Peptic hydrolysis of bovine beta-lactoglobulin under microwave treatment reduces its allergenicity in anex vivomurine allergy model

Characterization of the potential allergenicity of enzymatically hydrolyzed casein in Balb/c mouse model

Bovine casein is a major allergen present in cow milk to induce anaphylaxis. In this study, the potential allergenicity of enzymatically hydrolyzed casein (HC) was evaluated based on in vitro and in vivo. The results showed that Alcalase and Protamex treatment (AT, PT) reduced the potential allergenicity of CN, with the greatest reductions of 68.25% and 50.75%, respectively. In addition, in vivo results showed that HC effectively alleviated allergic response symptoms of Balb/c mice; a significant tendency toward decreased serum IgG1 and mast cell tryptase levels was observed, accompanied by a decrease of Th2-associated IL-4, IL-5, and IL-13 and an increase of IFN-γ levels in spleen. Moreover, the inflammation of the lung, jejunum, and ileum was remarkably ameliorated. The findings indicated that HC induced a shift toward Th1 response and maintained the Th1/Th2 immune balance. Importantly, our results provide the basis for the production of hypoallergenic dairy products.

Dairy, Plant, and Novel Proteins: Scientific and Technological Aspects

Alternative proteins have gained popularity as consumers look for foods that are healthy, nutritious, and sustainable. Plant proteins, precision fermentation-derived proteins, cell-cultured proteins, algal proteins, and mycoproteins are the major types of alternative proteins that have emerged in recent years. This review addresses the major alternative-protein categories and reviews their definitions, current market statuses, production methods, and regulations in different countries, safety assessments, nutrition statuses, functionalities and applications, and, finally, sensory properties and consumer perception. Knowledge relative to traditional dairy proteins is also addressed. Opportunities and challenges associated with these proteins are also discussed. Future research directions are proposed to better understand these technologies and to develop consumer-acceptable final products.

Current findings support the potential use of bioactive peptides in enhancing zinc absorption in humans

More than two billion people around the world are affected by zinc deficiency, mainly due to the inadequate intake and absorption of zinc. Based on recent research findings, the bioactive peptides could potentially be used to combat zinc deficiency particularly due to their Zinc chelating ability. The main aim of this review was to present current findings, supporting the potential use of bioactive peptides based on their ability to enhance zinc absorption. In-vivo, in-vitro, and ex-vivo studies have demonstrated that zinc chelating peptides can enhance the retention, transportation, and absorption of zinc. Comparative studies on zinc bioavailability from protein hydrolysates and zinc salts have demonstrated that the protein hydrolysates-zinc complexes are more bioavailable than the zinc salts. Data from the structure-function relationship of zinc chelating peptides suggest that the zinc chelating capacities of peptides increase in the following order; the position of zinc chelator > zinc chelator strength > abundance of zinc chelators > net charge > molecular weight. In addition, the transport mechanism of peptide-zinc complex is hypothesized, and the potential use of bioactive peptides based on their safety and taste and limitations to their commercialization are also discussed.

Whey allergens: Influence of nonthermal processing treatments and their detection methods

Whey and its components are recognized as value-added ingredients in infant formulas, beverages, sports nutritious foods, and other food products. Whey offers opportunities for the food industrial sector to develop functional foods with potential health benefits due to its unique physiological and functional attributes. Despite all the above importance, the consumption of whey protein (WP) can trigger hypersensitive reactions and is a constant threat for sensitive individuals. Although avoiding such food products is the most successful approach, there is still a chance of incorrect labeling and cross-contamination during food processing. As whey allergens in food products are cross-reactive, the phenomenon of homologous milk proteins of various species may escalate to a more serious problem. In this review, nonthermal processing technologies used to prevent and eliminate WP allergies are presented and discussed in detail. These processing technologies can either enhance or mitigate the impact of potential allergenicity. Therefore, the development of highly precise analytical technologies to detect and quantify the existence of whey allergens is of considerable importance. The present review is an attempt to cover all the updated approaches used for the detection of whey allergens in processed food products. Immunological and DNA-based assays are generally used for detecting allergenic proteins in processed food products. In addition, mass spectrometry is also employed as a preliminary technique for detection. We also highlighted the latest improvements in allergen detection toward biosensing strategies particularly immunosensors and aptasensors.

Milk Ingredients in Meat Products: Can Autoclaving and In Vitro Gastroduodenal Digestion Mitigate Their IgE-Binding Capacity?

The food industry commonly uses milk ingredients as technological aids in an uncounted number of products. On the other hand, milk contains allergenic proteins causing adverse allergic reactions in sensitized/allergic individuals. This work intends to evaluate the effect of autoclaving and in vitro digestion on the allergenicity of milk proteins incurred in meat products. Protein profiles of raw and autoclaved sausages without and with the addition of 10% of milk protein concentrates were analyzed by gel electrophoresis and liquid chromatography–mass spectrometry. Additionally, residual IgE-reactivity was evaluated by immunoblot analysis using pooled sera of cow’s-milk-allergic individuals followed by bioinformatic analysis. Results showed that autoclaving led to an increase in protein fragmentation (higher number of short peptides) and consequently to a higher digestion rate, that was found to be more pronounced in β-casein. The IgE-binding capacity of milk proteins seems to be reduced after autoclaving prior to digestion, with a residual reactivity in caseins, but was eliminated following digestion. This study highlights the importance of autoclaving as a processing strategy to produce hypoallergenic formulas.

Degradation of β-Lactoglobulin during sourdough bread production

The research featured various types and strains of lactic acid bacteria (LAB) and yeast. The research objective was to study their ability to utilize β-lactoglobulin during sourdough fermentation. The present paper also described the effect of sourdough fermentation and baking on β-lactoglobulin degradation. A set of experiments with various types and strains of LAB showed that β-lactoglobulin decreased in gluten-free sourdough with 30%, 60%, and 90% of skimmed milk powder (SMP). L.plantarum E36 demonstrated the highest biodegradation of β-lactoglobulin (by 53%) with SMP = 30%. L.helveticus ATCC8018T showed the lowest content of β-lactoglobulin with SMP = 60% and 90%: the content fell by 48% and 40%, respectively. The largest decrease in the content of β-lactoglobulin was observed in the sourdough with Saccharomyces cerevisiae 17 (by 28–42%) and Candida milleri Pushkinsky (by 25–41%). The content of total protein increased, which was not associated with yeast biomass growth. The content was determined after fermentation in sourdoughs with SMP = 60% and 90% using a bicinchoninic acid reagent kit. The content of β-lactoglobulin in the control and experimental samples did not exceed 1 μg/g in the finished bakery products. This fact indicated a significant effect of thermal treatment on β-lactoglobulin degradation in baking. Thus, temperature processing (baking) had a greater impact on the destruction of β-lactoglobulin than enzymatic processing (fermentation).

Taurine administration prevents the intestine from the damage induced by beta-lactoglobulin sensitization in a murine model of food allergy

BACKGROUND

Allergy to cow's milk proteins has often been associated with dysfunction of the intestinal mucosa caused by chronic inflammation in infants. This study evaluated the protective effect of taurine on intestinal damage induced by beta-lactoglobulin (β-Lg) in Balb/c mice used as an animal model of allergy to cow's milk proteins.

METHODS

Balb/c mice were treated with taurine administered orally by gavage (3mmol/kg/day) or intraperitoneally (100mg/kg/day) for two weeks, then sensitized intraperitoneally with β-Lg. The electrophysiological parameters: active ion transport of chloride (Short-circuit current: Isc) and the passive ion permeability (Conductance: G) were measured ex vivo in Ussing chamber by intestine challenge with β-Lg. Histological study was used to assess gut inflammation. Serum levels of TNF-α and IL-6 were measured. Serum IgG and IgE anti-β-Lg were determined by ELISA.

RESULTS

Compared with sensitized mice, β-Lg challenge of intestinal epithelium of taurine-pre-treated mice in Ussing chamber did not influence the intensity of Isc, nor produce any changes in the G, reflecting a reduction in the secretory response and epithelial permeability. Histological and morphometric analysis showed that taurine reduced the intestinal damage and limited intestine retraction caused by β-Lg sensitization. No statistically significant difference in the serum levels of TNF-α or IL-6 was found after oral or intraperitoneal administration of taurine. Treatment with taurine significantly decreased the IgG (p<0.001) and IgE anti β-Lg levels (p<0.05).

CONCLUSIONS

These results have for the first time provided evidence that pre-treatment with taurine appears to prevent intestinal damage induced by β-Lg.

Combined microwave processing and enzymatic proteolysis of bovine whey proteins: the impact on bovine β-lactoglobulin allergenicity

The main aim of this study was to develop a continuous microwave treatment system of whey proteins and then apply this process at 37 °C, 50 °C, 65 °C and 70 °C to achieve pepsinolysis and produce extensively hydrolysed bovine whey protein hydrolysates with low allergenic properties. The microwave process was compared to a conventional thermal treatment with similar temperature set points. Both processes were deeply analysed in terms of the thermal kinetics and operating conditions. The pepsin hydrolysates obtained by the continuous microwave treatment and conventional heating were characterized by SDS-PAGE and RP-HPLC. The allergenicity of the whey protein hydrolysates was explored using a human IgE sensitized rat basophil leukaemia cell assay. The results indicate that extensively hydrolysed whey protein hydrolysates were obtained by microwave only at 65 °C and in a shorter time compared with the conventional thermal treatment. In the same temperature conditions under conventional heating, β-lactoglobulin was resistant to pepsinolysis, and 37% of it remained intact. As demonstrated by an in vitro degranulation assay using specific human IgE-sensitized rat basophils, the extensively hydrolysed whey protein obtained by microwave showed maximum degranulation values of 6.53% compared to those of the native whey protein isolate (45.97%) and hence elicited no more allergenic reactions in basophils. This work emphasizes the potential industrial use of microwave heating specific to milk protein processing to reduce their allergenicity and improve their end-use properties.

Oral immunotherapy combined with omalizumab for high-risk cow's milk allergy: a randomized controlled trial

We evaluated the efficacy and safety of oral immunotherapy (OIT) combined with 24 weeks of omalizumab (OMB) at inducing desensitization in children with cow's milk allergy (CM) compared with an untreated group. The present study was a prospective randomized controlled trial. Sixteen patients (age, 6-14 years) with high IgE levels to CM were enrolled in the present study. Patients were randomized 1:1 to receive OMB-OIT group or untreated group. The primary outcome was the induction of desensitization at 8 weeks after OMB was discontinued in OMB-OIT treated group and at 32 weeks after study entry. None of the 6 children in the untreated group developed desensitization to CM while all of the 10 children in the OIT-OMB treated group achieved desensitization (P < 0.001). A significantly decreased wheal diameter in response to a skin prick test using CM was found in the OMB-OIT treated group (P < 0.05). These data suggest that OIT combined with OMB using microwave heated CM may help to induce desensitization for children with high-risk CM allergy. This prospective randomized controlled trial was intended for 50 participants but was prematurely discontinued due to overwhelming superiority of OMB combined with microwave heated OIT over CM avoidance.

Preventive effects of royal jelly against anaphylactic response in a murine model of cow's milk allergy

CONTEXT

Royal jelly (RJ) has long been used to promote human health.

OBJECTIVE

The current study investigated the preventive effects of RJ against the development of a systemic and intestinal immune response in mice allergic to cow's milk proteins.

MATERIALS AND METHODS

Balb/c mice treated orally for seven days with RJ at doses of 0.5, 1 and 1.5 g/kg were sensitized intraperitoneally with β-lactoglobulin (β-Lg). Serum IgG and IgE anti-β-Lg were determined by an enzyme-linked immunosorbent assay (ELISA). Plasma histamine levels, symptom scores and body temperature were determined after in vivo challenge to β-Lg. Jejunums were used for assessment of local anaphylactic responses by an ex vivo study in Ussing chambers and morphologic changes by histological analysis.

RESULTS

RJ significantly decreased serum IgG (31.15-43.78%) and IgE (64.28-66.6%) anti-β-Lg and effectively reduced plasma histamine level (66.62-67.36%) (p < 0.001) at all the doses tested. Additionally, no clinical symptoms or body temperature drops were observed in RJ-pretreated mice. Interestingly, RJ significantly reduced (p < 0.001) intestinal dysfunction by abolishing the secretory response (70.73-72.23%) induced by sensitization and prevented length aberrations of jejunal villi by 44.32-59.01% (p < 0.001).

DISCUSSION AND CONCLUSIONS

We speculate that using RJ may help prevent systemic and anaphylactic response in allergic mice. These effects may be related to its inhibitory effects on the degranulation of mast cells.

Characterization of the potential allergenicity of irradiated bovine α-lactalbumin in a BALB/c mouse model

Bovine α-lactalbumin (ALA) is a known food allergen present in milk to induce anaphylaxis. A previous study demonstrated that irradiated ALA (iALA) decreased the IgE-binding properties and weakened the degranulation capacity of basophils in vitro. The present study aimed to further assess the potential allergenicity of iALA in vivo in a BALB/c mouse model. The mice (n = 10/group) were intragastrically sensitized and orally challenged with either iALA or ALA using cholera toxin as adjuvant. In contrast to the ALA group, the iALA group did not show anaphylactic shock symptoms. A tendency toward decreased serum allergen-specific IgG/IgG₁/IgE levels, plasma histamine levels and mast cell protease-1 (mMCP-1) concentrations in the iALA group were also observed, accompanied by a decrease in Th2-related cytokine levels and an increase of IFN-γ production in spleen cell cultures. Moreover, the peritoneal mast cell surface expression of FcεRI and peripheral blood basophil CD200R⁺ expression were decreased by 64.3% and 35.19%, respectively. Conversely, the percentage of CD4⁺CD25⁺Foxp3⁺ regulatory T cells increased in the iALA group. All of these findings indicated that iALA induces a shift toward the Th1 response, which ultimately reduces its potential allergenicity.

Two-weeks-sustained unresponsiveness by oral immunotherapy using microwave heated cow's milk for children with cow's milk allergy

BACKGROUND

Several studies have reported that oral immunotherapy (OIT) is effective for children with cow's milk (CM) allergy. These studies reported the efficacy of OIT in terms of desensitization, but did not describe sustained unresponsiveness to CM. The aim of this study was to evaluate the efficacy of the OIT protocol using microwave heated cow's milk (MH-CM) in terms of 2-weeks-sustained unresponsiveness (2-weeks-SU) and safety.

METHODS

Forty-eight children were enrolled in this study. Thirty-one children agreed to receive rush OIT using MH-CM (the OIT group) and another 17 children who did not want to receive rush OIT formed the untreated group. Rates of desensitization and 2-weeks-sustained unresponsiveness were compared between the two groups at 1 year after the start of OIT. We followed up these rates and safety data for another year and for longer in the OIT group.

RESULTS

No children in the untreated group did not pass an open food challenge to CM. Of the 31 children in the OIT group, 14 (P = 0.002) achieved desensitization, and 8 (P = 0.036) achieved 2-weeks-SU to CM at 1 year from the start of OIT. Two years after the start of OIT, both the rate of desensitization and the rate of 2-weeks-SU in the OIT group significantly increased compared with the rates at 1 year (P = 0.025 and P = 0.008 respectively).

CONCLUSIONS

The rush OIT protocol using MH-CM was effective at inducing 2-weeks-SU s to CM and had a good safety profile in children with CM allergy. Trial registration Approval number: 324, Registered 3 February 2009.

β-Lactoglobulin mutant Lys69Asn has attenuated IgE and increased retinol binding activity

β-Lactoglobulin (β-LG) is a member of lipocalin superfamily of transporters for small hydrophobic molecules such as retinoids, fatty acids, drugs, and vitamins. β-LG also is one of the major allergens in milk. Despite a lot of research on decreasing cow's milk allergenicity, the effects of mutations of β-LG on recognition by IgE from cow's milk allergy (CMA) patients have not been investigated. We describe here the expression in the yeast Pichia pastoris of a mutant bovine β-LG, in which lysine at position 69, in the main epitopes of the protein, was changed into asparagine (Lys69Asn). The purity and native like folded structure of the recombinant Lys69Asn β-LG was confirmed by HPLC, SDS-PAGE, mass spectrometry and circular dichroism. Lys69Asn β-LG has a fourfold stronger affinity than the wild-type protein for retinol, palmitic acid, and resveratrol, as determined by quenching of the intrinsic tryptophan fluorescence. At the same time the Lys69Asn mutant had a 9 fold attenuated, compared with the wild-type, affinity for IgE of sera from patients suffering from cow's milk allergy, whereas no difference could be detected between mutant and wild-type for binding of the IgGs of four monoclonal antibodies. The results of this study demonstrated the significant role of Lys69 residue on the binding and immuoreactivity properties of β-LG.

β-lactoglobulin mutation Ala86Gln improves its ligand binding and reduces its immunoreactivity

β-Lactoglobulin (β-LG) is a member of lipocalin superfamily of transporters for small hydrophobic molecules. β-LG is also one of the major allergens in milk. Despite a lot of researches on decreasing of cow's milk allergenicity, the effects of the mutation of β-LG on its recognition by IgE from cow's milk allergy (CMA) patients have not been investigated. We described here the expression in the yeast Pichia pastoris of a mutant β-LG, in which Alanine 86 was changed into Glutamine (Ala86Gln; a mutation on one of the major epitopes of the protein). The purity and native like folded structure of the recombinant Ala86Gln have been demonstrated using circular dichroism, HPLC, SDS-PAGE and mass spectrometry. The effect of the mutation on the binding of IgE from CMA patients to mutant protein was evaluated by ELISA methods and the results showed that the mutation of Ala-86 was associated with weaker binding of IgE from CMA patients to Ala86Gln mutant protein. Subsequently, the binding of various ligands such as retinol, palmitic acid, resveratrol and serotonin, with native, recombinant wild type and Ala86Gln mutant β-LGs were investigated by fluorescence spectroscopy and an improvement on the binding affinity of the mutated protein to various ligands was observed.