Physical processing offers opportunities to tailor dairy protein functionality, but useful conditions depend on the target function and matrix. This narrative review compares electric-field, pressure and ultrasound treatments through function-specific processing windows. In a 10% (m/v) whey protein concentrate dispersion, pulsed electric fields at 17-21 kV cm- 1 and 8-15 kJ L- 1 improved solubility and emulsion stability after drying. Other exposures weakened whey protein gels or increased casein peptide release despite reduced cellular uptake. Pressure and ultrasound similarly produced endpoint-specific gains. Soluble-protein recovery, function-limiting aggregation, casein colloidal stability and native activity provide operational markers for defining useful conditions and detecting functional loss. Most upper boundaries remain unmeasured, and a milk-protein processing window for induction-generated electric fields remains unresolved. Integrating delivered exposure, matrix composition and matched controls with final-product performance can guide the design of dairy protein ingredients.
To achieve high-value utilization of Yunnan rubing cheese by-products, xanthine oxidase (XOD) inhibitory peptides were prepared from rubing cheese whey via enzymatic hydrolysis and ultrafiltration. The ultrafiltration fractions (molecular weight < 3 kDa) exhibited relatively high in vitro XOD inhibitory activity, non-toxicity (0.0625-1.5 mg mL(-1) in HepG2 cells), and good stability in acid, alkali, heat and gastrointestinal simulations. Two novel peptides, FPGPIP and WSPWQ, were identified by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) with in-vitro and in-silico. Both peptides showed good hydrophobicity and XOD inhibitory activity. FPGPIP and WSPWQ, were selected with IC50 values of 0.93 mM and 0.88 mM. Fourier transform infrared (FTIR) spectroscopy analysis revealed that the secondary structures of FPGPIP and WSPWQ are mainly composed of beta-turn/beta-sheet conformations, which are crucial for the stability and activity of the peptides. Circular dichroism (CD) indicated that FPGPIP and WSPWQ can alter the secondary structure of XOD. Molecular docking demonstrated their binding to XOD's active sites through hydrogen bonding and hydrophobic interaction. Molecular dynamics analysis further showed that both peptides FPGPIP and WSPWQ could form stable complexes with XOD, thus exerting inhibitory effects and showing good stability. Network pharmacology further predicts that these peptides may exert uric acid-lowering effects through synergistic multi-target and multi-pathway mechanisms. This study demonstrates rubing cheese whey's potential as a sustainable source of uric acid-lowering peptides, offering insights for developing functional ingredients from dairy by-products.
Chechil is a traditional Armenian string cheese produced without defined commercial starter cultures by repeated heating and stretching of the curd, followed by salting and artisanal ripening. This study characterized its bacterial microbiome through amplicon-based metagenomic sequencing of five batches, four artisanal and one industrial, focusing on diversity, community structure, taxonomic composition, and inferred functional potential. Analyses revealed a strongly lactic acid bacteria (LAB)-centered community, with Firmicutes accounting for >97% of annotated OTUs. Lactobacillus helveticus was the dominant taxon (42.54% mean abundance), followed by Lactobacillus kefiranofaciens (23.22%) and Lactococcus cremoris (8.58% median abundance). Recurrent minor taxa included Lentilactobacillus kefiri, Streptococcus thermophilus, and Lactococcus piscium, alongside persistent environmental taxa. Predicted functions were dominated by carbohydrate and amino acid metabolism, fermentation, lipid metabolism, and cofactor and vitamin biosynthesis. These findings establish a microbiological baseline for Armenian Chechil and support future strain-level and functional studies.
Bacillus cereus-group isolates were screened for cereulide production and characterised under dairy-relevant conditions. Three cereulide-producing B. paranthracis ST26 panC III were identified (BC25, BC80 and BC149) with growth > 10 degrees C, and cereulide production between 13 and 40 degrees C, maximum 20 degrees C. Despite close genetic relatedness, toxin production varied: BC25 (maximum 11 mu g/mL) > BC80 (maximum 9.79 mu g/mL) > BC149 (maximum 5.47 mu g/mL) after 72 h in UHT cream at 20 degrees C, whereas BC149 grew the fastest. More cereulide was produced in static than shaken culture and optimum sporulation temperatures in UHT cream varied. Spore D-95 degrees C-values ranged from 1.38 to 2.31 min. Growth occurred at pH >= 4.7, and cereulide was produced at pH >= 5. Cereulide was produced in co-cultures with Pseudomonas and Enterococcus species and biofilm formation differed between isolates. Combined detergent and sanitiser treatments removed biofilms from surfaces. Robust, multi-layered manufacturing controls in dairy minimise cell growth and subsequent cereulide risk.
Casein-derived sleep-enhancing peptides (CSEPs) possess significant research value and development potential. This study utilized casein bromelain hydrolysate (CBH) as a base to compare the effects of fermentation with different probiotics on the hydrolysis characteristics, physicochemical properties, and sleep-enhancing activities of the resulting casein protease-microbial synergistic hydrolysate (CPMSH). CSEPs were further screened to elucidate their structure-activity relationships. The results showed that Lacticaseibacillus casei GL8072 exhibited strong proteolytic capacity, and the CPMSH produced by its fermentation demonstrated the most potent sleepenhancing effect. Structure-activity analysis indicates that small peptides of 500-1500 Da containing nonpolar residues such as Pro and Leu display higher bioactivity. Their N-termini commonly feature aromatic residues, while the C-termini are enriched in Gln, Arg, Leu, or sequences adjacent to Pro, forming key structural motifs. Notably, molecular docking suggests that CSEPs may share a benzodiazepine-like binding mode at the GABAA receptor.
