Bovine Milk Casein Research Articles

Fe3O4@silica-thermolysin: A robust, advantageous, and reusable microbial nanobiocatalyst for proteolysis and milk-clotting

Thermolysin (TLN) is a microbial highly-priced thermostable metallo-endoprotease with complementary substrate specificity to those of proteases widely used in science and industry for protein digestion and milk-clotting. This study is the first to immobilize TLN on aminated superparamagnetic nanoparticles (Fe3O4@silica-NH2) aiming for higher stability, recoverability, reusability, and applicability in proteolysis and as a microbial rennet-like milk-clotting enzyme. The nanobiocatalyst developed (Fe3O4@silica-TLN) displays hydrolytic activity on a synthetic TLN substrate and, apparently, was fully recovered from reaction media by magnetic decantation. More importantly, Fe3O4@silica-TLN retains TLN catalytic properties in the presence of calcium ions even after exposure to 60 °C for 48 h, storage at 4 °C for 80 days and room temperature for 42 days, use in proteolyses, and in milk-clotting for up to 11 cycles. Its proteolytic activity on bovine milk casein in 24 h furnished 84 peptides, of which 29 are potentially bioactive. Also, Fe3O4@silica-TLN catalyzed the digestion of bovine serum albumin. In conclusion, Fe3O4@silica-TLN showed to be a new, less autolytic, thermostable, non-toxic, magnetically-separable, and reusable nanobiocatalyst with highly attractive properties for both science (peptide/protein chemistry and structure, proteomic studies, and the search for new bioactive peptides) and food industry (cheese manufacture).

The Severity of Gastrointestinal Disorders and Autistic-Like Behaviors Could Be Associated with a Selective Humoral Response to Bovine Milk Caseins: A Case Series

The Severity of Gastrointestinal Disorders and Autistic-Like Behaviors Could Be Associated with a Selective Humoral Response to Bovine Milk Caseins: A Case Series

Application of on-line sample preconcentration by large-volume dual preconcentration by isotachophoresis and stacking (LDIS) on straight-channel microchips.

In this study, large-volume dual preconcentration by isotachophoresis and stacking (LDIS) which is an on-line sample preconcentration technique coupling large-volume sample stacking with an electroosmotic flow pump (LVSEP) with transient isotachophoresis (tITP) was applied to microchip electrophoresis (MCE) for improving both detection sensitivities and peak shapes. To realize LDIS in MCE, we investigated experimental procedures for injecting a short plug of a leading electrolyte (LE) solution into a straight microchannel without any sophisticated injector apparatus. We found that a short LE plug could be injected into a sample-filled straight-channel only by making the liquid level of the LE solution in an outlet reservoir higher than that in an inlet one. By applying a reversed-polarity voltage to the microchip, anionic analytes injected throughout the microchannel were first enriched by LVSEP, followed by tITP. Through the second preconcentration effect by tITP in LDIS, sensitivity enhancement factor (SEF) and asymmetry factor for a standard dye were improved from 878 and 0.62 to 1330 and 1.14, respectively, relative to those in conventional LVSEP. It should be noted that more viscous running buffer containing sieving polymers could be employed to the LDIS analysis, which was effective for improving the SEF and the separation efficiencies, especially for bio-polymeric compounds. Finally, LDIS was applied to the oligosaccharide and protein analyses in MCE, resulting in the SEFs of 1410 and ca. 50 for maltotriose and bovine milk casein, respectively.

Generation and characterization of avian IgY antibodies for detecting beta-casein A1 in bovine milk

Beta-casein is a primary milk protein that constitutes approximately 30% of the casein in bovine milk, with the two most common types in cattle being A1 and A2. The A2 protein differs from the A1 version due to a mutation in the codon at position 67, resulting in a histidine to proline substitution. However, the bioactive peptide, beta-casomorphine-7 (BCM7), which originates from partial proteolysis of the A1 variant, has been linked to several gastrointestinal disorders in humans. Production of A1 beta casein-free products is increasing demand in the milk market, worldwide. This study generated and characterized a polyclonal IgY antibody that specifically recognizes the A1 beta-casein protein present in cow's milk. A commercially available IgY anti-A1 antibody was used as a positive control, and the sensitivity and specificity of both the commercial and produced anti-A1 antibodies were evaluated. The results showed 100% sensitivity and specificity of 100% of the commercial IgY anti-A1. The in-house produced anti-A1 antibody demonstrated a sensitivity of 95.2% and a specificity of 100%, indicating its potential as a reliable and cost effective tool for detecting A1 beta-casein protein in milk samples.

P29 | Bovine milk casein diet supplementation reduce Cd level in liver and kidney of cadmium intoxicated rats

Journal of Veterinary Pharmacology and TherapeuticsVolume 46, Issue S1 p. 99-99 POSTER PRESENTATIONS P29 | Bovine milk casein diet supplementation reduce Cd level in liver and kidney of cadmium intoxicated rats First published: 11 June 2023 https://doi.org/10.1111/jvp.13308Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume46, IssueS1Special Issue: 15th International Congress of the European Association for Veterinary Pharmacology and Toxicology held Bruges, Belgium, July 2–5, 2023June 2023Pages 99-99 RelatedInformation

Identification and evaluation of antioxidant activity of bioactive casein-derived peptides during in vitro digestion and transepithelial transport in Caco-2 cells

Dairy products are important sources of bioactive (antibacterial, antithrombotic, antihypertensive, immunomodulatory, and antioxidative) peptides, that need to be released from the target proteins. In the present study, bovine milk casein protein was hydrolyzed by pancreatin and trypsin (4 and 24 h) to evaluate the hydrolyses efficiency (ninhydrin reaction); to elucidate the sequence of casein-derived peptides (SDS-PAGE, LC-ESI-TOF-MS); and to assess the peptides antioxidant activity (DPPH and ORAC), bioactivity in silico, bioaccessibility after in vitro digestion, and bioavailablility by transepithelial transport in Caco-2 cells. The hydrolysis degree increased with the incubation time, with evident degradation of casein-derived proteins into low molecular weight peptides (<5 kDa) after 4 and 24 h incubation. Pancreatin showed higher hydrolysis degree (91%) than trypsin (21%). An increase in antioxidant activity was observed with increasing incubation time, with higher antioxidant effect observed for trypsin derived peptides (47% reduction of free radicals; 32112 μM Trolox equivalents) than pancreatin derived peptides (15% reduction; 2862 μM Trolox equivalents). A total of 69 caseins derived peptides were identified after trypsin (33 peptides) and pancreatin (36 peptides) hydrolysis for 24 h; with 26 peptides released from β-casein, 21 from α-s1-casein, 15 from α-s2-casein, and 7 from k-casein hydrolysis. Some of these peptides were described as antioxidant, anti-inflammatory, and antihypertensive. After in vitro digestion 123 peptides were found in gastric (56 peptides), duodenal (43 peptides) and colonic (24 peptides) fraction; while five peptides were bioavailable by crossing the intestinal barrier, with increased peptides’ abundance after trypsin hydrolysis treatment.

Goat casein peptides and their potential through an &lt;i&gt;in silico&lt;/i&gt; approach

The caprine caseins αs1, αs2, β, and κ from UniProtKB were characterised for amino acid profile, and hydrolysed in silico with pepsin or trypsin. The generated peptides were characterised for physical-defined properties, bioactive potential, Boman index, toxicity and allergenicity. The peptides generated are bioactive, predominating dipeptidyl peptidase IV and ACE inhibitors activities. Only two peptides are toxic, and most have been proposed to be allergenic by Allergen Online or SDAP, because they have < 50% identity with other confirmed allergenic proteins, including bovine milk caseins, however, they were considered non-allergenic by the methods MEME/MAST and BLAST in Algpred, requiring more studies for better evaluation. Despite of variations, bioinformatics tools are useful before bench tests, because allows time and cost savings, and provides studies projection for use by pharmaceutical and food industries, besides to identify sequences that may need other tests to evaluate the safety before being introduced in use.

The effect of casein and lactoferrin of bovine's milk on nestin expression of the exposed dental pulp

Background: Pulp tissue can regenerate if damage occurs. The pulp differentiates into new odontoblast-like cells in Progenitor cells. Nestin is a marker of the presence of new dontoblast-like and expressed in pathological conditions. Bovine's milk casein and lactoferrin contain proteins that accelerate cell growth. This study aimed to determine the effect of casein and lactoferrin on the expression of nested cells in the exposed dental pulp. Method: The research method is an experimental laboratory with male 30 Spraque Dawley rats. Rats were grouped as : casein, lactoferrin, casein-lactoferrin, and Ca-(OH)2. Each group consisted of 15 samples of molars which were divided into 5 samples of teeth for observation on the 7, 14, and 21 days. The first molars of rats were prepared until the pulp was exposed. The data of nestin quantity with immunohistochemical (IHC) analysis on histological preparations were analyzed using two-way ANOVA then the least significance difference (LSD) test. Result: The results of the average number of nested cells on 7,14 and 21 days were highest on combination of casein and lactoferrin. Two-way ANOVA statistical proved that there was a significant difference (p&lt;0.05) in each observation period and group and the number of expressions of nestin cells. LSD test showed that there was a significant difference (p&lt;0.05) between groups compared to the control group. Conclusion: Combination casein and lactoferrin extracts affect the expression of the number of nestin cells as a marker of new odontoblast-like cells in the exposed dental pulp.

Repeated exposure to epigallocatechin gallate solution or water alters bitterness intensity and salivary protein profile

Polyphenols, bitter and astringent compounds present in many healthy foods, induce varied sensory responses across individuals. These differences in liking and flavor intensity may be attributable, in part, to differences in saliva. In the current study, we tested the effect of repeated consumption of a bitter polyphenol (epigallocatechin gallate, EGCG) solution on perceived bitterness intensity and salivary protein composition. We hypothesized exposure to EGCG would cause an increase in concentrations of salivary proteins that inhibit bitterness of polyphenols. We also hypothesized that participants with higher habitual polyphenol, specifically the flavanols, intake would experience less bitterness from EGCG solutions than those with low habitual intake, and that the high flavanol consumers would be more resistant to salivary alterations. We also tested whether bovine milk casein, a food analog for salivary proteins that may suppress bitterness, would decrease bitterness intensity of the EGCG solution and mitigate effects of the intervention. Participants (N = 37) in our crossover intervention adhered to two-week periods of daily bitter (EGCG) or control (water) solution consumption. Bitterness intensity ratings and citric acid-stimulated saliva were collected at baseline and after each exposure period. Results indicate that bitterness intensity of the EGCG solution decreased after polyphenol (bitter EGCG) exposure compared to control (water) exposure. Casein addition also decreased bitterness intensity of the EGCG solution. While there was not a significant overall main effect of baseline flavanol intake on solution bitterness, there was an interaction between intervention week and baseline flavanol intake. Surprisingly, the higher flavanol intake group rated EGCG solutions as more bitter than the low and medium intake groups. Of proteins relevant to taste perception, several cystatins changed in saliva in response to the intervention. Interestingly, most of these protein alterations occurred more robustly after the control (water) exposure rather than the bitter (EGCG) exposure, suggesting that additional factors not quantified in this work may influence salivary proteins. Thus, we confirm in this study that exposure to bitterness suppresses ratings of bitterness over time, but more work needs to establish the causal factors of how diet influences salivary proteins.

Identification and Screening of Potential Bioactive Peptides with Sleep-Enhancing Effects in Bovine Milk Casein Hydrolysate.

Casein tryptic hydrolysate (CTH) has been proven to possess stress-relieving and sleep-enhancing effects, but only one decapeptide YLGYLEQLLR (α-CZP) in CTH was reported to exhibit affinity for the benzodiazepine site of a GABAA receptor (GABAAR). This study aimed to compare the sleep-enhancing effects between CTH and α-CZP and to explore novel sleep-enhancing peptides. Our results showed that CTH significantly prolonged sleep duration in mice, which was almost 2-fold longer than that of α-CZP. The α-CZP in CTH was degraded more slowly than the synthetic α-CZP; meanwhile, CTH could release other potential sleep-enhancing peptides during gastrointestinal digestion. Additionally, two peptides YPVEPF and YFYPEL with strong sleep-enhancing activity were explored by virtual screening. Especially, YPVEPF could significantly prolong the sleep duration from 559.00 ± 272.24 to 2501.63 ± 1021.21 s and increase the sleep rate from 58.33 to 83.33% in mice. Moreover, YPVEPF and YFYPEL could bind with the Ser-205 and Phe-77 residues of GABAAR via hydrogen bonds and lipid contacts. They were largely released after digestion with 11.19 ± 0.15 and 1.78 ± 0.01 g/kg, respectively.

Conformational and physicochemical characteristics of bovine skim milk obtained from cows with different genetic variants of β-casein

This study highlights differences in conformational and physicochemical characteristics of bovine skim milk and micellar casein from cows of different β-casein phenotypes. These genetic variants have been one of the predominant topics among dairy researchers due to their differences in β-casein structure, and thus their potential effects on dairy processing and human health. For characterising differences in milk protein structure, Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (1H NMR) spectroscopies combined with chemometric analysis were used. Additionally, physiochemical properties such as mineral content, particle size, and electrostatic charge in skim milk and micellar casein samples were analysed at 4 and 20 ᵒC. Results showed variation in the secondary structure of all three genetic variants independent of temperature. Moreover, the main differences involved a higher level of β-turn and α-helical structures in A1/A1 β-casein milk, while intermolecular β-sheets were more numerous in A1/A2 β-casein milk, whereas random or polyproline II (PPII) structures were more common in A2/A2 β-casein milk. Temperature slightly affected these differences, which was due to the dissociation of β-casein from the micelle at low temperature. In addition, A2/A2 β-casein milk and its micellar casein had a larger average particle size, which resulted in a lower negative ζ-potential. The A2/A2 β-casein samples contained greater amounts of phosphorus and less calcium compared to the other genetic variants of milk and their micellar caseins. The results also indicated that a combination of FTIR and 1H NMR spectroscopies could be used to establish conformational differences in milk and micellar caseins of different genetic variants.

Extraction of antibacterial peptides against H. pylori from bovine milk casein

IntroductionMore than half of the world’s population is infected with Helicobacter pylori, which may cause gastritis, peptic ulcer and even gastric cancer. The World Health Organization (WHO) has announced that H. pylori infection is a class I carcinogen and hence eradication of it is highly important. Bovine milk contains caseins, which can be digested by various enzymes in the human stomach to produce antibacterial peptides.Material and methodsThis study used in vitro methods to extract anti-H. pylori peptides from caseins by the gastric protease pepsin under environments with similar pH values to those found in the human stomach. The molecular weights and sequences of the peptides were identified by MALDI-TOF mass spectrometry and MS/MS Ion Search, respectively. Antibacterial activity tests were performed to calculate the minimum inhibitory concentration (MIC90) of the extracts.ResultsThe findings of this study revealed that the major products of bovine milk casein digestion by pepsin are casecidin 17 and β-casein 207–224. The extracts produced promising anti-H. pylori effects with the lowest MIC90 found at pH values of 1.5 and 2.0.ConclusionsThis study identified the anti-H. pylori effects of casecidin 17 and β-casein 207–224, which may help in developing therapeutic agents to modulate the effect of antibiotics on H. pylori infections.

The effect of atmospheric cold plasma treatment on the antigenic properties of bovine milk casein and whey proteins

Casein, β-lactoglobulin and α-lactalbumin are major milk protein allergens. In the present study, the structural modifications and antigenic response of these bovine milk allergens as induced by non-thermal treatment by atmospheric cold plasma were investigated. Spark discharge (SD) and glow discharge (GD), as previously characterized cold plasma systems, were used for protein treatments. Casein, β-lactoglobulin and α-lactalbumin were analyzed before and after plasma treatment using SDS-PAGE, FTIR, UPLC-MS/MS and ELISA. SDS-PAGE results revealed a reduction in the casein and α-lactalbumin intensity bands after SD or GD treatments; however, the β-lactoglobulin intensity band remained unchanged. FTIR studies revealed alterations in protein secondary structure induced by plasma, particularly contents of β-sheet and β-turn. The UPLC-MS/MS results showed that the amino acid compositions decreased after plasma treatments. ELISA of casein and α-lactalbumin showed a decrease in antigenicity post plasma treatment, whereas ELISA of β-lactoglobulin showed an increase in antigenicity. The study indicates that atmospheric cold plasma can be tailored to mitigate the risk of bovine milk allergens in the dairy processing and ingredients sectors.

Identification and characterization of proteinase B as an unstable factor for neutral lactase in the enzyme preparation from Kluyveromyces lactis

The stability of the commercial lactase enzyme is important for the dairy industry. A destabilizing factor for neutral lactase in the enzyme preparation from Kluyveromyces lactis was investigated. We found that lactase had lower thermal stability when fragmented bands of lactase were confirmed on SDS-PAGE. After the destabilizing factor of lactase was purified, that was identified by BLAST search as a hypothetical protein in K.lactis similar to proteinase B (PRB) of Saccharomyces cerevisiae. The molecular mass of protease was estimated to be approximately 30kDa with SDS-PAGE. The purified protease exhibited activity toward lactase and FITC-casein but not toward bovine serum albumin or milk casein. The optimal pH and temperature of the protease were 8.0 and 40°C, respectively. The protease activity was strongly inhibited by Fe2+, Cu2+, and a serine protease inhibitor, but activated by Ca2+. Based on these properties, the protease was identified as PRB. Lactase fragmentation was accelerated by the addition of purified PRB to the lactase preparation and was suppressed by protease inhibitors. Thus, this is the first report to identify and characterize PRB as the unstable factor of neutral lactase in the K.lactis preparation.

Evaluation of the Antidepressant Effect of the Functional Beverage Containing Active Peptides, Menthol and Eleutherosides, and Investigation of Its Mechanism of Action in Mice

SUMMARYResearch backgroundDepression has become a global threat to human health. In order to solve it, researchers have conducted multi-faceted studies including diet. Many food-derived bioactive substances have shown antidepressant effects. However, there are few studies on the design of industrialized food with antidepressant effect. This study aims to evaluate the antidepressant effect of a functional beverage made from several ingredients with potential antidepressant function and investigate its antidepressant mechanisms.Experimental approachThe beverage consists of peppermint oil, active peptides derived from bovine milk casein and Acanthopanax senticosus extract (ASE) whose active ingredient is eleutheroside. Different amounts of ASE were evaluated to determine the optimal concentration of eleutheroside in this functional beverage to deliver the best antidepressant effect through extensive behavioral testing, including preliminary acute stress experiments and further chronic unpredictable mild stress test.Results and conclusionsThe results demonstrated that the beverage with 15 mg/kg of eleutheroside could significantly reduce the mice’s immobility time of tail suspension test and forced swimming test, recover mice’s sucrose preference and behavior changes in the open field test, improve the contents of dopamine, norepinephrine, 5-hydroxytryptamine and the activity of superoxide dismutase and reduce the content of malondialdehyde in mice’s brains, which indicated that the improvement of monoamine neurotransmitter systems and antioxidation was one potential mechanism of antidepressant action.Novelty and scientific contributionThis study provides a design of antidepressant functional beverage and an efficient way for the prevention and treatment of depression.

Complex Gastrointestinal and Endocrine Sources of Inflammation in Schizophrenia.

A low level, inflammatory phenotype is prevalent in individuals with schizophrenia, but the source of this inflammation is not known. Studies of the gut–brain axis indicate that this inflammation may be related to the translocation of intestinal microbes across a permeabilized gut–vasculature barrier. In addition, studies of the endocrine system support that this inflammation may derive from effects of stress hormones and metabolic imbalances. Gastrointestinal (GI) and endocrine conditions are not mutually exclusive, but rather may have additive effects to produce this inflammatory phenotype in schizophrenia. Here, we examined a series of plasma biomarkers used to measure general inflammation and presumably microbial, gut-derived inflammation in 409 individuals with schizophrenia: c-reactive protein (CRP), lipopolysaccharide-binding protein (LBP), soluble CD14 (sCD14), and IgG antibodies to S. cerevisiae, bovine milk casein, and wheat gluten. Individuals were stratified according to whether or not they had a comorbid GI or endocrine condition, both, or neither. In multivariate regression models, the presence of GI and endocrine conditions was additive for the GI-based marker, LBP, with significant associations only when both conditions were present compared to when both conditions were absent (OR = 2.32, 95th% CI 1.05–5.13, p < 0.03). In contrast, the marker of general inflammation, CRP, was strongly associated with primarily endocrine conditions (OR = 3.64, 95th% CI 1.35–9.84, p < 0.05). Overall associations were largely driven by the GI condition, gastroesophageal reflux disease (GERD), and by the endocrine condition, obesity. In univariate comparisons, S. cerevisiae IgG levels were significantly elevated only in persons with GI conditions (p < 0.02), whereas antibodies to the food antigens were elevated in the presence of either or both conditions (p < 0.005–0.04). More severe psychiatric symptoms were associated only with GI conditions (p < 0.01–0.04). In conclusion, both GI and endocrine abnormalities may contribute to inflammation in schizophrenia, sometimes independently and sometimes as part of interactions which may represent complex integrated pathways. The accumulating evidence for multisystem inflammation in schizophrenia may lead to the development of new strategies to prevent and treat this devastating disorder.

Efficacy of mouthrinses with bovine milk and milk protein isolates to accumulate casein in the in situ pellicle.

The adsorption of bovine milk caseins on the tooth surface might have a positive impact on the prevention of dental diseases. Therefore, the present study aimed to investigate the efficacy of mouthrinses with different types of bovine milk and milk protein isolates to accumulate caseins in the pellicle. An indirect enzyme-linked immunosorbent assay (ELISA) was established to quantify the amount of caseins adsorbed into the in situ pellicle. In situ pellicle samples were collected from 2 volunteers on ceramic specimens (A = 8cm2). After 10min of pellicle formation, different types of bovine milk, 3% micellar casein in synthetic milk ultrafiltrate (SMUF) or 3% non-micellar caseinate in SMUF, were used as mouthrinses for 10min. The pellicle material was harvested after 30min in situ and examined for caseins by the indirect ELISA. Selected pellicle samples were subjected to TEM analysis. All mouthrinses accumulated caseins in the in situ pellicle (2.0 ± 0.7-20 ± 1.7μg/ml) that, under native conditions, expressed no casein signal. Micellar protein association increased the adsorption of casein into the pellicle. Milk homogenization also had an influence on the casein accumulation in the pellicle. TEM analysis confirmed the integration of micellar casein into the pellicle. The mouthrinses altered the protein composition and the ultrastructure of the in situ pellicle to a different extent: bovine milk with 3.8% fat content and 3% micellar casein in SMUF being particularly effective. The study provides interesting perspectives for innovative prevention strategies in dentistry.

Spontaneous aggregation of bovine milk casein micelles: Ultra-small angle x-ray scattering and mathematical modeling

We have used Ultra Small Angle X-ray Scattering (USAXS) and mathematical models to study seemingly-spontaneous aggregation structures in two pasteurized bovine milks. Although extensive studies of casein micelles and their aggregation have been carried out, few have been done to numerically characterize submicron structures to micron-scale structures. We measured the USAXS intensity, I(q), as a function of the scattering vector magnitude, q, for commercial pasteurized skim milk and nonhomogenized whole milk at two temperatures, 7 °C and 45 °C. We observed broad peaks, reported previously to be related to casein micelles, centered at q ≈ 2 × 10−2 Å−1 and at q ≈ 9 × 10−2 Å−1. At lower q values, log I(q) displayed a behavior characteristic of aggregation manifested for a slope in the region 3–7 × 10−4 Å−1 &amp;lt; q &amp;lt; 4 × 10−3 Å−1. This behavior appeared in the absence of (a) chymosin, (b) any change in pH or CaCl2 concentration, and (c) temperature changes. We introduced a model of milk and used computer simulations to investigate consequences of casein micelles possessing surface areas lacking the water-soluble components of κ-casein proteins. These components exist to provide stability against aggregation to the casein micelles. We propose that bovine casein micelles spontaneously formed 1-dimensional aggregates.

Binding analysis between monomeric β-casein and hydrophobic bioactive compounds investigated by surface plasmon resonance and fluorescence spectroscopy

β-Casein, a phosphoprotein representing 37% of the bovine milk caseins, has specific features promoting its application as a nanocarrier for hydrophobic bioactives. In this study, the interactions of β-casein with curcumin and vitamin D3 under the same physico-chemical conditions were investigated. The interaction kinetics have been studied by surface plasmon resonance (SPR) and fluorescence spectroscopy. The KD value for curcumin-β-casein interaction has been successfully evaluated (4.1 ± 0.7 × 10−4 M) using SPR by fitting data to a 1:1 Langmuir interaction model. Conversely, the SPR responses obtained for vitamin D3 show that the interactions between this hydrophobic compound and the β-casein immobilized on the sensor chip were below the sensitivity of the SPR apparatus. Moreover, the fluorescence quenching data show that curcumin has higher affinity to β-casein (KA = 23.5 ± 1.9 × 104 M−1) than vitamin D3 (KA = 5.8 ± 1.1 × 104 M−1).

Modification of IgE binding to αS1-casein by proteolytic activity of Enterococcus faecium isolated from Iranian camel milk samples

Milk is a perfect source of nutrients for neonates. When breast feeding cannot be done, an infant’s alimentation is usually initiated to cow’s milk, among the primary foods. It has been reported that about 2.5% of juveniles under the age of 3 years manifest allergic reactions to cow’s milk proteins. Among the cow’s milk proteins, casein fractions are considered as the strongest allergenic proteins. The proteolytic enzymes of lactic acid bacteria (LAB), during fermentation of dairy products, can break down milk proteins especially caseins and subsequently reduce the immune reactivity of allergenic proteins. In this research, raw bovine and camel milk samples were screened for cocci LAB strains and after isolation, their proteolytic activity against bovine milk caseins were evaluated by SDS-PAGE and RP-HPLC. The potential of cocci LAB strains on αS1-casein degradation and their potential to break down the principle allergenic epitopes of this protein was detected using indirect competitive ELISA. Molecular identification of the best proteolytic strain was fulfilled by 16S rDNA fragment sequencing with universal primers. The obtained results demonstrated that Enterococcus faecium isolated from raw camel milk samples was the most efficient isolate in hydrolyzing Na-caseinate and αS1-casein. Hydrolysated αS1-casein by Enterococcus faecium was also less recognized by IgE of bovine milk allergic patients’ sera in comparison with native αS1-casein. It has been proposed that Enterococcus faecium could be an efficient strain in allergenicity reduction of cow’s milk proteins. So it could be an excellent candidate to be potentially used in dairy industries.