Bovine whey proteins – Overview on their main biological properties

Effects of Industrial Thermal Treatments on the Release of Bovine Colostrum Glycoprotein N-Glycans by Endo-β-N-acetylglucosaminidase

N-Glycans are structurally similar to human milk oligosaccharides, the gold standard prebiotics for infants. Bovine milk N-glycans released by endo-β-N-acetylglucosaminidase (EndoBI-1) were shown to have similar prebiotic selectivity as human milk oligosaccharides, explaining the interest for N-glycan recovery for use as prebiotics. Industrial thermal treatments such as high-temperature short-time (HTST) and ultra-high-temperature (UHT) might favor the enzymatic deglycosylation of N-glycans through promoting protein denaturation. We investigated the effects of HTST (72 °C for 15 s) and UHT (135 °C for 3 s) on N-glycan release from bovine colostrum glycoproteins by nonimmobilized and amino-immobilized EndoBI-1. A total of 104 N-glycans including isomers/anomers were identified by high-resolution mass spectrometry. In both EndoBI-1 forms, HTST increased the release of N-glycans; however, the impact of UHT on releasing N-glycans was comparable to the nonthermal treatment. Although the amino-immobilized enzyme similarly released neutral N-glycans as the free form, it released fewer sialylated and fucosylated N-glycans.

Isolation and Self-Association Studies of Beta-Lactoglobulin

The aim of this study was to investigate isolated β-lactoglobulin (β-LG) from the whey protein isolate (WPI) solution using the column chromatography with SP Sephadex. The physicochemical characterization (self-association, the pH stability in various salt solutions, the identification of oligomeric forms) of the protein obtained have been carried out. The electrophoretically pure β-LG fraction was obtained at pH 4.8. The fraction was characterized by the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/TOF MS) technique. The use of the HCCA matrix indicated the presence of oligomeric β-LG forms, while the SA and DHB matrices enabled the differentiation of A and B isoforms in the sample. The impact of sodium chloride, potassium chloride, ammonium sulfate, and sodium citrate in dispersion medium on β-LG electrophoretic stability in solution was also studied. Type of the dispersion medium led to the changes in the isoelectric point of protein. Sodium citrate stabilizes protein in comparison to ammonium sulfate. Additionally, the potential of capillary electrophoresis (CE) with UV detection using bare fused capillary to monitor β-LG oligomerization was discussed. Obtained CE data were further compared by the asymmetric flow field flow fractionation coupled with the multi-angle light scattering detector (AF4-MALS). It was shown that the β-LG is a monomer at pH 3.0, dimer at pH 7.0. At pH 5.0 (near the isoelectric point), oligomers with structures from dimeric to octameric are formed. However, the appearance of the oligomers equilibrium is dependent on the concentration of protein. The higher quantity of protein leads to the formation of the octamer. The far UV circular dichroism (CD) spectra carried out at pH 3.0, 5.0, and 7.0 confirmed that β-sheet conformation is dominant at pH 3.0, 5.0, while at pH 7.0, this conformation is approximately in the same quantity as α-helix and random structures.

Development of TaqMan PCR assay for detection of A and B variants of the bovine β-lactoglobulin

β-Lactoglobulin (BLG) is one of the prevalent whey protein in cattle. To date, several variants of bovine BLG have been found, but the most common are A and B, which differ from each other by SNPs rs109625649 and rs110066229. Numerous studies showed effects of A and B variants of BLG on milk yield, fat and protein content and cheese-making properties. To date, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), allele-specific polymerase chain reaction (ASPCR), PCR single-strand conformation polymorphism (PCR-SSCP) and high resolution melting (HRM) methods have been proposed for detection of A and B variants of bovine BLG. These methods involve multistep sample processing, which is an essential disadvantage in conducting large-scale cattle genotyping projects. This article describes a development of TaqMan PCR assay for detection of A and B variants (rs109625649) of bovine BLG. In this method a primer pair, initiating amplification of 101-bp fragment of BLG gene, and two allele-specific TaqMan probes are used. Identification of B and A variants of BLG is based on comparison of final fluorescence intensity of FAM and VIC dyes, respectively. The developed one-step method requires less time and is more suitable for large-scale genotyping of cattle compared to the commonly used PCR-RFLP.

Peptidome comparison following gastrointestinal digesta of bovine versus caprine milk serum

Infant formula is used as a supplement for newborns. Although bovine milk-based infant formulas dominate the market, caprine milk-based infant formula has attracted increasing attention because of its lower allergenicity. This study compared the digestive peptidome of bovine and caprine milk serum proteins by using in vitro infant simulating conditions. The result showed that the degradation pattern of milk proteins was similar, whereas the digestive rates of milk proteins differed between bovine and caprine milks. Several proteins, such as α-lactalbumin (LALBA), β-lactoglobulin (LGB), serum amyloid A protein (SAA1), glycosylation-dependent cell adhesion molecule 1 (GLYCAM1), and lactotransferrin (LTF), released more peptides during digestion of caprine milk serum than during digestion of bovine milk serum; however, more peptides derived from α_S1-casein (CSN1S1) were found in bovine digesta. In addition, antimicrobial-related peptides were mostly only found in caprine intestinal digesta. The results of this study may be useful in understanding the digestion characteristics of milk serum proteins and providing guidance on the improvement of infant formula.

Whey Proteins and Its Derivatives: Bioactivity, Functionality, and Current Applications

With the increased consumer demand for nutritional foods, it is important to develop value-added products, which will not only catch the attention of a wider consumer group but also provide greater benefits in terms of enhanced nutrition and functionality. Milk whey proteins are one of the most valued constituents due to their nutritional and techno-functional attributes. Whey proteins are rich in bioactive peptides, possessing bioactive properties such as being antioxidant and antihypertensive as well as having antimicrobial activities, which, when ingested, confers several health benefits. These peptides have the potential to be used as an active food ingredient in the production of functional foods. In addition to their bioactivities, whey proteins are known to possess enhanced functional attributes that allow them to be utilized in broad applications, such as an encapsulating agent or carrier materials to entrap bioactive compounds, emulsification, and in edible and active packaging. Hence, over the recent years, several whey protein-based ingredients have been developed and utilized in making formulations for a wide range of foods to harness their beneficial properties. This review highlights the bioactive properties, functional characteristics, associated processing limitations, and applications of different whey protein fractions and derivatives in the field of food formulations, encapsulation, and packaging.

Mildly Pasteurized Whey Protein Promotes Gut Tolerance in Immature Piglets Compared with Extensively Heated Whey Protein

Human milk is the optimal diet for infant development, but infant milk formula (IMF) must be available as an alternative. To develop high-quality IMF, bovine milk processing is required to ensure microbial safety and to obtain a protein composition that mimics human milk. However, processing can impact the quality of milk proteins, which can influence gastro-intestinal (GI) tolerance by changing digestion, transit time and/or absorption. The aim of this study was to evaluate the impact of structural changes of proteins due to thermal processing on gastro-intestinal tolerance in the immature GI tract. Preterm and near-term piglets received enteral nutrition based on whey protein concentrate (WPC) either mildly pasteurized (MP-WPC) or extensively heated (EH-WPC). Clinical symptoms, transit time and gastric residuals were evaluated. In addition, protein coagulation and protein composition of coagulates formed during in vitro digestion were analyzed in more detail. Characterization of MP-WPC and EH-WPC revealed that mild pasteurization maintained protein nativity and reduced aggregation of β-lactoglobulin and α-lactalbumin, relative to EH-WPC. Mild pasteurization reduced the formation of coagulates during digestion, resulting in reduced gastric residual volume and increased intestinal tract content. In addition, preterm piglets receiving MP-WPC showed reduced mucosal bacterial adherence in the proximal small intestine. Finally, in vitro digestion studies revealed less protein coagulation and lower levels of β-lactoglobulin and α-lactalbumin in the coagulates of MP-WPC compared with EH-WPC. In conclusion, minimal heat treatment of WPC compared with extensive heating promoted GI tolerance in immature piglets, implying that minimal heated WPC could improve the GI tolerance of milk formulas in infants.

Antimicrobials offered from nature: Peroxidase-catalyzed systems and their mimics

The control of antimicrobial resistance requires the development of novel antimicrobial alternatives and naturally occurring peroxidase-catalyzed systems may be of great value in this era of emerging antimicrobial resistance. In the peroxidase system, a peroxidase enzyme catalyzes the oxidation of a halide/pseudohalide, at the expense of hydrogen peroxide, to generate reactive products with broad antimicrobial properties. The appropriate use of peroxidase systems needs a better understanding of the identities and properties of the generated antimicrobial oxidants, specific targets in bacterial cells, their mode of action and the factors favoring or limiting their activity. Here, the ABCs (antibacterial activity, bacterial "backtalk" and cytotoxicity) of these systems and their mimics are discussed. Particular attention is paid to the concomitant use of thiocyanate and iodide dual substrates in peroxidase/peroxidase-free systems with implications on their antimicrobial activity. This review also provides a summary of actual applications of peroxidase systems as bio-preservatives in oral healthcare, milk industry, food/feed specialties and related products, mastitis and wound treatment; lastly, this review points to opportunities for further research and potential applications.

Milk whey from different animal species stimulates the in vitro release of CCK and GLP-1 through a whole simulated intestinal digestion

Milk whey is effective in enhancing satiety mainly due to its protein composition. Peptides and amino acids derived from digestion of whey protein can act as suppressants of appetite by stimulation of receptors of satiety gut hormones. But, the protein fraction of whey can vary depending on species of animal, season, lactation period, etc. The aim of this study is to evaluate the satiety effect of milk whey from different species of ruminants (cow, sheep, goat and a mixture of them) through a simulated in vitro digestion, which performed the whole gastrointestinal process, from oral digestion to colonic fermentation. The satiety effect of each sample was measured by the production of satiating hormones (CCK and GLP-1) secreted by enteroendocrine cell line (STC-1) after 2 hours of incubation with non-digested, digested and fermented whey. Digested samples have shown to be potent CCK and GLP-1 secretagogues followed by fermented and non-digested samples, showing that the last one showed a weak hormone stimulation. Digested goat whey was the most efficient stimulator of GLP-1 (86.33 ± 4.55 pg mL^-1) and fermented mixture whey produced the major release of CCK (80.78±1.81 pg mL^-1). This study demonstrates that milk whey is a suitable ingredient to stimulate satiety through the effect of peptides, amino acids produced from digestion, and metabolites released by fermentation.

Kinetic interactions of nanocomplexes between astaxanthin esters with different molecular structures and β-lactoglobulin

The influence of different fatty acid carbon chains on the kinetic interactions of nanocomplexes between esterified astaxanthin (E-Asta) and β-lactoglobulin (β-Lg) were investigated by multi-spectroscopy and molecular modeling techniques. We synthesized ten different E-Asta bound to β-Lg and formed nanocomplexes (< 300 nm). Fluorescence spectroscopy showed moderate affinities (binding constants Ka = 10³-10⁴ M^-1). Docosahexaenoic acid astaxanthin monoester (Asta-C22:6) had the strongest binding affinity towards β-Lg (Ka = 3.77 × 10⁴ M^-1). The fluorescence quenching of β-Lg upon binding of E-Asta displayed a static mechanism, with binding sites (n) equal to 1. Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectroscopy revealed that E-Asta might enter the β-Lg hydrophobic cavity, leading to unfolding of the peptide chain skeleton. In summary, β-Lg and E-Asta can form stable nanocomplex emulsions to achieve an effective delivery process for E-Asta.

Proteomic analysis of differentially expressed whey proteins in Guanzhong goat milk and Holstein cow milk by iTRAQ coupled with liquid chromatography-tandem mass spectrometry

Guanzhong goat and Holstein cow milk are the major milks supplied in China. Whey proteins play an important role in immune defense for newborn mammals. This study aimed to analyze the differentially expressed whey proteins of Guanzhong goat milk and Holstein cow milk by using isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics techniques. A total of 165 whey proteins were quantified, 114 of which differed significantly in abundance in goat and cow milks. According to the "up_keywords," in the online DAVID tool (https://david.ncifcrf.gov/home.jsp), 75% of these differentially expressed whey proteins were related to the category of "signal." Gene Ontology analyses classified these differentially expressed proteins into biological processes, cellular components, and molecular functions. The most common biological process was response to stress, the most common cellular component was related to extracellular region, and the most prevalent molecular function was binding. Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that these proteins were mainly involved in the complement and coagulation cascade pathways. The results improve our understanding of the different biological properties of whey proteins in goat and cow milks.

Whey for Sarcopenia; Can Whey Peptides, Hydrolysates or Proteins Play a Beneficial Role?

As the human body ages, skeletal muscle loses its mass and strength. It is estimated that in 10% of individuals over the age of 60, this muscle frailty has progressed to sarcopenia. Biomarkers of sarcopenia include increases in inflammatory markers and oxidative stress markers and decreases in muscle anabolic markers. Whey is a high-quality, easily digested dairy protein which is widely used in the sports industry. This review explores the evidence that whey protein, hydrolysates or peptides may have beneficial effects on sarcopenic biomarkers in myoblast cell lines, in aged rodents and in human dietary intervention trials with the older consumer. A daily dietary supplementation of 35 g of whey is likely to improve sarcopenic biomarkers in frail or sarcopenia individuals. Whey supplementation, consumed by an older, healthy adult certainly improves muscle mTOR signaling, but exercise appears to have the greatest benefit to older muscle. In vitro cellular assays are central for bioactive and bioavailable peptide identification and to determine their mechanism of action on ageing muscle.

Interactions of Whey Proteins with Metal Ions

Whey proteins tend to interact with metal ions, which have implications in different fields related to human life quality. There are two impacts of such interactions: they can provide opportunities for applications in food and nutraceuticals, but may lead to analytical challenges related to their study and outcomes for food processing, storage, and food interactions. Moreover, interactions of whey proteins with metal ions are complicated, requiring deep understanding, leading to consequences, such as metalloproteins, metallocomplexes, nanoparticles, or aggregates, creating a biologically active system. To understand the phenomena of metal-protein interactions, it is important to develop analytical approaches combined with studies of changes in the biological activity and to analyze the impact of such interactions on different fields. The aim of this review was to discuss chemistry of β-lactoglobulin, α-lactalbumin, and lactotransferrin, their interactions with different metal ions, analytical techniques used to study them and the implications for food and nutraceuticals.

Performance of oil-in-water emulsions stabilized by different types of surface-active components

The emulsion stability depends on the physicochemical properties of the dispersed phase and their interaction with the continuous phase. Surface-active compounds (SAC) are added in emulsions to reduce the interfacial tension (IT) between these phases and keep the oil droplets stabilized. Moreover, small amounts of SAC can occupy intermolecular voids in the dried matrix, reducing the oxidation. However, the formulation must reflect a trade-off between protection and emulsion stabilization. Therefore, this work aimed to identify the minimum concentration of SAC (modified starch-MS, gelatin-GE, and whey protein isolate-WPI) ranging from 0.48 to 6 % (w/w) to form and stabilize droplets of an unsaturated triglyceride (fish oil-FO) or a volatile oil (orange essential oil-OEO). GE did not change the IT (6.7 mN/m) and stabilized the emulsions only through an increase of the viscosity (∼42 mPas for FO-emulsions and ∼97 mPas for OEO-emulsions), presenting high droplet size (∼10 μm) and low surface charge (∼1.5 mV). WPI reduced the IT to a limit value (4.5 mN/m at 1.2 % w/w for OEO and 5.3 mN/m at 2.4 % w/w for FO), whereas MS reduce constantly the IT with the increase of the concentration for both oils (∼4.2 mN/m at 6 % w/w). Both WPI and MS-emulsions presented similar droplet size (∼2.0 μm), but WPI presented higher surface charge of WPI-emulsions (-45 mV) than MS-emulsions (-30 mV). This study allowed to gain a consistent understanding of structure-property relationships on the use of SAC in emulsions.

Influence of Protein Type on the Antimicrobial Activity of LAE Alone or in Combination with Methylparaben

The cationic surfactant Lauric arginate (LAE) has gained approval for utilization in meat products (limit: 200 mg/kg). However, as for other antimicrobials, its activity is reduced when applied to complex food matrices. The current study therefore aims to better understand protein-antimicrobial agent-interactions and their influence on the antimicrobial activity of (i) LAE and (ii) methylparaben against Listeria innocua and Pseudomonas fluorescens in defined model systems (pH 6). Antimicrobials were utilized alone or in combination with nutrient broth containing either no protein or 2% bovine serum albumin, whey protein isolate, or soy protein hydrolysate. LAE was found to form complexes with all proteins due to electrostatic attraction, determined using microelectrophoretic and turbidity measurements. Minimal lethal concentrations of LAE were remarkably increased (4-13 fold) in the presence of proteins, with globular proteins having the strongest impact. Combinations of LAE (0-200 µg/mL) with the less structure-sensitive component methylparaben (approved concentration 0.1%) remarkably decreased the concentrations of LAE needed to strongly inhibit or even kill both, L. innocua and P. fluorescens in the presence of proteins. The study highlights the importance of ingredient interactions impacting microbial activity that are often not taken into account when examining antimicrobial components having different structure sensitivities.

Comparison of a central location test versus a home usage test for consumer perception of ready-to-mix protein beverages

Ready-to-mix (RTM) whey protein beverages are an expanding product category, and sensory properties strongly affect consumer acceptance and purchase intent. Because consumers themselves prepare RTM whey protein beverages, understanding possible gaps between central location test (CLT) and home usage test (HUT) results is critical. The objectives of this study were to compare results obtained from a CLT and a HUT and to identify the drivers of liking and disliking vanilla-flavored RTM whey protein beverages. Fourteen commercial vanilla-flavored RTM whey protein beverages were rehydrated with spring water at 15% solids (wt/vol) and evaluated by a trained panel (n = 8). Ten representative products were selected for consumer testing. Rehydrated beverages were subsequently evaluated by protein beverage consumers (n = 160) in a CLT. Nine representative products were selected for the HUT. Consumers prepared and evaluated individual beverages over 3 consecutive weeks, trying 3 samples each week. Overall liking and other attributes were scored by consumers in both tests. Data were evaluated by univariate and multivariate statistical analyses. Overall liking scores from the HUT were higher than scores from the CLT. The products with the highest and lowest overall liking scores were consistent between the CLT and HUT. More differences were observed among beverages by CLT compared with HUT when liking was averaged across all consumers. Both methods identified 2 distinct consumer clusters. Fruity flavor and sweet taste were drivers of liking, whereas cardboard flavor and bitter taste were drivers of disliking in both methods. The HUT exclusively identified thickness (viscosity) as a driver of liking and astringency as a driver of disliking. These results suggest that a CLT can be used to differentiate consumer acceptance among vanilla-flavored RTM whey protein beverages. A HUT should be used to provide more intensive insights for mouthfeel and mixing experience-related attributes.

Chrysin-loaded bovine serum albumin particles as bioactive nanosupplements

Freeze-dried Chrys-loaded BSAnp retained their properties after reconstitution and induced apoptosis on breast cancer cells. BSAnp-70-11 (smallest sized) was the most cytotoxic system with a gastrointestinal release of 14% Chrys.

A complete picture of protein unfolding and refolding in surfactants

Interactions between proteins and surfactants are of relevance in many applications including food, washing powder formulations, and drug formulation. The anionic surfactant sodium dodecyl sulfate (SDS) is known to unfold globular proteins, while the non-ionic surfactant octaethyleneglycol monododecyl ether (C₁₂E₈) can be used to refold proteins from their SDS-denatured state. While unfolding have been studied in detail at the protein level, a complete picture of the interplay between protein and surfactant in these processes is lacking. This gap in our knowledge is addressed in the current work, using the β-sheet-rich globular protein β-lactoglobulin (bLG). We combined stopped-flow time-resolved SAXS, fluorescence, and circular dichroism, respectively, to provide an unprecedented in-depth picture of the different steps involved in both protein unfolding and refolding in the presence of SDS and C₁₂E₈. During unfolding, core-shell bLG-SDS complexes were formed within ∼10 ms. This involved an initial rapid process where protein and SDS formed aggregates, followed by two slower processes, where the complexes first disaggregated into single protein structures situated asymmetrically on the SDS micelles, followed by isotropic redistribution of the protein. Refolding kinetics (>100 s) were slower than unfolding (<30 s), and involved rearrangements within the mixing deadtime (∼5 ms) and transient accumulation of unfolded monomeric protein, differing in structure from the original bLG-SDS structure. Refolding of bLG involved two steps: extraction of most of the SDS from the complexes followed by protein refolding. These results reveal that surfactant-mediated unfolding and refolding of proteins are complex processes with rearrangements occurring on time scales from sub-milliseconds to minutes.

Cheese whey as potential resource for antimicrobial edible film and active packaging production

Many cheese manufacturers still have not utilized cheese whey that damages to the environment as it is directly been drained into waters. Cheese whey can be used as active packaging material to prolong the shelf-life of food products. Fermented cheese whey contains bioactive peptides which are able to improve the functional properties of cheese whey as an antimicrobial agent. The combination of cheese whey with polysaccharides, lipid, and other additional ingredients can improve the physical characteristics of the active packaging in the form of edible film. Around 20-45% of plasticizer will expose the film formed. Cheese whey with agro-industrial waste starch-based formulation can be used as an alternative way to produce an antimicrobial edible film as an active packaging. The film has shown acceptable physical characteristics and high antimicrobial activity, which makes it possible to extend the shelf life of food products. An advanced process, for example, the use of transglutaminase enzyme and Candida tropicalis mutant, is also effective. The result of that is the formation of the essential compound which can improve the active packaging quality. The utilisation of cheese whey and agro-industrial waste based on starch contributes significantly to the environmental conservation.

Cheese whey as potential resource for antimicrobial edible film and active packaging production

Many cheese manufacturers still have not utilized cheese whey that damages to the environment as it is directly been drained into waters. Cheese whey can be used as active packaging material to prolong the shelf-life of food products. Fermented cheese whey contains bioactive peptides which are able to improve the functional properties of cheese whey as an antimicrobial agent. The combination of cheese whey with polysaccharides, lipid, and other additional ingredients can improve the physical characteristics of the active packaging in the form of edible film. Around 20-45% of plasticizer will expose the film formed. Cheese whey with agro-industrial waste starch-based formulation can be used as an alternative way to produce an antimicrobial edible film as an active packaging. The film has shown acceptable physical characteristics and high antimicrobial activity, which makes it possible to extend the shelf life of food products. An advanced process, for example, the use of transglutaminase enzyme and Candida tropicalis mutant, is also effective. The result of that is the formation of the essential compound which can improve the active packaging quality. The utilisation of cheese whey and agro-industrial waste based on starch contributes significantly to the environmental conservation.

The structure of bovine β-lactoglobulin in crystals grown at pH 3.8 exhibiting novel threefold twinning

Bovine β-lactoglobulin was crystallized from 3 M NaCl buffered at pH 3.8 with sodium citrate as thick hexagonal prisms of greater than 1 mm in edge length. Analyses of the X-ray diffraction intensities using three different current algorithms were unanimous in specifying the space group to be P6322, with unit-cell dimensions a = b = 75.47, c = 140.79 Å. No progress could be made, however, towards an acceptable solution by molecular replacement using this symmetry. In the end, it was found that the true space group was C2221, a subgroup of P6322, with a = 65.89, b = 114.12, c = 140.51 Å, with the apparent 622 symmetry arising from an unusual threefold or tritohedral twinning. An assembly based on a model of the protein in another crystal form (PDB entry 1beb) containing three molecules in the asymmetric unit was refined to 2.3 Å resolution with a final R factor of 0.23 and Rfree of 0.26. NCS restraints were maintained throughout. For the most part, the molecules found in this crystal form are virtually the same as in PDB entry 1beb, although there are numerous local variations, particularly in loop elements, rotamer conformation differences and some alterations, including additions, at the termini.

Antihepatocarcinogenic activity of whey protein concentrate and lactoferrin in diethylnitrosamine-treated male albino mice

Hepatocellular carcinoma is considered one of the most prevalent and lethal malignancies worldwide. Chemotherapy with cytotoxic agents showed a low response rate with possible toxic effects. Recently, some emphases have been placed on the anticancer properties of bovine whey protein and its components, especially lactoferrin. The present study aimed to evaluate and compare the antihepatocarcinogenic activity of bovine whey protein concentrate (WPC, 300 and 600 mg/kg body weight) and lactoferrin (30 and 60 mg/kg body weight), orally and daily for 14 weeks, in the mice model of diethylnitrosamine (DEN)-induced hepatocarcinogenesis. The results showed that both WPC and lactoferrin (in a dose-dependent manner) alleviated significantly (P < .001) the elevation in serum markers of liver carcinoma and inflammation in the DEN-treated mice. Also, they exhibited a great amelioration in the livers' histological structure of the DEN-treated mice by 37.0% to 66.7%. In addition, they decreased significantly (P < .001) the hepatic DNA fragmentation in the DEN-treated mice by 23.1% to 32.7%. Only, the high doses of WPC and lactoferrin completely modulated the decrease in the activity of liver enzymic antioxidant defense system (catalase, glutathione peroxidase, and superoxide dismutase) and improved significantly (P < .01-.001) the concentration of hepatic reduced glutathione of the DEN-treated mice. Moreover, the high doses of WPC and lactoferrin reduced significantly (P < .05-.001) the elevation in the concentrations of hepatic active caspases 3, 8, and 9 of the DEN-treated mice. In conclusion, both WPC and lactoferrin were effective in inhibiting the hepatocarcinogenic activity of DEN in mice model through their ability to alleviate the hepatic inflammation and apoptosis.

Polymorphism association and expression analysis of alpha-lactalbumin (LALBA) gene during lactation in Nili Ravi buffalo

Alpha-lactalbumin has been reported as a highly polymorphic gene that potentially alters the gene expression and is associated with milk composition in dairy breeds. Current study was conducted in two phases. In the first phase, polymorphisms identification in alpha-lactalbumin (LALBA) gene and its association with milk composition was performed. To identify the genetic polymorphism, Nili Ravi buffaloes at their second lactation were selected from Government livestock farm (Buffalo Research Institute, Pattoki). Genomic DNA was extracted from blood samples. After PCR amplification, products were sequenced, and data was analyzed. Results showed that the identified polymorphisms at chromosomal position 34310940 were found associated with major whey protein. In the second phase of study, milk samples were collected from five healthy mastitis-free Nili Ravi buffaloes in their second lactation for expression analysis of alpha-lactalbumin gene at their transition (day 15), mid (day 90), and late (day 250) lactation. Gene expression was observed highest in transition phase with a gradual decrease of expression in mid and late phase of lactation. Further studies are needed to explore the regulation of milk production genes and their translational efficiency during the course of lactation.

Glycerol-Plasticized Films Obtained from Whey Proteins Denatured at Alkaline pH

Whey represents the major by-product of cheese industry. One possibility to recycle the whey wastes is the use of their globular proteins as a polymer source for the production of biodegradable plastic materials. Whey protein (WP)-based films are usually obtained by protein heat treatment in the presence of glycerol (GLY) as plasticizer at pH 7, a method which would require commercially high costing process. In this work we explored the possibility of producing manageable whey-derived materials without any heat-treatment but under alkaline conditions. The reported results demonstrated that the casting at pH 12 of the unheated WP film forming solutions (FFSs), containing either 40% or 50% GLY, led to produce more resistant and flexible materials than the ones obtained at pH 7. Film opacity was observed significantly increased, being higher in the samples obtained at alkaline pH without WP heating and with higher GLY concentrations. Finally, moisture content decreased with the reduction of GLY content, both in heated and unheated WP-based films, whereas water uptake of the different films prepared at pH 12 did not significantly change.

Characterization of physicochemical properties of casein mixture preparation extracted from organic milk for use as an emulsifier in organic processed foods

BACKGROUND

Sodium caseinate (SC) is not considered suitable for use as an emulsifier in organic processed food in the food industry because of the use of prohibited synthetic chemical substances during its production. Casein mixture preparation (CMP), one of the permissible substances specified in the regulations, was isolated from organic milk using citric acid and dibasic potassium phosphate for organic processed foods.

RESULTS

To compare CMP and SC, model emulsions stabilized with each substance were prepared at various concentrations and their physicochemical properties were analyzed. The emulsions' stability was determined using Turbiscan under various environmental stresses. The zeta potential of SC and CPM showed a high surface charge (≤ 30 mV) at all protein concentrations. Because the concentration of the protein preparation increased to 0.75% (w/v), the particle size of the CMP emulsion decreased with the surface load increased as much as that of SC. The CMP and SC emulsions were stable at neutral pH and room temperature. However, at acidic pH and high temperature, both emulsions were destabilized by creaming and flocculation and increased the creaming migration rates.

CONCLUSION

Overall, our data suggest the use of CMP as an emulsifier substitute for SC in organic processed foods. © 2018 Society of Chemical Industry.

Whey protein concentrate limits venous thrombosis in rats

To study the influence of whey protein concentrate (WPC-80) on the development of thrombosis, rats were supplemented with 2 doses of WPC-80 (0.3 or 0.5 g/kg) for 7, 14, or 21 days. Then, a 1-h venous thrombosis model was performed in half of the animals. Coagulation parameters, platelet count, and thrombus weight were assessed. Thrombus weight was decreased in rats obtaining WPC-80 and that was significant only for 14- and 21-day supplementation. There were slight differences between groups in coagulation parameters and platelet count but without evident direction. Further research is needed to clarify the observed effects.

Protein-Based Nanostructures for Food Applications

Proteins are receiving significant attention for the production of structures for the encapsulation of active compounds, aimed at their use in food products. Proteins are one of the most used biomaterials in the food industry due to their nutritional value, non-toxicity, biodegradability, and ability to create new textures, in particular, their ability to form gel particles that can go from macro- to nanoscale. This review points out the different techniques to obtain protein-based nanostructures and their use to encapsulate and release bioactive compounds, while also presenting some examples of food grade proteins, the mechanism of formation of the nanostructures, and the behavior under different conditions, such as in the gastrointestinal tract.

Characterization of a soy protein hydrolyzate for the development of a functional ingredient

Argentina is a leading country in biodiesel production from soy. Extruded soy is a low-cost byproduct of the soybean oil industry, from which animal feeds are prepared as well as flour for human consumption. Soy proteins can be isolated from flours and digested with enzymes in order to obtain bioactive fractions. In this work, a commercial soy isolate (PRO-FAM 974) was characterized. Maximal solubility was achieved at a concentration of 90 mg/mL. Protein profiles obtained by SDS-PAGE showed that the isolate was constituted mostly by globulins. Conformational and thermal analyses (differential scanning calorimetry) showed that proteins were almost completely denatured. The isolate was hydrolyzed with a commercially available enzyme (COROLASE 7089). The peptide profile (MALDI-TOF) showed peptides ranging from 800 to 10,000 Daltons. We conclude that the product obtained has the potential to be used as functional ingredient for the development of functional foodstuffs, giving the opportunity to add value to the byproducts of the soybean oil industry.

Evaluation of the osteoprotective potential of whey derived-antioxidative (YVEEL) and angiotensin-converting enzyme inhibitory (YLLF) bioactive peptides in ovariectomised rats

Milk contains various bioactive components with osteoanabolic properties. This study investigates the comparative effect of the whey-derived antioxidative (YVEEL) and angiotensin-converting enzyme inhibitory (YLLF) bioactive peptides on bone remodelling in ovariectomised (OVX) osteoporotic rat model. OVX animals were administered with antioxidative (AO) (500 μg kg-1 day-1) and angiotensin-converting enzyme inhibitory (ACE inhibitory) (50 μg kg-1 day-1) peptides for eight weeks. Trabecular microarchitectural parameters of femoral and tibiae bone were determined using micro-CT scan. Bone formation, resorption, turnover markers (ALP, RANKL, OCN) and inflammatory cytokines (TNF-α, TGF-β, IFN-γ) were determined by ELISA. Both AO and ACE inhibitory peptides inhibited the increase in bone turnover and inflammatory cytokines while increased the bone formation markers. The altered morphometric parameters of femoral and tibiae bones due to OVX were strikingly attenuated by the peptide administration. The results indicated that AO peptide exerts more osteoprotective potential than ACE inhibitory peptide by suppressing inflammatory status and enhancing bone formation markers.

Separation and Enrichment of Antioxidant Peptides from Whey Protein Isolate Hydrolysate by Aqueous Two-Phase Extraction and Aqueous Two-Phase Flotation

At present, peptides are separated by molecular exclusion chromatography and liquid chromatography. A separation method is needed in any case, which can be scaled up for industrial scale. In this study, aqueous two-phase extraction (ATPE) and aqueous two-phase flotation (ATPF) were applied to separate and enrich antioxidant peptides from trypsin hydrolysates of whey protein isolates (WPI). The best experimental conditions were investigated, and the results were evaluated using the 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) free radical scavenging activity of the peptides-per-unit concentration and the recovery rate (Y) of peptides in the top phase of both ATPE and ATPF. Under optimal conditions, the Y and ABTS free radical scavenging activity per unit concentration in top phase of ATPE could reach 38.75% and 12.94%, respectively, and in ATPF could reach 11.71% and 29.18%, respectively. The purified peptides were characterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and reversed-phase high-performance liquid chromatography (RP-HPLC). PeptideCutter and PeptideMass were applied to analyze and calculate the peptide sequencing. KILDKVGINYWLAHK, VGINYWLAHKALCSEK, and TPEVDDEALEKFDKALK sequences having antioxidant activity were detected in the top phase of ATPE, and VGINYWLAHKALCSEK, KILLDKVGINYWLAHK, ILLDKVGINYWLAHK, IIAEKTKIPAVFK, KIIAEKTKIPAVFK, and VYVEELKPTPEGDLEILLQK sequences having antioxidant activity were detected in the top phase of ATPF. In conclusion, antioxidant peptides were successfully separated from the WPI hydrolysate by ATPE and ATPF; compared with ATPE, ATPF has superior specificity in separating antioxidant peptides.

Identification of angiotensin converting enzyme and dipeptidyl peptidase-IV inhibitory peptides derived from oilseed proteins using two integrated bioinformatic approaches

Angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) play critical roles in the development of hypertension and type 2 diabetes, respectively. Inhibiting ACE and DPP-IV activity using peptides has become part of new therapeutic strategies for supporting medicinal treatment of both diseases. In this study, oilseed proteins, including soybean, flaxseed, rapeseed, sunflower and sesame are evaluated for the possibility of generating ACE and DPP-IV inhibitory peptides using different integrated bioinformatic approaches (UniProt knowledgebase, ProtParam, BLAST, BIOPEP, PeptideRanker, Pepsite2 and ToxinPred), and three bovine proteins (β-lactoglobulin, β-casein and κ-casein) as comparisons. Compared with bovine proteins, the potency indices of ACE and DPP-IV inhibitory peptides, calculated using the BIOPEP database, suggest that oilseed proteins may be considered as good precursors of ACE inhibitory peptides but generate a relative lower yield of DPP-IV inhibitory peptides following subtilisin, pepsin (pH = 1.3) or pepsin (pH > 2) hydrolysis. Average scores aligned using PeptideRanker confirmed oilseed proteins as significant potential sources of bioactive peptides: over 105 peptides scored over 0.8. Pepsite2 predicted that these peptides would largely bind via Gln281, His353, Lys511, His513, Tyr520 and Tyr523 of ACE to inhibit the enzyme, while Trp629 would be the predominant binding site of peptides in reducing DPP-IV activity. All peptides were capable of inhibiting ACE and DPP-IV whilst 65 of these 105 peptides are not currently recorded in BIOPEP database. In conclusion, our in silico study demonstrates that oilseed proteins could be considered as good precursors of ACE and DPP-IV inhibitory peptides as well as so far unexplored peptides that potentially have roles in ACE and DPP-IV inhibition and beyond.

Whey Protein Isolate-Supplemented Beverage, Fermented by Lactobacillus casei BL23 and Propionibacterium freudenreichii 138, in the Prevention of Mucositis in Mice

Mucositis is a clinically important gastrointestinal inflammatory infirmity, generated by antineoplastic drugs cytotoxic effects. The inflammatory process caused by this disease frequently leads to derangements in the alimentary tract and great malaise for the patient. Novel strategies are necessary for its prevention or treatment, as currently available treatments of mucositis have several limitations in relieving its symptoms. In this context, several research groups have investigated the use of probiotic bacteria, and in particular dairy bacterial strains. Compelling evidences reveal that milk fermented by certain probiotic bacteria has the capacity to ameliorate intestinal inflammatory disorders. In addition, innovative probiotic delivery strategies, based on probiotics incorporation into protective matrices, such as whey proteins, were able to increase the therapeutic effect of probiotic strains by providing extra protection for bacteria against environmental stresses. Therefore, in this study, we evaluated the role of the whey protein isolate (WPI), when added to skim milk fermented by Lactobacillus casei BL23 (L. casei BL23) or by Propionibacterium freudenreichii CIRM-BIA138 (P. freudenreichii 138), as a protective matrix against in vitro stress challenges. In addition, we investigated the therapeutic effect of these fermented beverages in a murine model of mucositis induced by 5-Fluorouracil (5-FU). Our results demonstrated that milk supplementation with 30% (w/v) of WPI increases the survival rate of both strains when challenged with acid, bile salts, high temperature and cold storage stresses, compared to fermented skim milk without the addition of WPI. Moreover, treatment with the probiotic beverages prevented weight loss and intestinal damages in mice receiving 5-FU. We conclude that the presence of WPI maximizes the anti-inflammatory effects of L. casei BL23, but not for P. freudenreichii 138, suggesting that whey protein enhancement of probiotic activity might be strain-dependent.

Fabrication and Characterization of β-Lactoglobulin-Based Nanocomplexes Composed of Chitosan Oligosaccharides as Vehicles for Delivery of Astaxanthin

Astaxanthin (Ax), a type of carotenoid, has limited use as a result of its poor water solubility, low bioavailability, and decomposition under harsh conditions. This study reports a delivery system for Ax through a simple affinity binding with β-lactoglobulin and then coated with chitosan oligosaccharides. Ax-loaded β-lactoglobulin nanocomplexes and chitosan oligosaccharide-coated nanocomplexes were successfully prepared. The nanocomplexes exhibited a smooth spherical shape with diameters of about 40 and 60 nm measured by transmission electron microscopy. Spectroscopic techniques (ultraviolet-visible, fluorescence, and Fourier transform infrared spectroscopy) combined with molecular docking were used to determine the binding mechanism of Ax and β-lactoglobulin. In comparison to native Ax, the nanocomplexes maintain the hydroxyl radical scavenging activity of Ax under the treatment of acid, high temperature, and ultraviolet radiation. The release experiment of nanocomplexes revealed that the encapsulation could provide prolonged release of Ax in simulated gastrointestinal juices. This study aimed to fabricate and characterize Ax-β-lactoglobulin nanocomplexes, which can improve the Ax stability and slow release.