Antihypertensive effects of whey protein hydrolysate involve reshaping the gut microbiome in spontaneously hypertension rats

Novel angiotensin-converting enzyme(ACE)inhibitory peptides were identified from whey protein hydrolysates(WPH)in vitro in our previous study and the antihypertensive abilities of WPH in vivo were further investigated in the current study.Results indicated that WPH significantly inhibited the development of high blood pressure and tissue injuries caused by hypertension.WPH inhibited ACE activity(20.81%,P<0.01),and reduced renin concentration(P<0.05),thereby reducing systolic blood pressure(SBP)(12.63%,P<0.05)in spontaneously hypertensive rats.The increased Akkermansia,Bacteroides,and Lactobacillus abundance promoted high short chain fatty acid content in feces after WPH intervention.These changes jointly contributed to low blood pressure.The heart weight and cardiomyocyte injuries(hypertrophy and degeneration)were alleviated by WPH.The proteomic results revealed that 19 protein expressions in the heart mainly associated with the wingless/integrated(Wnt)signaling pathway and Apelin signaling pathway were altered after WPH supplementation.Notably,WPH alleviated serum oxidative stress,indicated by the decreased malondialdehyde content(P<0.01),enhanced total antioxidant capacity(P<0.01)and superoxide dismutase activity(P<0.01).The current study suggests that WPH exhibit promising antihypertensive abilities in vivo and could be a potential alternative for antihypertensive dietary supplements.

Differentially expressed whey proteins of donkey and bovine colostrum revealed with a label-free proteomics approach

This study aimed to analyze and compare the differentially expressed whey proteins(DEWPs)of donkey and bovine colostrum using high-performance liquid chromatography with tandem mass spectrometry-based proteomics.A total of 620 and 696 whey proteins were characterized in the donkey and bovine colostrum,respectively,including 383 common whey proteins.Among these common proteins,80 were identified as DEWPs,including 21 upregulated and 59 downregulated DEWPs in donkey colostrum compared to bovine colostrum.Gene Ontology analysis revealed that these DEWPs were mainly related to cellular components,such as extracellular exosome,plasma membrane,and mitochondrion;biological processes,such as oxidation-reduction process,cell-cell adhesion,and small guanosine triphosphate(GTP)ase-mediated signal transduction;and molecular functions,such as GTP binding,GTPase activity,and soluble N-ethylmaleimide-sensitive factor(NSF)attachment protein receptor activity.Metabolic pathway analysis suggested that the majority of the DEWPs were associated with soluble NSF factor attachment protein receptor interactions in vesicular transport,fatty acid biosynthesis,and estrogen signaling pathways.Our results provide a vital insight into the differences between donkey and bovine colostrum,along with important information on the significant components as nutritional and functional factors to be included in infant formula based on multiple milk sources.

Donkey whey proteins ameliorate dextran sulfate sodium-induced ulcerative colitis in mice by downregulating the S100A8-TRAF6-NF-κB axis-mediated inflammatory response

Donkey milk has a variety of physiological functions, including antibacterial and anti-inflammatory. Donkey whey proteins(DWPs), as the main functional component in donkey milk, its inhibitory effect on colitis is still unclear. In this study, the inhibitory effect and potential mechanism of DWPs on dextran sulfate sodium(DSS)-induced colitis were investigated. Firstly, the DWPs and bovine milk whey proteins(BWPs)were characterized using proteomics. Then, we administered DWPs and BWPs to mice with colitis via oral gavage. The results of immunohistochemistry and flow cytometry indicated that DWPs increased T regulatory cell accumulation and increased the abundance of the cluster of differentiation 205+(CD205+)macrophages compared to those with BWPs and in model groups. In addition, DWPs exhibited a more remarkable ability to inhibit pro-inflammatory proteins(S100A8, TRAF6, and NF-κB)expression and inflammatory secretion than BWPs. In addition, DWPs significantly decreased NF-κB and CD86 levels more than BWPs or the negative control in both LPS-stimulated human peripheral blood mononuclear cells or cell lines. These findings indicate that DWPs comprise a promising anti-colitis functional food, and this work has established a foundation for future research on these compounds.

Influence of particle size and ionic strength on the freeze-thaw stability of emulsions stabilized by whey protein isolate

The influence of particle size and ionic strength on the freeze-thaw(FT) stability of emulsions stabilized by whey protein isolate(WPI) was investigated in this study. The destabilization of emulsions during the FT process could be suppressed in a way by decreasing the particle size of the initial emulsions, which was the result of retarding the coalescence between oil droplets. To further improve the FT stability of emulsions, different amounts of Na Cl were added before emulsification. The emulsions with the ionic strength at 30–50 mmol/L exhibited good FT stability. Notably, the ionic strength in this range would not lower the freezing point of emulsions below the freezing temperature used in this study. Salt addition could improve the structural properties of proteins, which was available to strengthen the rigidity and thickness of interfacial layers, sequentially building up the resistance that the destruction of ice crystals to emulsions. Moreover, stronger flocculation between emulsion droplets could promote the formation of a gel-like network structure dominated by elasticity in the emulsion system, which might effectively inhibit the movement of droplets, and improve the FT stability of emulsions eventually. The result was of great significance for the preparation of emulsion-based foods with improved FT stability.

The Secondary Structure of Heated Whey Protein andIts Hydrolysates Antigenicity

Fourier transform infrared spectroscopy(FTIR) and circular dichroism(CD) were used to investigate the conformational changes of heated whey protein(WP) and the corresponding changes in the hydrolysates immunoreactivity were determined by competitive enzyme-linked immunosorbent assay(ELISA).Results showed that the contents of α-helix and β-sheet of WP did not decrease much under mild heating conditions and the antigenicity was relatively high;when the heating intensity increased(70 ℃ for 25 min or 75 ℃ for 20 min),the content of α-helix and β-sheet decreased to the minimum,so was the antigenicity;However,when the WP was heated at even higher temperature and for a longer time,the β-sheet associated with protein aggregation begun to increase and the antigenicity increased correspondingly.It was concluded that the conformations of heated WP and the antigenicity of its hydrolysates are related and the optimum structure for decreasing the hydrolysates antigeniity is the least content of α-helix and β-sheet.Establishing the relationship between the WP secondary structure and WP hydrolysates antigenicity is significant to supply the reference for antigenicity reduction by enzymolysis.

Amino acid fortified diets for weanling pigs replacing fish meal and whey protein concentrate:Effects on growth,immune status,and gut health

Background： Limited availability of fish meal and whey protein concentrate increases overall feed costs. Availability of increased number of supplemental amino acids including Lys, Met, Thr, Trp, Val, and lie allows replacing expensive protein supplements to reduce feed costs. This study was to evaluate the effect of replacing fish meal and/or whey protein concentrate in nursery diets with 6 supplemental amino acids on growth performance and gut health of post-weaning pigs. Treatments were 1） FM-WPC： diet with fish meal （FM） and whey protein concentrate （WPC）; 2） FM-AA： diet with FM and crystalline amino acids （L-Lys, L-Thr, L-Trp, DL-Met, L-Val, and L-lie）; 3） WPC-AA： diet with WPC and crystalline amino acid; and 4） AA： diet with crystalline amino acid. Results： Pigs in FM-AA, WPC-AA, and AA had greater （P 〈 0.0.5） ADG and gain：feed than pigs in FM-WPC during wk ] （phase 1）. Plasma insulin concentration of pigs in AA tended to be greater （P = 0.064） than that of FM-WPC at the end of wk 1 （phase 1）. Plasma concentrations of IgG in AA was lower （P 〈 0.05） compared with WPC-AA and FW, and FM-AA had lower （P 〈 0.05） IgG concentration than WPC-AA at the end of wk 1 （phase 1）. Concentration of acetate in cecum digesta in FM-AA tended to be greater （P = 0.054） than that of FM-WPC and WPC-AA. Concentration of isovalerate in cecum digesta of pigs in FM-AA was greater （P 〈 0.05） than that of FW and WPC-AA. Conclusions： This study indicates that use of 6 supplemental amino acids can replace fish meal and/or whey protein concentrate without adverse effects on growth performance, immune status, and gut health of pigs at d 21 to 49 of age. Positive response with the use of 6 supplemental amino acids in growth during the first week of post-weaning may due to increased plasma insulin potentially improving uptake of nutrients for protein synthesis and energy utilization. The replacement of fish meal and/or whey protein concentrate with 6 supplemental amino acids could decrease the crude protein level in nursery diets, and potentially lead to substantial cost savings in expensive nursery diets.

Effect of Partial Fat Replacement by Whey Protein, Oat, Wheat Germ and Modified Starch on Sensory Properties, Viscosity and Antioxidant Activity of Reduced Fat Ice Cream

Several studies are conducted to improve nutritional enrichment of ice cream. The aim of the present study was to produce healthy ice cream by partial replacement of fat with whey protein (WP), dietary fibers (oat (OT) and wheat germs (WG)) and modified starch (MS). Reduced fat ice cream (8% fat) was prepared as control. Healthy reduced fat ice cream was prepared by replacing 1% and 2% of fat with WP, OT, WG and MS. The fat replacement with OT and WG increased the fiber content of ice cream. In addition, ice cream from all treatments characterized by a significant great free radical scavenging activity when compared with control, especially when fat was replaced with WG, WP and OT, respectively. The sensory evaluation of ice cream revealed an enhancement of flavor when fat was replaced with 1% WP and OT and 2% WP (P < 0.05 vs. control). The modified starch treatments (1% and 2%) showed the highest viscosity followed by OT (2%) treatment (P < 0.05). In conclusion, these results showed that dietary fibers (OT & WG), WP and MS could be used to replace fat in ice cream and to give a healthy reduced fat ice cream with high fiber content and with high antioxidant activity.

New development of whey protein products as nutritional food ingredients

Whey protein products provided ideal ingredients for nutritional food applications.Whey proteins are known to have high nutritional quality due to their high content of essential amino acids,high digestibility and biological value.Research in the past decades has shown that many of the whey protein fractions and peptides derived from them possess various biological activities.The technology developments in the last decade,such as those in the areas of protein fractionation technologies have made industrial scale production of fractionated whey protein products commercially feasible.The development in hydrolysis technology and the peptide analytical capability allowed production of whey protein hydrolysates with designed bioactivity and functionalities.People are continuously finding new biological activities of the various whey protein fractions or their hydrolysis products.Significant amount of research has also been carried out to study the clinical benefits of some of the whey protein fractions and whey protein derived peptides.Examples of these studies will be reviewed and discussed.

Characterization of goat whey proteins and their bioactivity and toxicity assay

Goat whey is an industry-discarded dairy by-product that has interesting nutritional value and a nutrient composition with important functional potential,where proteins have a high biological value and play an important role in the organism’s physiology.Therefore,the aim of this study was to identify,quantify,concentrate and investigate the capacity of goat whey proteins to perform different biological activities and to evaluate their acute toxicity.Concentrated proteins were quantified and identified by Bradford,Kjehdal and SDS-PAGE methods.Antibacterial activity was performed against Listeria monocytogenes,Salmonella spp.,Staphylococcus aureus,Pseudomonas aeruginosa and Escherichia coli microorganisms and showed MIC ranging from 15 to 120μg mL-1,with the highest inhibition for L.monocytogenes growth.Antiproliferative activity was performed against human malignant melanoma cells and their proliferation inhibition was up to 66.8%within 72 h of exposure.The highest antioxidant capacity was obtained at concentration 2 mg that showed 29.69%of inhibition of DPPH radical oxidation.The acute toxicity test was performed using Artemia franciscana larvae in which whey proteins were able to preserve larval survival throughout exposure.Thus,we can conclude that goat’s whey has proteins that can play a positive effect on health,with antimicrobial activity and without toxicity.The present study highlights the great potential of goat’s whey to be developed as a safe biopreservative or as a functional ingredient in the food industry.

Gastrointestinal digestive fate of whey protein isolate coated liposomes loading astaxanthin:Lipolysis,release,and bioaccessibility

Whey protein isolate coated astaxanthin-loaded liposomes were prepared in this work.The gastrointestinal digestive fate of whey protein isolate coated astaxanthin-loaded liposomes was evaluated in terms of particle size,size distribution,zeta potential,and morphology during in vitro digestion as a function of time.Analysis on the particle size and morphology of whey protein isolate coated astaxanthin-loaded liposomes showed that the majority of particles maintained spherical shape with a progressive increase of particle size after passage through the digestion.The zeta potential on whey protein isolate coated astaxanthin-loaded liposomes became highly negative after digestion.As compared in uncoated liposomes,the astaxanthin release in whey protein isolate coated liposomes was slower in simulated gastric fluid digestion,while was faster in simulated intestinal fluid digestion.Through in vitro digestion,the bioaccessibility of astaxanthin was improved significantly after whey protein isolate coating.It was also found that the whey protein isolate coating could protect liposomes against destruction and suppress the lateral mobility of pyrene,resulting in lower micropolarity and fluidity of liposomal membrane during the digestion.These findings may guide the potential application of whey protein isolate coated liposomes for improving the bioaccessibility and stability of astaxanthin in nutraceuticals and pharmaceutics.

Microencapsulation of dodecyl acetate by complex coacervation of whey protein with acacia gum and its release behavior

Complex coacervation of whey protein（WP） with acacia gum（AG） was carried out in water with the presence of dodecyl acetate （DA）,a component of insect sex pheromones,in order to obtain microcapsules with DA as the core material and WP-AG coacervate as the wall materials.Through variations in wall/core ratios,concentrations of the wall materials in capsule preparations,DA encapsulation was optimized,which showed a high DA encapsulation was achieved when coacervation was conducted at pH 3.5 with wall/core mass ratio at 3 combined with concentration of wall materials at 1.0 wt%.Morphology and the structure of DA loaded microcapsules were examined by scanning electron microscope,which showed the microcapsules were of core/shell structure with DA encapsulated in the inner of the microcapsules.DA release was examined and the behavior of the release was discussed.

Functional properties of peptides obtained from whey proteins by ficin extract hydrolysis

Enzymatic whey proteins concentrates (WPC) hydrolysis under optimal conditions of ficin crude extract (FCE) in two ratios E/S (0.5 and 1%) was studied,assessing the impact of hydrolysis on WPC by determination degree of hydrolysis (DH),Fast proteins liquid chromatography (FPLC),Tricine SDS-PAGE,antioxidant activity at sampling time beside,and technological properties (solubility,emulsifying activity index (EAI) and foaming activity (FA)) at the best condition (maximum DH and antioxidant activity) other side.Results showed,in the first 30 min,DH reached 22.76% at E/S (1%) with a total degradation of α-lactalbumin (α-La) and almost of β-lactoglobulin (β-Lg).A significant increase in antioxidant activity and solubility was observed,while not for EAI,and FA.These results indicate for the first time that β-Lg is susceptible to hydrolyse by FCE that rarely found for other enzymes.Ficin hydrolysates showed very relevant performance,and suggest that could be appropriate production of functional ingredients.

Development and characterization of whey protein films incorporated with tarbush polyphenols and candelilla wax

Edible films were prepared with whey protein incorporating candelilla wax,and glycerol in aqueous solution.Tarbush polyphenols were added as bioactive agent.An optimization based on the water vapor permeability(WVP)of the formulation was performed using a Box-Behnken design.The films were characterized by the determination of WVP,moisture,solubility,color,antioxidant and antifungal activity.Scanning electron microscopy(SEM)was also performed to observe the surface and cross-section micrographs.The lowest permeability values were found with concentrations of 1.27,0.3 and 0.5% of protein,wax and glycerol respectively.It was proved that the addition of polyphenols into films causes a significant effect only on solubility and transparency characteristics.Edible films have suitable properties as a barrier for the goods they could be applied on.It is proposed for use in foods such as fresh or minimally processed fruits and vegetables.

A Protective Film Produced by Whey Protein for Photonic Crystals： Inspired by the Epidermis Structure of Chameleon

Self-assembly technology of sub-micrometer-sized colloidal particles is the most promising approach for the preparation of large-area Photonic Crystals （PCs）. However, PCs obtained by this method are facile to be destroyed by external factors such as friction, impact, and pollutants. The highly keratinized epidermis of chameleon skin acts as a protective role for the dermis with photon ceils of the tunable band-gap structure. Inspired by the epidermis structure of chameleon, we use whey protein to develop a sort of protective film on the surface of artificially synthesized PCs. The film possesses positive mechanical properties that make the PCs friction and impact re- sistant. In addition, favorable resistance to water and C02 could prevent PCs from being destroyed by pollutants. Consequently, PCs with protective film are well preserved when subjected to external factors （such as friction） and the optical properties of the PCs are successfully maintained, that may significantly promote the utilization of PCs in optical devices.

Changes in structure and functional properties of whey proteins induced by high hydrostatic pressure:A review

High hydrostatic pressure(HHP)is an alternative technology to heat processing for food product modifications.It does not cause environmental pollution and eliminates the use of chemical additives in food products.This review covers the research conducted to understand the effect of HHP on structure and functional properties of whey proteins.In this paper,the mechanism underlying pressure-induced changes inβ-lactoglobulin andα-lactabumin is also discussed and how they related to functional properties such as hydrophobicity,foam stability,and flavor-binding capacity.

Combination of microwave heating and transglutaminase cross-linking enhances the stability of limonene emulsion carried by whey protein isolate

In this study,we examined the effect of transglutaminase(TG)cross-linking time(0 h,2 h,4 h,8 h,and 12 h)on the stability of limonene emulsion loaded by microwave-heated WPI(MWPI).Size exclusion chromatography results showed that molecular weight of TG-treated MWPI and WPI was enhanced with the increase in TG cross-linking time(0–12 h).Microwave and TG cross-linking decreased particle size(7.55%)and increasedζ-potential(5.33%)and protein adsorption(4.58%)of WPI emulsion at TG cross-linking time of 12 h.CLSM results showed smaller droplet size of MWPI-TG emulsion and its uniform size.The obtained limonene emulsion loaded by MWPI-TG at 12 h showed the lowest creaming index and the strongest oxidative stability under aerobic conditions after 10th days of storage.Thus,the combination of microwave heating and TG cross-linking effectively enhanced the stability of limonene emulsion stabilized by WPI and facilitating the application of WPI in the fields of food,medicine,cosmetics,and other areas.

Physicochemical properties and antibacterial application of silver nanoparticles stabilized by whey protein isolate

Nano metal materials have been widely explored to be applied in medical,environmental,and material science.Among these nanoparticles,especially silver nanoparticles(AgNPs),have drawn increasing attention for antimicrobial applications.Most researchers are keen on the development of the biologically friendly capping reagents for the synthesis of AgNPs,instead of unfriendly organic polymers.In this study,the liquid chemical reduction method was used to synthesize AgNPs with edible whey protein isolate(WPI)as a capping reagent.These WPI-AgNPs had a broad size distribution(average diameter of 138.6 nm),and their dimensions could be readily controlled in the range of 22.5-149.6 nm by introducing different concentrations of chloride.Subsequently,it was confirmed that WPI-AgNPs were formed through two mechanisms,which were respectively reduced in situ(without the addition of NaCl)and ex situ(in presence of NaCl)to yield silver nanoparticles.The WPI-AgNPs synthesized in presence of 10 mM of NaCl as mediation reagent were stable at room temperature or 4℃ up to 3 months.Furthermore,the synthesized WPI-AgNPs had a good antibacterial activity toward pathogens including Gram-negative E.coli and Gram-positive S.aureus.The results shed light on method and capping reagent to stabilize silver nanoparticles,which highlighted the potential of WPI and chloride in metal nanoparticle synthesis.

Bioactives and extracts affect the physico-chemical properties of concentrated whey protein isolate dispersions

Non-covalent complexation interactions are known to occur between bioactive compounds and proteins. While formulating with these components can have positive outcomes such as stabilization of colors and actives, it can also result in changes to the structures and physical properties of proteins, affecting product functionality and sensory attributes. Previous experiments reported measurable changes in the physico-chemical properties of whey protein isolate (WPI) dispersions upon formulation with Aronia berry extract, ascribing changes to protein-polyphenol (PP) interactions in the systems. Pure gallotannin, beet extract, and cranberry extract, providing a diverse variety structures and sizes, were selected for further experimentation and comparison with the effects of Aronia extract. Concentrated dispersions with varying WPI:sucrose ratios, formulated with several bioactives contents from multiple different sources were analyzed to identify the effects of different bioactives on physico-chemical properties of dispersions. Dispersions formulated with cranberry extract demonstrated the largest increases in surface tensions, viscosities, and particle sizes, while those formulated with beet extract were the least affected by the presence of bioactives, suggesting that different bioactives and extracts had varying propensities for complexation interactions with WPI, despite their relatively low levels of addition (0, 0.5, and 1%).

Production of whey protein hydrolyzates and its incorporation into milk

Whey proteins provide an excellent source of low-molecular-weight bioactive peptides with important functional properties and bioactivities like antihypertensive,opioid,and antimicrobial effects.Presence of peptide molecules with lower molecular weight has a great role in food for health promotion.In this investigation,the release of low-molecular-weight peptides from whey protein concentrate was attempted by using enzymatic digestion.The hydrolyzate was then incorporated into milk to obtain enriched milk(EM)with low-molecular-weight peptides.Based on sensory analysis of EM,electrophoretic and RP-HPLC studies,hydrolyzates of 10%protein(degree of hydrolysis 5%;enzyme/substrate E/S,1:50)were finally incorporated into milk at 20%(v/v)to develop an acceptable product enriched with low-molecular-weight peptides.EM had higher protein content,viscosity and emulsifying properties than control milk with 3%fat.It is recommended that EM should not be sterilized as it results in coagulation,but can be safely pasteurized and spray dried without any undesirable effects.Maximum ACE-inhibition activity was obtained in hydrolyzate,followed by EM.This study is expected to boost the opportunity for the dairy industry to venture further into the nutraceutical dairy market.

Effects of Aronia polyphenols on the physico-chemical properties of whey,soy,and pea protein isolate dispersions

Bioactive compounds including polyphenols(PP)have been observed to naturally form non-covalent complexation interactions with proteins under mild pH and temperature conditions,affecting protein structures and functionality.Previously,addition of Aronia berry PP to liquid dispersions containing whey protein isolate(WPI)and sucrose was found to alter characteristics including viscosity,surface tension,and particle sizes,with changes being attributed to protein-PP interactions.In this study we aimed to investigate whether Aronia PP would interact with soy and pea protein isolates(SPI and PPI,respectively)to a similar extent as with WPI in liquid protein-sucrose-PP mixtures.We hypothesized that formulations containing PPI(comprised of larger proteins)and hydrolyzed SPI(containing more carboxyl groups)may exhibit increased viscosities and decreased aggregate sizes due to enhanced protein-PP interactions.Concentrated liquid dispersions of varied ratios of protein to sucrose contents,containing different protein isolates(WPI,SPI,and PPI),and varied Aronia PP concentrations were formulated,and physical properties were evaluated to elucidate the effects of PP addition.PP addition altered physical characteristics differently depending on the protein isolate used,with changes attributed to protein-PP interactions.SPI and PPI appeared to have higher propensities for PP interactions and exhibited more extensive shifts in physical properties than WPI formulations.These findings may be useful for practical applications such as formulating products containing fruit and proteins to obtain desirable sensory attributes.