Sheep Whey Research Articles

Assessment of the impact of pasteurisation on protein denaturation in sheep sweet whey by asymmetrical flow field-flow fractionation according to sampling period

Whey recovery is limited in artisanal cheese manufacture. This by-product of cheese manufacture was traditionally considered as waste and is highly polluting. However, interest in the nutritional properties of native whey and its proteins has recently increased. Pretreatment is required to preserve highly perishable whey for processing. Only a few studies have focused on sheep whey, despite its considerable nutritional and technological potential. Here, we investigated the effect of heat treatment on the denaturation and formation of protein aggregates in sweet sheep whey collected in January, April and July. Two pasteurisation protocols were studied (72 °C for 1 min and 80 °C for 15 s). Microbiological quality was assessed by checking for the presence of microbes after five days of storage at 4 °C. Asymmetrical flow field-flow fractionation (AF4) coupled to UV detector, multiangle light scattering (MALS) and refractometer (dRi) is a mild, non-naturing technique for determining the extent of denaturation of whey proteins and the size of whey protein aggregates. Greater whey protein denaturation and larger whey protein aggregates were observed for the 80 °C/15 s protocol than for the 72 °C/1 min protocol, for the January and April samples. A decrease in Immunoglobulin G (IgG) content was observed after heat treatments in the samples from July but not significantly for the other proteins. Moreover, the retention times of the monomeric whey protein peaks on the AF4 fractogram were higher for this period, indicating that the proteins were larger. Microbiological testing showed that both pasteurisation treatments were sufficiently effective to ensure good sanitary quality. The pasteurisation schedule best preserving native proteins was heating at 72 °C for 1 min.

Development and Characterization of a Functional Ice Cream from Sheep Milk Enriched with Microparticulated Whey Proteins, Inulin, Omega-3 Fatty Acids, and Bifidobacterium BB-12®

The aim of this work was develop a technological process for the manufacturing of an ice cream from sheep milk, enriched with both functional ingredients and probiotic bacteria. The studied process involved the use of an enriched milk (EM) obtained by mixing predetermined amounts of sheep skimmed milk concentrated by ultrafiltration (retentate), cream from sheep’s milk and whey, microparticulated whey proteins (MWP), obtained by ultrafiltration of sweet sheep whey as a source of whey proteins, marine algal oil from Schizochytrium spp. as a source of the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), inulin as a prebiotic fiber, and locust bean gum as a stabilizer. The resulting EM was inoculated with starter and aroma cultures together with the probiotic culture of Bifidobacterium animalis subsp. lactis (BB-12®) in order to obtain a fermented functional product (FFP) with a physico-chemical composition similar to that of EM. FFP was the main ingredient (~80%, w/w) in the ice cream mixture. Two sucrose-alternative sweeteners (trehalose and erythritol), together with dextrose, were subsequently added to obtain the final ice cream formulation. The resulting ice cream met three nutritional claims: “Source of protein”, “Source of fiber” and “High in omega-3 fatty acids” listed in Regulations (EC) No 1924/2006 and (EU) No 116/2010. Furthermore, the ice cream satisfied the requirement of “probiotic food” according to the Italian Ministry of Health’s guidelines for probiotics. The nutritional characteristics of the ice cream, including the concentration of the probiotic culture, remained stable up to 120 days of storage at −20 ± 2 °C.

Germination Behavior and Geographical Information System-Based Phenotyping of Root Hairs to Evaluate the Effects of Different Sources of Black Soldier Fly (Hermetia illucens) Larval Frass on Herbaceous Crops.

Insect larval frass has been proposed as a fertilizer and amendment, but methods for testing its effects on plants are poorly developed and need standardization. We obtained different types of black soldier fly (Hermetia illucens) frass via the factorial combination of (a) two insect diets, as follows: G (Gainesville = 50% wheat bran, 30% alfalfa meal, 20% maize meal) and W (43% sheep whey + 57% seeds); (b) two frass thermal treatments: NT = untreated and T = treated at 70 °C for 1 h. We tested the effects on the germination of cress (Lepidium sativum L.) and wheat (Triticum durum Desf.) by applying 1:2 w:w water extracts at 0, 25, 50, 75 and 100% concentration. Standardizing frass water content before extraction affected chemical composition. Frass extracts showed high electrical conductivity (8.88 to 13.78 mS cm-1). The W diet was suppressive towards Escherichia coli and showed a lower content of nitrates (e.g., WNT 40% lower than GNT) and a concentration-dependent phytotoxic effect on germinating plants. At 25% concentration, germination indices of G were 4.5 to 40-fold those at 100%. Root and shoot length and root hair area were affected by diet and concentration of frass extracts (e.g., root and shoot length in cress at 25% were, respectively, 4.53 and 2 times higher than at 100%), whereas the effects of the thermal treatment were few or inconclusive. On barley (Hordeum vulgare L.) grown in micropots on a silty loam soil, root mass was reduced by 37% at high extract concentration. A quick procedure for root hair surface area was developed based on the geographic information system (GIS) and may provide a fast method for incorporating root hair phenotyping in frass evaluation. The results indicate that below-ground structures need to be addressed in research on frass effects. For this, phyotoxicity tests should encompass different extract dilutions, and frass water content should be standardized before extraction in the direction of canonical procedures to allow comparisons.

Utilization of Dairy By-Products as a Source of Functional and Health Compounds-The Role of Ovine Colostrum and Milk Whey on Chronic Myeloid Leukemia Cells.

Nowadays, the search for food products that promote consumers' health has gained interest, and dairy by-products, due to their biological quality, could have a prominent position among products with health benefits. However, little is known about their activity on cancer cells. This study aimed to provide evidence about the effect of ovine colostrum and milk whey on K562 cells, a model of the human chronic myeloid leukemia cell line. The exposure of K562 cells to a single administration of sheep by-products at different concentrations for three days and three treatments for three days was carried out. Using a flow cytometric approach, we found that CD235a expression remained stable in the cells exposed to ovine whey (milk and colostrum) at concentrations ranging from 1 ng/mL to 100 μg/mL, after three days from one or three administrations, respectively. A significant reduction in fluorescent cells was observed in the populations exposed to 1 mg/mL of both milk and colostrum at the same time points. In these conditions, the size and granularity of the leukemic cells also changed, with a substantial reduction in the number of actively dividing cells in the S phase of the cell cycle. This phenomenon was highlighted by the Annexin V/PI cytofluorimetric test, which is able to provide quantitative results regarding the population of cells in early or late apoptosis or necrotic cells after exposure to a single dose or three doses of colostrum or sheep whey for three days, respectively. This report showed that both colostrum and milk whey were able to modify the phenotypic profile and cell cycle of the K562 cell line, inducing apoptosis at the highest concentration.

Effects of sheep whey protein combined with Fu brick tea polysaccharides and stachyose on immune function and intestinal metabolites of cyclophosphamide-treated mice.

Sheep whey protein (SWP), Fu brick tea polysaccharides (FBTP) and stachyose (STA) have been shown to improve immunity, but little is known about the regulatory effect of SWP, FBTP, STA and their combined formula (CF) on immune function and intestinal metabolism of immunosuppressed mice induced by cyclophosphamide (CTX). Administration of SWP, FBTP, STA or CF restored the levels of body weight, immune organ index, immune organ morphology, cytokines and immunoglobulins in CTX immunosuppressed mice. Interestingly, CF improved all the mentioned parameters more effective than administration of SWP, FBTP or STA alone. In addition, CF was more effective to increase the levels of intestinal immune-related gene expression than FBTP, SWP or STA alone in immunosuppressed mice, suggesting that CF exhibited excellent intestinal immune regulation function. CF also significantly improved cecal concentrations of short-chain fatty acids of CTX-treated mice. Furthermore, metabolomics analysis demonstrated that CF recovered the levels of 28 metabolites associated with the CTX treatment to the levels of normal mice. Conclusively, these findings suggested that CF as a functional food combination of SWP, FBTP and STA could promote the immune function against human diseases, which providing theoretical support for the co-ingestion of SWP and functional sugars as a feasible strategy for improving the body immunity in the future. © 2023 Society of Chemical Industry.

Cytoxic Effect Levels Of Sheep Whey Protein in Colorectal Adenocarcinoma Cell Line (Caco-2)

Abstract Objective: It was aimed to determine the antitumor and antiproliferative activity of whey protein (whey) obtained from sheep colostrum isolation on colorectal cancer cells (Caco-2). Method: Colostrum was separated into fractions as whey proteins using the isoelectric point. Before cell culture was studied, whey protein was sterilized by a membrane filter. Antitumoral activity levels of different concentrations of lyophilized proteins were measured by MTT viability test on cells and IC50 values were determined. Results: Sheep whey proteins were incubated with Caco-2 cells for 24, 48 and 72 hours with serial dilutions starting with 3200 µg/ml and decreasing. When incubated with sheep whey Caco-2 cells, cell viability: 66.34% at 24 h; IC50 value of 8.414 µg/ml; IC50 value of 46.61% at 48 h was 5,838 µg/ml; The IC50 value of 4.61% at 72 h was found to be 4,741 µg/ml. Conclusion: It was concluded that whey proteins obtained from sheep colostrum isolation have apoptotic and anticarcinogenic effects on Caco-2 cancer cell line and significantly inhibit the growth of tumor cells. We think that the results of this study will lead to studies to be carried out in vitro.

Microencapsulation upholds biological activities of sheep whey hydrolysates and protects against in vitro gastrointestinal digestion

Recycling of dairy by-products as sources of bioactive compounds is an interesting approach for improving sustainable food production. This study aimed to encapsulate a sheep whey hydrolysate (SWH) with antioxidant and antihypertensive properties, produced by a novel proteinase P7. SWH encapsulation was achieved by spray-drying and freeze-drying methods using prebiotic gum Arabic as the encapsulating material. The morphology, colour, moisture, water activity, hygroscopicity, antioxidant and antihypertensive properties, and in vitro digestion of the microcapsules were evaluated. Spray-drying process produced powders with better characteristics as compared with freeze-drying, showing 3.9% moisture, 18.9% hygroscopicity, highest ABTS radical scavenging (65.7%) and iron chelating (78.4%) activities and 70.1% inhibition of the angiotensin I-converting enzyme. Additionally, these biological properties were not affected during simulated gastrointestinal conditions. SWH encapsulation may be an interesting strategy for valorisation of dairy industry by-products, as an ingredient for development of functional foods and potentially increasing nutritional value and shelf life.

Antibacterial and Antioxidant Activity of Sheep Whey Protein Hydrolysates and Their Fractions

Antibacterial and Antioxidant Activity of Sheep Whey Protein Hydrolysates and Their Fractions

Identification of two novel dipeptidyl peptidase-IV inhibitory peptides from sheep whey protein and inhibition mechanism revealed by molecular docking

In this study, the peptides with dipeptidyl peptidase-IV (DPP-IV) inhibitory activities were obtained by trypsin hydrolysis from sheep whey protein. The results showed that the highest DPP-IV inhibitory activity of the hydrolysate (77.80% ± 1.87%) was obtained by trypsin enzymolysis for 4.0 h with 24.50% ± 0.05% of the degree of hydrolysis (DH). Peptides with inhibitory activity against DPP-IV were purified using anion-exchange (DEAE-52) and size-exclusion (G15 dextran gel) chromatography. A total of 86 peptides were identified using LC-MS/MS. The binding energies of RLYLHENK(RL8) and MQEHFTCCR(MQ9) to DPP-IV were determined to be -11.29 kcal/mol and -10.79 kcal/mol with molecular docking in silico, respectively. RL8 and MQ9 could bind to DPP-IV mainly through hydrogen bonds and hydrophobic interactions, and inhibit the DPP-IV enzyme by occupying the S2 pocket. The IC50 values of RL8 and MQ9 in vitro were 166.4 μmol/L and 214.8 μmol/L, respectively. The inhibitory activities in situ modes of the two peptides were evaluated using Caco-2 cells. The IC50 values of RL8 and MQ9 in situ were 158.3 μmol/L and 251.6 μmol/L, respectively. The RL8 and MQ9 derived from sheep whey protein can be considered as a potential source of natural DPP-IV inhibitor.

Elaboration of an unfermented dairy beverage from sheep's milk whey / Elaboração de uma bebida láctea não fermentada a partir de soro de leite de ovelha

Sheep whey is a by-product of cheese production, rich in compounds with high added value, such as proteins and free amino-acids. Sheep's milk and, consequently, its whey, have higher levels of solids, such as proteins, being nutritionally richer than cow's milk. The objective of this paper is to develop a drink composed of passion fruit juice and sheep milk whey, with the purpose of being a sweet drink with outstanding nutritional properties, in addition to adding value to the by-product of sheep cheese factories, which so far does not have industrial use. The formulation was developed with passion fruit juice and sheep milk whey. The microbiological and physicochemical results of the sample were satisfactory. The formulation pleased the consumer and showed positive results, highlighting the flavor (7.02 and viscosity (7.18). The global assessment, this formulation had an average of 7.46 and buy intention of 3.82. The results obtained in this study may help sheep milk producers as well as dairy industries, as an alternative to use sheep milk whey that is currently utilized for animal feed.

The Differential Composition of Whey Proteomes in Hu Sheep Colostrum and Milk during Different Lactation Periods.

Simple SummaryTo reveal the temporal variation of ovine whey protein after lambing and provide basic data for lamb feeding and feed product development, the differential proteomes of whey during the transition from colostrum to mature milk in Hu sheep were studied. A total of 52 differentially expressed protein spots were detected among milk samples from six time points after lambing, identifying 25 differentially expressed proteins. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed the differentially expressed proteins involved in multiple biological functions, especially in immunity. Most of the differential proteins were highly expressed in the first 7 d after lambing, and the expression level decreased to a minimum value at 56 d.Colostrum and milk proteins are essential resources for the growth and development of the newborns, while their kinds and amounts vary greatly during the lactation period. This study was conducted to better understand whey proteome and its changes at six lactation time points (0 d, 3 d, 7 d, 14 d, 28 d, and 56 d after lambing) in Hu sheep. Using two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF/TOF MS) technologies, a total of 52 differentially expressed protein spots (DEPS), corresponding to 25 differentially expressed proteins (DEPs), were obtained. The protein spots abundance analysis revealed that the proteins are the most abundant at 0 d after lambing. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to explore the biological functions of the DEPs. The biological process was mainly involved in localization, the single-organism process, the cellular process, and a series of immune processes. The cellular components engaged in the extracellular region were the cell, organelle, and membrane. The most prevalent molecular function was binding activity. In addition, the DEPs were involved in nine significant pathways, including the Hippo signaling pathway and Complement and coagulation cascades. These results intuitively presented the changes in Hu sheep whey proteins during a 56-d lactation period, and revealed potential biological functions of the DEPs, providing a scientific basis for early weaning.

Screening ultrafiltration membranes to separate lactose and protein from sheep whey: application of simplified model.

Several studies demonstrated that protein from whey milk could be a new strategy to reduce energy intake and increase satiety. Sheep whey has high protein content, but it is also rich in lactose. The aim of this study was to screening different ultrafiltration membranes to separate protein and lactose from sheep whey in one step. Protein was recovered in the concentrate feed, and lactose passed through three membranes and was recovered in the permeate feed. Membranes with different chemical composition and molecular weight cut-offs were assayed, and the influence of operating pressure and lactose concentration feed in the permeate flux and lactose rejection coefficients were studied. Lactose separation was not affected by pressure in GR60PP or GR90PP, and 85% and 80%, respectively of the lactose was separated into permeate feed. When the feed concentration increased, lactose separation remained stable in all three membranes, being GR60PP the most efficient, as 90% of the disaccharides were separated. In all cases 100% of the protein was recovered. Finally, the Spiegler-Kedem-Katchalsky model perfectly fitted the results obtained about lactose rejection coefficients.

Valorisation of Dairy Wastes Through Kefir Grain Production

The main aim of this work was to investigate on kefir grains (KGs) increase using different dairy by-products. To this purpose, whey and deproteinized whey from cow, goat and sheep milk were compared to the pasteurized milk of the corresponding animal species. Each substrate was inoculated with 3% (w/v) of KGs cultivated in ultra-high temperature cow milk and evaluated for pH decrease, total titratable acidity increase and development of lactic acid bacteria (LAB) and yeasts released in the matrices after 24 h incubation at three different temperatures (20, 25 and 30 °C). The genotypic characterization of the dominating microbial populations resulted in the identification of two LAB belonging to the species Lactococcus lactis and Leuconostoc mesenteroides and one yeast strain within the species Kluyveromyces marxianus. Among whey based fermentation media deproteinized sheep whey allowed the highest KGs increase (almost 50%). Results of the present investigations reveal the potential of the dairy wastes for KGs production at industrial level.

Characterization of nanoliposomes containing bioactive peptides obtained from sheep whey hydrolysates

Whey is recognized by the excellent nutritional and functional properties of its proteins, which can be hydrolyzed to peptides with an array of biological activities. In this work, sheep whey was treated with a novel proteinase from Bacillus sp. P7, resulting in hydrolysates with antioxidant and angiotensin-converting enzyme I (ACE-I) inhibitory activity. The hydrolysates were purified by gel filtration chromatography on Sephadex G-25 and the active fractions were subjected to ultrafiltration through 10 kDa cut-off membranes. The fraction enriched in bioactive peptides was encapsulated into phosphatidylcholine liposomes, which were characterized and evaluated by their ability to maintain biological activities. The physicochemical parameters of the liposomes showed constant values during 30 days, with mean diameter around 166 nm and zeta potential −17 mV. Both antioxidant and ACE-I-inhibitory activities were detected in the liposome preparations. In addition, the residual antioxidant activity was 87% after 30 days storage, suggesting the bioactive peptides are stable in this formulation. Liposome encapsulated peptides may offer the possibility of application in areas such as food science and technology, in order to increase the nutritional value and shelf life of food products, as well as for the development of functional foods.

Use of denatured whey protein in the production of artisanal cheeses from cow, goat and sheep milk

The objective of this study was to assess the potential of a whey protein (WP) heat-denaturation and recovery process adapted to small artisanal cheese plants. The effects of cheese’s milk origin (cow, goat or sheep) and cheese whey type (sweet or acid) on the recovery rates and characteristics of WP aggregates were evaluated. The influence of the WP aggregate addition and dispersion method on the cheese-making properties of milk was also investigated. Gravity separation combined with sediment drainage was compared to centrifugation for the recovery of WP aggregates, and showed similar or slightly lower recovery rates depending on milk origin. The higher WP denaturation rate in sheep whey (both sweet and acid) resulted in better protein-aggregate recovery when compared to goat or cow whey. The diameter of WP aggregates was affected by the dispersion method, and large aggregates (6.94–30.56 μm) were obtained with a rotor-stator disperser, and smaller aggregates (0.38–2.68 μm) were obtained with a valve homogenizer. Regardless of whey origin, adding larger-diameter WP aggregates to cheese milk had no negative impact on rennet-induced coagulation, whereas smaller aggregates decreased curd firmness. WP aggregates of both diameter ranges reduced curd contraction capacity, which increased the curd mass fraction and moisture after the cooking step. Adding WP aggregates to milk increased cheese yield and moisture, and the dispersion method had no influence on these parameters, suggesting that a valve homogenizer is not required, which simplifies the process for artisanal cheese production.

Substantiation of the method of protein extraction from sheep and cow whey for producing the cheese "Urda"

We substantiated the methods of protein extraction from sheep and cow whey for the production of the cheese Urda. We established a similar dependence of the effect of the method of protein extraction from both sheep and cow whey on the yield of bulk protein. The largest yield of bulk protein was achieved when using the chloro-calcium method of extraction. Slightly less – when applying the acid-alkaline and acid methods. The lowest yield was observed when employing the thermal technique. The yield of bulk protein from sheep whey is 1.60 times higher than that from the cow whey. The bulk protein, received from sheep whey by the chloro-calcium and acid-alkaline methods, has rather low titrated acidity, which causes unpronounced sour milk taste and smell in the cheese Urda. The cheese, produced from bulk protein received from sheep whey by the acid method, has extremely high values of acidity (115.5±1.5 °T), excessive sour milk taste and flavor. The indicated results will not enable a long term of its storage. That is why, for the extraction of proteins from sheep whey, we recommend using the thermal method in the technology of the albumin cheese Urda, similar for protein extraction from cow whey. Thus, we can state that for the production of the albumin cheese Urda, it is possible to apply the thermal method of protein extraction from the mixtures of sheep and cow whey in the ratio of 1:1 or 3:1

STUDY OF THE DIFFERENT WAYS OF PROTEINS EXTRACTION FROM SHEEP AND COW WHEY FOR “URDA” CHEESE PRODUCTION

The necessary stage of technological process of “Urda” albumin cheese production is whey proteins extraction from sheep whey (in classic technology of product) or from the whey mixtures, offered in the work. For whey proteins extraction from whey the following ways are used: thermal, acid, acid-alkaline and chlorine-calcium. There was established the equal dependence of the influence of the way of proteins extraction from both sheep and cow whey on the output of protein mass. The most output of protein mass (3,47±0,10 %) is at the chlorine-calcium way of proteins extraction, a bit less – 3,41±0,08 % – at the acid-alkaline way. But the acidity of such protein mass, received by the chlorine-calcium and acid-alkaline ways is not high – 37,2±1,8 and 45,6±1,4 % respectively that negatively influences the gustatory qualities of product. The least output is registered at the thermal way. Albumin cheese, received from such protein mass, was the best by its gustatory qualities. The output of protein mass from sheep whey is 1,60 times higher than from cow whey. The mass share of proteins in protein mass, received from sheep whey is by 6,9…8,0 % higher comparing with one, received from cow whey. Protein mass, received from sheep whey by the chlorine-calcium and acid-alkaline ways has the low titrated acidity. Cheese, received from protein mass, received of sheep whey by the acid method, has the extremely high acidity values (115,5±1,5 °Т), excessive sour-milk flavor and smell. These results don-t allow to provide the long storage term. That is why it is recommended to use the thermal way for proteins extraction from sheep whey and for proteins extraction from cow way in the technology of “Urda” albumin cheese. So the thermal way of proteins extraction from the mixture of sheep and cow whey in ratio 1:1 or 3:1 can be used for “Urda” albumin cheese production. The use of cow whey gives a possibility to cheapen the product because cow whey is cheaper than sheep one. Such cheese has the improved organoleptic parameters, namely homogenous consistence, tender sour-milk flavor and smell.

Розрахунок рецептур та розробка технологічної схеми виробництва альбумінового сиру «Урда» для промислових підприємств

Виробництво сиру «Урда» у промислових умовах може зайняти вагоме місце в асортиментному ряді молочних продуктів, оскільки сир має високі біологічну цінність та смакові якості. Одержання сиру «Урда» залежить від кількості свіжої овечої молочної сироватки. Відомо, що з 10 дм3 овечого молока можна отримати 450…500 г сиру «Урда», тому що такий продукт виготовляють виключно з овечої сироватки. Він є значно дорожчим порівняно з іншими видами сиру. Однак, використавши як додаткову сировину сироватку з коров’ячого молока, можна значно здешевити вартість готового продукту, а також раціонально використати вторинну сировину, що утворюється при виробництві сирів із коров’ячого і овечого молока. У статті запропоновано науково обґрунтовані рецептури для виробництва альбумінового сиру «Урда»; розроблено технологічну схему виробництва продукту. Технологія альбумінового сиру «Урда» пройшла промислову апробацію на ПАТ «Ковельмолоко», м. Ковель. На продукт розроблено технічні умови ТУУ 01.4-00492990-004:2014. В основі розрахунку рецептур альбумінового сиру «Урда» було проведення експериментальних досліджень, які дали можливість визначити раціональне співвідношення овечої та коров’ячої сироваток для виробництва продукту. Встановлено, що для виробництва сиру «Урда» можна використовувати суміші сироваток (овеча:коров’яча) у співвідношеннях 1:1 та 3:1. Розроблена технологія альбумінового сиру «Урда» може бути впроваджена на молокопереробному підприємстві, де налагоджено випуск твердих сичужних сирів і розсольного сиру бринза. Впровадження нової технології не потребує великих виробничих площ, дороговартісного обладнання і додаткового переоснащення виробництва. Виробництво альбумінового сиру «Урда» може бути реалізовано на діючих виробничих площах паралельно з випуском основної продукції.

Antioxidant Effects of Sheep Whey Protein on Endothelial Cells

Excessive production of reactive oxygen species (ROS) may cause endothelial dysfunction and consequently vascular disease. In the present study, the possible protective effects of sheep whey protein (SWP) from tert-butyl hydroperoxide- (tBHP-) induced oxidative stress in endothelial cells (EA.hy926) were assessed using oxidative stress biomarkers. These oxidative stress biomarkers were glutathione (GSH) and ROS levels determined by flow cytometry. Moreover, thiobarbituric acid-reactive substances (TBARS), protein carbonyls (CARB), and oxidized glutathione (GSSG) were determined spectrophotometrically. The results showed that SWP at 0.78, 1.56, 3.12, and 6.24 mg of protein mL−1 increased GSH up to 141%, while it decreased GSSG to 46.7%, ROS to 58.5%, TBARS to 52.5%, and CARB to 49.0%. In conclusion, the present study demonstrated for the first time that SWP protected endothelial cells from oxidative stress. Thus, SWP may be used for developing food supplements or biofunctional foods to attenuate vascular disturbances associated with oxidative stress.

In-Depth Characterization of Sheep (Ovis aries) Milk Whey Proteome and Comparison with Cow (Bos taurus).

An in-depth proteomic study of sheep milk whey is reported and compared to the data available in the literature for the cow whey proteome. A combinatorial peptide ligand library kit (ProteoMiner) was used to normalize protein abundance in the sheep whey proteome followed by an in-gel digest of a 1D-PAGE display and an in-solution digestion followed by OFFGEL isoelectric focusing fractionation. The peptide fractions obtained were then analyzed by LC-MS/MS. This enabled identification of 669 proteins in sheep whey that, to our knowledge, is the largest inventory of sheep whey proteins identified to date. A comprehensive list of cow whey proteins currently available in the literature (783 proteins from unique genes) was assembled and compared to the sheep whey proteome data obtained in this study (606 proteins from unique genes). This comparison revealed that while the 233 proteins shared by the two species were significantly enriched for immune and inflammatory responses in gene ontology analysis, proteins only found in sheep whey in this study were identified that take part in both cellular development and immune responses, whereas proteins only found in cow whey in this study were identified to be associated with metabolism and cellular growth.