milk formula-fed infants. However, due to limited statistical power, AD incidence difference was not found to be significant. This study aims to explore a potential risk reduction of AD by feeding a formula based on whole goat milk (as a source of protein and fat) compared with a formula based on cow milk proteins and vegetable oils. METHODS AND ANALYSIS: This two-arm (1:1 allocation), parallel, randomised, double-blind, controlled nutritional trial shall enrol up to 2296 healthy term-born infants until 3 months of age, if parents choose to start formula feeding. Ten study centres in Spain and Poland are participating. Randomised infants receive investigational infant and follow-on formulas either based on whole goat milk or on cow milk until the age of 12 months. The goat milk formula has a whey:casein ratio of 20:80 and about 50% of the lipids are milk fat from whole goat milk, whereas the cow milk formula, used as control, has a whey:casein ratio of 60:40 and 100% of the lipids are from vegetable oils. The energy and nutrient levels in both goat and cow milk formulas are the same. The primary endpoint is the cumulative incidence of AD until the age of 12 months diagnosed by study personnel based on the UK Working Party Diagnostic Criteria. The secondary endpoints include reported AD diagnosis, measures of AD, blood and stool markers, child growth, sleep, nutrition and quality of life. Participating children are followed until the age of 5 years. ETHICS AND DISSEMINATION: Ethical approval was obtained from the ethical committees of all participating institutions. TRIAL REGISTRATION NUMBER: NCT04599946.

Safety and tolerance assessment of milk fat globule membrane-enriched infant formulas in healthy term Chinese infants: a randomised multicenter controlled trial.

BACKGROUND: Milk fat globule membrane (MFGM), natural to breast milk, is essential for neonatal development, but lacking from standard infant formulas. OBJECTIVES: To evaluate the safety and tolerability of MFGM supplementation in formula for infants 0 to 12 months. METHODS: In a prospective, multicentre, double-blind, randomized trial, healthy term infants were randomized to a standard formula (SF, n = 104) or an MFGM-enriched formula (MF, n = 108) for 6 months and a corresponding follow-on formula until 12 months. Exclusively breast-fed infants (n = 206) were recruited as the reference group (BFR). Tolerance and safety events were recorded continuously. Anthropometric measurements were assessed at enrolment, 42 days and 4, 6, 8 and 12 months. RESULTS: Infants (n = 375) completed the study with average dropout of < 20%. Stool frequency, color, and consistency between SF and MF were not significantly different throughout, except the incidence of loose stools in MF at 6 months being lower than for SF (odds ratio 0.216, P < 0.05) and the frequency of green-colored stools at 12 months being higher in MF (CI 95%, odds ratio 8.92, P < 0.05). The BFR had a higher frequency of golden stools and lower rate of green stools (4-6 months) than the two formula-fed groups (P < 0.05). SF displayed more diarrhoea (4.8%) than MF (1%) and BFR (1%) at the 8-month visit (P < 0.05). BFR (0-1%) had significantly less (P < 0.05) lower respiratory infections than MF (4.6-6.5%) and SF (2.9-5.8%) at 6- and 8-months, respectively. Formula intake, frequency of spit-up/vomiting or poor sleep were similar between SF and MF. Growth rate (g/day) was similar at 4, 6, 8 and 12 months between the 3 groups, but growth rate for BFR was significantly higher than for SF and MF at 42 days (95% CI, P = 0.001). CONCLUSIONS: MFGM-enriched formula was safe and well-tolerated in healthy term infants between 0 and 12 months, and total incidences of adverse events were similar to that for the SF group. A few differences in formula tolerance were observed, however these differences were not in any way related to poor growth.

Development of the digestive system in early infancy and nutritional management of digestive problems in breastfed and formula-fed infants.

Food digestion and absorption in infants are closely related to early growth and long-term health. Human milk and infant formula are the main food sources for 0-6 month-old infants. Due to the immature gastrointestinal tract of newborns, mild digestive problems, such as inefficient digestion and impaired absorption of proteins, lipids and lactose, and gut dysbiosis, are often seen in infancy. The differences in composition between infant formula and human milk make mild digestive problems more likely to occur in formula-fed infants. In recent years, several types of infant formulas have been developed to treat or reduce gastrointestinal digestive problems in infants. This review summarizes the gastrointestinal environment of infants and the digestion of human milk and different infant formulas. We particularly focus on the common digestive problems and appropriate nutritional solutions that may occur in healthy term infants during the first six months of life.

Quantitative methods to detect phospholipids at the oil-water interface.

Phospholipids are the main constituents of cell membranes and act as natural stabilizers of milk fat globules. Phospholipids are used in a wide range of applications, e.g. as emulsifiers in cosmetic, pharmaceutical and food products. While processed emulsion droplets are usually stabilized by a monolayer of phospholipids, cell membranes have a phospholipid bilayer structure and milk fat globules are stabilized by a complex phospholipid trilayer membrane. Despite the broad relevance of phospholipids, there are still many scientific challenges in understanding how their behavior at the fluid-fluid interface affects microstructure, stability, and physico-chemical properties of natural and industrial products. Most of these challenges arise from the experimental difficulties related to the investigation of the molecular arrangement of phospholipids in situ at the fluid-fluid interface and the quantification of their partitioning between the bulk phase and the interface, both under static and flow conditions. This task is further complicated by the presence of other surface-active components, such as proteins, that can interact with phospholipids and compete for space at the interface. Here, we review the methodologies available from the literature to detect and quantify phospholipids, focusing on oil-water interfaces, and highlight current limitations and future perspectives.

Supplementation with milk enriched with complex lipids during pregnancy: A double-blind randomized controlled trial.

BACKGROUND: Gangliosides are a class of sphingolipids that are present in the cell membranes of vertebrates. Gangliosides influence a broad range of cellular processes through effects on signal transduction, being found abundantly in the brain, and having a role in neurodevelopment. OBJECTIVE: We aimed to assess the effects of maternal daily consumption of ganglioside-enriched milk vs non-enriched milk and a non-supplemented group of pregnant women on maternal ganglioside levels and pregnancy outcomes. DESIGN: Double-blind parallel randomized controlled trial. METHODS: 1,500 women aged 20-40 years were recruited in Chongqing (China) between 11 and 14 weeks of a singleton pregnancy, and randomized into three groups: Control-received standard powdered milk formulation (≥4 mg gangliosides/day); Complex milk lipid-enhanced (CML-E) group-same formulation enriched with complex milk lipids (≥8 mg gangliosides/day) from milk fat globule membrane; Reference-received no milk. Serum ganglioside levels were measured in a randomly selected subsample of 250 women per group. RESULTS: CML-E milk was associated with marginally greater total gangliosides levels in maternal serum compared to Control (13.02 vs 12.69 µg/ml; p = 0.034) but not to Reference group. CML-E milk did not affect cord blood ganglioside levels. Among the 1500 women, CML-E milk consumption was associated with a lower rate of gestational diabetes mellitus than control milk [relative risk 0.80 (95% CI 0.64, 0.99)], but which was not different to the Reference group. CML-E milk supplementation had no other effects on maternal or newborn health. CONCLUSIONS: Maternal supplementation with milk fat globule membrane, as a source of gangliosides, was not associated with any adverse health outcomes, and did not increase serum gangliosides compared with the non-supplemented reference group. TRIAL REGISTRATION: Chinese Clinical Trial Register (ChiCTR-IOR-16007700). CLINICAL TRIAL REGISTRATION: ChiCTR-IOR-16007700; www.chictr.org.cn/showprojen.aspx?proj=12972.

Effect of supplementation of complex milk lipids in pregnancy on fetal growth: results from the Complex Lipids in Mothers and Babies (CLIMB) randomized controlled trial.

BACKGROUND: Gangliosides (GAs) are important for neuronal function and development of the brain, accumulating rapidly in the fetal brain during the last trimester of pregnancy. No study in humans has investigated whether maternal supplementation of GAs during pregnancy has an effect on fetal growth, particularly of the head circumference. OBJECTIVE: To evaluate the effect of maternal dietary supplementation of complex milk lipids (CML; gangliosides and phospholipids) from the milk fat globule membrane (MFGM) during pregnancy on fetal growth. DESIGN: Double-blind three-arm parallel randomized controlled trial of 1500 pregnant women from the Chongqing Municipality of China, recruited between 11 and 14 weeks of pregnancy. Intervention was in the form of supplementation with: control maternal milk formulation containing a minimum of 2 mg GA per serving (4 mg GA per day) versus a CML-enriched (CML-E) maternal milk formulation containing a minimum of 4 mg GA per serving (8 mg GA per day) versus no maternal milk supplementation, but with standard obstetric care including prenatal folic acid supplementation. Main outcomes and measures were ultrasonographically-derived estimates of fetal growth in head circumference (HC) & biparietal diameter (BPD) (primary outcomes); and abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW) (secondary outcomes) (Clinical trial registry: ChiCTR-IOR-16007700). RESULTS: Supplementation with CML-E milk had no effects on size at midpregnancy or growth trajectories in any of the fetal biometric dimensions. CONCLUSIONS: Supplementation of CML from the MFGM from the end of the first trimester did not have any effects on fetal growth. The absence of any adverse growth outcomes suggests that maternal MFGM supplementation during pregnancy is safe and using CML-E milk formula can be a method of providing an increased GA and phospholipid supply in early life, which has been associated with neurodevelopmental benefits. CLINICAL TRIAL REGISTRY: ChiCTR-IOR-16007700 (http://www.chictr.org.cn/enindex.aspx).

Comparison of the Bifidogenic Effects of Goat and Cow Milk-Based Infant Formulas to Human Breast Milk in an in vitro Gut Model for 3-Month-Old Infants.

Human milk contains prebiotic components, such as human milk oligosaccharides (HMOs), which stimulate the growth of specific members of the infant gut microbiota (e.g., Bifidobacteria). Plant-based or synthetic oligosaccharides are often added to infant formulas to simulate the bifidogenic effect of HMOs. Cow milk, the most common source of protein in infant formula, and goat milk, used increasingly in the manufacture of infant formula, contain naturally-occurring prebiotics. This study compared the upper gastrointestinal digestion and subsequent colonic fermentation of human milk vs. goat and cow milk-based infant formulas (goat IF and cow IF, respectively), without additional oligosaccharides using an in vitro model for 3-month-old infants based on the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®). First, a dialysis approach using 3.5 kDa membranes was demonstrated to simulate small intestinal absorption of carbohydrates in conditions similar to those in vivo. During the in vitro digestion experiment, oligosaccharides were detected in human milk and goat IF but barely detected in the cow IF. Further, all three milk matrices decreased colonic pH by boosting acetate, lactate, and propionate production, which related to increased abundances of acetate/lactate-producing Bifidobacteriaceae for human milk (+25.7%) and especially goat IF (33.8%) and cow IF (37.7%). Only cow IF stimulated butyrate production which correlated with an increase in Lachnospiraceae and Clostridiaceae. Finally, Enterobacteriaceae and Acidaminococcaceae also increased with all three milk matrices, while production of proteolytic metabolites (branched-chain fatty acids) was only detected for the cow IF. Overall, goat and cow milk-based formulas without added oligosaccharides impacted gut microbial activity and composition similarly to human milk. This suggests that even without supplementation of formula with oligosaccharides, whole goat milk, whole cow milk and cow milk ingredients already supply compounds in formulas that exert beneficial bifidogenic effects. Further clinical research is warranted to elucidate the effect of whole goat milk-based formulas on the infant gut microbiome.

Whole Goat Milk as a Source of Fat and Milk Fat Globule Membrane in Infant Formula.

Cow milk is the most common dairy milk and has been extensively researched for its functional, technological and nutritional properties for a wide range of products. One such product category is infant formula, which is the most suitable alternative to feed infants, when breastfeeding is not possible. Most infant formulas are based on cow milk protein ingredients. For several reasons, consumers now seek alternatives such as goat milk, which has increasingly been used to manufacture infant, follow-on and young child formulas over the last 30 years. While similar in many aspects, compositional and functional differences exist between cow and goat milk. This offers the opportunity to explore different formulations or manufacturing options for formulas based on goat milk. The use of whole goat milk as the only source of proteins in formulas allows levels of milk fat, short and medium chain fatty acids, sn-2 palmitic acid, and milk fat globule membrane (MFGM) to be maximised. These features improve the composition and microstructure of whole goat milk-based infant formula, providing similarities to the complex human milk fat globules, and have been shown to benefit digestion, and cognitive and immune development. Recent research indicates a role for milk fat and MFGM on digestive health, the gut-brain axis and the gut-skin axis. This review highlights the lipid composition of whole goat milk-based infant formula and its potential for infant nutrition to support healthy digestion, brain development and immunity. Further work is warranted on the role of these components in allergy development and the advantages of goat milk fat and MFGM for infant nutrition and health.

A novel infant milk formula concept: Mimicking the human milk fat globule structure.

Human milk (HM) provides all nutrients to support an optimal growth and development of the neonate. The composition and structure of HM lipids, the most important energy provider, have an impact on the digestion, uptake and metabolism of lipids. In HM, the lipids are present in the form of dispersed fat globules: large fat droplets enveloped by a phospholipid membrane. Currently, infant milk formula (Control IMF) contains small fat droplets primarily coated by proteins. Recently, a novel IMF concept (Concept IMF) was developed with a different lipid architecture, Nuturis(®), comprising large fat droplets with a phospholipid coating. Confocal laser scanning microscopy (CLSM), with appropriate fluorescent probes, and transmission electron microscopy were used to determine and compare the interfacial composition and structure of HM fat globules, Concept IMF fat droplets and Control IMF fat droplets. The presence of a trilayer-structured HM fat globule membrane, composed of phospholipids, proteins, glycoproteins and cholesterol, was confirmed; in addition exosome-like vesicles are observed within cytoplasmic crescents. The Control IMF fat droplets had a thick protein-only interface. The Concept IMF fat droplets showed a very thin interface composed of a mixture of phospholipids, proteins and cholesterol. Furthermore, the Concept IMF contained fragments of milk fat globule membrane, which has been suggested to have potential biological functions in infants. By mimicking more closely the structure and composition of HM fat globules, this novel IMF concept with Nuturis(®) may have metabolic and digestive properties that are more similar to HM compared to Control IMF.

Effect of food matrix microstructure on stomach emptying rate and apparent ileal fatty acid digestibility of almond lipids.

Almond lipids can be consumed in different forms such as nuts, oil-in-water emulsions or oil. The stomach emptying rate (SER) of almond lipids (0.2 g of fat per 2 mL of almond lipid suspension) as a function of the food matrix was studied using magnetic resonance spectroscopy based on the stomach emptying of a marker (AlCl3-6H2O) in the growing rat. Chyme and digesta samples were collected following serial gavaging (0.2 g of fat per 2 mL of almond lipid suspension) to study microstructural changes and determine the apparent ileal digestibility of almond fatty acids as a function of the native food matrix. The T(1/2) for the stomach emptying of crushed whole almonds and almond cream (194 ± 17 min and 185 ± 19 min, respectively) were not different (P > 0.05) from that of a gastric-stable Tween-oil emulsion (197 ± 19 min). The T(1/2) values for a sodium caseinate (NaCas)-oil emulsion (145 ± 11 min) and a gastric-unstable Span-oil emulsion (135 ± 7 min) were different (P < 0.05) from those for crushed whole almonds, almond cream and Tween-oil emulsion, while almond milk and oil emptied at an intermediate rate (157 ± 9 min and 172 ± 11 min, respectively). Extensively coalesced emulsions under gastric conditions (almond oil, almond cream and Span-oil) had lower (P < 0.05) overall apparent ileal fatty acid digestibility (85.8%, 75.8% and 74.3%, respectively) than crushed whole almonds, almond milk, NaCas-oil and Tween-oil emulsions (91.0%, 92.2%, 92.1% and 88.7%, respectively). The original food matrix and structural changes occurring within the gastrointestinal tract had an impact on SER and ileal fatty acid digestibility of the almond preparations.

Adsorption of bile salts to milk phospholipid and phospholipid-protein monolayers.

The adsorption of bile salts to milk phospholipid and phospholipid-protein monolayers at the air-water interface was studied under simulated intestinal conditions using a Langmuir trough, epifluorescence microscopy, and atomic force microscopy. Surface pressure changes were affected by temperature, initial surface pressure, and bile composition. The rate of addition of bile salts and the initial surface pressure of the monolayers had an impact on the microstructure of the mixed monolayers. The presence of proteins in monolayers at different ratios did not affect the surface pressure change upon addition of bile. However, at 20 °C, the addition of bile to phospholipid and phospholipid-protein monolayers led to different features with branching and clustering of liquid-ordered domains and possible formation of bile salt-rich areas within liquid-ordered domains. This study provides a basic understanding of the interfacial changes occurring at the surface of milk fat globules and milk phospholipid liposomes during their passage in the duodenum.

In vivo digestion of bovine milk fat globules: effect of processing and interfacial structural changes. II. Upper digestive tract digestion.

The aim of this research was to study the effect of milk processing on the in vivo upper digestive tract digestion of milk fat globules. Fasted rats were serially gavaged over a 5h period with cream from raw, pasteurised, or pasteurised and homogenised milk. Only a few intact dietary proteins and peptides were present in the small intestinal digesta. Significantly (P<0.05) more longer chain (C≥10) fatty acids were present in the digesta of rats gavaged with raw (448 mg g(-1) digesta dry matter (DDM)) and homogenised creams (528 mg g(-1) DDM), as compared to pasteurised and homogenised cream (249 mg g(-1) DDM). Microscopy techniques were used to investigate the structural changes during digestion. Liquid-crystalline lamellar phases surrounding the fat globules, fatty acid soap crystals and lipid-mucin interactions were evident in all small intestinal digesta. Overall, the pasteurised and homogenised cream appeared to be digested to a greater extent.

In vivo digestion of bovine milk fat globules: effect of processing and interfacial structural changes. I. Gastric digestion.

The aim was to study the in vivo gastric digestion of fat globules in bovine cream from raw, pasteurised or pasteurised and homogenised milk. Fasted rats were gavaged once and chyme samples were collected after 30, 120 and 180 min post-gavage. Proteins from raw (RC) and pasteurised (PC) creams appeared to be digested faster and to a greater extent. Free fatty acids (FAs) increased throughout the 3h postprandial period. Short and medium chain FAs were released more rapidly than long chain FAs which were hydrolysed to a greater degree from PC. The size of the fat globules of all creams increased in the stomach. Protein aggregates were observed in pasteurised and homogenised cream chyme. Protrusions, probably caused by the accumulation of insoluble lipolytic products, appeared at the surface of the globules in RC and PC chyme. Overall, PC proteins and lipids appeared to be digested to a greater extent.

In vitro gastric and intestinal digestion of a walnut oil body dispersion.

An oil body dispersion (11.3% fat) was prepared by wet disintegration of walnuts and was then subjected to a two-step model of in vitro digestion. In a gastric environment, proteolysis by pepsin led to the destabilization and coalescence of the oil bodies. Aggregation of the coalesced oil bodies was apparent under a confocal microscope, with aggregates up to 275 µm in size. Pepsin-resistant peptides and proteins remained at the surface of the oil bodies, and some were further resistant to intestinal proteases. Under intestinal conditions, the hydrolysis of walnut triglycerides led to the spontaneous formation of a new type of multiple emulsions, ranging from 2 to 45 µm in size and with protein material inside the inner water droplets. Transmission electron microscopy revealed the presence of a liquid-crystalline phase of bile salts and lipolytic products at the surface of the oil droplets and some bile salt crystals at the surface of the inner water droplets.

Behavior of almond oil bodies during in vitro gastric and intestinal digestion.

An aqueous suspension of almond oil bodies (about 10% lipids) was prepared and subjected to in vitro gastric (with pepsin) and intestinal (with bile salts and pancreatin) digestion, simulating fasting conditions. The physicochemical and structural changes of the almond oil body emulsion were examined. The almond oil body emulsion behaved similarly to a protein-stabilized emulsion, with flocculation of the oil bodies occurring under gastric conditions. Proteins, peptides, and phospholipids covered the surface of the oil bodies throughout gastric digestion. Under intestinal conditions, bile salts displaced the interfacial peptides and phospholipids, and disrupted the flocs. Gastric pepsinolysis of almond proteins was a prerequisite for their digestion in the duodenum. The oil body membrane had a negative impact on the efficiency of gastric digestion, and long chain fatty acids, the main lipolytic products, accumulated at the surface of the oil bodies and therefore limited the activity of pancreatic lipase.

Surface characterization of bovine milk phospholipid monolayers by Langmuir isotherms and microscopic techniques.

Monolayers were prepared from phospholipids extracted from bovine milk and used as a model system to mimic the native milk fat globule membrane (MFGM) surface structure in various microscopic experiments. The natural complex mixtures of phospholipids were isolated from bovine raw milk, raw cream, processed whole milk, and buttermilk powder by total lipid extraction and solid-phase extraction. A Langmuir film balance mounted on an epifluorescence microscope was used to analyze the physical behavior of the monolayer films and the phase coexistence resulting from the formation of phospholipid microdomains within these films. Atomic force microscopy was used for nanometer-scale topographic resolution of the microdomains. This study allowed comparison of the behavior of phospholipid monolayers from dairy products at different stages of processing, analysis of the formation of microdomains, and the study of the effect of milk processing on lipid-lipid interactions and phase coexistence. It was observed that milk processing changes the physical behavior of phospholipid monolayers by altering the phospholipid profile and the fatty acid distribution.

Composition and fatty acid distribution of bovine milk phospholipids from processed milk products.

The aim of this work was to assess the accuracy of different extraction methods of phospholipids and to measure the effect that processing has on phospholipid composition. Four methods of extracting phospholipids from buttermilk powder were compared to optimize recovery of sphingomyelin. Using the optimal method, the phospholipid profile of four dairy products (raw milk, raw cream, homogenized and pasteurized milk, and buttermilk powder) was determined. A total lipid extraction by the Folch method followed by a solid-phase extraction using the Bitman method was the most efficient technique to recover milk sphingomyelin. Milk processing (churning, centrifuging, homogenization, spray-drying) affected the profile of milk phospholipids, leading to a loss of sphingomyelin and phosphatidylcholine after centrifugation for cream separation. A corresponding decrease in the saturation content of the raw cream phospholipids and a loss of phosphatidylethanolamine after spray-drying to produce buttermilk powder were also observed.