Differential impact of Holder and High Temperature Short Time pasteurization on the dynamic in vitro digestion of human milk in a preterm newborn model

Peptidomic profile of human milk as influenced by fortification with different protein sources: An in vitro dynamic digestion simulation

Fortification of human milk (HM) is often necessary to meet the nutritional requirements of preterm infants. The present experiment aimed to establish whether the supplementation of HM with either an experimental donkey milk-derived fortifier containing whole donkey milk proteins, or with a commercial bovine milk-derived fortifier containing hydrolyzed bovine whey proteins, affects peptide release differently during digestion. The experiment was conducted using an in vitro dynamic system designed to simulate the preterm infant's digestion followed by digesta analysis by means of LC-MS-MS. The different fortifiers did not appear to influence the cumulative intensity of HM peptides. Fortification had a differential impact on the release of either donkey or bovine bioactive peptides. Donkey milk peptides showed antioxidant/ACE inhibitory activities, while bovine peptides showed opioid, dipeptil- and propyl endo- peptidase inhibitory and antimicrobial activity. A slight delay in peptide release from human lactoferrin and α-lactalbumin was observed when HM was supplemented with donkey milk-derived fortifier.

Human milk vs. Infant formula digestive fate: In vitro dynamic digestion and in vivo mini-piglet models lead to similar conclusions

Infant formula (IF), the only nutritionally adequate substitute for human milk (HM), still needs to be improved to be more biomimetic with HM, including in terms of digestive fate. The latter can be explored using different digestion models. The present study aimed to compare IF and HM digestion using in vivo (mini-piglet) and in vitro (dynamic system, DIDGI®) models. Fresh mature HM was collected and compared with a standard bovine IF. In vivo, 18 Yucatan mini-piglets (24-day-old) received HM or IF and were euthanized 30 min after the last meal. The entire digestive content was collected from the stomach to the colon. In vitro, the same meals were fed to an in vitro dynamic digestion model simulating the term infant at four weeks of age. Digesta were sampled regularly in the gastric and intestinal compartments. Structure (confocal microscopy and laser light scattering) and proteolysis (SDS-PAGE for residual intact proteins, OPA for hydrolysis degree, LC-MS/MS for peptides) were investigated along digestion. The digesta microstructure differed between HM and IF in a similar way between in vitro and in vivo digestion. In vitro gastric proteolysis of caseins and α-lactalbumin was significantly slower for HM than for IF, such as for the early intestinal proteolysis degree. In vitro bioaccessibility of free AAs explained only 30 % of the true ileal digestibility of AAs. Peptide mapping of caseins differed between HM and IF along their digestion. The relative peptide mapping data over six proteins from HM and IF were highly correlated between in vitro and in vivo digestion, particularly at 80 and 120 min of in vitro gastric digestion vs. in vivo stomach data and at 20 and 40 min of in vitro intestinal digestion vs. in vivo proximal jejunum data (r = 0.7-0.9, p < 0.0001, n = 1604). 40 to 50 % of the bioactive peptides identified in vivo were also found in vitro, with a good correlation of their abundances (r = 0.5, p < 0.0001, n = 61). Overall, in vitro and in vivo digestion were in good agreement, both indicating a different digestive fate for HM and IF.

Donor human milk: the influence of processing technologies on its nutritional and microbial composition

Human milk is regarded as the gold standard nutrition for newborn infants, providing all nutrients required for adequate growth and development from birth to 6 months. In addition, human milk is host to an array of bioactive factors that confer immune protection to the newborn infant. For this reason, the supply of human milk is crucial for premature, seriously ill, or low birth weight infants (<1,500 g). When a mother's own milk is unavailable, donor human milk is the recommended alternative by the World Health Organization. Prior to consumption, donor human milk undergoes pasteurization to ensure the eradication of bacterial agents and prevent the transfer of potentially pathogenic organisms. Currently, Holder Pasteurization, a heat-based treatment, is the widely adopted pasteurization technique used by milk banks. Holder pasteurization has demonstrated degradative effects on some of milk's biologically active factors, thus depleting critical bioactive agents with known functional, protective, and beneficial properties, ultimately reducing the immunoprotective value of donor human milk. As a result, alternative strategies for the processing of donor human milk have garnered much interest. These include thermal and non-thermal techniques. In the current review, we describe the effects of Holder pasteurization and alternative milk processing technologies on the nutritional and bioactive properties of milk. In addition, the capacity of each technique to ensure microbial inactivation of milk is summarized. These include the most extensively studied, high-temperature short-time and high-pressure processing, the emerging yet promising techniques, microwave heating and UV-C irradiation, and the lesser studied technologies, thermoultrasonication, retort processing, pulsed electric field, and gamma irradiation. Herein, we collate the findings of studies, to date, to allow for greater insight into the existing gaps in scientific knowledge. It is apparent that the lack of a cohesive standardized approach to human milk processing has resulted in contrasting findings, preventing a direct comparative analysis of the research. We conclude that donor human milk is a unique and valuable resource to the health sector, and although substantial research has been completed, persistent data disparities must be overcome to ensure optimal nutrition for the vulnerable newborn preterm infant group, in particular.

Application of pressure homogenization on whole human milk pasteurized by high hydrostatic pressure: Effect on protein aggregates in milk fat globule membrane and skim milk phases

This study explored the impact of homogenization (at pressures of 16, 30, and 45 MPa) on both raw and high hydrostatic pressure (HHP)-treated human milk (HM). It focused on protein compositions and binding forces of soluble and insoluble fractions for both milk fat globule membrane (MFGM) and skim milk. Mild homogenization of HHP-treated milk increased lactoferrin (LF) levels in the insoluble fractions of both MFGM and skim milk, due to insoluble aggregation through hydrophobic interactions. Intense homogenization of HHP-treated milk decreased the LF level in the MFGM fractions due to the LF desorption from the MFGM, which increased LF level in the insoluble skim milk fraction. Homogenized-HHP treated milk showed noticeably higher casein (CN) level at the MFGM compared to homogenized-raw milk, attributed to HHP effect on CN micelles. Overall, the combined use of HHP and shear-homogenization should be avoided as it increased the biological proteins in insoluble fractions.

The impact of complexation or complex coacervation of lactoferrin and osteopontin on simulated infant gastrointestinal digestion, intestinal inflammation, and in vivo bone development

Lactoferrin (LF) and osteopontin (OPN) are bioactive milk proteins which can form heteroprotein complexes and complex coacervates. This research studied the effect of LF-OPN complexation and complex coacervation on the simulated infant gastrointestinal digestion of LF with subsequent examination of gut and bone health bioactivities in preclinical models. In an infant digestion model, the proteolytic profile of LF was unaltered by the pre-association of LF and OPN. Gastric proteolysis of LF was increased when the model gastric pH was reduced from 5.3 to 4.0, but less so when complexed with OPN. In a model of intestinal inflammation, undigested (79% inhibition) and gastric digestates (26% inhibition) of LF, but not gastrointestinal digestates, inhibited lipopolysaccharide (LPS)-induced NF-κB activation in intestinal epithelial cells. LF-OPN complexation sustained the inhibitory effect (21-43% of the undigested effect, depending on the type of complex) of LF after gastrointestinal digestion, suggesting that the peptides produced were different. In a neonatal rodent model used to study bone development, coacervating LF and OPN improved bone structures with a significant increase of trabecular proportion (BV/TV increase by 21.7%). This resulted in an 11.3% increase in stiffness of bones. Feeding the LF and OPN proteins in coacervate format also increased the levels of OPN, P1NP and M-CSF in blood, signifying a more pronounced impact on bone development. This research demonstrated that LF-OPN complexation and complex coacervation can delay simulated infant gastrointestinal digestion of LF and protect or improve the bioactivity of the proteins.

New alternatives to holder pasteurization in processing donor milk in human milk banks

Infectious and toxicological risks are the main potential hazards that operators of Human Milk Banks (HMBs) encounter and must eliminate. HMBs are trying to implement procedures that allow to manage and sanitize human milk without altering significantly its nutritional and biologically protective components, obtaining a product characterized by a valid balance between safety and biological quality. The history of human milk processing is linked to the origins of HMBs themselves. And although other forms of sterilization were used originally, pasteurization soon became the recognized most effective means for sanitizing milk: all the milk that arrives at the HMB must be pasteurized. Holder pasteurization (HoP) is the most used methodology, and it is performed using low temperature and long time (+62.5°C for 30 min). With HoP some bioactive milk components are lost to varying degrees, but many other precious bioactive compounds are completely or partially preserved. To improve the quality of human milk processed by HMBs, maintaining in the meantime the same microbiological safety offered by HoP, new technologies are under evaluation. At present, High-Temperature Short-Time pasteurization (HTST) and High-Pressure Processing are the most studied methodologies. HTST is already utilized in some HMBs for daily practical activity and for research purposes. They seem to be superior to HoP for a better preservation of some nutritional and biologically protective components. Freeze-drying or lyophilization may have advantages for room temperature storage and transportation. The aim of this study is to evaluate the advancement regarding the processing of DHM with a literature search from 2019 to 2022. The effects of the new technologies on safety and quality of human milk are presented and discussed. The new technologies should assure microbiological safety of the final product at least at the same level as optimized HoP, with an improved preservation of the nutritional and bioactive components of raw human milk.

The triacylglycerol structures are key factors influencing lipid digestion in preterm formulas during in vitro digestion

Preterm formulas are usually supplemented with medium-chain triacylglycerols (MCT) whereas breast milk contains more medium and long-chain triacylglycerols (MLCT). Different types of triacylglycerol (TAG) containing medium-chain fatty acids may influence lipid digestion. In this study, the digestive characteristics of breast milk and preterm formulas with different MCT contents were evaluated using a dynamic in vitro system simulating the gastrointestinal tract of preterm infants. The lipolysis products, including diacylglycerols, monoacylglycerols (MAGs), free fatty acids, and undigested TAGs, were analyzed. Formulas with MCT addition has significantly (P < 0.05) lower lipolysis degree (LD, 69.35%-71.28%) than breast milk (76.93%). Higher amounts of C8:0 and C10:0 were released in the formulas with MCT addition. Breast milk released more C18:1n-9, C18:2n-6, and MAG containing C16:0, whereas formulas released more free C16:0. The Pearson correlation heatmap showed that the LD value was significantly and positively (P < 0.05) related to the MLCT and sn-2 C16:0 content.

Investigating Milk Fat Globule Structure, Size, and Functionality after Thermal Processing and Homogenization of Human Milk

Human milk provides bioactive compounds such as milk fat globules (MFGs), which promote brain development, modulate the immune system, and hold antimicrobial properties. To ensure microbiological safety, donor milk banks apply heat treatments. This study compares the effects of heat treatments and homogenization on MFG's physicochemical properties, bioactivity, and bioavailability. Vat pasteurization (Vat-PT), retort (RTR), and ultra-high temperature (UHT) were performed with or without homogenization. UHT, RTR, and homogenization increased the colloidal dispersion of globules, as indicated by increased zeta potential. The RTR treatment completely inactivated xanthine oxidase activity (a marker of MFG bioactivity), whereas UHT reduced its activity by 93%. Interestingly, Vat-PT resulted in less damage, with 28% activity retention. Sialic acid, an important compound for brain health, was unaffected by processing. Importantly, homogenization increased the in vitro lipolysis of MFG, suggesting that this treatment could increase the digestibility of MFG. In terms of color, homogenization led to higher L* values, indicating increased whiteness due to finer dispersion of the fat and casein micelles (and thus greater light scattering), whereas UHT and RTR increased b* values associated with Maillard reactions. This study highlights the nuanced effects of processing conditions on MFG properties, emphasizing the retention of native characteristics in Vat-PT-treated human milk.

Characterization of protein aggregates in cream and skimmed human milk after heat and high-pressure pasteurization treatments

Preservation processes applied to ensure microbial safety of human milk (HM) can modify the native structure of proteins and their bioactivities. Consequently, this study evaluated the effect of pasteurization methods (Holder pasteurization, high-temperature short-time (HTST), and high hydrostatic pressure (HHP)) of whole human milk (HM) on protein aggregates in skim milk and cream fractions. For heat-treated whole milk, insoluble protein aggregates at milk fat globule membrane (MFGM) were formed by disulfide and non-covalent bonds, but insoluble skim milk protein aggregates were only stabilized by non-covalent interactions. Contrary to heat treatment, the insolubilization of main proteins at the MFGM of HHP-treated HM was only through non-covalent interactions rather than disulfide bonds. Moreover, only heat treatment induced the insoluble aggregation of ⍺-lactalbumin. Overall, compared to heat treatment, HHP produced a milder effect on protein aggregation, validating the use of this process to better preserve the native state of HM bioactive proteins.

HAMLET in human milk is resistant to digestion and carries essential free long chain polyunsaturated fatty acids and oleic acid

The oleic acid/alpha-lactalbumin complex HAMLET (human alpha-lactalbumin made lethal to tumors) is cytotoxic to various cancerous cell lines and is assembled from alpha-lactalbumin (ALA) and free oleic acid (OA). HAMLET is also cytotoxic to normal immature intestinal cells. It remains unclear if HAMLET, experimentally assembled with OA and heat, can spontaneously assemble in frozen human milk over time. To approach this issue, we used a set of timed proteolytic experiments to evaluate the digestibility of HAMLET and native ALA. The purity of HAMLET in human milk was confirmed by ultra high performance liquid chromatography coupled to tandem mass spectrometry and western blot to resolve the ALA and OA components. Timed proteolytic experiments were used to identify HAMLET in whole milk samples. Structural characterization of HAMLET was performed by Fournier transformed infrared spectroscopy and indicated a transformation of secondary structure with increased alpha-helical character of ALA upon binding to OA.

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.

Digestion of human milk processed by high pressure processing and Holder pasteurization using a dynamic in vitro model of the preterm infant

Holder pasteurization (HoP) (62.5 °C, 30 min) of donor human milk is widely used to inactivate potential pathogens but may lead to denaturation and aggregation of bioactive proteins, reducing their functionality. In contrast, high pressure processing (HPP) is a non-thermal technique that minimally affects assessed bioactive components; however, it is unclear how HPP affects protein digestion, and retention of functional bioactive proteins. Raw or processed (HoP; HPP[500 MPa,10 min]) pools of milk (N = 3, from 9 donors) were subjected in triplicate to in vitro digestion simulating the preterm infant gastrointestinal tract. Compared to raw or HPP, HoP increased intestinal proteolysis of lactoferrin and bioactive milk fat globule membrane proteins. Lysozyme activity was impacted by digestion following HoP (72 % to 7 %)-significantly more than HPP (75 % to 34 %) or raw (100 % to 39 %), which did not differ. Proteins in HPP-treated donor milk are digested no different than raw milk, while preserved bioactivity remains functional upon digestion.

Development of a human milk protein concentrate from donor milk: Impact of the pasteurization method on static in vitro digestion in a preterm newborn model

The impact of high temperature short time (HTST, 72 °C, 15 s), Holder pasteurization- (63 °C, 30 min) and high hydrostatic pressure (HHP, 600 MPa-10 min) was evaluated on the digestibility of human milk protein concentrate (HMPC) by using a static in vitro gastrointestinal digestion system. The results showed that the processing steps used to produce the HMPC induced a decrease in readily available nitrogen (non-protein nitrogen and peptides). Overall, digestibility was similar between pasteurized and raw HMPC (degree of hydrolysis ranged from 26 to 34 %). Lactoferrin was more susceptible to gastric and intestinal digestion after thermal pasteurization. Additionally, the resistance of β-casein to digestion increased after HHP and Holder pasteurization due to aggregation and changes in protein structure. During intestinal digestion, Holder pasteurization induced a higher release of arginine, phenylalanine and tyrosine from HMPC compared to raw and HHP-treated HMPC. Overall, protein structural changes induced by human milk (HM) processing (freeze-thawing and filtration) and pasteurization treatments affected HMPC proteolysis during in vitro digestion. However, protein digestion behaviors were quite similar for raw and HHP-treated HMPC compared to the thermal-treated HMPC, with no effect on lactoferrin digestion. Consequently, pasteurization of HMPC by HHP represents an interesting non-thermal process that preserves the HM bioactive proteins during digestion.

Donor human milk processing and its impact on infant digestion: A systematic scoping review of in vitro and in vivo studies

When there is an inadequate supply of mother's milk, pasteurized donor human milk is preferred over formula to supplement feeds for preterm infants. Although providing donor milk helps to improve feeding tolerance and reduce necrotizing enterocolitis, changes to its composition and reductions in bioactivity during processing, are thought to contribute to the slower growth often exhibited by these infants. To improve the clinical outcomes of recipient infants by maximizing the quality of donor milk, research is currently investigating strategies to optimize all aspects of processing, including pooling, pasteurization, and freezing; however, reviews of this literature typically only summarize the impact of a processing technique on composition or bioactivity. Reviews of published research investigating the impact of donor milk processing on infant digestion/absorption are lacking and thus, was the objective for this systematic scoping review, Open Science Framework (https://doi.org/10.17605/OSF.IO/PJTMW). Databases were searched for primary research studies evaluating donor milk processing for pathogen inactivation or other rationale and subsequent effect on infant digestion/absorption. Non-human milk studies or those assessing other outcomes were excluded. Overall, 24 articles from 12,985 records screened were included. Most studied thermal methods to inactivate pathogens, predominantly Holder pasteurization (HoP) (62.5°C, 30 min) and high-temperature short-time. Heating consistently decreased lipolysis and increased proteolysis of lactoferrin and caseins; however, protein hydrolysis was unaffected from in vitro studies. The abundance and diversity of released peptides remain unclear and should be further explored. Greater investigation into less-harsh methods for pasteurization, such as high-pressure processing, is warranted. Only 1 study assessed the impact of this technique and found minimal impact on digestion outcomes compared with HoP. Fat homogenization appeared to positively impact fat digestion (n = 3 studies), and only 1 eligible study investigated freeze-thawing. Identified knowledge gaps regarding optimal methods of processing should be further explored to improve the quality and nutrition of donor milk.

Impact of holder, high temperature short time and high hydrostatic pressure pasteurization methods on protein structure and aggregation in a human milk protein concentrate

This work evaluated the impact of high temperature short time (HTST, 72 °C, 15 s), high hydrostatic pressure (HHP, 400-600 MPa at 5 and 10 min) and Holder pasteurization (HoP, 62.5 °C, 30 min) on protein profile and aggregation in a human milk protein concentrate (HMPC). The structural changes induced in milk proteins were investigated in HMPC as well as in sedimentable and non-sedimentable fractions recovered after ultracentrifugation. The results showed that heat treatments induced more protein denaturation and aggregation than did HHP treatments. Indeed, heat-induced protein aggregates observed in HMPC and the sedimentable fraction were mainly composed of lactoferrin and α-lactalbumin. More specifically, the concentration of lactoferrin in HMPC decreased by 86% after HTST and HoP whereas no effect was observed after HHP treatment. These results show the potential of HHP processing as a pasteurization method for HMPC since it minimizes the impact on protein structure, which generally correlates to protein quality and bioactivity.

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 β-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.

The impact of thermal processing on the simulated infant gastrointestinal digestion, bactericidal and anti-inflammatory activity of bovine lactoferrin - An in vitro study

Lactoferrin (LF) is a multifunctional glycoprotein which, when thermally processed, undergoes significant physicochemical changes. The link between such changes and the bioactivity of LF is not well characterised and requires much research. In this work, bovine LF solutions (1%, w/v, protein, pH 7) were thermally processed using high temperature short time conditions (72, 80, 85 or 95 °C with 15 s holding times). Following this, it was shown that LF and heat induced LF aggregates were largely resistant to simulated infant gastric, but not intestinal, digestion. Also, the efficacy of LF bactericidal activity, and inhibition of lipopolysaccharide-induced NF-κB activation were negatively impacted by thermal processing. This study confirmed that the efficacy of LF bio-functionalities was affected by the extent of heat-induced changes in protein structure whereby processing conditions of least severity (i.e. pasteurisation) had the least impact on bioactivity.

Human milk proteome: what's new?

PURPOSE OF REVIEW

The proteome is one of the most complicated and multifunctional components in human milk. Recently, numerous novel characteristics of the human milk proteome have been discovered, which are described and critically examined in this review.

RECENT FINDINGS

Recent human milk proteomics studies have focused on how external factors like geography and environment, or maternal and infant's factors affect the milk proteins, endogenous peptides, their posttransitional modifications (PTMs) and infant utilization. Most of these studies have shown that major protein and endogenous peptide profiles are similar for healthy women and infants. The human milk proteome has been expanded by providing novel insights into PTMs like glycosylation and phosphorylation, and how the proteins and peptides are digested and utilized by the infant. All human milk proteomics studies are subject to conditions in which the samples were collected, handled and stored.

SUMMARY

Significant technological advancements in mass spectrometry have considerably enabled a deeper and more comprehensive identification and characterization of the expanded human milk proteome. However, data concerning human milk from mothers with infections or illnesses and mothers nursing more vulnerable infants are still limited and the roles of the components of the human milk proteome have not yet been sufficiently elucidated.

Lipid Composition, Digestion, and Absorption Differences among Neonatal Feeding Strategies: Potential Implications for Intestinal Inflammation in Preterm Infants

Necrotizing enterocolitis (NEC) is a significant cause of morbidity and mortality in the neonatal population. Formula feeding is among the many risk factors for developing the condition, a practice often required in the cohort most often afflicted with NEC, preterm infants. While the virtues of many bioactive components of breast milk have been extolled, the ability to digest and assimilate the nutritional components of breast milk is often overlooked. The structure of formula differs from that of breast milk, both in lipid composition and chemical configuration. In addition, formula lacks a critical digestive enzyme produced by the mammary gland, bile salt-stimulated lipase (BSSL). The gastrointestinal system of premature infants is often incapable of secreting sufficient pancreatic enzymes for fat digestion, and pasteurization of donor milk (DM) has been shown to inactivate BSSL, among other important compounds. Incompletely digested lipids may oxidize and accumulate in the distal gut. These lipid fragments are thought to induce intestinal inflammation in the neonate, potentially hastening the development of diseases such as NEC. In this review, differences in breast milk, pasteurized DM, and formula lipids are highlighted, with a focus on the ability of those lipids to be digested and subsequently absorbed by neonates, especially those born prematurely and at risk for NEC.

Antimicrobial Potential of Food Lactic Acid Bacteria: Bioactive Peptide Decrypting from Caseins and Bacteriocin Production

Lactic acid bacteria (LAB) potential in the food industry and in the biotechnological sector is a well-established interest. LAB potential in counteracting especially food-borne infections has received growing attention, but despite being a road full of promises is yet poorly explored. Furthermore, the ability of LAB to produce antimicrobial compounds, both by ribosomal synthesis and by decrypting them from proteins, is of high value when considering the growing impact of multidrug resistant strains. The antimicrobial potential of 14 food-derived lactic acid bacteria strains has been investigated in this study. Among them, four strains were able to counteract Listeria monocytogenes growth: Lactococcus lactis SN12 and L. lactis SN17 by high lactic acid production, whereas L. lactis 41FLL3 and Lactobacillus sakei I151 by Nisin Z and Sakacin P production, respectively. Strains Lactococcus lactis MG1363, Lactobacillus rhamnosus 17D10 and Lactobacillus helveticus 4D5 were tested and selected for their potential attitude to hydrolyze caseins. All the strains were able to release bioactive peptides with already known antimicrobial, antihypertensive and opioid activities. These features render these strains or their bioactive molecules suitable for use in food as biocontrol agents, or as nutraceutical supplements to treat mild disorders such as moderate hypertension and children insomnia. These results highlight once again that LAB potential in ensuring food safety, food nutraceutical value and ultimately in favoring human health is still underexplored and underexploited.

Impact of Storage Conditions on the Breast Milk Peptidome

Human donor milk (HDM) provides appropriate nutrition and offers protective functions in preterm infants. The aim of the study is to examine the impact of different storage conditions on the stability of the human breast milk peptidome. HDM was directly frozen at −80 °C or stored at −20 °C (120 h), 4 °C (6 h), or room temperature (RT for 6 or 24 h). The milk peptidome was profiled by mass spectrometry after peptide collection by ultrafiltration. Profiling of the peptidome covered 3587 peptides corresponding to 212 proteins. The variance of the peptidome increased with storage temperature and time and varied for different peptides. The highest impact was observed when samples were stored at RT. Smaller but significant effects were still observed in samples stored at 4 °C, while samples showed highest similarity to those immediately frozen at −80 °C when stored at −20 °C. Peptide structures after storage at RT for 24 h point to the increased activity of thrombin and other proteases cleaving proteins at lysine/arginine. The results point to an ongoing protein degradation/peptide production by milk-derived proteases. They underline the need for immediate freezing of HDM at −20 °C or −80 °C to prevent degradation of peptides and enable reproducible investigation of prospectively collected samples.