Simulated In Vitro Infant Gastrointestinal Digestion of Infant Formulas Containing Different Fat Sources and Human Milk: Differences in Lipid Profiling and Free Fatty Acid Release

Human milk fat substitutes rich in 1,3-dioleoyl-2-palmitoylglycerol and 1-oleoyl-2-palmitoyl-3-linoleoylglycerol simultaneously: Preparation strategy and simulated infant in vitro digestion

In this study, fractionated palm stearin, oleic acid, and linoleic acid were selected as the base materials to prepare human milk fat substitutes (HMFS) rich in OPO and OPL by enzymatic acidolysis combined with physical blending. Under optimum conditions, contents of OPO, OPL, and sn-2 palmitic acid in the OPO and OPL-rich triacylglycerols (TAGs) were higher than that in commercial OPO-rich TAGs, with values of 37.25%, 28.12%, and 79.44%, respectively. Physical blending the OPO and OPL-rich TAGs (47%), bovine milk fat (18%), sunflower oil (13%), coconut oil (13%), corn oil (8%), and palm oil (1%) can obtain HMFS with a fat composition that like HMF. The fatty acid, sn-2 saturated fatty acid, and TAG contents of HMFS were within the lower and upper limit of HMF. The lipolysis degree of infant formula (IF) with HMFS as fat source is 9.0% higher than that of commercial plant oil-based infant formula (PIF), and 3.4% lower than that of human milk. IF with HMFS as fat source released less saturated free fatty acids and more saturated monoacylglycerols during digestion than that of PIF, which would help improve the IF fat utilization by infants.

The effect of citral loading and fatty acid distribution on the oleogels: Physicochemical properties and in vitro digestion

Oleogels containing bioactive substances such as citral (CT) are used as functional food ingredients. However, little information is available on the influence of different oleogel network structure caused by CT addition and fatty acid distribution on its digestion behavior. Coconut oil, palm oil, high oleic peanut oil, safflower seed oil, and perilla seed oil were used in this study. The results showed that perilla seed oil-CT-based oleogels had the highest oil-holding capacity (99.03 ± 0.3), whereas CT addition higher than 10 wt% could lead to the morphology collapse of oleogels. Physical and thermodynamic analyses revealed that CT could reduce oleogel hardness and higher unsaturated fatty acid content is more likely to form oleogel with stable and tight crystalline network. Moreover, the dense structure of oleogels hinders the contact between oleogels and lipase, thus weakening triglyceride digestion. These findings provide valuable insights into the design of oleogels loading with CT.

Exploring lipid digestion discrepancies between preterm formula and human milk: Insights from in vitro gastrointestinal digestion and the impact of added milk fat

Lipids play a pivotal role in the nutrition of preterm infants, acting as a primary energy source. Due to their underdeveloped gastrointestinal systems, lipid malabsorption is common, leading to insufficient energy intake and slowed growth. Therefore, it is critical to explore the reasons behind the low lipid absorption rate in formulas for preterm infants. This study utilized a simulated in intro gastrointestinal digestion model to assess the differences in lipid digestion between preterm human milk and various infant formulas. Results showed that the fatty acid release rates for formulas IF3, IF5, and IF7 were 58.90 %, 56.58 %, and 66.71 %, respectively, lower than human milk's 72.31 %. The primary free fatty acids (FFA) and 2-monoacylglycerol (2-MAG) released during digestion were C14:0, C16:0, C18:0, C18:1n-9, and C18:2n-6, in both human milk and formulas. Notably, the higher release of C16:0 in formulas may disrupt fatty acid balance, impacting lipid absorption. Further investigations are necessary to elucidate lipid absorption differences, which will inform the optimization of lipid content in preterm infant formulas.

Influence of pasteurization and spray drying on the fat digestion behavior of human milk fat analog emulsion: a simulated in vitro infant digestion study

BACKGROUND

Human milk fat analog emulsion (HMFAE) is an emulsion that mimics the composition and structure of human milk (HM) fat globules. The application of HMFAE in infant formula requires a series of milk powder processing steps, such as pasteurization and spray drying. However, the effect of milk powder processing on fat digestion of HMFAE is still unclear. In this study, the influence of pasteurization and spray drying on the lipolysis behavior of HMFAE was studied and compared with HM using a simulated infant in vitro digestion model.

RESULTS

Pasteurization and spray drying increased the flocculation and aggregation of lipid droplets in HMFAE during digestion. Spray drying destroyed the lipid droplet structure of HMFAE, and partial milk fat globule membrane-covered lipid droplets turned into protein-covered lipid droplets, which aggravated lipid-protein aggregation during gastric digestion and hindered fat digestion in the small intestine. The final lipolysis degree was in the order HM (64.55%) > HMFAE (63.41%) > pasteurized HMFAE (61.75%) > spray-dried HMFAE (60.57%). After complete gastrointestinal digestion, there were no significant differences in free fatty acid and sn-2 monoacylglycerol profile among the HMFAE, pasteurized HMFAE, and spray-dried HMFAE.

CONCLUSION

Milk powder processing can reduce lipolysis by altering the lipid droplet structure of HMFAE and the degree of lipid droplet aggregation during digestion. © 2024 Society of Chemical Industry.

Comprehensive analysis of phospholipid in milk and their biological roles as nutrients and biomarkers

Phospholipids (PL) have garnered significant attention due to their physiological activities. Milk and other dairy products are important dietary sources for humans and have been extensively used to analyze the presence of PL by various analytical techniques. In this paper, the analysis techniques of PL were reviewed with the eight trigrams of phospholipidomics and a comprehensive fingerprint of 1295 PLs covering 8 subclasses in milk and other dairy products, especially. Technology is the primary productive force. Based on phospholipidomics technology, we further review the relationship between the composition of PL and factors that may be involved in processing and experimental operation, and emphasized the significance of the biological role played by PL in dietary supplements and biomarkers (production, processing and clinical research), and providing the future research directions.

Tibetan Plateau yak milk: A comprehensive review of nutritional values, health benefits, and processing technology

Yak milk is a characteristic animal product of yaks in the Qinghai-Tibet Plateau. Although yak milk production is low, it is richer in nutrients such as protein, fat, and lactose, a more comprehensive range of bioactive components, and unique microbial resources than Holstein cow milk. The plateau environment makes yak milk resistant to hypoxia, anti-fatigue, antioxidant, antibacterial, and relieves chronic diseases. In this paper, based on the systematic analysis of yak milk research results in the past 20 years using CiteSpace 6.1.R2, we reviewed yak lactation performance and nutritional efficacy of yak milk. This paper summarizes the improvement of traditional yak dairy processing technology, and also focuses on the microbial diversity of yak milk sources and their beneficial effects. The purpose of this review is to provide scientific support for the development of a quality yak milk industry on the Tibetan plateau.

Differences in fat digestion from milk of different Species: In vitro gastrointestinal digestion model for infants

The differences in the milk fat digestion from goat milk (GM), camel milk (CM), bovine milk (BM), sheep milk (SM), mare milk (MM) and human milk (HM) using an in vitro gastrointestinal digestion model for simulated infants were investigated. The particle size distributions in goat and mare milk were similar to that of HM after digestion in the small intestine. During in vitro digestion, the zeta-potential change of MM was more consistent with that of HM. After 60 min of gastric digestion, the lipolysis degree (LD) of different milks were<2%, of which the highest LD was MM (1.84%), followed by HM (1.45%). At the end of intestinal digestion, the LD of HM was the highest, reaching 88.47%, and the LD of SM was similar to that of HM, reaching 83.92%, followed by GM (57.00%), BM (40.98%) and MM (39.37%), respectively, the LD of CM was only 29.99%, which was much lower than HM. The results of the glyceride composition hierarchical clustering analysis revealed that MM and HM were clustered into one category at the end of gastric and intestinal digestion. This study provides a scientific basis for the development of lipid ingredients in infant formula.

Novel trends and challenges in fat modification of next-generation infant formula: Considering the structure of milk fat globules to improve lipid digestion and metabolism of infants

Differences in the composition and structure of lipid droplets in infant formula (IF) and human milk (HM) can affect the fat digestion of infants, leading to high risk of metabolic diseases during later stages of growth. Recently, interest in simulating HM fat (HMF) has gradually increased due to its beneficial functions for infants. Much research focuses on the simulation of fatty acids and triacylglycerols. Enzymatic combined with new technologies such as carbodiimide coupling immobilization enzymes, solvent-free synthesis, and microbial fermentation can improve the yield of simulated HMF. Furthermore, fat modification in next-generation IF requires attention to the impact on the structure and function of milk fat globules (MFG). This review also summarizes the latest reports on MFG structure simulation, mainly related to the addition method and sequence of membrane components, and other milk processing steps. Although some of the simulated HMF technologies and products have been applied to currently commercially available IF, the cost is still high. Furthermore, understanding the fat decomposition of simulated HMF during digestion and assessing its nutritional effects on infants later in life is also a huge challenge. New process development and more clinical studies are needed to construct and evaluate simulated HMF in the future.

Bioactive Functions of Lipids in the Milk Fat Globule Membrane: A Comprehensive Review

The milk fat globule membrane (MFGM) is a complex tri-layer membrane that wraps droplets of lipids in milk. In recent years, it has attracted widespread attention due to its excellent bioactive functions and nutritional value. MFGM contains a diverse array of bioactive lipids, including cholesterol, phospholipids, and sphingolipids, which play pivotal roles in mediating the bioactivity of the MFGM. We sequentially summarize the main lipid types in the MFGM in this comprehensive review and outline the characterization methods used to employ them. In this comprehensive review, we sequentially describe the types of major lipids found in the MFGM and outline the characterization methods employed to study them. Additionally, we compare the structural disparities among glycerophospholipids, sphingolipids, and gangliosides, while introducing the formation of lipid rafts facilitated by cholesterol. The focus of this review revolves around an extensive evaluation of the current research on lipid isolates from the MFGM, as well as products containing MFGM lipids, with respect to their impact on human health. Notably, we emphasize the clinical trials encompassing a large number of participants. The summarized bioactive functions of MFGM lipids encompass the regulation of human growth and development, influence on intestinal health, inhibition of cholesterol absorption, enhancement of exercise capacity, and anticancer effects. By offering a comprehensive overview, the aim of this review is to provide valuable insights into the diverse biologically active functions exhibited by lipids in the MFGM.

Interfacial composition in infant formulas powder modulate lipid digestion in simulated in-vitro infant gastrointestinal digestion

The interface structure and composition of fat globules are very important for the digestion and metabolism of fat and growth in infants. Interface composition of fat globules in infant formula (IF) supplemented with milk fat globule membranes (MFGM) and lecithin in different ways were analyzed and their effects on fat digestion properties were evaluated. The results showed that the distribution of phospholipids at the interface and structural of Concept IF1 and Concept IF2 that were more similar to those of human milk (HM) than that of conventionally processed IF3. Concept IF2 and IF3 supplemented with lecithin had larger initial particle size and more sphingomyelin (SM) (23.12 ± 0.26 %, 26.94 ± 0.34 %) than Concept IF1, and Concept IF2 had the smallest proportion of casein in the interfacial. Due to its interface composition, Concept IF2 had the highest degree of lipolysis (85.07 ± 0.76 %), the phospholipid ring structure can always be observed during gastric digestion, and a final fatty acid composition released that was more similar to HM. Concept IF1 and IF3 were different from HM and Concept IF2 in terms of structure and lipolysis rate, although superior to commercial IF4. These indicate that changes in the interfacial composition and structure of fat globules improve the digestive properties of fats in IF. Overall, the results reported herein are useful in designing new milk formulas that better simulate HM.

The influence of MPL addition on structure, interfacial compositions and physicochemical properties on infant formula fat globules

The lack of milk fat globule membrane phospholipids (MPL) at the interface of infant formula fat globules has an impact on the stability of fat globules, compared to human milk. Therefore, infant formula powders with different MPL contents (0%, 10%, 20%, 40%, 80%, w/w of MPL/whey protein mixture) were prepared, and the effect of interfacial compositions on the stability of globules was investigated. With increasing MPL amount, the particle size distribution had two peaks and returned to a uniform state when 80% MPL was added. At this composition, the MPL at the oil-water interface formed a continuous thin layer. Moreover, the addition of MPL improved the electronegativity and the emulsion stability. In terms of the rheological properties, increasing the concentration of MPL improved the elastic properties of the emulsion and the physical stability of the fat globules, while reducing the aggregation and agglomeration between fat globules. However, the potential for oxidation increased. Based on these results, the interfacial properties and stability on infant formula fat globules was significantly influenced by the level of MPL, which should be considered in the design of infant milk powders.

Interaction between whey protein and soy lecithin and its influence on physicochemical properties and in vitro digestibility of emulsion: A consideration for mimicking milk fat globule

In this study, from the perspective of simulating the milk fat globule (MFG) emulsion, the interaction between soybean lecithin (SL) and the main protein in milk, whey protein (WP), and its effect on physical characteristics and lipid digestion were investigated through multiple spectroscopic techniques and in vitro digestion. The mechanism of SL and WP was static quenching, indicating that a complex formed between WP and SL through hydrophobic interaction and hydrogen bonding. The addition of SL changed the secondary structure of WP. When the ratio of SL to WP was 1:3, the obtained SL-WP emulsion that simulated milk fat globule exhibited the smallest particle size distribution and the highest absolute value of zeta potential. In addition, the emulsion exhibited high encapsulation efficiency (91.67 ± 1.24 %) and good stability. Compared with commercially available infant formula (IF), the final free fatty acid release of prepared SL-WP emulsion was close to that of human milk (HM). The addition of lecithin increased the digestibility of fat and the release of free fatty acids, and the digestive characteristic and particle size change also were closer to that of HM from results of kinetics of free fatty acid release and microstructure analysis.

The Association between Breastfeeding Duration and Lipid Profile among Children and Adolescents

To investigate the relationship between breastfeeding duration and lipid profile among children and adolescents, a cross-sectional survey using random cluster sampling was performed, and a national sample of 12,110 Chinese children and adolescents aged 5–19 years were collected. Breastfeeding duration and sociodemographic factors were collected by questionnaires. Fasting blood samples were obtained to test the lipid profile. Linear regression and logistic regression models were employed to evaluate the association between breastfeeding duration and lipid profile. We found that prolonged breastfeeding was related with a low level of total cholesterol (TC), LDL-C, HDL-C, and TC/HDL-C in children and adolescents. With an increased duration of breastfeeding, the magnitude of the association between breastfeeding and lipid profile enlarged. The levels of TC, LDL-C, HDL-C, and TC/HDL-C in participants who were breastfed for more than 12 months decreased by 6.225 (95% CI: −8.390, −4.059), 1.956 (95% CI: −3.709, −0.204), 1.273 (95% CI: −2.106, −0.440) mg/dL, and 0.072 (95%CI: −0.129, −0.015), respectively, compared with those who were not breastfed. The corresponding risk of high TC declined by 43% (aOR: 0.570, 95% CI: 0.403, 0.808). The association was similar in both boys and girls, but only statistically significant in children and young adolescents aged 5–14 years. This suggested that prolonged breastfeeding duration was related with low lipid levels and decreased abnormal lipid risk, especially in children and young adolescents. These findings support the intervention of prompting a prolonged duration of breastfeeding to improve the childhood lipid profile.