A review of recent developments in the use of moderately hydrolyzed whey formulae in infant nutrition

Bioactive Dairy-Fermented Products and Phenolic Compounds: Together or Apart

Fermented dairy products (e.g., yogurt, kefir, and buttermilk) are significant in the dairy industry. They are less immunoreactive than the raw materials from which they are derived. The attractiveness of these products is based on their bioactivity and properties that induce immune or anti-inflammatory processes. In the search for new solutions, plant raw materials with beneficial effects have been combined to multiply their effects or obtain new properties. Polyphenols (e.g., flavonoids, phenolic acids, lignans, and stilbenes) are present in fruit and vegetables, but also in coffee, tea, or wine. They reduce the risk of chronic diseases, such as cancer, diabetes, or inflammation. Hence, it is becoming valuable to combine dairy proteins with polyphenols, of which epigallocatechin-3-gallate (EGCG) and chlorogenic acid (CGA) show a particular predisposition to bind to milk proteins (e.g., α-lactalbumin β-lactoglobulin, αs1-casein, and κ-casein). Reducing the allergenicity of milk proteins by combining them with polyphenols is an essential issue. As potential 'metabolic prebiotics', they also contribute to stimulating the growth of beneficial bacteria and inhibiting pathogenic bacteria in the human gastrointestinal tract. In silico methods, mainly docking, assess the new structures of conjugates and the consequences of the interactions that are formed between proteins and polyphenols, as well as to predict their action in the body.

Peptide profiles and allergy-reactivity of extensive hydrolysates of milk protein

Milk protein concentrate (MPC) is one of the major allergens in food. This study aimed to analyze the peptide profiles and potential allergenicity of the extensive hydrolysates of MPC (EMPHs) using the peptidomics approach. Results demonstrated that when the hydrolysis time was 4 h, the degree of hydrolysis of the four EMPHs (AX, Alcalase-Protamex), (AD, Alcalase-Protease A 2SD), (AE, Alcalase-Flavourzyme) and (AH, Alcalase-ProteAXH) were 12.45 %, 18.48 %, 18.87 % and 16.77 %, respectively. The results of size exclusion chromatography showed no significant difference, when the hydrolysis time exceeded 3 h. A total of 16 allergic peptides were identified in the EMPHs by LC-MS/MS. The peptide profiles and the coverage of master protein of the four EMPHs were different. The results of the enzyme-linked immunoassay and KU812 cell model showed that the allergenicity of the EMPHs samples was significantly reduced. This study provided strong support for the application of EMPHs in hypoallergenic formula foods.

A Method for Screening Proteases That Can Specifically Hydrolyze the Epitope AA83-105 of αs1-Casein Allergen

Milk protein hydrolysates are common in infant formula, but some of them retain allergenicity due to incomplete hydrolysis of the epitopes for milk allergens. This study explored a method for screening proteases that could specifically hydrolyze the epitope of αs1-casein allergen. Firstly, the αs1-casein epitope AA83-105 was synthesized by the solid-phase synthesis method. Then, after purification and identification, the complete antigen was prepared through coupling with bovine serum albumin (BSA) and was used to raise monoclonal antibodies (mAb) in BALB/c mice. Additionally, an indirect competitive-enzyme-linked immunosorbent assay (icELISA) was established. The mAb raised against αs1-casein protein was used as a control. The results showed that the purity of the synthetic epitope was >90%, and the coupling rate with BSA was 6.31. The mAb subtype is IgG1, with a titer of 1:320,000. The mAb reacted specifically with αs1-casein but did not cross-react with soybean protein. The linear regression equation of the competitive inhibition curve was y = −9.22x + 100.78 (R2 = 0.9891). The detection limit of icELISA method was more sensitive, and the method showed good accuracy and repeatability. The amounts of antigen residues in papain protease hydrolysates were relatively small, and the epitope fragment was detected in papain hydrolysate via mass spectrometry. This study provides ideas and methods for screening proteases that specifically hydrolyze the epitopes of milk allergens and also provides a superior foundation for the development of an advanced hypoallergenic formula.

Characterization of a Commercial Whey Protein Hydrolysate and Its Use as a Binding Agent in the Whey Protein Isolate Agglomeration Process

The first objective of this study was to characterize the chemical properties of three lots of whey protein hydrolysate (WPH) obtained from a commercial manufacturer. The degree of hydrolysis (DH) of WPH was between 13.82 and 15.35%, and was not significantly (p > 0.05) different between the batches. From MALDI-TOF, 10 to 13 different peptides were observed in the range of 2.5−5 kDa and 5−8 kDa, respectively. The second objective of the study was to evaluate the effectiveness of WPH as a binder in whey protein isolate (WPI) wet agglomeration. For this purpose, a 3 × 3 × 2 factorial design was conducted with pre-wet mass (60, 100, and 140 g), WPH concentration (15, 20, and 25%), and flow rate (4.0 and 5.6 mL·min−1) as independent variables. WPI agglomeration was carried out in a top-spray fluid bed granulator (Midi-Glatt, Binzen, Germany). Agglomerated WPI samples were stored at 25 °C and analyzed for moisture content (MC), water activity, relative dissolution index (RDI), and emulsifying capacity. Pre-wet mass, flow rate, and the WPH concentration had a significant (p < 0.05) effect on the MC. Moreover, all interactions among the main effects had also a significant (p < 0.05) effect on MC. High MC and water activity were observed for the treatments with a higher pre-wet volume and higher flow rate, which also resulted in clumping of the powders. The treatment with the 60 g pre-wet mass, 20% WPH concentration, and 5.6 mL·min−1 flow rate combination had the highest RDI among all the samples. In conclusion, WPH can be used as a potential alternative to soy lecithin in WPI wet agglomeration.

Detection of β-Lactoglobulin by a Porous Silicon Microcavity Biosensor Based on the Angle Spectrum

In this paper, carbon quantum dot-labelled β-lactoglobulin antibodies were used for refractive index magnification, and β-lactoglobulin was detected by angle spectroscopy. In this method, the detection light is provided by a He-Ne laser whose central wavelength is the same as that of the porous silicon microcavity device, and the light source was changed to a parallel beam to illuminate the porous silicon microcavity’ surface by collimating beam expansion, and the reflected light was received on the porous silicon microcavity’ surface by a detector. The angle corresponding to the smallest luminous intensity before and after the onset of immune response was measured by a detector for different concentrations of β-lactoglobulin antigen and carbon quantum dot-labelled β-lactoglobulin antibodies, and the relationship between the variation in angle before and after the immune response was obtained for different concentrations of the β-lactoglobulin antigen. The results of the experiment present that the angle variations changed linearly with increasing β-lactoglobulin antigen concentration before and after the immune response. The limit of detection of β-lactoglobulin by this method was 0.73 μg/L, indicating that the method can be used to detect β-lactoglobulin quickly and conveniently at low cost.

Effect of two-step enzymatic hydrolysis on the antioxidant properties and proteomics of hydrolysates of milk protein concentrate

Food protein and peptides are generally considered a source of dietary antioxidants. The antioxidant activity and peptide profiles of four extensive hydrolysates of milk protein concentrate (MPC) were examined using the two-step enzymatic method. The hydrolysis combinations were Alcalase-Flavourzyme (AE), Alcalase-ProteAXH (AH), Alcalase-Protamex (AX) and Alcalase-Protease A 2SD (AD). The results showed that highest degree of hydrolysis corresponded to the AE sample (20.41%). High-efficiency gel-filtration chromatography results indicated that the relative proportions of extensive hydrolysates with molecular weights < 3 kDa were 99.89%, 99.57%, 99.93%, and 99.89% for AX, AE, AD and AH, respectively. The hydrolysates of the MPC exhibited increased radical-scavenging capacity, as evidenced through an analysis with 1,1-diphenyl-2-pycryl-hydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazo-line-6-sulfonic acid) diammonium salt (ABTS), reducing power and hydroxyl-radical scavenging activity testing. The main bioactive peptides were identified through EASY-nLC-orbitrap MS/MS and bioinformatics. The study may provide useful information regarding the antioxidant properties of extensive hydrolysates of MPC.

Effect of ultrasonic-ionic liquid pretreatment on the hydrolysis degree and antigenicity of enzymatic hydrolysates from whey protein

With the aim to reduce the antigenicity of whey protein hydrolysate in milk, the pretreatment method of coupling ultrasonic and ionic liquid (US-IL) and further enzymatic treatments were studied. Papain and alcalase were found to be suitable for ultrasonic-ionic liquid pretreatment. After ultrasound-ionic liquid treatment, the antigenic decline rates of ALA and BLG upon alcalase hydrolysis were 82.82% and 88.01%, and that of the papain hydrolysis was 81.87% and 88.46%, respectively. Upon ultrasonic-ionic liquid pretreatment, the molecular weight of whey protein did not change significantly, but the small molecular weight proportion of components in the enzymatic hydrolysate obviously increased. The findings showed that combining with US-IL pretreatment for further protease hydrolysis of whey proteins, the hydrolysate can be used in order to produce hypoallergenic bovine whey proteins.

Effect of Ultrasound Treatment on Allergenicity Reduction of Milk Casein via Colloid Formation

Cow's milk protein allergy, which occurs in approximately 5-10% of the population of infants and children, has become an important public food safety problem. As a major allergen in cow's milk, the most abundant protein casein (CN) is considered to be potent in inducing food allergy. In recent years, ultrasound treatment has played a significant role in the field of colloidal particulate system. In this study, we found that ultrasound treatment dramatically decreased the diameter of a CN particle to less than 100 nm in the presence of Tween 80, producing colloidal casein (c-CN) with high transparency. The electrophoretic and transmission electron microscopy analysis showed that the advanced protein structure of CN changed significantly. In addition, the enzyme-linked immunosorbent assay with allergic sera showed that the immunoglobulin-E-binding capacity of c-CN was significantly decreased. In the meantime, the LAD2 mast cell line degranulation assay demonstrated that ultrasound treatment made CN hypoallergenic. The colloidal and hypoallergenic properties of c-CN were stably maintained for more than 30 days. Likewise, the allergenicity of fresh whole milk also decreased after ultrasound treatment. This work provided an effective way to reduce the allergenicity of milk allergen, which could be beneficial to the production of hypoallergenic cow's milk.

Aptamer based fluorometric β-lactoglobulin assay based on the use of magnetic nanoparticles and carbon dots

The authors describe a fluorometric aptamer based assay for detecting β-lactoglobulin by using carbon dots (C-dots) as a signal indicator. The aptamer was immoblized on magnetite (Fe₃O₄) nanoparticles (MNPs), and the C-dots served as a label for the complementary oligonucleotide (cDNA). The assay is based on the hybridization that takes place between aptamer and cDNA. In the presence of β-lactoglobulin (β-LG), the aptamer preferentially binds to β-LG, and this leads to a partial release of the C-dots-cDNA into the solution. After magnetic separation, the supernatant of the solution contains the released C-dots-cDNA which are quantified by fluorometry, best under excitation/emission wavelengths of 354/447 nm. Under the optimal conditions, the fluorescence intensity is proportional to the logarithm of the β-LG concentration in the 0.25 to 50 ng mL^-1 range, with a 37 pg mL^-1 detection limit. The method was successfully applied to the determination of β-LG in hypoallergenic formulations, and the results demonstrated that this assay is a promising tool in food quality control. Conceivably, it also provides the opportunity for detection of other analytes. Graphical abstract Schematic of a novel aptamer based fluorometric β-lactoglobulin assay based on the use of magnetite (Fe₃O₄) nanoparticles (MNPs) and carbon dots (C-dots). C-dots were used as a signal indicator and Fe₃O₄ MNPs acted as a magnetic separator. This assay exhibits high sensitivity and selectivity with a detection limit as low as 37 pg mL^-1.

Preparation, properties, and uses of enzymatic milk protein hydrolysates

Enzymatic hydrolysis of milk proteins has been a subject of numerous research studies and patents. The driving force for these studies has been the increased utilization of milk proteins. The industrial uses of milk proteins are based on their unique composition, functionality, and nutritive values. The diversity of milk protein fraction, the large number of proteinases, and controlled hydrolysis conditions used resulted in the preparation of hydrolysates suitable for several purposes. Enzymatic hydrolysis of milk proteins modifies the techno-functional and biofunctional properties of hydrolysates depending on the enzyme(s) and hydrolysis conditions used. Milk protein hydrolysates (MPH) are used commonly in normal and clinical nutrition and as a functional food ingredient. In the present review, emphasis has been made to highlight methods applied for the preparation of MPH, and the functional properties and utilization of the obtained hydrolysates.

Health-promoting properties of bioactive peptides derived from milk proteins in infant food: a review

Milk proteins have attracted extensive interest in terms of their bioavailability following ingestion. Enzymatic digestion of dairy products generates numerous peptides with various biological activities. Both human milk and infant formulas based on cow's milk are potential sources of bioactive peptides. This review aims to present current knowledge on the formation and fate of bioactive peptides from milk feeds intended for infants. Emphasis is placed on the source of the bioactive peptides with the nutritional impact of human milk and cow milk-based formulas on infant health being critically discussed from that perspective. Furthermore, the effect of processing and in vitro or in vivo digestion on the release and availability of peptides with bioactive sequences is evaluated. Considerable differences with respect to bioavailability and metabolic effects between the biologically active fragments generated following ingestion of human milk and infant formulas are documented. Peptides from milk protein of bovine origin could be a valuable supplement to human milk as multiple health-promoting properties are attributed to peptide fractions identified in standard cow milk-based infant formulas.

Development of an SDS-gel electrophoresis method on SU-8 microchips for protein separation with LIF detection: Application to the analysis of whey proteins

This work describes the development of an SDS-gel electrophoresis method for the analysis of major whey proteins (α-lactalbumin, β-lactoglobulin, and BSA) carried out in SU-8 microchips. The method uses a low-viscosity solution of dextran as a sieving polymer. A commercial coating agent (EOTrol LN) was added to the separation buffer to control the EOF of the chips. The potential of this coating agent to prevent protein adsorption on the walls of the SU-8 channels was also evaluated. Additionally, the fluorescence background of the SU-8 material was studied to improve the sensitivity of the method. By selecting an excitation wavelength of 532 nm at which the background fluorescence remains low and by replacing the mercury arc lamp by a laser in the detection system, an LOD in the nanomolar range was achieved for proteins derivatized with the fluorogenic reagent Chromeo P540. Finally, the method was applied to the analysis of milk samples, demonstrating the potential of SU-8 microchips for the analysis of proteins in complex food samples.

Milk processing as a tool to reduce cow's milk allergenicity: a mini-review

Milk processing technologies for the control of cow’s milk protein allergens are reviewed in this paper. Cow’s milk is a high nutritious food; however, it is also one of the most common food allergens. The major allergens from cow’s milk have been found to be β-lactoglobulin, α-lactalbumin and caseins. Strategies for destroying or modifying these allergens to eliminate milk allergy are being sought by scientists all over the world. In this paper, the main processing technologies used to prevent and eliminate cow’s milk allergy are presented and discussed, including heat treatment, glycation reaction, high pressure, enzymatic hydrolysis and lactic acid fermentation. Additionally, how regulating and optimizing the processing conditions can help reduce cow’s milk protein allergenicity is being investigated. These strategies should provide valuable support for the development of hypoallergenic milk products in the future.

Halting the allergic march

The prevalence of childhood allergic diseases, such as allergic asthma, allergic rhinitis, and atopic dermatitis, has increased exponentially. In Singapore, the prevalence of asthma at all ages exceeds 20%, and around 50% of Singaporean children show features of an underlying allergy. The exact environmental causes for the increase of allergic diseases have not yet been identified, but most researchers agree that a decreased bacterial load in young children may be one of the reasons for the increase. However, the causes of allergy are multiple, and the development of an allergic disease is the result of complex interactions between genetic constitution and environmental factors. In this review article, different aspects of allergic sensitization are covered, including prenatal and postnatal sensitization. The phenomenon of the "allergic march" (switching from one clinical expression of allergy to another) and its underlying mechanisms are discussed. The last part of this review article is on prevention and treatment of allergic diseases, including the role of bacterial products (probiotics, prebiotics, and synbiotics) and the role of immunotherapy, including sublingual immunotherapy.

Capillary electrophoresis with laser-induced fluorescence detection of proteins from two types of complex sample matrices: food and biological fluids

Sample preparation and laser-induced fluorescence detection are two key steps of the analytical methodology to determine by capillary electrophoresis low concentrations of proteins in complex sample matrices. In this chapter the options of performing both steps in different ways are shown by detailing the analysis of the allergen β-lactoglobulin in food products for infants and the analysis of the isoforms of alpha 1-acid glycoprotein, a potential biomarker, in serum and secretome.

Economic evaluation of a 100% whey-based partially hydrolyzed infant formula in the prevention of atopic dermatitis among Swiss children

OBJECTIVE

A pharmacoeconomic analysis was undertaken to determine costs, consequences, and cost-effectiveness of a partially hydrolyzed 100% whey-based infant formula, NAN-HA®, manufactured by Nestlé S.A, Switzerland (PHF-W), branded under BEBA HA® in Switzerland, in the prevention of atopic dermatitis (AD) in 'at risk' Swiss children when compared to standard cow's milk formula (SF).

METHODS

Based on a 12-month time horizon including 6 months of formula consumption, an economic model was developed synthesizing treatment pathways, resource utilization, and costs associated with the treatment of AD in healthy 'at risk' Swiss newborns who could not be exclusively breastfed. Model inputs were retrieved from the literature, official formularies, and expert opinion. The treatment pathways considered a medical treatment approach, supplemented in some instances by a change of formula. The final outcome was the expected cost per avoided case of AD, yielding an incremental cost effectiveness ratio (ICER) for PHF-W vs SF. Outcomes were presented from three perspectives: the Swiss public healthcare system (MOH), the subject's family, and society (SOC). A secondary analysis compared PHF-W to whey-based extensively hydrolyzed formula (EHF) in prevention.

RESULTS

The model yielded 1653 avoided AD cases by selecting PHF-W over SF in a birth cohort of 22,933 'at risk' infants. The base case analyses generated an expected ICER of CHF 982 from the MOH perspective as well as savings of CHF 2202 and CHF 1220 from the family and SOC perspectives, respectively. PHF-W yielded CHF 11.4M savings against EHF when the latter was assumed to be used in prevention. One-way and probabilistic sensitivity analyses confirmed the robustness of the model.

CONCLUSION

Under a range of assumptions, this analysis has established the dominance from the family and societal perspectives and cost-effectiveness from the MOH perspective of PHF-W vs SF in the prevention of AD among 'at risk' Swiss infants.

Cost-effectiveness of partially-hydrolyzed formula for prevention of atopic dermatitis in Australia

OBJECTIVE

To perform an economic evaluation of a specific brand of partially hydrolyzed infant formula (PHF-W) in the prevention of atopic dermatitis (AD) among Australian infants.

METHODS

A cost-effectiveness analysis was undertaken from the perspectives of the Department of Health and Aging (DHA), of the family of the affected subject and of society as a whole in Australia, based on a decision-analytic model following a hypothetical representative cohort of Australian newborns who are not exclusively breastfed and who have a familial history of allergic disease (i.e., are deemed 'at risk'). Costs, consequences, and incremental cost-effectiveness ratios (ICER) were calculated for PHF-W vs standard cow's milk based infant formula (SF), and, in a secondary analysis, vs extensively hydrolyzed infant formula (EHF-Whey), when the latter was used for the prevention of AD.

RESULTS

From a representative starting cohort of 87,724 'at risk' newborns in Australia in 2009, the expected ICERs for PHF-W vs SF were AU$496 from the perspective of the DHA and savings of AUD1739 and AU$1243 from the family and societal perspectives, respectively. When compared to EHF-Whey, PHF-W was associated with savings for the cohort of AU$5,183,474 and AU$6,736,513 from the DHA and societal perspectives.

LIMITATIONS

The generalizability and transferability of results to other settings, populations, or brands of infant formula should be made with caution. Whenever possible, a conservative approach directing bias against PHF-W rather than its comparators was applied in the base case analysis. Assumptions were verified in one-way and probabilistic sensitivity analyses, which confirmed the robustness of the model.

CONCLUSIONS

PHF-W appears to be cost-effective when compared to SF from the DHA perspective, dominant over SF from the other perspectives, and dominant over EHF-Whey from all perspectives, in the prevention of AD in 'at risk' infants not exclusively breastfed, in Australia.

Economic evaluation of a 100% whey-based partially hydrolyzed infant formula in the prevention of atopic dermatitis among Danish children

OBJECTIVE

A pharmacoeconomic analysis was undertaken to determine costs, consequences, and cost-effectiveness of a brand of partially hydrolyzed 100%-whey formula manufactured by Nestlé (PHF-W), in the prevention of atopic dermatitis (AD) in 'at risk' Danish children compared to extensively hydrolyzed formula (EHF-Whey or Casein).

METHODS

Given the non-significant differences between PHF-W and EHF, the base case analytic approach amounted to a cost-minimization analysis (CMA) reporting the difference in formula acquisition costs over the period of formula consumption for the population of interest. However, sensitivity analyses (SAs) were undertaken to explore applying the nominal efficacy of PHF-W and EHF, thus leading to a cost-effectiveness analysis (CEA). Hence, an economic model based on a 12-month time horizon was developed synthesizing treatment pathways, resource utilization, and costs associated with the treatment of AD in the population of interest. The final economic outcome of the SAs was the incremental cost per avoided case (ICER) defined as the expected cost per avoided case of AD for PHF-W vs EHF, determined from three perspectives: the Ministry of Health (MOH), the family of the subject, and society (SOC).

RESULTS

In the base case CMA, savings of DKK 9 M, DKK 20 M, and DKK 29 M were generated for PHF-W vs EHF from the MOH, family, and SOC perspectives. In the sensitivity CEA, PHF-W was dominant over EHF-Whey from all perspectives, while EHF-Casein displayed against PHF-W unattractive ICERs of DKK 315,930, DKK 408,407, and DKK 724,337 from the MOH, family, and SOC perspectives. Probabilistic SAs indicated that PHF-W was 86% likely to be dominant over EHF-Whey, whereas EHF-Casein had no likelihood of dominating PHF-W.

CONCLUSION

Under a range of assumptions, this analysis demonstrated the attractiveness of PHF-W vs both types of EHF in the prevention of AD among 'at risk' Danish infants who are not or cannot be exclusively breastfed.

Economic evaluation of a 100% whey-based, partially hydrolysed formula in the prevention of atopic dermatitis among French children

OBJECTIVE

A pharmacoeconomic analysis was performed to determine costs, consequences and cost effectiveness of a partially hydrolysed 100% whey-based infant formula, NAN HA, manufactured by Nestlé S.A, Switzerland (PHF-W) and branded under Nidal Excel HA in France, in the prevention of atopic dermatitis (AD) in 'at risk' children when compared to standard cows' milk formula (SF) in France.

METHODS

A decision-analytic economic model depicting AD treatment pathways, as well as resource utilisation and costs associated with the treatment of AD in healthy yet 'at risk' French newborns who cannot be exclusively breastfed was constructed for a 12-month time horizon, including an initial 6 months of intervention with formula consumption. Model inputs were based on the literature, official formularies and expert opinion. The modelled treatment pathways included a dietary management approach (formula change), a medical treatment approach and a combination thereof. The final outcome was the expected cost per avoided case of AD, yielding an incremental cost per avoided case (ICER) of AD when comparing subjects who used PHF-W versus SF. Outcomes were presented from three perspectives: the French Ministry of Health (MOH), the subjects' family and society as a whole. A secondary analysis also compared PHF-W to extensively hydrolysed formula (EHF) in prevention.

RESULTS

The number of avoided AD cases by selecting PHF-W over SF was 13,356 cases in a birth cohort of 185,298 'at risk' infants. The base case analysis, at 65% reimbursement, yielded expected ICERs of €1343, € -624 (savings) and €719 from the MOH, family and societal perspectives, respectively. From all three perspectives, the highest cost was attributable to formula. In case of a 35% reimbursement rate for PHF-W, the ICER was €615 from the MOH perspective, while the use of PHF-W was cost neutral at 10% reimbursement. PHF-W was cost-saving against EHF (€98-€116 million savings depending on type of EHF), when this latter was used in prevention. One-way and probabilistic sensitivity analyses confirmed the robustness of the model.

CONCLUSION

Under a certain range of assumptions, this analysis based on predictive modelling has established the cost effectiveness of PHF-W in the prevention of AD in infants.

Development and application of an HILIC-MS/MS method for the quantitation of nucleotides in infant formula

A method for the quantitation of nucleotides (adenosine 5'-monophosphate (AMP), guanosine 5'-monophosphate (GMP), uridine 5'-monophosphate (UMP), cytidine 5'-monophosphate (CMP), and inosine 5'-monophosphate (IMP)) in infant formula was developed by hydrophilic interaction chromatography with tandem mass spectrometry (HILIC-MS/MS). The internal standards used (AMP-13C10, 15N5; GMP-13C10, 15N5; UMP-13C9, 15N2; CMP-13C9, 15N3) were prepared with centrifugal ultrafiltration (CUF). Data acquisition was achieved by using multiple reaction monitoring (MRM) of product ions of protonated molecules of the five nucleotides generated by the positive-ion ESI. HILIC conditions were performed with 30 mmol/L ammonium formate in water (pH 2.5, adjusted with formic acid) and methanol. The LOD and LOQ were 5-10 μg/mL and 10-30 μg/mL for standard solution, respectively. Recovery for intra- and interday assays ranged from 98.1 to 108.9% (RSD: 0.7-5.4%) spiked with three concentration levels (5, 25, and 250 μg/g powder infant formula). This method could be applied for the determination of nucleotides in infant formula samples. The detected concentrations of five nucleotides ranged from not detected (n.d.) to 278 μg/g powder infant formula. The total nucleotide level ranged from n.d. to 600.2 μg/g powder infant formula.

Development of an optimized ELISA and a sample preparation method for the detection of beta-lactoglobulin traces in baby foods

Dairy products can induce allergic reactions even when present at very low levels, such as levels found in involuntary contamination during food manufacturing. beta-Lactoglobulin (betaLG) is the main allergen in cow's milk. The objective of this work was to develop a sensitive method for betaLG detection in baby foods through the optimization of an innovative sample preparation method. Three types of baby foods deliberately contaminated with dairy products or dairy desserts were sterilized to simulate the potential contamination occurring during manufacturing and then used as samples. Different sample preparation methods were compared. The best results were provided by an extraction solution containing beta-mercaptoethanol, guanidine hydrochloride, and a saline solution. An ELISA method was optimized for the detection of betaLG (LOD = 9.7 x 10(-13) M). The developed method allowed detection of even 1 part of dairy product in 100,000 parts of baby food for some of the analyzed foods.

Interaction of early diet and the development of the immune system

The present review focuses on the specific effects of nutrients on the development of the immune system in early life. There is a big gap regarding the specific mechanisms that regulate immunity at the intestinal level and their impact in the systemic immune function. For this reason, during the last few years there has been great interest in ascertaining the mechanisms that regulate the intestinal immune function, as well as to understand how specific nutrients interact with the gut-associated lymphoid tissue. We have reviewed this topic with special emphasis on how human milk, and its components, influence the early development of intestinal immunity in breast-fed infants compared with formula-fed infants. Interactions between nutrients and intestinal microbiota have also been reviewed. Some micronutrients such as nucleotides and gangliosides, which are present in human milk and also in most foods, are able to influence immune functionality at very low concentrations. The specific action of these micronutrients on some parameters of immunity, as well as their potential mechanisms of action, have been considered in detail. However, there are limited data on how other specific nutrients, namely protein and non-protein N-containing compounds, lipids, carbohydrates, and others, such as minerals, vitamins, fibre, non-nutritional dietary compounds (flavonoids, carotenoids, phyto-oestrogens, etc), influence immunity. In the present review we have provided data regarding the potential effects of these compounds on the immune response in early life. The increasing use of functional foods by the public to improve their general health and prevent the incidence of chronic diseases has become a major area of interest within the nutrition community. Of the many functional foods available, probiotics have been most studied in infancy and childhood, particularly with regard to the prevention of allergic diseases. Infant formulae and fermented milks containing large quantities of probiotics are produced and consumed by Europeans and in other industrialized countries. In the present review we cover the clinical effects of probiotics in preventing disease during early life, as well as the potential mechanisms of interaction between probiotics and the gastrointestinal tract.

A new sample preparation method compatible with capillary electrophoresis and laser-induced fluorescence for improving detection of low levels of beta-lactoglobulin in infant foods

Beta-lactoglobulin (betaLG) is the main allergenic protein in cow's milk and can cause allergy even when present at very low concentration. The aim of this work is to develop an innovative sample preparation method fully compatible with capillary electrophoresis and laser-induced fluorescence detection for improving the sensitivity when analyzing betaLG. Different types of baby food were on purpose contaminated with diverse dairy desserts and submitted to thermal treatment to simulate potential contamination at production. Sample preparation prior to CE analysis was performed by the classical extraction method and by the innovative one, and the results were compared. Analysis was performed by capillary electrophoresis with laser-induced fluorescence detection. The innovative method permitted to detect contaminations as low as 1 part of yoghurt in 10,000 parts of baby food.

Identification and quantification of inhibitors for Angiotensin-converting enzyme in hypoallergenic infant milk formulas

The potential of hypoallergenic (HA) infant milk formulas containing hydrolyzed milk proteins as main constituents to inhibit angiotensin-converting enzyme (ACE) in vitro was investigated. Seven commercially available HA products designed for babies up to 4 months showed a potent inhibition of ACE in vitro, with IC 50 values ranging between 3.2 and 68.5 mg of nitrogen/L. For six samples of conventional milk-based infant formulas and three breast milk samples, no inhibition was observed. Inhibitory potential did not correlate with the degree of hydrolysis. Using reversed-phase high-pressure liquid chromatography (RP-HPLC) coupled to electrospray ionization-time of flight-mass spectrometry (ESI-TOF-MS), 15 peptides known to inhibit ACE were identified. Among them, the highly potent ACE inhibitor Ile-Trp (IC 50 = 0.7 microM) was detected and quantified for the first time in the HA samples, representing the most effective ACE-inhibiting peptide that has ever been detected in food items. The overall inhibitory potential of the HA infant milk formulas could partly be explained by Ile-Trp.

Development of a method for quantitative analysis of the major whey proteins by capillary electrophoresis with on-capillary derivatization and laser-induced fluorescence detection

The main whey proteins have been derivatized on-capillary with 3-(2-furoyl)quinoline-2-carboxaldehyde (FQ) and analyzed using a laboratory-made capillary electrophoresis apparatus provided with a laser-induced fluorescence detector. Several parameters controlling on-capillary derivatization of proteins, including pH, mixing time, reaction time, concentration of the reagents (potassium cyanide and FQ), and reaction temperature, were optimized. Coefficient variations were lower than 1% for migration time and 7% for peak height. Assay detection limits for the different proteins were in the range 5 nM to 10 nM. The method developed was applied to the separation of the major whey proteins in a laboratory-made cheese whey and in an infant food formulated with milk. In addition, the beta-LG content of these samples was quantitated. The results showed good agreement with those given by an RP-HPLC method and with those reported in the literature.

Analysis of trace amounts of bovine β-lactoglobulin in infant formulas by capillary electrophoresis with on-capillary derivatization and laser-induced fluorescence detection

Bovine beta-lactoglobulin (betaLG) has been described by several authors as the main allergen present in cow's milk. It can induce allergic reactions even at the low concentration existing in hypoallergenic formulas based on hydrolyzed cow's milk proteins (generally lower than microM). In this paper, the usefulness of a capillary electrophoresis method with on-capillary derivatization and laser-induced fluorescence detection for the analysis of trace amounts of betaLG in a commercial hypoallergenic formula has been demonstrated. To confirm the identity of the peak of betaLG based on migration time, an immunorecognition step employing an anti-betaLG antibody was performed. BetaLG was quantitated in the whey and casein fractions of the hypoallergenic formula. The concentration of betaLG in the whey fraction of the formula was about 3 orders of magnitude lower than the average value present in cow's milk. In the casein fraction of the formula, the concentration of betaLG was about 1 order of magnitude lower than in the whey fraction. The method developed was also used for the quality control of three cereal-based infant foods formulated without milk to test the presence or absence of betaLG as an indicator of milk contamination during the fabrication process. BetaLG in a concentration of 10(-7) M or higher was not observed in any of the cereal-based infant formulas analyzed.

Safety of a new extensively hydrolysed formula in children with cow's milk protein allergy: a double blind crossover study

BACKGROUND

Formulae for infants with cow's milk protein allergy (CMA) should be based on extensively hydrolysed protein. 'Extensively' however is not strictly defined. Differences in molecular weight and peptide chain length may affect its clinical outcome. We studied the safety of a new extensively hydrolysed casein based formula (Frisolac Allergycare: FAC) for children with IgE mediated CMA.

METHODS

Thirty children, aged 1.5 - 14.8 years old (median 4.9 years) with persistent CMA were enrolled in this double-blind reference product (Nutramigen: NUT) controlled crossover study. All had positive skin prick tests (SPT) and IgE mediated allergy, showing immediate reactions after ingestion of small amounts of milk. Twenty-five children also had positive radio allergen sorbent tests (RAST) to cow's milk. Formulae provided consisted of 80% elementary formula in combination with 20% reference or test product. Crossover periods lasted for two weeks. From both products molecular weight (MALDI-TOF method and HPLC) and peptide chain length distribution (adapted Edman degradation) were determined.

RESULTS

Maximum molecular weights of NUT and FAC are 2.1 and 2.56 kDa, respectively. The contribution of free amino acids and small peptides <0.5 kDa is 46% for FAC and 53% for NUT. About 50% of the protein fraction of both products consists of peptides longer than four amino acids. Three children did not complete the study. The other children all tolerated FAC very well; no adverse reactions were reported.

CONCLUSIONS

The new extensively hydrolysed casein-based formula (FAC) can safely be used in children with IgE mediated cow's milk allergy.

Food allergy

Allergic disease is a major contributor to illnesses and mortality worldwide. Food hypersensitivity is often the first phenomenon in the allergic march that includes gastroenteropathy, eczema, asthma and hay fever. Recent evidence indicates that prevention of food hypersensitivity in early life is associated with reduction in the incidence of eczema and asthma in later childhood. Strategies for prevention include exclusive breast feeding, restriction of mother's diet during lactation, hydrolyzed formula, delayed introduction of allergenic solid foods and reduced exposure to house dust mites and tobacco smoke. This is a highly cost-beneficial and cost-effective approach.