The Impact of Processing and Extraction Methods on the Allergenicity of Targeted Protein Quantification as Well as Bioactive Peptides Derived from Egg

This review article discusses advanced extraction methods to enhance the functionality of egg-derived peptides while reducing their allergenicity. While eggs are considered a nutrient-dense food, some proteins can cause allergic reactions in susceptible individuals. Therefore, various methods have been developed to reduce the allergenicity of egg-derived proteins, such as enzymatic hydrolysis, heat treatment, and glycosylation. In addition to reducing allergenicity, advanced extraction methods can enhance the functionality of egg-derived peptides. Techniques such as membrane separation, chromatography, and electrodialysis can isolate and purify specific egg-derived peptides with desired functional properties, improving their bioactivity. Further, enzymatic hydrolysis can also break down polypeptide sequences and produce bioactive peptides with various health benefits. While liquid chromatography is the most commonly used method to obtain individual proteins for developing novel food products, several challenges are associated with optimizing extraction conditions to maximize functionality and allergenicity reduction. The article also highlights the challenges and future perspectives, including optimizing extraction conditions to maximize functionality and allergenicity reduction. The review concludes by highlighting the potential for future research in this area to improve the safety and efficacy of egg-derived peptides more broadly.

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.

A heuristic, computer-driven and top-down approach to identify novel bioactive peptides: A proof-of-principle on angiotensin I converting enzyme inhibitory peptides

Bioactive peptides are short peptides (3-20 amino acid residues in length) endowed of specific biological activities. The identification and characterization of bioactive peptides of food origin are crucial to better understand the physiological consequences of food, as well as to design novel foods, ingredients, supplements, and diets to counteract mild metabolic disorders. For this reason, the identification of bioactive peptides is also relevant from a pharmaceutical standpoint. Nevertheless, the systematic identification of bioactive sequences of food origin is still challenging and relies mainly on the so defined "bottom-up" approaches, which rarely results in the total identification of most active sequences. Conversely, "top-down" approaches aim at identifying bioactive sequences with certain features and may be more suitable for the precise identification of very potent bioactive peptides. In this context, this work presents a top-down, computer-assisted and hypothesis-driven identification of potent angiotensin I converting enzyme inhibitory tripeptides, as a proof of principle. A virtual library of 6840 tripeptides was screened in silico to identify potential highly potent inhibitory peptides. Then, computational results were confirmed experimentally and a very potent novel sequence, LMP was identified. LMP showed an IC₅₀ of 15.8 and 6.8 µM in cell-free and cell-based assays, respectively. In addition, a bioinformatics approach was used to search potential food sources of LMP. Yolk proteins were identified as a possible relevant source to analyze in further experiments. Overall, the method presented may represent a powerful and versatile framework for a systematic, high-throughput and top-down identification of bioactive peptides.

A Narrative Review of the Anti-Hyperglycemic and Satiating Effects of Fish Protein Hydrolysates and Their Bioactive Peptides

Prevalence of type 2 diabetes and overweight/obesity are increasing globally. Food supplementation as a preventative option has become an attractive option in comparison to increased pharmacotherapy dependency. Hydrolysates of fish processing waste and by-products have become particularly interesting in a climate of increased food wastage awareness and are rapidly gaining traction in food research. This review summarizes the available research so far on the potential effect of these hydrolysates on diabetes and appetite suppression. Scopus and Web of Science are searched using eight keywords (fish, hydrolysate, peptides, satiating, insulinotropic, incretin, anti-obesity, DPP-4 [dipeptidylpeptidase-4/IV]) returning a total of 2549 results. Following exclusion criteria (repeated appearances, non-fish marine sources [e.g., macroalgae], and irrelevant bioactivities [e.g., immunomodulatory, anti-thrombotic]), 44 relevant publications are included in this review. Stimulation of hormone secretion, regulation of glucose uptake, anorexigenic potential, identified mechanisms of action, and research conducted on the most potent bioactive peptides identified within these hydrolysates are all specifically addressed. Results of this review conclude that despite wide methodological variation between studies, there is significant potential for the application of fish protein hydrolysates in the management of bodyweight and hyperglycemia.

Influence of Different Tetracycline Antimicrobial Therapy of Mycoplasma (Mycoplasma synoviae) in Laying Hens Compared to Tea Tree Essential Oil on Table Egg Quality and Antibiotic Residues

The food of animal origin that is the most consumed is the table egg, but laying hens treated with antibiotics can produce eggs contaminated with antibiotic residues. Residues of antibiotics may present a risk for consumer health. Keeping in mind that laying hens almost always suffer from Mycoplasma (Mycoplasma synoviae), for which they are treated with antibiotics, high-quality egg production is even harder. Our research aimed to investigate the influence of three different antibiotics compared to the tea tree (Melaleuca alternifolia) essential oil administered to naturally infected laying hens with M. synoviae, on antibiotic residues in eggs as well as the egg nutritive and sensory qualities. A total of 20,000 laying hens, housed in one facility and divided into four lines each consisting of 5000 hens naturally infected with M. synoviae, was used. For the antimicrobial therapy, tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) were used, respectively. As a control, tea tree essential oil (TT) was used. Based on the gained results all tetracyclines treatment residue values were significantly (p < 0.05) higher compared to the control treatment (TT), but without any significant differences (p > 0.05) between themselves. The results showed no differences in the nutritive and the sensory qualities of eggs between the control and the experimental treatments (p > 0.05). Keeping in mind the obtained results from this study, it can be concluded that tea tree essential oil could be successfully used as a natural antibiotic in the treatment of M. synoviae, without any adverse effects on table egg quality.