Antioxidant, antihypertensive and antimicrobial properties of ovine milk caseinate hydrolyzed with a microbial protease

Molecular Cloning, Characterization, and Application of Organic Solvent-Stable and Detergent-Compatible Thermostable Alkaline Protease from Geobacillus thermoglucosidasius SKF4

Several thermostable proteases have been identified, yet only a handful have undergone the processes of cloning, comprehensive characterization, and full exploitation in various industrial applications. Our primary aim in this study was to clone a thermostable alkaline protease from a thermophilic bacterium and assess its potential for use in various industries. The research involved the amplification of the SpSKF4 protease gene, a thermostable alkaline serine protease obtained from the Geobacillus thermoglucosidasius SKF4 bacterium through polymerase chain reaction (PCR). The purified recombinant SpSKF4 protease was characterized, followed by evaluation of its possible industrial applications. The analysis of the gene sequence revealed an open reading frame (ORF) consisting of 1,206 bp, coding for a protein containing 401 amino acids. The cloned gene was expressed in Escherichia coli. The molecular weight of the enzyme was measured at 28 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The partially purified enzyme has its highest activity at a pH of 10 and a temperature of 80°C. In addition, the enzyme showed a half-life of 15 h at 80°C, and there was a 60% increase in its activity at 10 mM Ca2+ concentration. The activity of the protease was completely inhibited (100%) by phenylmethylsulfonyl fluoride (PMSF); however, the addition of sodium dodecyl sulfate (SDS) resulted in a 20% increase in activity. The enzyme was also stable in various organic solvents and in certain commercial detergents. Furthermore, the enzyme exhibited strong potential for industrial use, particularly as a detergent additive and for facilitating the recovery of silver from X-ray film.

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.

Unconventional microbial proteases as promising tools for the production of bioactive protein hydrolysates

Enzymatic hydrolysis is the most prominent strategy to release bioactive peptides from different food proteins and protein-rich by-products. Unconventional microbial proteases (UMPs) have gaining increased attention for such purposes, particularly from the 2010s. In this review, we present and discuss aspects related to UMPs production, and their use to obtain bioactive protein hydrolysates. Antioxidant and anti-hypertensive potentials, commonly evaluated through in vitro testing, are mainly reported. The in vivo bioactivities of protein hydrolysates and peptides produced through UMPs action are highlighted. In addition to bioactivities, enzymatic hydrolysis acts by modulating the functional properties of proteins for potential food uses. The compiled literature indicates that UMPs are promising biocatalysts to generate bioactive protein hydrolysates, adding up to commercially available enzymes. From the recent interest on this topic, continuous and in-depth research is needed to advance toward the applicability and commercial utility of both UMPs and obtained hydrolysates.

Single and Co-Cultures of Proteolytic Lactic Acid Bacteria in the Manufacture of Fermented Milk with High ACE Inhibitory and Antioxidant Activities

In this study, single and co-cultures of proteolytic Lactobacillus delberueckii subsp. bulgaricus ORT2, Limosilactobacillus reuteri SRM2 and Lactococcus lactis subsp. lactis BRM3 isolated from different raw milk samples were applied as starter cultures to manufacture functional fermented milks. Peptide extracts from fermented milk samples were evaluated after fermentation and 7 days of cold storage for proteolytic, angiotensin-converting enzyme (ACE) inhibitory and antioxidant activity by different methods including 2, 2′-diphenyl-1-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP), OH-radical scavenging, and total antioxidant (molybdate-reducing activity). The highest proteolysis was found in milk fermented by co-cultures of three strains. Fermentation with the mentioned bacteria increased ACE inhibitory and antioxidant activity of the final products which were dependent on peptide concentration. The crude peptide extract obtained from fermented milk with triple co-culture showed the highest ACE inhibitory activity (IC50 = 0.61 mg/mL) which was reduced after 7 days of cold storage (IC50 = 0.78 mg/mL). Similar concentration-dependent activities were found in antioxidant activity at different antioxidant assays. Overall, high proteolytic activity resulted in increased ACE inhibitory and antioxidant activities, but the highest activity was not necessarily found for the samples with the highest proteolytic activity. The results of this study suggest the potential of using co-cultures of L. delberueckii subsp. bulgaricus, L. reuteri and L. lactis subsp. Lactis to manufacture antihypertensive fermented milk.

An integrated approach to the analysis of antioxidative peptides derived from Gouda cheese with a modified β-casein content

This study is the first to present an integrated approach involving in silico and in vitro protocols that was pursued to analyse an antioxidative potency of Gouda cheese with modified content of β-casein. Firstly, the predictions of the presence of antioxidant peptides in the casein sequences were computed using the BIOPEP-UWM database. Then, the antioxidative bioactivity of six variants of Gouda cheese (with reduced, normative, and increased content of β-casein at the initial and final stage of ripening) was assessed. Finally, the RP-HPLC–MS/MS was applied to identify antioxidative peptides in Gouda-derived water-soluble extracts (WSEs). Analyses were supported with the heatmaps and the computation of parameters describing the efficiency of proteolysis of caseins in the modified Gouda cheeses, i.e., the frequency and the relative frequency of the release of antioxidative fragments during cheese ripening (A_Eexp and W_exp., respectively). All Gouda cheese variants exhibited the antioxidative potential which differed depending on the assay employed. The highest antioxidative activity (ABTS^·+ radical scavenging effect, FRAP, and Fe-chelating) was observed for WSEs derived from Gouda cheese with increased content of β-casein after the 60th day of ripening. The results obtained suggest the potential of Gouda cheese as the antioxidant-promoting food.

Evaluating the effect of conjugation on the bioactivities of whey protein hydrolysates

In this study, the ability of a whey protein hydrolysate to exhibit the antimicrobial, antioxidant, and antihypertensive behavior after combining with a reducing carbohydrate was studied. Whey protein hydrolysates with varying degrees of hydrolysis (WPH10, WPH15, and WPH20) were determined for their antimicrobial, antioxidant, and antihypertensive activities. Of these, hydrolysate (WPH10) exhibited the highest antimicrobial activity (with 10-11.2 mm zone of inhibition) against tested microorganisms: Listeria innocua, Staphylococcus aureus, and Bacillus coagulans. Also, the WPH10 exhibited the highest antioxidant (866.56 TEAC µmol/L) and antihypertensive (67.52%) attributes. Hence, based on the highest bioactivity, hydrolysate WPH10 was selected for conjugation with maltodextrin, and the effect of conjugation on the bioactivities was evaluated. The conjugated WPH10 solution demonstrated higher antimicrobial (17.16 mm) and antioxidant activity (1044.37 TEAC µmol/L), whereas a slight decrease in the antihypertensive activity (65.4%) was observed, as compared to WPH10 alone. The conjugated solution was further spray dried and alternatively, freeze-dried. The dried WPH10 conjugate exhibited even higher antimicrobial (18.5 mm) and antioxidant activity (1268.89 TEAC µmol/L) while retaining the antihypertensive activity (65.6%). Overall, the results indicate the ability of the WPH10-maltodextrin to retain the bioactive behavior after combining with a reduced carbohydrate. PRACTICAL APPLICATION: Whey protein hydrolysates upon conjugation with carbohydrates retain the bioactive properties of whey protein, which provides opportunities for application as an ingredient to develop novel health formulations.

Anti-inflammatory and Antioxidant Activity of Peptides From Ethanol-Soluble Hydrolysates of Sturgeon (Acipenser schrenckii) Cartilage

Research has shown that cartilage containing chondroitin sulfate and protein presents versatile bioactivities. Chondroitin sulfate in cartilage is beneficial to activate the immune system while the protein/peptide has not been fully understood. The current study investigated the antioxidant and anti-inflammatory properties of ethanol-soluble hydrolysates of sturgeon cartilage (ESCH) prepared through hot-pressure, enzymatic hydrolysis and ethanol extraction. UV spectrum, IR and agarose gel electrophoresis results suggested the successful exclusion of chondroitin sulfate from peptides. Nitric oxide (NO) floods in cells activated by inflammation. It was inhibited when administrated with ESCH. To further explain the observed anti-inflammatory activity, ESCH was separated with Sephadex G-15 into 3 components, among which F3 showed a higher NO inhibition rate and significantly reduced the production of the proinflammatory cytokine IL-6. In addition, the yield of IL-10 increased. Western blotting suggested that F3 downregulated the NO content and IL-6 level by suppressing Mitogen-activated protein kinases (MAPK) channels. Moreover, both ESCH and F3 showed DPPH and ABTS free radical scavenging abilities which was possibly related to the anti-inflammatory property. These results indicated that ESCH behaved anti-inflammatory and antioxidant activities. Cartilage may be a good source to produce anti-inflammatory peptides.

The effect of grape seed protein hydrolysate on the properties of stirred yogurt and viability of Lactobacillus casei in it

In this study, the effect of grape seed protein hydrolysate (GPH) on the physicochemical and sensory properties of stirred yogurt was evaluated. At first, the antioxidant properties and degree of hydrolysis (DH) of GPH were determined using the microbial protease enzymes (alcalase and flavourzyme), the results showed that alcalase enzyme can produce GPH with higher DH and antioxidant properties (p < .05). Also, increasing the hydrolysis time had a positive effect on these properties (p < .05). The DH, free radical scavenging DPPH, and ferric reducing power for GPH by alcalase at 30 min was 21.51%, 88.68%, and 0.33 μmol ferrous/ g, respectively. Therefore, this treatment was used for further experiments. In the next part, the mentioned GPH was added to the stirred yogurt with three concentrations (0.5, 1.5, and 1.5%) and physicochemical properties and viability of Lactobacillus casei and sensory properties were measured during 15 days of storage. The results showed that the GPH treatment had higher pH, viscosity, and texture firmness and less acidity and syneresis compared with the control sample (p < .05). Also, in these samples, the decreasing trend of L. casei viability was slower than the control treatment during the storage period (p < .05). In most parameters, better results were observed with increasing the concentration GPH and all the treatments were acceptable in terms of sensory properties. Therefore, by producing yogurt containing GPH, a new functional food can be provided for consumers of dairy products, which in addition to the desired taste, good nutritional properties can be also achieved from its consumption.

A comprehensive review on bioactive peptides derived from milk and milk products of minor dairy species

Abstract

Milk from different species has been exploited for the isolation of various functional ingredients for decades. Irrespective of the source, milk is considered as a complete food, as it provides essential nutrients required by the human body. Proteins and their fractions are valuable sources of bioactive peptides that might exert a health beneficial role in the human body such as immune-modulation, antioxidant activity, ACE-inhibitory activity, anti-neoplastic, anti-microbial, etc. In milk, bioactive peptides may either be present in their natural form or released from their parental proteins due to enzymatic action. The increasing interest in bioactive peptides among researchers has lately augmented the exploration of minor dairy species such as sheep, goat, camel, mithun, mare, and donkey. Alternative to cow, milk from minor dairy species have also been proven to be healthier from infancy to older age owing to their higher digestibility and other nutritive components. Therefore, realizing the significance of milk from such species and incentivized interest towards the derivatization of bioactive peptides, the present review highlights the significant research achievements on bioactive peptides from milk and milk products of minor dairy species.

Graphical abstract

Performance of Black Bengal goat: a 50-year review

Black Bengal goat (BBG) is the most widely recognized legacy goat breed in Bangladesh. The breed is black in color yet likewise earthy, white, or dim colors additionally found. The breed has medium body size with grown-up weight 25-30 kg, little horns, short legs, and tight body structure. The BBG is one of the most compliant, all around adjusted, early maturing, prolific, productive, and tropical disease-resistant goat types of the world that produces incredible quality meat, milk, and skin. The breed is versatile in hot, moist, cruel, climatic conditions and flourishes well on a cacophonous dietary regimen from uncultivable decrepit grounds, residences, riversides, banks, sloping, and hilly territories where crop culture or dairy nourishing is inconceivable. In Bangladesh, the BBG is one of the main red meat-producing small ruminants which shares remarkable local interest during Eid-Ul-Adha, Eid-Ul-Fitr, wedding ceremony, birthday festival, circumcision, memorial programs, and other social celebrations with no social, cultural, and religious limitations. Being little in size, the BBG has been an amazing asset to advance supportable vocations for the negligible, little, and landless ranchers who rely upon free regular grazing lands for raising domesticated animals. Regardless of incredibly exceptional components and features, the production of BBG has not yet been popularized widely since meager consideration has been paid for improving their efficiency. Development of cutting edge hereditary, dietary, and health as well as disease control procedure and utilization of modern management frameworks may procure considerable changes in improving the overall performance of the BBG.

Dromedary Milk Protein Hydrolysates Show Enhanced Antioxidant and Functional Properties

Research background

Milk protein hydrolysates have received particular attention due to their health-promoting effects. Dromedary milk differs from the milk of other dairy animals in the composition and structure of its protein components, which give it unique properties. The bioactivity and functionality of whole dromedary milk proteins and their enzymatic hydrolysates have not received much attention, hence this study aims to investigate the effect of enzymatic hydrolysis of dromedary milk proteins on their antioxidant activities and functional properties.

Experimental approach

Dromedary milk proteins were treated using four proteolytic enzymes (pepsin, trypsin, α-chymotrypsin and papain) and two mixtures of enzymes (pancreatin and pronase). The degree of hydrolysis was measured to verify the hydrolysis of the proteins. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography served to determine the molecular mass distribution of the hydrolysates while reversed phase-high performance liquid chromatography (RP-HPLC) was conducted to explore their hydrophobicity. The antioxidant activities were evaluated using various in vitro tests, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging capacities, iron(III) reducing ability and chelating activity. Besides, functional properties such as solubility, foaming and emulsification were assessed.

Results and conclusions

Dromedary milk protein hydrolysates exhibited different degrees of hydrolysis ranging from 17.69 to 41.86%. Apart from that, the hydrolysates showed different electrophoretic patterns, molecular mass distribution and RP-HPLC profiles demonstrating the heterogeneity of the resulting peptides in terms of molecular mass and polarity. The hydrolysates displayed significantly higher antioxidant capacities than the undigested proteins at all the tested concentrations. Iron(II) chelating activity was the most improved assay after proteolysis and the hydrolysate generated with pancreatin had the highest chelating power. Dromedary milk protein hydrolysates possessed good solubility (>89%). Further, foaming and emulsifying properties of dromedary milk proteins were enhanced after their proteolysis. These interfacial properties were influenced by the enzymes employed during proteolysis.

Novelty and scientific contribution

Enzymatic hydrolysis of dromedary milk proteins is an effective tool to obtain protein hydrolysates with great antioxidant and functional properties. These results suggest that dromedary milk protein hydrolysates could be used as a natural source of antioxidant peptides to formulate functional foods and nutraceuticals.

Biochemical Properties of a Partially Purified Protease from Bacillus sp. CL18 and Its Use to Obtain Bioactive Soy Protein Hydrolysates

Microbial proteases are relevant biocatalysts with diverse applications. Production of protein hydrolysates is recently focused, since they might display biological activities. Therefore, the extracellular protease from Bacillus sp. CL18 was partially purified through ammonium sulfate precipitation (25-50% saturation) and gel filtration chromatography, with a 60.7-fold purification (40,593 U/mg protein) and 21.3% recovery. The partially purified protease (PPP) was characterized as a serine protease, with optimal activity at 51-59 °C and pH 7.4-8.8 and low thermal stability. Thermal inactivation followed first-order kinetics. PPP depended on Ca²⁺ for higher thermal stability, depicted by increases in half-lives (t_1/2), activation energy (E_a), and free energy (ΔG^#) for kinetic inactivation. PPP preferentially hydrolyzed casein > soy protein isolate (SPI) >>> keratinous materials. SPI hydrolysis by PPP was further investigated, and the obtained hydrolysates exhibited increased in vitro bioactivities. Hydrolysates displayed antioxidant capacities through the scavenging of synthetic organic radicals and Fe³⁺-reducing ability. In addition, hydrolysates inhibited the activities of dipeptidyl peptidase IV (DPP IV) and angiotensin-converting enzyme (ACE), suggesting antidiabetic and antihypertensive potentials, respectively. From its biochemical properties, PPP might be used to produce protein hydrolysates with multifunctional bioactivities. Both PPP and SPI hydrolysates can find applications in food biotechnology.

Biochemical and functional properties of wheat middlings bioprocessed by lactic acid bacteria

The present study aimed to investigate the bioprocessing of wheat middlings with different lactic acid bacteria (LAB) in order to improve biological activities of this by-product of wheat flour production. The concentration of lactic acid, reducing sugars, and total phenolics, as well as antioxidant, antibrowning, antibacterial and prebiotic activities of fermented samples were analyzed. All LAB strains were capable to growth on wheat middlings, and pH decreased in the medium associated with lactic acid production during cultivation. Samples inoculated with Lactobacillus plantarum DSM20174 presented the maximum growth, lactic acid concentration above 2 mg/ml, and pH values around 3.8. The amount or reducing sugars decreased after 24 hr growth, except for maltose. Bioprocessed wheat middlings exhibited antioxidant, antibrowning, antibacterial, and prebiotic properties, related with the increase of total phenolic content. Highest values for antioxidant activities were obtained for L. plantarum and Streptococcus thermophilus strains, reaching values around 400 and 640 μM Trolox equivalents (TE) ml^-1 for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric ion reducing antioxidant power (FRAP) assays, respectively. Bioprocessing techniques using LAB can be an interesting approach to improve the availability of compounds with health-promoting properties from lignocellulosic waste material. PRACTICAL APPLICATIONS: The processing of secondary products from wheat milling can represent an important benefit to the industry. Wheat middlings bioprocessed with LAB showed improved biological activities and may represent an interesting ingredient to be incorporated in food and feed formulations.

Egg white hydrolysates improve vascular damage in obese Zucker rats by its antioxidant properties

Metabolic Syndrome (MS) is related to increased risk of early death due to cardiovascular complications, among others. Dietary intervention has been suggested as the safest and most cost-effective alternative for treatment of those alterations in patients with MS. The aim of this study was to investigate the effects of different egg white hydrolysates (HEW1 and HEW2) in obese Zucker rats, focus on the development of cardiovascular complications. Blood pressure, heart rate, basal cardiac function and vascular reactivity in aorta and mesenteric resistance arteries were evaluated. Reactive oxygen species production by dihydroethidium-emitted fluorescence, NOX-1 mRNA levels by qRT-PCR, angiotensin-converting enzyme activity by fluorimetry and kidney histopathology were also analysed. Both hydrolysates improve the endothelial dysfunction occurring in resistance arteries. Additionally, HEW2 reduced vascular oxidative stress. PRACTICAL APPLICATIONS: Egg white is a good source of bioactive peptides, some of them with high antioxidant activity. They may be used as functional foods ingredients and could serve as an alternative therapeutic option to decrease some Metabolic Syndrome-related complications. This study suggests that these hydrolysates could be an interesting non-pharmacological tool to control cardiovascular complications related to Metabolic Syndrome.

High Hydrostatic Pressure-Assisted Extraction of High-Molecular-Weight Melanoidins from Black Garlic: Composition, Structure, and Bioactive Properties

Melanoidin is one of the most important ingredients in black garlic due to the high nutritional values and biological functions. High hydrostatic pressures from 200 to 500 MPa were employed to extract the melanoidins from black garlic for improving the extraction efficiency and enhancing the activities. The results indicated that total phenolics, flavonoids, and sugar yields were all increased when pressure was applied and the antioxidant and overall reducing power was maximized. The bioactive properties of protein tyrosine phosphatase 1B, angiotensin-converting enzyme, and trypsin inhibitory activities were also enhanced compared with the control. Moreover, FT-IR spectroscopy indicated high pressure altered the melanoidin structures to different degrees. It was found that an application of 300 MPa for 5 min was the optimal treatment protocol under all operating conditions.

The Effect of In Vitro Digestion on Antioxidant, ACE-Inhibitory and Antimicrobial Potentials of Traditional Serbian White-Brined Cheeses

This study deals with the effect of in vitro digestion on the functional potential of traditional Serbian white-brined cheeses. The total antioxidant capacity, reducing power and iron (II) chelating properties as well as angiotensin-converting enyzme-inhibitory (ACE-inhibitory) and antimicrobial activities of traditional Serbian white-brined cheeses before and after in vitro digestion were assayed. The traditional cheeses had different antioxidant properties as well as different ACE-inhibitory activities. In vitro digestion improved the total antioxidant capacity (8.42⁻58.56 times) and the reducing power (by 17.90⁻99.30%) of investigated cheeses, whereas their chelating ability was slightly improved or unaffected after digestion. In vitro digestion reduced the ACE-inhibitory potential of water-soluble protein fractions, and digested water-insoluble fractions were the major source of ACE-inhibitory peptides. The digestates did not exhibit any antibacterial potential, whereas they showed moderate antifungal potential toward selected micromycetes. The best antifungal potential had Svrljig ovine cheese and Homolje cow cheese. The results of this study clearly point to a significant functionality of traditional white-brined cheeses.

Effect of enzymatic hydrolysis on the functional, antioxidant, and angiotensin I-converting enzyme (ACE) inhibitory properties of whole horse gram flour

Horse gram hydrolysate (HGH) with different degree of hydrolysis (DH) (20, 25, 35, 40, and 45%) was prepared from whole horse gram flour using alcalase. The amino acid composition of HGH showed the presence of essential amino acids. The alcalase hydrolysis (DH ≥ 20%) increased protein solubility with a notable difference in the pH range of 3-5 (p < 0.05). The emulsifying activity and stability of HGH improved with increase in pH, especially at DH ≥ 25% (p < 0.05). With increase in DH, the foaming properties reduced while the antioxidant and angiotensin I-converting enzyme inhibitory activities increased. Sensory evaluation showed no significant difference (p > 0.05) in preference between control soup and soup mixed with HGH. Thus, these results suggest the possibility of HGH to be used as an appropriate functional ingredient with different food applications including in management of oxidative stress as well as in controlling hypertension .

Quality and storage stability of goat meat emulsion during refrigerated storage upon incorporation of α-chymotrypsin hydrolysed camel milk casein

Three different levels, viz. T1 (0.03%), T2 (0.06%) and T3 (0.09%) (w/w) of α-chymotrypsin hydrolysed camel milk casein was incorporated into goat meat emulsion, and compared with control (C: 0% hydrolysate) and positive control (PC: 0.02% butylated hydroxytoluene (BHT), w/w) for changes in quality at 4±1°C. During storage, the water activity, extract release volume and emulsion stability decreased significantly, while pH increased. Except in T3, improvement in antioxidant potential of treated emulsions was recorded. Lower fatty acid oxidation was recorded in treated emulsions during storage. The treated emulsions had better instrumental colour profile, however, lightness (L*), redness (a* value) and yellowness (b*) values decreased with the advancement of storage period. The microbiological counts in treated emulsions were initially reduced, and at the end of storage, significantly lower counts were recorded. In microbial challenging test (MCT), the colony forming units in treated emulsions decreased upto 4th day for all the tested pathogens, thereafter increased significantly on 6th day except in T3, whereas, in C and PC groups, the counts increased significantly throughout the storage period. The findings suggested that camel milk casein hydrolysate with α-chymotrypsin could be used as a potential food ingredient to improve its quality.

Seasonal Variability of the Biochemical Composition and Antioxidant Properties of Fucus spiralis at Two Azorean Islands

This study evaluates, for the first time, the seasonal (winter and summer) and geographical (São Miguel⁻SMG and Santa Maria⁻SMA Islands) variability of Fucus spiralis (Fs) biochemical composition (dry weight basis) and antioxidant properties. Protein and carbohydrates presented higher values in Fs-SMGwinter, lipids, total dietary fiber, and energy value in Fs-SMAsummer, and ash and soluble dietary fiber/insoluble dietary fiber ratio in Fs-SMAwinter. The fatty acid (FA) profiles showed a lower SFA in Fs-SMGsummer, whereas MUFA and PUFA presented higher values in Fs-SMGsummer and Fs-SMGwinter, respectively. Excellent dietary ratios of n6/n3 PUFA and hypocholesterolemic/hypercholesterolemic FA were found, with lower values in Fs-SMAwinter and higher in Fs-SMGsummer, respectively. The highest total phenolics was found in Fs-SMAsummer acetone:water extract and total flavonoids showed the higher value in Fs-SMGwinter methanol extract. The best free radical-scavenging activity was observed in the Fs-SMAwinter methanol (EC50 = 0.045 mg/mL) and acetone:water (EC50 = 0.059 mg/mL) extracts. The ferric-reducing antioxidant power showed the best results in Fs-SMAwinter methanol extract (EC50 = 0.016 mg/mL) and Fs-SMAsummer acetone:water extract (EC50 = 0.017 mg/mL). The best ferrous ion-chelating activity was found in Fs-SMGwinter acetone:water extract. Overall, results revealed that F. spiralis nutritional and functional bioactivity values have geographical and seasonal variations and that its regular consumption may add benefits to human health.

Improving antioxidant and antiproliferative activities of colla corii asini hydrolysates using ginkgo biloba extracts

Colla corii asini hydrolysates (ACCH) and ginkgo biloba extracts (EGb) possess more potent antioxidant effects when used in combination than when used alone. The mixture of ACCH and EGb at a dose ratio of 20:4(w:w) showed the highest radical scavenging activity with IC 50 of 0.17 ± 0.01, 0.43 ± 0.02 and 1.52 ± 0.07 mg/ml against DPPH, ABTS and HO · free radicals, respectively. Furthermore, the inhibition of breast cancer cells MCF-7 and MDA-MB-231 proliferation increased when these cell lines were treated with a combination of ACCH and EGb for 72 hr, with IC 50 of 4.32 ± 0.12 mg/ml and 0.39 ± 0.01 mg/ml, respectively. The findings indicated that the mixtures of ACCH and EGb could be used to prevent and treat some diseases caused by the excessive free radicals, especially cancer. Therefore, the mixtures of ACCH and EGb might serve as a natural source of desirable antioxidant and anticancer agents for the nutraceutical and pharmaceutical industries.

Dairy Fats and Cardiovascular Disease: Do We Really Need to be Concerned?

Cardiovascular diseases (CVD) remain a major cause of death and morbidity globally and diet plays a crucial role in the disease prevention and pathology. The negative perception of dairy fats stems from the effort to reduce dietary saturated fatty acid (SFA) intake due to their association with increased cholesterol levels upon consumption and the increased risk of CVD development. Institutions that set dietary guidelines have approached dairy products with negative bias and used poor scientific data in the past. As a result, the consumption of dairy products was considered detrimental to our cardiovascular health. In western societies, dietary trends indicate that generally there is a reduction of full-fat dairy product consumption and increased low-fat dairy consumption. However, recent research and meta-analyses have demonstrated the benefits of full-fat dairy consumption, based on higher bioavailability of high-value nutrients and anti-inflammatory properties. In this review, the relationship between dairy consumption, cardiometabolic risk factors and the incidence of cardiovascular diseases are discussed. Functional dairy foods and the health implications of dairy alternatives are also considered. In general, evidence suggests that milk has a neutral effect on cardiovascular outcomes but fermented dairy products, such as yoghurt, kefir and cheese may have a positive or neutral effect. Particular focus is placed on the effects of the lipid content on cardiovascular health.

Angiotensin I-Converting Enzyme (ACE) Inhibitory Activity, Antioxidant Properties, Phenolic Content and Amino Acid Profiles of Fucus spiralis L. Protein Hydrolysate Fractions

Food protein-derived hydrolysates with multi-bioactivities such as antihypertensive and antioxidant properties have recently received special attention since both activities can play significant roles in preventing cardiovascular diseases. This study reports, for the first time, the angiotensin I-converting enzyme (ACE)-inhibition and antioxidant properties of ultrafiltrate fractions (UF) with different molecular weight ranges (<1, 1-3 and ≥3 kDa) obtained from Fucus spiralis protein hydrolysate (FSPH) digested with cellulase-bromelain. The amino acids profile, recovery yield, protein, peptide and total phenolic contents of these FSPH-UF, and the in vitro digestibility of F. spiralis crude protein were also investigated. FSPH-UF ≥3 kDa presented remarkably higher ACE-inhibition, yield, peptide and polyphenolic (phlorotannins) contents. Antioxidant analysis showed that FSPH-UF <1 kDa and ≥3 kDa exhibited significantly higher scavenging of 2,2-diphenyl-1-picrylhydrazyl radical and ferrous ion-chelating (FIC) activity. FSPH-UF ≥3 kDa had also notably higher ferric reducing antioxidant power (FRAP). Strong correlations were observed between ACE-inhibition and antioxidant activities (FIC and FRAP). The results suggest that ACE-inhibition and antioxidant properties of FSPH-UF may be due to the bioactive peptides and polyphenols released during the enzymatic hydrolysis. In conclusion, this study shows the potential use of defined size FSPH-UF for the prevention/treatment of hypertension and/or oxidative stress-related diseases.

Antioxidant and antibacterial activities of bioactive peptides in buffalo's yoghurt fermented with different starter cultures

The effect of Lactobacillus acidophilus 20552 ATCC (T2) or Lactobacillus helveticus CH 5 (T3) in combination with yoghurt starter (1:1) on the antioxidant and antibacterial activities of the bioactive peptides present in buffalo's yoghurt was studied. The SDS-PAGE results indicate that all caseins were completely hydrolyzed by both strains, whereas whey protein fractions were still present. All starter cultures have the ability to produce low-molecular-weight bioactive peptides, most of which were originated from β-casein and fewer from αs₁ casein. The antioxidant activity (%) of the water-soluble peptide extract from yoghurt samples increased in all samples during storage. Samples containing Lb. helveticus CH 5 showed the highest values. All yoghurt treatments displayed antibacterial activity against Escherichia coli. Control yoghurt and T3 showed higher antibacterial activity on E. coli, Staphylococcus aureus, and Bacillus cereus as compared to T2.

Antioxidant potential of buffalo and cow milk Cheddar cheeses to tackle human colon adenocarcinoma (Caco-2) cells

Objective

The aim of present study was to assess the anti-oxidant potential of water-soluble peptides (WSPs) extract derived from buffalo and cow milk Cheddar cheeses at different stages of ripening.

Methods

The antioxidant potential of WSPs extract was assessed through 2,2’-azinobis-3-ethylbenzothiazoline-6sulfonic acid (ABTS)-radical scavenging activity. In addition, impact of WSPs extract on cell viability and production of reactive oxygen species (ROS) in human colon adenocarcinoma Caco-2 (tert-butylhydroperoxide-induced) cell lines was also evaluated.

Results

The ABTS-radical scavenging activity increased progressively with ripening period and dose-dependently in both cheeses. However, peptide extract from buffalo milk Cheddar cheese demonstrated relatively higher activity due to higher contents of water-soluble nitrogen. Intracellular ROS production in Caco-2 cells decreased significantly (p<0.05) till 150th day of cheese ripening and remained constant thereafter. Additionally, dose-dependent response of WSPs extract on antioxidant activity was noticed in the Caco-2 cell line.

Conclusion

On the basis of current in vitro study, the Cheddar cheese WSPs extract can protect intestinal epithelium against oxidative stress due to their antioxidant activity.

Protective Effects of Functional Chicken Liver Hydrolysates against Liver Fibrogenesis: Antioxidation, Anti-inflammation, and Antifibrosis

Via an assay using an Amino Acid Analyzer, pepsin-digested chicken liver hydrolysates (CLHs) contain taurine (365.57 ± 39.04 mg/100 g), carnosine (14.03 ± 1.98 mg/100 g), and anserine (151.58 ± 27.82 mg/100 g). This study aimed to evaluate whether CLHs could alleviate thioacetamide (TAA)-induced fibrosis. A dose of 100 mg TAA/kg BW significantly increased serum liver damage indices and liver cytokine contents. Cell infiltration and monocytes/macrophages in livers of TAA-treated rats were illustrated by the H&E staining and immunohistochemical analysis of cluster of differentiation 68 (CD68, ED1), respectively. A significantly increased hepatic collagen accumulation was also observed and quantified under TAA treatment. A significant up-regulation of transforming growth factor-beta (TGF-β) and SMAD family member 4 (SMAD4) caused by TAA treatment further enhanced alpha smooth muscle actin (αSMA) gene and protein expressions. The liver antioxidant effects under TAA treatment were significantly amended by 200 and 600 mg CLHs/kg BW. Hence, the ameliorative effects of CLHs on liver fibrogenesis could be attributed by antioxidation and anti-inflmmation.

Bioactive Peptides in Animal Food Products

Proteins of animal origin represent physiologically active components in the human diet; they exert a direct action or constitute a substrate for enzymatic hydrolysis upon food processing and consumption. Bioactive peptides may descend from the hydrolysis by digestive enzymes, enzymes endogenous to raw food materials, and enzymes from microorganisms added during food processing. Milk proteins have different polymorphisms for each dairy species that influence the amount and the biochemical characteristics (e.g., amino acid chain, phosphorylation, and glycosylation) of the protein. Milk from other species alternative to cow has been exploited for their role in children with cow milk allergy and in some infant pathologies, such as epilepsy, by monitoring the immune status. Different mechanisms concur for bioactive peptides generation from meat and meat products, and their functionality and application as functional ingredients have proven effects on consumer health. Animal food proteins are currently the main source of a range of biologically-active peptides which have gained special interest because they may also influence numerous physiological responses in the organism. The addition of probiotics to animal food products represent a strategy for the increase of molecules with health and functional properties.

Novel angiotensin-converting enzyme inhibitory peptides from caseins and whey proteins of goat milk

Angiotensin-converting enzyme (ACE) plays a central role in blood pressure regulation by producing the vasoconstrictor angiotensin II. The inhibition of ACE with natural inhibitors, as alternatives to avoid the side effect of synthetic drugs, is a major target in the prevention of hypertension. In this study, we examined the separated caseins and whey proteins of goat milk for the presence of ACE inhibitory peptides. Digestion of isolated whey proteins and caseins of goat milk by gastric pepsin generated soluble hydrolysates exhibiting significant inhibition of ACE compared to weak inhibition by undigested proteins. The hydrolysates were fractionated by size exclusion chromatography, Sephacryl S-100 column, into four fractions (F1–F4). The late-eluting fraction (F4) of either whey or caseins exhibited greater ACE inhibition. Peptides in both F4 fractions, isolated by RP-HPLC, exhibited variable ACE inhibitory activities with the hydrophobic peptide peaks being the most potent ACE inhibitors. MALDI-TOF MS/MS resulted in identification of three potent ACE inhibitory peptides: PEQSLACQCL from β-lactoglobulin (residues 113–122), QSLVYPFTGPI from β-casein (residues 56–66), and ARHPHPHLSFM from κ-casein (residues 96–106). The peptides from whey and caseins exert significant ACE inhibitory activities comparable to that of captopril, an antihypertensive drug, exhibiting IC50 values of 4.45 μM and 4.27 μM, respectively. The results introduce, for the first time, new potent ACE-inhibitory peptides that can be released by gastric pepsin of goat milk whey and caseins and thus may pave the way for their candidacy as anti-hypertensive bioactive peptides and prevention of associated disorders.

Investigation of the antimicrobial activity of soy peptides by developing a high throughput drug screening assay

Background

Antimicrobial resistance is a great concern in the medical community, as well as food industry. Soy peptides were tested against bacterial biofilms for their antimicrobial activity. A high throughput drug screening assay was developed using microfluidic technology, RAMAN spectroscopy, and optical microscopy for rapid screening of antimicrobials and rapid identification of pathogens.

Methods

Synthesized PGTAVFK and IKAFKEATKVDKVVVLWTA soy peptides were tested against Pseudomonas aeruginosa and Listeria monocytogenes using a microdilution assay. Microfluidic technology in combination with Surface Enhanced RAMAN Spectroscopy (SERS) and optical microscopy was used for rapid screening of soy peptides, pathogen identification, and to visualize the impact of selected peptides.

Results

The PGTAVFK peptide did not significantly affect P. aeruginosa, although it had an inhibitory effect on L. monocytogenes above a concentration of 625 µM. IKAFKEATKVDKVVVLWTA was effective against both P. aeruginosa and L. monocytogenes above a concentration of 37.2 µM. High throughput drug screening assays were able to reduce the screening and bacterial detection time to 4 h. SERS spectra was used to distinguish the two bacterial species.

Conclusions

PGTAVFK and IKAFKEATKVDKVVVLWTA soy peptides showed antimicrobial activity against P. aeruginosa and L. monocytogenes. Development of high throughput assays could streamline the drug screening and bacterial detection process.

General significance

The results of this study show that the antimicrobial properties, biocompatibility, and biodegradability of soy peptides could possibly make them an alternative to the ineffective antimicrobials and antibiotics currently used in the food and medical fields. High throughput drug screening assays could help hasten pre-clinical trials in the medical field.

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Soy peptide PGTAVFK above 312.5 µM concentrations inhibits Listeria monocytogenes.

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IKAFKEATKVDKVVVLWTA restricts motility and aggregation of Listeria monocytogenes.

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Microfluidic 3D device generate multiplex parallel drug concentration gradients.

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RAMAN spectroscopy microfluidics provides a high throughput drug-screening assay.

Iron (II)-chelating activity of buffalo αS-casein hydrolysed by corolase PP, alcalase and flavourzyme

Iron is a vital substance for human health which participates in many biochemical reactions. It also act as initiator for many harmful oxidative process. Buffalo αS-casein enriched fraction (80 %) was hydrolysed independently by corolase PP (H1), alcalase (H2), flavourzyme (H3) and sequentially by alcalase-flavourzyme (H4). After ultrafiltration (10 and 3 kDa) hydrolysates were analysed for their iron chelation activity using ferrozine. For H1 group of hydrolysates highest iron (II)-chelation activity (265.58 μM Fe(2+/)mg protein) was found after 8 h of hydrolysis for H2 (267.56 μM Fe(2+/)mg protein) and H3 group of hydrolysates (380.68 μM Fe(2+/)mg protein) after 6 h of hydrolysis. Sequential hydrolysis was not effective for iron (II)-chelation activity. 3 kDa fractions show higher iron (II)-chelation activity than 10 kDa fraction. Flavourzyme was more effective for generation of iron (II)-chelating peptides from buffalo αS-casein.

Antimicrobial and radical scavenging properties of bovine collagen hydrolysates produced by Penicillium aurantiogriseum URM 4622 collagenase

A 2(3) full factorial design was used to identify the main effects and interactions of pH, collagen concentration and temperature on the degree of collagen hydrolysis (DH) by collagenase from Penicillium aurantiogriseum URM 4622. Increases in both pH and collagen concentration improved DH, and a positive interaction effect was observed for these variables. On the other hand, temperature had a negative main effect on DH. The maximum value of DH (4.65 μg/mL) was achieved at 7.5 mg/mL collagen concentration, pH 8.0 and 25 °C. The peptide profile showed several peptides with molecular weights lower than 2 kDa and exhibited antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. An antioxidant activity of 84.7 ± 0.24 % towards the radical ABTS• + was obtained with 50 mg/mL hydrolysates. This study demonstrated that collagen hydrolysed by P. aurantiogriseum URM 4622 collagenase possesses interesting antibacterial and antioxidant activities.

Soy protein hydrolysis with microbial protease to improve antioxidant and functional properties

Soybean proteins are widely used as nutritional and functional food ingredients. This investigation evaluated through a 2(3) central composite design the effect of three variables (pH, temperature and enzyme/substrate (E/S) ratio) on the production of soy protein isolate (SPI) hydrolysates with a microbial protease. Soluble peptides, antioxidant activity, and foaming and emulsifying capabilities of the hydrolysates were analyzed. All variables, as well as their interactions, were significant for the soluble peptides content of SPI hydrolysates. Optimal conditions for obtaining soluble peptides were around 30-35 °C, pH 6.5-9.5, and E/S ratios of 1,650-6,300 U g(-1). SPI hydrolysates produced at 30-45 °C, pH 8.0-9.5, and E/S ratios of 4,000-8,000 U g(-1) showed higher capacity to scavenge the 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical. Models for soluble peptides and ABTS activity of hydrolysates were obtained. In the range studied, the variables had not significant influence on the ability of hydrolysates to scavenge the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. SPI hydrolysates also presented reducing power and ability to chelate iron. Hydrolysis temperature was significant for the Fe(2+)-chelating ability of hydrolysates. Temperature of hydrolysis was significant for the foaming capacity of hydrolysates, with higher values observed at 45 °C and 8,000 U g(-1). For emulsifying capacity, only E/S ratio presented a significant effect. Temperature and E/S ratio appeared to be more significant variables influencing the properties of the SPI hydrolysates. The results of this study indicate that specific hydrolysis conditions should be selected to obtain SPI hydrolysates with preferred characteristics.

Antioxidant capacity of hydrolyzed porcine tissues

The antioxidative capacity of seven different porcine tissue hydrolysates (colon, appendix, rectum, pancreas, heart, liver, and lung) were tested by four different assays, including iron chelation, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, 2,2-Diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) radical scavenging, and inhibition of lipid oxidation. All hydrolyzed tissues displayed antioxidant capacity in all four assays, with colon, liver, and appendix as the three most potent inhibitors of lipid oxidation (47, 29, and 27 mmol/L trolox equivalent antioxidant capacity [TEAC], respectively) and liver, colon, pancreas, and appendix as the four most potent iron chelators (92% ± 1.1, 79.3% ± 3.2, 77.1% ± 1.8, and 77% ± 2.3, respectively). Furthermore, colon and appendix showed good radical scavenging capacities with ABTS scavenging of 86.4% ± 2.1 and 84.4% ± 2.9 and DPPH scavenging of 17.6% ± 0.3 and 17.1% ± 0.2, respectively. Our results provide new knowledge about the antioxidant capacity of a variety of animal by-products, which can be transformed into antioxidant hydrolysates, thereby creating added value.