Search Results (228)

Background/Objectives: Gastroesophageal reflux disease (GERD) is prevalent in infants and frequently managed with acid-suppressive medications that elevate gastric pH. This pilot study aimed to evaluate how varying gastric pH levels (2.5, 4.0 and 6.0) influence the hydrolysis of milk proteins in human milk (HM), cow’s milk-based infant formula (CMF), and goat milk-based infant formula (GMF). Methods: Samples were subjected to a 30 min in vitro gastric digestion using pediatric human gastric juice obtained from clinical donors. Protein degradation was analyzed via SDS-PAGE densitometry, comparing digested aliquots to undigested controls. Results: At pH 2.5, caseins were highly digested in all samples, especially in HM and GMF. At pH 4.0, GMF displayed an apparent 51% greater casein degradation relative to CMF and HM in this pilot analysis. α-lactalbumin degradation was markedly higher in GMF at all pH levels; notably, at pH 4.0 and 6.0, only GMF exhibited digestion of this protein. Albumin showed almost complete degradation in HM and GMF at pH 2.5, and GMF maintained greater degradation at higher pH levels. β-lactoglobulin (absent in HM) was better digested in GMF at pH 2.5, whereas CMF showed higher hydrolysis observed at pH 4.0 and 6.0. Lactoferrin digestion was most efficient in HM and GMF at pH 2.5, with no differences observed at higher pH levels. Conclusions: These preliminary findings suggest that GMF may offer digestive advantages for infants with GERD under pharmacological acid suppression, particularly regarding casein and α-lactalbumin breakdown at higher pH. The distinct digestion kinetics of CMF and GMF at different pH levels provide a physiological basis for targeted infant feeding strategies. Further large-scale studies are required to validate these exploratory observations. Full article

Milk is a complex biochemical mixture in which proteins significantly influence the behaviour of xenobiotics and bioactive compounds. Interactions between milk proteins and substances such as veterinary drugs or natural bioactives can modify molecular stability, binding dynamics, and exposure pathways, affecting food safety and the One Health concept. This study presents a comparative, matrix-focused investigation on how three chemically distinct ligand classes, sulfanilamide antibiotics, naturally occurring phenolic compounds and zinc–polyphenol complexes, interact with major milk proteins, β-lactoglobulin and casein. Protein–ligand interactions were examined using steady-state fluorescence spectroscopy to assess quenching behaviour and comparative interaction trends. Molecular docking was employed as a qualitative tool to provide structural context. Distinct interaction patterns were observed across ligand classes, reflecting differences in molecular structure, hydrophobicity, and coordination chemistry. Importantly, zinc coordination modified interaction profiles relative to the corresponding free ligands, indicating that metal coordination can affect ligand–protein interactions within the milk matrix. These findings support the concept that milk proteins may function as matrix-dependent modulators of ligand behaviour. The study is positioned as a hypothesis-generating framework highlighting the importance of food matrices as active biochemical environments. Herein, we provide a foundation for hypothesising how the milk matrix affects residue behaviour and bioactive interactions, with relevance to veterinary pharmacology and food safety risk assessment. Full article

Balancing microbial safety and the retention of heat-sensitive components has long been a key issue in dairy processing research. This study systematically compared the effects of instantaneous ultra-high-temperature treatment (INF, 145–155 °C/0.09 s) with that of conventional pasteurization (75–95 °C/15 s) as well as ultra-high-temperature treatment (UHT, 135 °C/5 s), on the microbial evaluation, nutritional composition, and physicochemical quality of bovine milk. The results showed that all heat treatments completely inactivated Staphylococcus aureus, coliforms, while only UHT and INF achieved full spore elimination. In the INF group, α-lactalbumin remained almost completely native and native β-lactoglobulin retention was approximately 83% relative to raw milk. The retention of lactoferrin and immunoglobulin G was about 30% and 12% after INF treatment, respectively, which were higher than that of 13% and 8% in the 85 °C/15 s group, and complete denaturation in the 95 °C/15 s and UHT groups. Furthermore, vitamin B₂ remained stable after INF treatment. The glycation content of proteins was lower in INF treatment compared to conventional heat treatments, especially for the concentration of furosine, which was about 6–7 mg/100 g protein in the INF group, and 15 mg/100 g protein in the 95 °C/15 s group, and 67 mg/100 g protein in the UHT group. Overall, the INF process achieved sterilization equivalent to UHT while substantially reducing thermal load, thus better balancing microbial safety, nutritional integrity, and immune-active proteins, which provides a scientific basis for establishing standardized INF parameters and promoting high-quality dairy production. Full article

This investigation focused on developing nutrient-dense Medjool date-based bars (MDBs) formulated with Medjool date paste, milk protein concentrate, whey proteins, and other functional ingredients. Comprehensive proximate analysis, mineral profiling, amino acid determination, and instrumental assessments, including color measurement, scanning electron microscopy, differential scanning calorimetry, and texture analysis, were performed, followed by organoleptic evaluation. Medjool date paste served as the primary carbohydrate source (76.44%), while whey protein isolate and milk protein concentrate contributed substantially to the protein fraction (89.26% and 81.62%, respectively). The resulting bars contained 19.32–26.78% crude protein, 10.96% fat, and 12.35–12.71% moisture, delivering 414.72–416.04 Kcal 100 g⁻¹. Sugar profiles remained consistent across formulations (total sugars: 36.77–36.98%), with appreciable mineral content including potassium (884–923 mg 100 g⁻¹), calcium (418–585 mg 100 g⁻¹), and phosphorus (402–459 mg 100 g⁻¹). The essential amino acid composition equaled or surpassed that of hen’s egg, establishing the product as a superior protein source. Antioxidant analysis demonstrated total phenolic content of 452.22–554.12 mg GAE 100 g⁻¹ and total flavonoids of 358.06–374.24 mg QE 100 g⁻¹, with consistent radical scavenging capacity, reduced browning via protein–polyphenol binding (ΔG −58 to −72 kJ mol⁻¹), a balanced texture (hardness 157–189 N), and consistent sensory scores (87.63–93.28% acceptability), without significant differences among formulations. Molecular docking confirmed β-lactoglobulin’s tight antioxidant shielding and caseinate’s flexible bioavailability boost, yielding shelf-stable functional snacks that advance date palm valorization. The results demonstrate the successful development of functional MDBs with an excellent nutritional profile and strong panelist acceptance. Full article

To promote sustainable food production, the effective valorization of agricultural byproducts is essential. This study investigated the potential of underutilized chestnut inner skin (CIS) and thinned young persimmon fruit (YPF) extracts as functional ingredients in pudding gels, selected as a complex model system utilizing heat-induced egg gelation with milk and sugar. Puddings were prepared by replacing water with 10% or 50% CIS or YPF extracts. We comprehensively evaluated the physicochemical properties (texture, color, viscosity), microstructure (SEM), and sensory quality. Additionally, immunoreactive allergenic proteins (ovalbumin, casein, β-lactoglobulin) were quantified using ELISA, and antioxidant activity was measured via DPPH and H-ORAC assays. Results indicated that while high extract concentrations (50%) negatively impacted texture by increasing hardness and forming air pockets, the 10% YPF treatment yielded a smooth, homogeneous microstructure comparable to the control. Crucially, the 10% YPF extract significantly reduced the concentration of detectable allergenic proteins, attributed to the formation of insoluble tannin–protein complexes, without compromising sensory acceptance. Furthermore, the addition of these extracts significantly enhanced the antioxidant activity of the puddings in a concentration-dependent manner. These findings demonstrate that 10% YPF is a promising candidate for developing sustainable, hypoallergenic, and antioxidant-rich functional food products. Full article

During gastrointestinal digestion, dietary proteins are hydrolyzed into peptides and free amino acids that modulate enteroendocrine function and satiety-related hormone secretion along the gut–brain axis, thereby contributing to obesity prevention. We investigated whey protein concentrate (WPC) as a source of bioactive peptides and evaluated the effects of its digests on cholecystokinin (CCK) secretion in STC-1 enteroendocrine cells by integrating the standardized INFOGEST in vitro digestion protocol, peptidomics (LC–MS/MS), and in silico bioactivity prediction. In STC-1 cells, the <3 kDa intestinal peptide fraction exhibited the strongest CCK stimulation, positioning these low-molecular-weight peptides as promising bioactive components for satiety modulation and metabolic health applications. Peptidomic analysis of this fraction identified short sequences derived primarily from β-lactoglobulin (β-La) and α-lactalbumin (α-La), enriched in hydrophobic and aromatic residues, including neuropeptide-like sequences containing the Glu–Asn–Ser–Ala–Glu–Pro–Glu (ENSAEPE) motif of β-La f(108–114). In silico bioactivity profiling with MultiPep predicted antihypertensive, angiotensin-converting enzyme (ACE)–inhibitory, antidiabetic, dipeptidyl peptidase-IV (DPP-IV)–inhibitory, antioxidant, antibacterial, and neuropeptide-like activities. Overall, digestion of WPC released low-molecular-weight peptides and amino acids that enhanced CCK secretion in vitro; these findings support their potential use in nutritional strategies to enhance satiety, modulate appetite and energy intake, and improving cardiometabolic health. Full article

Cheese whey, the major by-product of the dairy industry, poses an environmental challenge due to its high organic load but simultaneously represents a nutrient-dense matrix suitable for biotechnological valorization. This review synthesizes recent advances positioning whey as (i) a fermentation substrate for lactic acid bacteria, yeasts/fungi, and microalgae, enabling the production of functional biomass, organic acids, bioethanol, exopolysaccharides, enzymes, and wastewater bioremediation; (ii) a platform for postbiotic generation, supporting cell-free preparations with functional activities; and (iii) a food-grade encapsulating material, particularly through whey proteins (β-lactoglobulin, α-lactalbumin), which can form emulsions, gels, and films that protect biotics and bioactive compounds during processing, storage, and gastrointestinal transit. We analyze key operational variables (whey type and pretreatment, supplementation strategies, batch and continuous cultivation modes), encapsulation routes (spray drying, freeze-drying, and hybrid protein–polysaccharide systems), and performance trade-offs relevant to industrial scale-up. Finally, we outline future directions, including precision fermentation, mixed-culture processes with in situ lactase activity, microfluidics-enabled encapsulation, and life-cycle assessment, to integrate product yields with environmental performance. Collectively, these strategies reframe whey from a high-impact waste into a circular bioeconomy resource for the food, nutraceutical, and environmental sectors. Full article

The prediction of polypeptide chain fragmentation during digestion (proteolysis) of protein substrates by trypsin was carried out for globular β-lactoglobulin (β-LG) and micellar β-casein (β-CN). Despite significant differences in the protein structures of these substrates, the concentrations of peptide fragments are calculated as functions of time or degree of hydrolysis using the same equations derived from the general proteolysis model. This model considers the opening of protein substrates in the course of proteolysis, the so-called demasking process, and the subsequent hydrolysis of specific peptide bonds at different rates determined by the amino acid sequence of hydrolyzed sites. The use of this model for in silico prediction of proteolysis is discussed. An algorithm for calculating demasking rate constants based on the experimental distribution of peptide fragments is presented. The calculated concentration dependence on the degree of hydrolysis of peptide bonds was compared with the experimental data for the intermediate and final peptide fragments of β-LG and β-CN. The predicted and experimental concentration curves for the final products were compared based on their curvatures. For both substrates, the predicted redistribution of peptide fragments in the course of proteolysis was found to be consistent with the experimental one. Full article

Low-flow liquid chromatography has become the primary tool for advanced chromatographic analysis and is an indispensable technique for the sensitive detection of biomolecules. In this study, we developed a new 4-tritylphenyl methacrylate-based monolithic nano-column with an internal diameter of 20 µm for bioanalytical separations in nano-liquid chromatography (nano-LC). The composition of the monolith was optimized with regard to the monomer and porogenic solvent. The column was characterized using Fourier Transformed Infrared Spectroscopy (FT-IR) spectroscopy, scanning electron microscopy (SEM) and chromatographic analyses. Chromatographic characterization was performed using homologous alkylbenzenes (ABs) and polyaromatic hydrocarbons (PAHs), which facilitate hydrophobic and π–π interactions. Run-to-run and column-to-column reproducibility values were found to be <2.51% and 2.4–3.2%, respectively. The final monolith was then used to separate six standard proteins, including β-lactoglobulin A, carbonic anhydrase, ribonuclease A (RNase A), α-chymotrypsinogen (α-chym), lysozyme (Lys), cytochrome C (Cyt C) and myoglobin (Myo), as well as three dipeptides: Alanine-tyrosine (Ala-Tyr), Glycine-phenylalanine (Gly-Phe) and L-carnosine. The nano-column was then applied to profiling peptides and proteins in the MCF-7 cell line, enabling high-resolution peptide analysis. Full article

Donkey milk is increasingly recognized as a functional food due to its unique nutritional profile and richness in bioactive compounds. This longitudinal observational study investigated changes in both chemical composition (total solids, protein, fat, lactose, and ash) and immune-active proteins (lactoferrin, α-lactalbumin, β-lactoglobulin, and lysozyme) across lactation. A total of 153 donkey milk samples were collected from five farms from very early (1–3 days in milk) to late lactation (30–210 days in milk). Chemical composition was determined using mid-infrared spectroscopy, while the concentrations of the immune-active proteins were determined by ELISA Quantitative Sandwich. Chemical analysis showed high values in colostrum, including total solids (10.13%), protein (3.1%), and ash (0.73%), which declined progressively during lactation to 8.45%, 1.14%, and 0.64%, respectively. Fat varied modestly, between 0.55 and 0.25%, while lactose remained stable at 5.75–6.41%. In parallel, bioactive proteins measured between 31 and 210 days exhibited distinct trajectories. Lactoferrin increased from 0.07 to 0.14 mg/mL, α-lactalbumin peaked mid-lactation at 2.58 mg/mL (compared with 1.91 mg/mL early and 2.25 mg/mL late), β-lactoglobulin declined from 0.84 to 0.55 mg/mL, and lysozyme decreased from 0.95 mg/mL early to 0.64 mg/mL late. Across lactation, we observed dilution of total solids and protein, relatively stable lactose and fat, and distinct trajectories of lactoferrin, α-lactalbumin, β-lactoglobulin, and lysozyme, indicating that donkey milk modulates rather than loses its protective protein profile. These results refine reference values for donkey milk and support its nutraceutical relevance for human nutrition and health. Full article

A common strategy for a protein’s functionality modification is the covalent binding of phenolic compounds (PCs) under alkaline conditions. Whether intentionally applied or arising during food processing and storage, such reactions are highly relevant, as alkaline pH promotes oxidation, covalent adduct formation, and polymerization, thereby altering both PC and protein properties. However, the interplay of these reactions and the impact of PC structure remain insufficiently understood. This study aimed at characterizing covalent binding products of structurally related PCs with tryptic peptides of the model protein β-lactoglobulin (β-Lg) at pH 9. Emphasis was given on substitution patterns and steric effects influencing polymerization and peptide adduct building. Hydroxycinnamic acid and flavonoid derivatives differing in hydroxyl substitution and carrying polar (glycosidic) groups were selected. Incubation products were characterized by HPLC–DAD and high-resolution mass spectrometry. Results showed that both mono- and dihydroxy PC undergo oxidation under alkaline conditions, but with distinct reactivity. Monohydroxy PCs form only limited peptide adducts due to resonance stabilization and steric hindrance. In contrast, dihydroxy PCs displayed a higher reactivity, producing more polymerization products and covalent adducts. Their enhanced reactivity is linked to the ability of quinone formation with reduced electrostatic repulsion, while additional polar substituents promote interactions with polar amino acids. At the same time, these substituents impose steric constraints on PC polymerization, modulating oligomer size and thereby influencing peptide binding. Overall, the findings highlight structural determinants of PC reactivity and provide mechanistic insight into the balance between polymerization and covalent peptide modification under alkaline conditions. Full article

Fermented mare’s milk, or koumiss, has been consumed for centuries across Central Asia for its nutritional and therapeutic value. Mare’s milk differs from bovine milk by its near 1:1 casein-to-whey ratio, high lysozyme and lactoferrin, abundant immunoglobulins, and low β-lactoglobulin, which enhance digestibility, reduce allergenicity, and increase antimicrobial activity. During fermentation, lactic acid bacteria and yeasts transform this substrate into a reservoir of bioactive proteins, peptides, and metabolites. Multi-omics profiling has identified more than 2300 peptides and over 350 metabolites, including sequences with angiotensin-converting enzyme (ACE)-inhibitory, antioxidant, antimicrobial, and immunomodulatory activities. Preclinical and limited clinical data indicate potential benefits for lipid metabolism, cardiovascular function, and gut health. Mechanistically, these effects appear to arise from synergistic actions of native proteins, fermentation-derived peptides, and probiotic consortia. Technological advances such as rational starter culture design, controlled proteolysis, and microencapsulation offer strategies to enhance bioactive yield and stability. However, standardized fermentation protocols and clinical validation remain necessary to position koumiss as a scientifically supported functional food. Full article

Bioactive peptides (BAPs) from dairy products have garnered increasing attention as natural agents with health-promoting properties, including antihypertensive, antioxidant, antimicrobial, immunomodulatory, opioid, and antidiabetic activities. This systematic review synthesizes research published between 2014 and 2024, retrieved from Scopus and PubMed, and selected according to PRISMA guidelines. A total of 192 studies met the inclusion criteria, collectively reporting over 3200 distinct peptides, with antihypertensive sequences, predominantly angiotensin-converting enzyme (ACE) inhibitors, constituting the largest category (n = 1237). β-casein was the principal precursor across bioactivities, followed by αs1-casein, β-lactoglobulin, and α-lactalbumin. Peptides were primarily produced via enzymatic hydrolysis, microbial fermentation, and gastrointestinal digestion, with peptide profiles influenced by the type of milk, microbial strains, and processing conditions. While cow’s milk remained the dominant source, investigations into goat, sheep, camel, buffalo, and donkey milk revealed species-specific biopeptides. Recent advances in proteomics have enhanced peptide identification and bioactivity prediction, enabling the discovery of novel sequences. These findings underscore the significant potential of dairy-derived BAPs as functional food components and nutraceutical ingredients, while highlighting the need for further in vivo validation, bioavailability studies, and broader exploration of underrepresented milk sources. Full article

β-lactoglobulin (β-Lg), the major whey protein containing nine lysine residues, serves as an ideal model for studying protein glycation and thermal processing safety in dairy products. This study systematically compared three different high-temperature treatment methods, namely superheated steam (SS), hot air (HA), and oil bath (OB), to investigate their effects on the spatial conformation and glycation product formation of proteins in the β-Lg-glucose system. The results show that compared with OB and HA, SS has a lower degree of glycation, lower consumption of free amino groups, and less unfolding of the protein’s three-dimensional structure. It leads to a lower proportion of α-helix transformation into β-sheet and random coil in the protein. SS resulted in the least browning and produced less 5-hydroxymethylfurfural, pentosidine, fluorescent advanced glycation end products, and melanogenin, yet produced the highest amount of Carboxymethyllysine. Mass spectrometry analysis shows that lysine residues were the primary glycation sites. Therefore, this work provides molecular-level insights into how different heating techniques modulate protein glycation and structural stability, supporting the potential of superheated steam as a gentler alternative to control glycation for β-Lg in food thermal processing. Full article

Background: β-lactoglobulin (BLG) is a protein found within whey protein (WP) that is rich in essential amino acids, most notably, leucine (LEU). LEU is considered the most potent EAA in the postprandial stimulation of muscle protein synthesis (MPS), such that suboptimal protein/essential amino acid (EAA) doses containing higher LEU content elicit muscle anabolism comparable to larger protein doses. Our objective was to test the effects of naturally LEU-rich BLG (~10 g protein) versus isonitrogenous whey protein isolate (WPI, ~10 g) on MPS. Methods: Ten healthy young men (26 ± 2 y; 179 ± 2 cm; 81 ± 3 kg) received BLG (1.57 g LEU) or WPI (1.02 g LEU) in a randomised double-blind cross-over fashion. A primed constant intravenous infusion of [1,2 ¹³C₂] LEU was used to determine MPS (isotope ratio mass spectrometry) at baseline and in response to feeding (FED) and feeding-plus-exercise (FED-EX; 6 × 8 unilateral leg extensions; 75% 1-RM). Plasma insulin and EAA’s were quantified. Results: Plasma EAA, branched-chain amino acid (BCAA), and LEU concentrations increased rapidly following both protein supplements but exhibited a significantly greater EAA/BCAA/leucinemia following BLG (p < 0.05 for all). MPS increased significantly in both FED (~52%) and FED-EX (~58%) states, with no significant differences between supplements. Conclusions: Both BLG and WPI effectively stimulated MPS doses in young healthy males, with BLG offering an advantage in EAA/BCAA/LEU bioavailability. It follows that future research should explore the potential of BLG in populations exhibiting anabolic resistance and exercise anabolism deficiency, such as older adults as well as frail and clinical populations, to assess its utility in preserving muscle mass under conditions of suboptimal protein intake. Full article