Cow’s milk is rich in protein, fat, and other high-quality nutrients, which is an important nutritional source for infants. On the other hand, milk protein is the main factor inducing food allergy in infants and young children. In this study, five kinds of commercially available infant milk powder were selected for static digestion in vitro. The digestive stability of proteins in the five kinds of milk powder was analyzed by electrophoresis and degree of hydrolysis measurement. An enzyme-linked immunosorbent assay (ELISA) was used to evaluate the antigenicity of whey protein in milk powder. The results showed that α-lactalbumin and β-lactoglobulin showed good digestive stability in samples 1, 2, and 4. After gastrointestinal digestion, the antigenicity of α-lactalbumin and β-lactoglobulin decreased in sample 1 but increased in sample 2. The antigenicity of α-lactalbumin increased, while that of β-lactoglobulin decreased in sample 4. Both allergens had lower digestion stability in sample 3 and 5. The antigenicity of α-lactalbumin and β-lactoglobulin increased in sample 5. The antigenicity of α-lactalbumin increased while that of β-lactoglobulin decreased in sample 3.

In this study, casein was hydrolyzed with seven food-grade proteases, including flavourzyme, trypsin, chymotrypsin, alkaline protease, papain, bromelain, and neutral protease and the allergenicity of the resultant hydrolysates was assessed using a serum pool of patients with milk allergy. Moreover, the molecular mass distribution, degree of hydrolysis and residual epitope information were evaluated in order to select the most suitable protease for the production of casein products with reduced allergenicity. The results showed that under the same conditions, the binding ability of casein to specific antibodies decreased to the greatest extent after being treated with chymotrypsin or flavourzyme, so they could be used as a candidate protease for the preparation of subsequent hypoallergenic casein hydrolysates. The results of T-cell epitope prediction and analysis of casein hydrolysates showed that only one T-cell epitope peptide consisting of more than nine amino acids LHSMKEGIHAQQK remained after chymotrypsin hydrolysis of casein.

In this study, we explored the effect of ozone treatment on the structure and allergenicity of milk whey protein. The changes in amino acid composition, sulfhydryl group and disulfide bond contents of whey protein were measured after ozone treatment for 0, 5, 10, 15, 20 and 25 s. Circular dichroism spectroscopy, ultraviolet spectroscopy and fluorescence spectroscopy were applied for analyzing the structural changes. Finally, the ability to bind to specific antibodies in vitro was determined by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to evaluate the potential allergenicity. The results showed that ozone treatment reduced the contents of some amino acids in whey protein. It reduced the contents of free sulfhydryl and total sulfhydryl groups from 5.78 to 2.13 µmol/g and from 14.98 to 12.97 µmol/g, respectively, but increased the content of disulfide bonds from 4.60 to 5.42 µmol/g. Spectroscopic analysis showed that the secondary structure of whey protein was changed. At the early stage of ozone treatment, the tertiary structure became loose, but as the treatment time increased, some protein molecules gathered together and the content of disulfide bonds increased, causing the spatial structure of whey protein to return to its original ordered state. The results of ic-LISA showed that the allergenicity of whey protein decreased significantly after ozone treatment. In conclusion, ozone treatment holds great potential in improving the safety of milk-containing foods.

In this study, phage display technology combined with bioinformatics was used to identify the B cell epitopes of α-lactalbumin and β-lactoglobulin from bovine whey. The amino acid composition and spatial distribution of different types of epitopes was analyzed. The results showed that some linear epitopes were part of the conformational epitopes. IgE and IgG-binding epitopes shared some common sequences. At the same time, we identified a new linear IgE-binding epitope in β-lactoglobulin. The epitopes we obtained are candidate biomarkers for the diagnosis and prognosis of milk allergy, and can be used for guiding the development of hypoallergenic dairy products.

In recent years, milk allergy has attracted more and more attention because of its increasing incidence and indepth research on it. The glycosylation modification of milk proteins not only can improve the functional properties of dairy products, but also reduce the allergenicity of dairy products by destroying or shielding the epitope of allergen proteins. This modification has found applications in various fields such as food flavor, antioxidants and carriers. This paper introduces common glycosylation reactions in the dairy industry, discusses their advantages and disadvantages and the pattern of changes in functional properties and allergenicity of milk proteins after glycosylation, and summarizes the methods to avoid the negative effects of glycosylation reactions. This review provides a reference for the research, development and application of glycosylation modification in milk allergy and dairy processing.

A degranulation model was established using mouse bone marrow-derived mast cell (BMMC) to investigate the anti-allergic activity of milk exosomes (M-Exo). Casein was removed from cow’s milk using a rennet-assisted method, and then M-Exo was isolated from the milk by ultracentrifugation and characterized. Different concentrations of M-Exo were used to treat sensitized BMMCs, and the release rate of activated β-hexosaminidase (β-HEX) and cytokine secretion were measured. The results showed that the prepared M-Exo had a typical tea tray-like bilayer membrane structure, with particle size ranging from 30 to 200 nm. M-Exo contained exosome marker proteins CD81, tumor susceptibility gene 101 (TSG101) and heatshockprotein 70 (HSP70). It was further found that M-Exo could be taken up by BMMCs. In the degranulation model, it was confirmed that M-Exo could significantly inhibit the release rate of β-HEX and downregulate the expression of tumor necrosis factor-α (TNF-α), interleukin-4 (IL-4), and IL-13 in a dose-dependent manner, indicating that M-Exo has anti-allergic activity.

Bioactive peptides (BPs) not only have nutritional value, but also have a wide range of biological activities, such as opioid activity, antibacterial activity, antioxidant properties and immunomodulatory which were associated with potential health benefits. Milk-derived BPs are the most researched, deepest and most widely used food-derived BPs. Milk-derived BPs perform an increasingly important role in regulating inflammatory balance in food allergy (FA) due to the immunomodulatory effect. This review outlines its immunomodulatory role in FA around cytokine level and gut regulation, and also emphasizes the production methods and current market applications of milk-derived BPs.

Silkworm pupa is a nourishing food with high nutritional value, but its consumption has been greatly limited given its allergenicity. Enzyme hydrolytic technique is recognized as an effective method to reduce the allergenicity of protein. In this study, we aimed to investigate the effect of enzymolysis on the allergenicity of silkworm pupa. Crude silkworm pupa protein was extracted through alkali extraction and acid precipitation, which included 5 proteins with the molecular weights ranging from 34 kDa to 76 kDa, and silkworm pupa were then hydrolyzed by alkaline protease. The allergenicity of silkworm pupa protein and its enzymatic hydrolysates was evaluated by establishing BALB/c mice model, and the mice were immunized via intragastric gavage and intraperitoneal injection, respectively. The results indicated that the intraperitoneal injection immunization route induced more by detecting with antibodies, histamine and Th2-related cytokines. Moreover, mice treated with silkworm pupa protein peptide displayed no obvious allergic symptoms, indicating that enzyme hydrolytic technique could significantly reduce the allergenicity of silkworm pupa.

Milk allergy is a common allergic reaction found in infants and young children, most of them appear tolerance after growing up. In this study, infant formula was digested by simulated in vitro digestion method. The potential non-allergenic peptides were further screened from undigested products by exclusion of the known epitopes from β-lactoglobulin (BLG) and α-lactalbumin (ALA). These potential non-allergenic peptides were synthesized and their transferability were determined by Caco-2 cell monolayer model. Finally, the potential allergenicity were evaluated by KU812 cell degranulation model. The results showed that 7 peptides were screened as non-allergenic sequences, among which were 3 from ALA and 4 from BLG. The Caco-2 cell model showed that all the synthetic peptides were absorbed and transported well. However, only peptide BLG_107-118 showed potential allegencity by KU812 model. In conclusion, six peptides, including ALA_29–51, ALA_80–90, ALA_94–103, BLG_1–20, BLG_24–50, and BLG_123–139 were evaluated as hypoallergenic peptides, which could be used for candidates of peptides inducing immune tolerance for persons with milk allergy.