Impact of the Plastein Reaction of Casein Hydrolysates in the Presence of Exogenous Amino Acids on Their Anti-Inflammatory Effect in the Lipopolysaccharide-Stimulated Macrophages

In this study, papain-generated casein hydrolysates (CH) with a degree of hydrolysis of 13.7% were subjected to a papain-mediated plastein reaction in the absence or presence of one of the exogenous amino acids—Gly, Pro, and Hyp—to prepare four plastein modifiers, or mixed with one of three amino acids to prepare three mixtures. The assay results confirmed that the reaction reduced free NH2 for the modifiers and caused amino acid incorporation and peptide condensation. When RAW264.7 macrophages were exposed to the CH, modifiers, and mixtures, these samples promoted macrophage growth and phagocytosis in a dose-dependent manner. In addition, the CH shared similar activity in the cells as the mixtures, while the modifiers (especially the PCH-Hyp prepared with Hyp addition) exerted higher potential than CH, the mixtures, and PCH (the modifier prepared without amino acid addition). The plastein reaction thus enhanced CH bioactivity in the cells. When RAW264.7 macrophages were stimulated with lipopolysaccharide (LPS), the inflammatory cells produced more lactate dehydrogenase (LDH) release and reactive oxygen species (ROS) formation, and caused more four inflammatory mediators (NO, PGE2, TNF-α, and IL-6) and two anti-inflammatory mediators (TGF-β1 and IL-10). However, the PCH-Hyp, PCH, and CH at dose levels of 100 μg/mL could combat against the LPS-induced inflammation. Overall, the PCH-Hyp was more active than the CH and PCH in reducing LDH release, ROS formation, and the secretion of these inflammatory mediators, or in increasing the secretion of the anti-inflammatory mediators. The qPCR and Western blot analysis results further confirmed that these samples had anti-inflammatory effects on the stimulated cells by suppressing the LPS-induced activation of the NF-κB signaling pathway, via regulating the mRNA/miRNA expression of iNOS, IL-6, TNF-α, IL-1β, COX-2, TLR4, IL-10, TGF-β1, miR-181a, miR-30d, miR-155, and miR-148, as well as the protein expression of MyD88, p-IKKα, p-IκBα, p-NF-κB p65, and iNOS, involved in this signaling pathway. In addition, the immunofluorescence assay results revealed that these samples could block the LPS-mediated nuclear translocation of the p65 protein and displayed the same function as the NF-κB inhibitor BAY 11-7082. It was concluded that CH could be endowed with higher anti-inflammatory activity to the macrophages by performing a plastein reaction, particularly that in the presence of exogenous Hyp.

Chronic Milk-Dependent Food Protein-Induced Enterocolitis Syndrome in Children from West Pomerania Region

Characteristics of chronic milk-dependent food protein-induced enterocolitis syndrome (FPIES) in children from the region of Western Pomerania were studied. Prospectively, 55 children were diagnosed at a median of 2.2 months. The open food challenges (OFC), morphologies, milk-specific IgE (sIgE) (FEIA method, CAP system), and skin prick tests (SPTs) were examined. Vomiting and diarrhea escalated gradually but quickly led to growth retardation. Of the infants, 49% had BMI < 10 c, 20% BMI < 3 c; 25% had anemia, and 15% had hypoalbuminemia. During the OFCs we observed acute symptoms that appeared after 2–3 h: vomiting diarrhea and pallor. A total of 42% children required intravenous hydration. Casein hydrolysates or amino acids formulae (20%) were used in treatment. In 25% of children, SPT and milk sIgE were found, in 18%—other food SPTs, and in 14% allergy to other foods. A transition to IgE-dependent milk allergy was seen in 3 children. In the twelfth month of life, 62% of children had tolerance to milk, and in the twenty-fifth month—87%. Conclusions. Chronic milk-dependent FPIES resolves in most children. By the age of 2 children are at risk of multiple food sensitization, and those who have milk sIgE are at risk to transition to IgE-mediated milk allergy. Every OFC needs to be supervised due to possible severe reactions.

In Vitro Assessment of Antioxidative Potential of Goat Milk, Casein and its Hydrolysates: Comparison of Goat Milk with Bovine and Buffalo milk

The present study was executed with an aim to explore the antioxidative potential of goat, cow, and buffalo milk. Buffalo milk has showed highest antioxidative potential than goat and cow milk as measured by ABTS, ORAC, and DPPH assays, whereas goat milk has showed better antioxidative potential than cow milk when measured by ORAC and DPPH. Further, the effect of temperature on the antioxidative potential of goat milk was assessed. An increase in temperature has a negatively affect the antioxidative potential of goat milk. The antioxidative potential of goat milk was in the following order: raw milk > pasteurized milk > boiled milk. Casein derived from goat milk by isoelectric precipitation was hydrolyzed by gastrointestinal enzymes pepsin (P), trypsin (T), chymotrypsin (C), and their combinations PT, PC, TC, and PTC. Among all the casein hydrolysates, the maximum antioxidative potential was found in PT hydrolysate, further fractionated by 10, 3 and 1 kDa ultrafiltration membranes. 3–10 kDa fraction exhibited maximum antioxidative potential in comparison to other fractions of PT hydrolysate. Our results suggested that antioxidative potential of goat milk and its hydrolysates could be an important mean to obtain natural antioxidative peptides.

Casein Proteolysis in Bioactive Peptide Production: Optimal Operating Parameters

Introduction. Public health is gradually deteriorating as a result of unhealthy lifestyle and diet, which triggers allergic reaction to certain foods. Milk and dairy products are rich in biologically active substances, which makes them a good dietary supplement for athletes, diabetic patients, etc. However, this popular food contains allergens, for instance, such proteins as αS1-casein, αS2-casein, β-casein, and κ-casein. Therefore, one of the most urgent tasks of modern food science is to reduce the allergenic properties of casein. Heat treatment is an option, but thermal exposure leads to denaturation and produces new antigenic determinants, e.g. epitopes. Biotechnological processing is a more promising method. It is based on the catalytic properties of proteolytic enzymes. Enzymes make it possible to obtain a protein hydrolyzate with amino acids of various molecular weights. The present research provided the optimal working parameters of casein proteolysis by various enzymes (endopectidases), namely trypsin, chymotrypsin, and thermolysin. Study objects and methods. Casein hydrolysates are casein-based biopeptides, and casein is an accessible and valuable milk protein. Trypsin, chymotrypsin, and thermolysin were used as proteases. The experiment was based on standard methods. Results and its discussion. At 47 ± 2°C and pH 7.5 ± 0.2, the production of low-molecular-weight components of casein hydrolyzate proved feasible when thermolysin was used at a ratio of 1:100 for 24.00 ± 0.05 h, and chymotrypsin and trypsin – at a ratio of 1:25 for 24.00 ± 0.05 h. Conclusion. The resulting casein hydrolysates contain biologically active peptides and can be used in formulations of low-allergy functional dairy products in allergy-friendly, sports, and baby diets.