Milk Peptides Research Articles

Anti-inflammatory effects of dietary β-Casein peptides and its peptide QEPVL in a DSS-induced inflammatory bowel disease mouse model

β-Casein (β-CN) can be a good source of bioactive peptides in milk. It has several beneficial bioactive components that have anti-inflammatory and immunomodulatory properties. However, it is still unclear which peptides offer the strongest anti-inflammatory properties. The purpose of this research is to contrast the anti-inflammatory activity to alleviate inflammatory bowel disease (IBD) symptoms of β-CN hydrolyzed peptide (BP) and Gln-Glu-Pro-Val-Leu (QEPVL) peptide from β-CN (QP). Currently, we used a dextran sodium sulfate (DSS)-induced inflammatory bowel disease mouse model to assess the anti-inflammatory activity of the dietary β-CN peptides and its peptide QEPVL. The results showed that BP and QP groups had anti-inflammatory effect on the recovery of mice with ulcerative colitis caused by DSS. Compared with the QP group, the BP group can better alleviate the pathological characteristics of mice and suppress the production of inflammatory cytokines and genes associated with the NLRP3/NF-κB signaling pathway. In addition, the BP group improved microbial biodiversity, especially for the level of intestinal microbiota, by enriching the abundance of Erysipelotrichaceae in Firmicutes. These results enhance our understanding of the differential anti-inflammatory effects between β-Casein peptides and its characteristic peptide QEPVL. And how they can alleviate intestinal inflammation by regulating intestinal microbiota.

Comprehensive species- and processing-specific peptide profiling of pasteurized, extended shelf-life and ultra-high temperature milk from cow, goat, sheep, buffalo, and mare

The present study aimed to identify endogenous milk peptides for species differentiation independent of heat exposure. Thus, comprehensive milk peptide profiles from five species and three types of heat treatments were analyzed by micro-flow liquid chromatography ion mobility quadrupole time-of-flight mass spectrometry (microLC-IM-QTOF) with subsequent database search leading to ≥ 3000 identified peptides. In the milks, 1154 peptides were unique for cow, 712 for sheep, 466 for goat, 197 for buffalo, and 69 for mare. Most peptides were detected in extended-shelf life (ESL) milk (2010), followed by ultra-high temperature (UHT) processed (1474) and pasteurized milk (1459 peptides), with 693 peptides present in all milk types. A blind test set of 64 samples confirmed eight species-specific, but heat-independent marker peptides in milk from cow, seven from goat, six from sheep, nine from buffalo, and three from mare. The generated peptide profiles can also be used to identify species- and heat-specific markers.

Bioaccessibility of novel antihypertensive short-chain peptides in goat milk using the INFOGEST static digestion model by effect-directed assays.

Short-chain peptides (SCPs, 2-4 amino acids) offer potential health benefits. A customized workflow was designed to screen SCPs in goat milk during INFOGEST digestion in vitro and 186 SCPs were preliminarily identified. Based on a two-terminal position numbering method and genetic algorithm combined with a support vector machine, 22 SCPs with predicted IC50 values less than 10μM were obtained using a quantitative structure-activity relationship (QSAR) model with satisfactory fitting and predictive capacity (R2, RMSE, Q2, and R2pre of 0.93, 0.27, 0.71, and 0.65, respectively). Four novel antihypertensive SCPs were confirmed by testing in vitro and molecular docking analysis, and their quantification results (0.06 to 1.53mg L-1) suggested distinct metabolic fates. This study facilitated the discovery of unknown potential food-derived antihypertensive peptides and the understanding of bioaccessible peptides during digestion.

Screening, Characterization, and Mechanistic Evaluation of Angiotensin Converting Enzyme Inhibitory Peptides Derived from Milk Fermented with Lactobacillus delbrueckii QS306 with and without Ultrahigh-Pressure Treatment.

In this study, the peptides in milk fermented with Lactobacillus delbrueckii QS306 with and without ultrahigh-pressure treatment were identified using UPLC-Q-exactive-HF-X-MS/MS. In total, 27 novel pentapeptides with potential angiotensin converting enzyme inhibitory (ACEI) activity were screened via bioinformatic analysis, and the activities of seven novel pentapeptides were assessed. Among them, HLPLP, PYPQR, and VAPFP exhibited better IC50 values. Stability assessment via in vitro simulation revealed that the three pentapeptides were significantly reduced (P < 0.05) during digestion but exhibited 85% activity after digestion. HLPLP was a competitive inhibitor, while PYPQR and VAPFP were noncompetitive inhibitors of ACE. Molecular docking indicated that the three peptides could stably bind to ACE. Molecular dynamics (MD) simulation and activity verification indicated that PYPQR and VAPFP had better stability and activity. This study demonstrated that novel ACEI pentapeptides in milk fermented with L. delbrueckii QS306 with and without ultrahigh-pressure treatment could be considered promising candidates for controlling hypertension.

Fingerprinting of Proteases, Protease Inhibitors and Indigenous Peptides in Human Milk.

The presence of proteases and their resulting level of activity on human milk (HM) proteins may aid in the generation of indigenous peptides as part of a pre-digestion process, of which some have potential bioactivity for the infant. The present study investigated the relative abundance of indigenous peptides and their cleavage products in relation to the abundance of observed proteases and protease inhibitors. The proteomes and peptidomes in twelve HM samples, representing six donors at lactation months 1 and 3, were profiled. In the proteome, 39 proteases and 29 protease inhibitors were identified in 2/3 of the samples. Cathepsin D was found to be present in higher abundance in the proteome compared with plasmin, while peptides originating from plasmin cleavage were more abundant than peptides from cathepsin D cleavage. As both proteases are present as a system of pro- and active- forms, their activation indexes were calculated. Plasmin was more active in lactation month 3 than month 1, which correlated with the total relative abundance of the cleavage product ascribed to plasmin. By searching the identified indigenous peptides in the milk bioactive peptide database, 283 peptides were ascribed to 10 groups of bioactivities. Antimicrobial peptides were significantly more abundant in month 1 than month 3; this group comprised 103 peptides, originating from the β-CN C-terminal region.

Effects of lactotripeptide ingestion and physical activity intervention on the fatigue status of middle-aged and older adults: a randomized controlled trial

This randomized controlled trial aimed to investigate the effects of eight weeks of lactotripeptide (LTP) ingestion, physical activity (PA) intervention, and combined intervention on the fatigue status of middle-aged and older adults. A total of 78 middle-aged and older adults (63 ± 8 years of age) were randomly assigned to four groups: placebo, LTP, placebo with PA intervention (placebo + PA), and LTP with PA intervention (LTP + PA). All participants ingested the placebo or LTP tablets daily (three tablets/day). The placebo + PA and LTP + PA groups participated in a weekly supervised exercise class and were instructed to increase their moderate- to vigorous-intensity PA at home. The visual analog scale, Brief Fatigue Inventory, Profile of Mood States second edition (POMS2), and Beck Depression Inventory second edition (BDI-II) were administered before and after the intervention. No significant interactions or main effects were observed between LTP ingestion and PA intervention on any of the fatigue scales. The main-effect analyses revealed that the PA intervention improved the total mood disturbance score of the POMS2 (F = 5.22, P = 0.03) and BDI-II score (F = 4.81, P = 0.03). After the post hoc paired comparisons, the total mood disturbance and BDI-II scores improved more with the combined intervention than with the PA intervention alone (percentage difference between the effect of combined intervention and PA intervention alone was 3.7% for total mood disturbance score and 13.7% for BDI-II score). The present study suggests that eight weeks of LTP ingestion and PA intervention did not have a significant effect on fatigue status. However, the PA intervention improved mood status and depressive symptoms, and these effects were enhanced by LTP ingestion.

Effect of Heat Treatment on Protein Self-Digestion in Ruminants' Milk.

This study investigated whether heat treatments (raw, 63 °C for 30 min, and 85 °C for 5 min) affect protein hydrolysis by endogenous enzymes in the milk of ruminants (bovine, ovine, and caprine) using a self-digestion model. Self-digestion consisted of the incubation for six hours at 37 °C of the ruminants' milk. Free amino group concentration was measured by the o-phthaldialdehyde method, and peptide sequences were identified by chromatography-mass spectrometry. Results showed that heat treatments prior to self-digestion decreased the free NH2 by 59% in bovine milk heated at 85 °C/5 min, and by 44 and 53% in caprine milk heated at 63 °C/30 min and 85 °C/5 min, respectively. However, after self-digestion, only new free amino groups were observed for the raw and heated at 63 °C/30 min milk. β-Casein was the most cleaved protein in the raw and heated at 63 °C/30 min bovine milk. A similar trend was observed in raw ovine and caprine milk. Self-digestion increased 6.8-fold the potential antithrombin peptides in the bovine milk heated at 63 °C/30 min. Enhancing bioactive peptide abundance through self-digestion has potential applications in the industry for functional products. Overall, heat treatments affected the free amino groups according to the species and heat treatment applied, which was reflected in the varying degrees of cleaved peptide bonds and peptides released during self-digestion.

Antimicrobial activity and stability evaluation of soap from caprine milk, yogurt, and kefir

Caprine milk is a nutraceutical source with various benefits for human health. The content of bioactive peptides in caprine milk has biological functions as an antioxidant, anti-inflammatory, and antimicrobial. Based on the benefits of caprine and its dairy products, we utilized them as the main ingredient for soap formulation. Stability evaluation is important to determine the shelf life and safety of the soap. This study aimed to examine the effect of different temperatures and storage time on the physical characteristic, pH level, heavy metal contents, and the antimicrobial activity of the soaps. We showed that the color and aroma of the soaps were relatively stable with a minor change in their hardness levels. The level of pH for all samples was around 7,00–8,70, which could be safely used on human skin. The level of heavy metal including Cd, Pb, and Hg were below the maximum standard allowed for the soap products. A little increase in the number of bacteria colonies were found when the soaps were stored at the longer durations. Based on the physical stability, pH level, heavy metal contents, and antimicrobial activity, these soaps might be safe for application on human skin.

Peptidomics approaches to the discovery and ACE inhibitory effect of casein peptides derived from fermented bovine milk by kefir grains

IntroductionKefir grains with efficient proteolytic system is an excellent starter culture for the production of bioactive peptides and milk products. This study explores the casein peptides derived from fermented bovine milk by kefir grains using the peptidomics approaches. The angiotensin converting enzyme (ACE) inhibitory activity of these peptides were also investigated.MethodsAfter fermentation, peptidomics based on the LC-MS/MS was used to investigate the dynamic profile and the structure specificity of generated peptides. The ACE inhibitory activity of peptides was determined by measuring the amount of hippuric acid (HA) by a spectrophotometer at 228 nm.ResultsThe results indicated that the cell envelope proteinases (CEPs) were the PI-/PIII-type. A total of 122 peptides were identified. The β-casein was preferentially hydrolyzed by kefir grains, and the main hydrolysis regions were f57-93, f132-160 and f192-209. The αs1-, and κ-casein were also hydrolyzed by a weaker degree. In the process of fermentation, the accumulated peptides increased with the fermentation time. The fermentation products exhibited ACE inhibitory activity, and this bioactivity remained 63% after simulated gastrointestinal (GI) digestion in vitro. Additionally, 14 Pro-containing peptides with ACE inhibitory activity were also identified.ConclusionThese results provide new insights and evidence to investigate the bioactive milk peptides generated by kefir grains fermentation, as well as a reference for the development of functional foods.

Influence of Complexation with β- and γ-Cyclodextrin on Bioactivity of Whey and Colostrum Peptides.

Dairy protein hydrolysates possess a broad spectrum of bioactivity and hypoallergenic properties, as well as pronounced bitter taste. The bitterness is reduced by complexing the proteolysis products with cyclodextrins (CDs), and it is also important to study the bioactivity of the peptides in inclusion complexes. Hydrolysates of whey and colostrum proteins with extensive hydrolysis degree and their complexes with β/γ-CD were obtained in the present study, and comprehensive comparative analysis of the experimental samples was performed. The interaction of CD with peptides was confirmed via different methods. Bioactivity of the initial hydrolysates and their complexes were evaluated. Antioxidant activity (AOA) was determined by fluorescence reduction of fluorescein in the Fenton system. Antigenic properties were studied by competitive enzyme immunoassay. Antimutagenic effect was estimated in the Ames test. According to the experimental data, a 2.17/2.78-fold and 1.45/2.14-fold increase in the AOA was found in the β/γ-CD interaction with whey and colostrum hydrolysates, respectively. A 5.6/5.3-fold decrease in the antigenicity of whey peptides in complex with β/γ-CD was detected, while the antimutagenic effect in the host-guest systems was comparable to the initial hydrolysates. Thus, bioactive CD complexes with dairy peptides were obtained. Complexes are applicable as a component of specialized foods (sports, diet).

Antifungal activity and identification of bioactive peptide from Etawa crossbreed goat (Capra hircus) milk protein hydrolyzed using trypsin enzyme

There had been a growing interest in biopreservation in recent years due to the increasing demand for food products that were free of synthetic preservatives and therefore safer to consume. This made it necessary to explore natural bioactive with antifungal properties that can inhibit microbial spoilage and extend shelf life. Etawa crossbreed goat milk (Capra hircus) peptide fraction has antifungal activity. Therefore, this study aimed to determine the peptide with antifungal activity resulting from the casein and whey proteins of goat milk hydrolysis by trypsin. The hydrolyzate was fractionated using a Strong Cationic Exchange (SCX) catridge and the antifungal activity test was performed against Aspergillus sp. using the disc diffusion method. The most active peptide fraction with the highest antifungal activity was identified using Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS). Based on the results, the ratio of the enzyme substrates used to hydrolyze casein and whey proteins is 1:10; 1:20; 1:30 and 1:40. The greatest degree of hydrolysis of casein and whey proteins was obtained at a 1:40 enzyme-substrate ratio of 66.8% and 75.4%, respectively. The analysis of Sodium Dodecylsulfate - Polyacrylamide Gel Electrophoresis (SDS PAGE) showed that goat milk casein contained αS1-casein and β-casein, while the whey proteins contained beta-lactoglobulin and α-lactalbumins. The casein and whey protein hydrolysates were fractionated using an SCX with pH variations of 3–9. The Goat Milk Casein (GMC) 5, 6, 7 dan 8 peptide fractions inhibited Aspergillus sp, and the most active was a fraction from GMC6 with an inhibition zone of 26.95 ± 0.63 mm and Minimum Inhibitory Concentration (MIC) value of 31.25 μg/mL. Furthermore, the morphology of Aspergillus sp. mycelia after treatment with peptide fraction showed that the mycelia were wrinkled and withered. The fractions with the highest antifungal activity contained 4 peptide sequences, namely YNVPQLEIVPK, KENNINELSK, GLSPEVPNENLLR, and YLGYLEQLLK. These results showed that peptide from goat milk had potential applications as a natural antifungal compound.

Effect of Bovine Milk Peptides on Cell Inflammation, Proliferation and Differentiation: Milk Potential Benefits Are Preserved in an Unconventional Cow Feeding Strategy.

Animal feeding through the reuse of agro-industrial by-products in one of the ultimate goals of sustainable agriculture. Olive oil pomace (OOP) produced as a waste product during olive oil milling has been used as an ingredient in the diet for Holstein lactating cows. Recent findings have shown no decrease in animal performance, feed intake or detrimental effect on rumen microbiota. In contrast, an improvement in C18 polyunsaturated fatty acids has been observed. In this work, the milk protein content from cows fed a commercial diet (CON) or an experimental one supplemented with OOP was determined and compared, and the peptides derived from the simulated gastrointestinal digestion of raw milk were analyzed. After fractionation via RP-HPLC, peptides were characterized for their biological activity on different cell lines. The ability to reduce both the intracellular ROS content and the expression of inflammatory markers, such as Cyclooxygenase, isoenzyme 2 (COX-2) and inducible Nitric Oxide Synthase (iNOS), as well as the remarkable properties to induce cell differentiation and to slow down the proliferation of human intestinal cancer cells, enable us to define them as bioactive peptides. In spite of there being no observed significant difference between the healthy activity of CON and OOP peptides, the results allow us to broaden the knowledge about the biological activity of these bioactive peptides and to confirm that agro-industrial by-products may be successfully incorporated into the feeding strategy of dairy cows.

Bioactive peptides in preterm human milk: Impact of maternal characteristics and their association to neonatal outcomes.

Human milk adipokines in term babies seem partially determined by maternal factors and affect infant's development. We aimed to describe bioactive peptide concentration in very preterm human milk and associations to maternal characteristics and postnatal growth. Mothers delivering ≤32 weeks of gestation and their infant/s were recruited. At 4 weeks of lactation, an aliquot of 24-h-pooled milk was collected for exclusively breastfeeding dyads. Insulin, leptin, adiponectin, and milk fat globule epidermal growth factor-8 (MFG-E8) were measured by enzyme-linked immunoabsorbent assay in skimmed milk. One hundred mothers (28.8 ± 2.3 weeks at delivery) provided a milk sample. Milk insulin was related to gestational age, pre-pregnancy body mass index (BMI), and galactagogue treatment (final model: adjusted R2 : 0.330, p < 0.0001; adjusted β coefficients: galactagogue treatment: 0.348, p 0.001; pre-pregnancy BMI: 0.274, p 0.009; gestational age: -0.290, p 0.007). Adiponectin was higher in mothers with gestational diabetes (30.7 ± 6.5 vs. 24.8 ± 8 ng/mL, p 0.044). Leptin was associated with pre-pregnancy BMI (Spearman's ρ: 0.648, p < 0.0001) and MFG-E8 to presence of labor and multiple pregnancy (final linear regression model, R2 : 0.073, p 0.028, adjusted β coefficients: presence of labor -0.229, p 0.050; twins: -0.192, p 0.099). Milk adiponectin was associated with a greater decrease in length z-scores from birth to 28 days (Pearson's r: -0.225, p 0.032) and to discharge (Pearson's r: -0.290, p 0.003). Milk MFG-E8 was lower in milk of mothers whose babies experienced late-onset sepsis (13.3 ± 5.8 vs. 16.8 ± 6.3 μg/mL, p 0.023). Adipokines levels in preterm human milk are partially related to maternal metabolic status. Milk peptide concentration associates with early neonatal growth trajectories.

Small polystyrene microplastics interfere with the breakdown of milk proteins during static in vitro simulated human gastric digestion

Human ingestion of microplastics (MPs) is common and inevitable due to the widespread contamination of food items, but implications on the gastric digestion of food proteins are still unknown. In this study, the interactions between pepsin and polystyrene (PS) MPs were evaluated by investigating enzyme activity and conformation in a simulated human gastric environment in the presence or absence of PS MPs. The impact on food digestion was also assessed by monitoring the kinetics of protein hydrolysis through static in vitro gastric digestion of cow's milk contaminated with PS. The binding of pepsin to PS showed that the surface chemistry of MPs dictates binding affinity. The key contributor to pepsin adsorption seems to be π−π interactions between the aromatic residues and the PS phenyl rings. During quick exposure (10 min) of pepsin to increasing concentrations (222, 2219, 22188 particles/mL) of 10 μm PS (PS10) and 100 μm PS (PS100), total enzymatic activities were not affected remarkably. However, upon prolonged exposure at 1 and 2 h, preferential binding of pepsin to the small, low zeta-potential PS caused structural changes in the protein which led to a significant reduction of its activity. Digestion of cow's milk mixed with PS10 resulted in transient accumulation of larger peptides (10–35 kDa) and reduced bioavailability of short peptides (2–9 kDa) in the gastric phase. This, however, was only observed at extremely high PS10 concentration (0.3 mg/mL or 5.46E+05 particles/mL). The digestion of milk peptides, bound preferentially over pepsin within the hard corona on the PS10 surface, was delayed up to 15 min in comparison to bulk protein digestion. Intact caseins, otherwise rapidly digested, remained bound to PS10 in the hard corona for up to 15 min. This work presents valuable insights regarding the interaction of MPs, food proteins, and pepsin, and their dynamics during gastric digestion.

Camel milk peptides alleviate hyperglycemia by regulating gut microbiota and metabolites in type 2 diabetic mice

This study aimed to investigate the hypoglycemic effect of Camel milk peptides (CMPs) on Type 2 diabetes mellitus (T2DM) mice and reveal its related mechanism from the aspect of gut microbiota and metabolites. The administering CMPs significantly alleviated the weight loss, polydipsia and polyphagia, reduced fasting blood glucose (FBG), improved insulin resistance and sensitivity, and restored the level of serum hormones, lipopolysaccharide (LPS), lipid metabolic and tissue damage. Furthermore, CMPs intervention remarkably reversed gut microbiota dysbiosis in T2DM mice by reducing the relative abundance of Proteobacteria, Allobaculum, Clostridium, Shigella and the Firmicutes/Bacteroidetes ratio, while increasing the relative abundance of Bacteroidetes and Blautia. Metabolomic analysis identified 84 different metabolites between T2DM and CMPs-treated groups, participating in three pathways of Pantothenate and CoA biosynthesis, Phenylalanine metabolism and Linoleic acid metabolism. Ureidopropionic acid, pantothenic acid, hippuric acid, hydrocinnamic acid and linoleic acid were identified as key acidic metabolites closely related to hypoglycemic effect. Correlation analysis indicated that CMPs might have a hypoglycemic effect through their impact on gut microbiota, leading to variations in short-chain fatty acids (SCFAs), acidic metabolites and metabolic pathways. These findings suggest that CMPs could be a beneficial nutritional supplement for intervention T2DM.

In vitro and in silico studies for the identification of anti-cancer and antibacterial peptides from camel milk protein hydrolysates.

Today, breast cancer and infectious diseases are very worrying that led to a widespread effort by researchers to discover natural remedies with no side effects to fight them. In the present study, we isolated camel milk protein fractions, casein and whey proteins, and hydrolyzed them using pepsin, trypsin, and both enzymes. Screening of peptides with anti-breast cancer and antibacterial activity against pathogens was performed. Peptides derived from whey protein fraction with the use of both enzymes showed very good activity against MCF-7 breast cancer with cell viability of 7.13%. The separate use of trypsin and pepsin to digest whey protein fraction yielded peptides with high antibacterial activity against S. aureus (inhibition zone of 4.17 ± 0.30 and 4.23 ± 0.32 cm, respectively) and E. coli (inhibition zone of 4.03 ± 0.15 and 4.03 ± 0.05 cm, respectively). Notably, in order to identify the effective peptides in camel milk, its protein sequences were retrieved and enzymatically digested in silico. Peptides that showed both anticancer and antibacterial properties and the highest stability in intestinal conditions were selected for the next step. Molecular interaction analysis was performed on specific receptors associated with breast cancer and/or antibacterial activity using molecular docking. The results showed that P3 (WNHIKRYF) and P5 (WSVGH) peptides had low binding energy and inhibition constant so that they specifically occupied active sites of protein targets. Our results introduced two peptide-drug candidates and new natural food additive that can be delivered to further animal and clinical trials.

Peptidomics analysis of human breast milk from women with postpartum depression reveals its potential pathogenesis.

Postpartum depression (PPD) is a prevalent psychiatric disorder during the postnatal period, and it exerts adverse impacts not only on mothers but also on infants, impairing the well-being of the whole family. However, the role of peptides in the breast milk of mothers with PPD has not been studied. The purpose of this study was to unveil the peptidomic profile of PPD from breast milk samples. We performed comparative peptidomic profiling of human breast milk from PPD and control mothers using liquid chromatography-tandem mass spectrometry technology with iTRAQ-8 labelling. GO and KEGG pathway analyses of precursor proteins were used to predict the underlying biological functions of differentially expressed peptides (DEPs). Ingenuity Pathway Analysis (IPA) was further performed to explore the interactions and involved pathways of DEPs. A total of 294 peptides from 62 precursor proteins were identified to be differentially expressed in the breast milk of PPD mothers compared with the control group. Bioinformatics analysis predicted that these DEPs were associated with ECM-receptor interaction, neuroactive ligand-receptor interaction, cell adhesion molecule binding and oxidative stress in macrophages. These results indicate that DEPs from human breast milk may play a part in PPD and become promising noninvasive biomarkers.

The role of lactic acid bacteria in production of bioactive peptides in fermented milk with antioxidant and antidiabetic properties

The role of lactic acid bacteria in production of bioactive peptides in fermented milk with antioxidant and antidiabetic properties

Advances in separation and identification of biologically important milk proteins and peptides.

Milk is a rich source of biologically important proteins and peptides. In addition, milk contains a variety of extracellular vesicles (EVs), including exosomes, that carry their own proteome cargo. EVs are essential for cell-cell communication and modulation of biological processes. They act as nature carriers of bioactive proteins/peptides in targeted delivery during various physiological and pathological conditions. Identification of the proteins and protein-derived peptides in milk and EVs and recognition of their biological activities and functions had a tremendous impact on food industry, medicine research, and clinical applications. Advanced separation methods, mass spectrometry (MS)-based proteomic approaches and innovative biostatistical procedures allowed for characterization of milk protein isoforms, genetic/splice variants, posttranslational modifications and their key roles, and contributed to novel discoveries. This review article discusses recently published developments in separation and identification of bioactive proteins/peptides from milk and milk EVs, including MS-based proteomic approaches.

Effects of Nitrogen Sources and Inorganic Salts on Antioxidant Activity of Goat Milk Fermented by Lactobacillus plantarum L60

Abstract This study investigated the effects of various nitrogen sources (peptone, casein hydrolysate) and inorganic salts (KH2PO4, MgSO4 and NaCl) on the antioxidant activity (specifically, DPPH and superoxide anion scavenging rate), acidity, and pH of peptides in goat milk (GM) fermented by Lactobacillus plantarum L60 by individual factor experiments. The results indicated that nitrogen sources and inorganic salts significantly affected L. plantarum L60’s antioxidant and acid-producing abilities, and when the supplemental levels of peptone, casein hydrolysate, KH2PO4, MgSO4 and NaCl were 0.7%, 0.3%, 0.3%, 0.15% and 0.9%, respectively, the scavenging ability of antioxidant peptides on DPPH radical and superoxide anion reached the maximum.