Intestinal health benefits of bovine whey proteins after simulated gastrointestinal digestion

Digestion of whey peptide induces antioxidant and anti-inflammatory bioactivity on glial cells: Sequences identification and structural activity analysis

Whey derived peptides have shown potential activity improving brain function in pathological condition. However, there is little information about their mechanism of action on glial cells, which have important immune functions in brain. Astrocytes and microglia are essential in inflammatory and oxidative defense that take place in neurodegenerative disease. In this work we evaluate antioxidant and anti-inflammatory potential bioactivity of whey peptide in glial cells. Peptides were formed during simulated gastrointestinal digestion (Infogest protocol), and low molecular weight (<5kDA) peptides (WPHf) attenuated reactive oxygen species (ROS) production induced by hydrogen peroxide stimulus in both cells in dose-dependent manner. WPHf induced an increase in the antioxidant glutathione (GSH) content and prevented GSH reduction induced by lipopolysaccharides (LPS) stimulus in astrocytes cells in a cell specific form. An increase in cytokine mRNA expression (TNFα and IL6) and nitric oxide secretion induced by LPS was attenuated by WPHf pre-treatment in both cells. The inflammatory pathway was dependent on NFκB activation. Bioactive peptide ranking analysis showed positive correlation with hydrophobicity and negative correlation with high molecular weights. The sequence identification revealed 19 peptides cross-referred with bioactive database. Whey peptides were rich in leucine, valine and tyrosine in the C-terminal region and lysine in the N-terminal region. The anti-inflammatory and antioxidant potential of whey peptides were assessed in glia cells and its mechanisms of action were related, such as modulation of antioxidant enzymes and anti-inflammatory pathways. Features of the peptide structure, such as molecular size, hydrophobicity and types of amino acids present in the terminal region are associated to bioactivity.

Enrichment and Quantitation of Dipeptidyl Peptidase IV Inhibitory Peptides in Quinoa upon Systematic Malting

Food-derived peptides with an inhibitory effect on dipeptidyl peptidase IV (DPP-IV) can be used as an additive treatment for type 2 diabetes. The inhibitory potential of food depends on technological protein hydrolysis and gastrointestinal digestion, as the peptides only act after intestinal resorption. The effect of malting as a hydrolytic step on the availability of these peptides in grains has yet to be investigated. In this study, quinoa was malted under systematic temperature, moisture, and time variations. In the resulting malts, the DPP-IV inhibition reached a maximum of 45.02 (±10.28) %, whereas the highest overall concentration of literature-known inhibitory peptides was 4.07 μmol/L, depending on the malting parameters. After in vitro gastrointestinal digest, the inhibition of most malts, as well as the overall concentration of inhibitory peptides, could be increased significantly. Additionally, the digested malts showed higher values in both the inhibition and the peptide concentration than the unmalted quinoa. Concerning the malting parameters, germination time had the highest impact on the inhibition and the peptide concentration after digest. An analysis of the protein sizes before and after malting gave first hints toward the origin of these peptides, or their precursors, in quinoa.

Emerging Trends in Bioavailability and Pharma-Nutraceutical Potential of Whey Bioactives

Whey, a component of milk and a useful by-product of the dairy industry's casein and cheese-making, has been used for generations to augment animal feed. It contains a range of proteins, including α-lactalbumin, β-lactoglobulin, bovine serum albumin, heavy and light chain immunoglobulins, lactoferrin, glycomacropeptide, and lactoperoxidase. Whey proteins exhibit great potential as biopolymers for creating bioactive delivery systems owing to their distinct health-enhancing characteristics and the presence of numerous amino acid groups within their structures. Whey has considerable factors such as antitumor, anti-inflammatory, antihypertensive, hypolipidemic, antiviral, and antibacterial properties in addition to chelating. The global market of whey protein stood at USD 5.33 billion in 2021, with a projected compound annual growth rate of 10.48% spanning the interval from 2022 to 2030. The escalating demand for whey protein is intrinsically linked to the amplifying consciousness surrounding healthy lifestyles. Notably, protein supplements are recurrently endorsed by fitness and sports establishments, thereby accentuating the focal point of customers toward whey protein. This review focuses on nutritional composition, whey bioactives, and their bioavailability with potential health benefits.

Synergistic effects of MFG-E8 and whey protein on mitigating d-galactose-induced sarcopenia through PI3K/AKT/PGC-1α and MAPK/ERK signaling pathways

Milk fat globule epidermal growth factor 8 (MFG-E8) and whey protein have emerged as promising bionutrient supplements for enhancing skeletal muscle mass and function. In the present study, aging-related sarcopenia rat model was employed to elucidate the effects of the combined administration of MFG-E8 and whey protein on the catabolism and anabolism of gastrocnemius protein. Combined intervention led to notable enhancements in the antioxidative stress status and mitochondrial biogenesis capacity of gastrocnemius muscle fibers in the aging rats, concomitant with a significant inhibition of lipid accumulation. Moreover, the synergistic effect of MFG-E8 and whey protein was found to exert modulatory effects on key signaling pathways, including PI3K/Akt/PGC-1α pathway and MAPK/ERK signaling pathways in the gastrocnemius muscle of the aging rats. Specifically, this combined intervention was observed to promote mitochondrial biogenesis and regulate the expression of protein anabolism and catabolism-related regulators, thereby facilitating the alleviation of mitochondrial oxidative stress and enhancing biogenesis in gastrocnemius tissues. The findings of our study provide compelling evidence for the potential of MFG-E8 as a promising dietary supplement with antisarcopenic properties to ameliorate muscle protein metabolism disorders and mitigate mitochondrial-mediated myoblast apoptosis induced by oxidative stress.

Effect of Milk Origin and Seasonality of Yogurt Acid Whey on Antioxidant Activity before and after In Vitro Gastrointestinal Digestion

Yogurt acid whey (YAW) is a by-product of Greek strained yogurt production. The disposal of YAW constitutes an environmental problem, and given the increasing demand of Greek yogurt worldwide, its handling is a challenge. However, whey-derived peptides, resulting from microbial fermentation as well as those resulting from further hydrolysis during the digestion process, have been linked to enhanced biological activities. In this study, the antioxidant capacity of 33 samples of YAW obtained from Greek dairy companies of bovine, ovine or caprine origin was investigated using both cell-free and cell-based assays. The YAW samples, their in vitro digestion products (YAW-Ds) and a fraction of the digests (less than 3 kDa; YAW-D-P3) were assessed using four biochemical assays, namely ORAC, ABTS, FRAP and P-FRAP. Our data revealed a higher antioxidant capacity for digested samples compared with undigested samples, with all four methods. ORAC values after in vitro digestion were higher for the ovine samples compared to their bovine (YAW-D and YAW-D-P3) and caprine (YAW-D-P3) counterparts. Furthermore, the YAW-D-P3 fraction derived from samples collected in the summer months exhibited higher ORAC values when compared to the respective fraction from the winter months' samples. The cellular antioxidant activity of ovine YAW-D-P3 was improved in H2O2-treated HT29 cells compared to the control H2O2-treated cells. However, YAW-D-P3 could not trigger either the pathways involving the transcription factors NF-κB or NFE2L2 or the gene expression of SOD1, CAT and HMOX1 in LPS-challenged THP-1-derived macrophages. These results suggest that YAW, and particularly YAW from ovine origin, could be used as a natural source for its antioxidant potential in human and animal nutrition.

Digestion-resistant whey peptides promote antioxidant effect on Caco-2 cells

Enteric endothelial cells are the first structure to come in contact with digested food and may suffer oxidative damage by innumerous exogenous factors. Although peptides derived from whey digestion have presented antioxidant potential, little is known regarding antioxidant pathways activation in Caco-2 cell line model. Hence, we evaluated the ability to form whey peptides resistant to simulated gastrointestinal digestive processes, with potential antioxidant activity on gastrointestinal cells and associated with sequence structure and activity. Using the INFOGEST method of simulated static digestion, we achieved 35.2% proteolysis, with formation of peptides of low molecular mass (<600 Da) evaluated by FPLC. The digestion-resistant peptides showed a high proportion of hydrophobic and acidic amino acids, but with average surface hydrophobicity. We identified 24 peptide sequences, mainly originated from β-lactoglobulin, that exhibit various bioactivities. Structurally, the sequenced peptides predominantly contained the amino acids lysine and valine in the N-terminal region, and tyrosine in the C-terminal region, which are known to exhibit antioxidant properties. The antioxidant activity of the peptide digests was on average twice as potent as that of the protein isolates for the same concentration, as evaluated by ABTS, DPPH and ORAC. Evaluation of biological activity in Caco-2 intestinal cells, stimulated with hydrogen peroxide, showed that they attenuated the production of reactive oxygen species and prevented GSH reduction and SOD activity increase. Caco-2 cells were not responsive to nitric oxide secretion. This study suggests that whey peptides formed during gastric digestion exhibit biological antioxidant activity, without the need for previously hydrolysis with exogenous enzymes for supplement application. The study's primary contribution was demonstrating the antioxidant activity of whey peptides in maintaining the gastrointestinal epithelial cells, potentially preventing oxidative stress that affects the digestive system.

Antioxidant Activity of Sweet Whey Derived from Bovine, Ovine and Caprine Milk Obtained from Various Small-Scale Cheese Plants in Greece before and after In Vitro Simulated Gastrointestinal Digestion

Whey-derived peptides have been associated with different biological properties, but most peptides are usually further hydrolyzed during the digestive process. In the present study, the antioxidant capacity of 48 samples of sweet whey (SW) derived from cheeses obtained from small-scale cheese plants made with bovine, ovine, caprine or a mixture of ovine/caprine milk was assessed using both cell-free and cell-based assays. SW digestates (SW-Ds) and a fraction (<3 kDa; SW-D-P3) thereof were obtained after in vitro digestion and subsequent ultrafiltration. Antioxidant properties using four different assays were evaluated before and after digestion. Our data showed higher values (p < 0.05) for ORAC, ABTS, FRAP and P-FRAP after in vitro digestion (SW-Ds and SW-D-P3) when compared with the corresponding values before digestion. In the non-digested SW, ORAC values were higher (p < 0.05) for the bovine SW compared with all the other samples. In contrast, the ABTS assay indicated a higher antioxidant activity for the ovine SW both before digestion and for SW-D-P3 compared with the bovine SW. The fraction SW-D-P3 of the ovine SW, using HT29 cells and H2O2 as an oxidizing agent, increased (p < 0.05) the cellular antioxidant activity. Furthermore, the same fraction of the ovine/caprine mixed SW increased, through the NF-κB pathway, the expression of SOD1 and CAT, genes implicated in the oxidative response in macrophage-like THP-1 cells. These findings indicate that SW, and particularly bovine and ovine SW, could be a candidate source for physical antioxidants in human and animal nutrition.

Infant formulae - Key components, nutritional value, and new perspectives

Breastfeeding is the most effective strategy for meeting the nutritional demands of infants, whilst infant formulae are manufactured foods that mimic human milk and can be safely used to replace breastfeeding. In this paper, the compositional differences between human milk and other mammalian milk are reviewed, and thus nutritional profiles and compositions of standard bovine milk-based formulae as well as special formulae are discussed. Differences between breast milk and other mammalian milk in composition and content affect their digestion and absorption in infants. Characteristics and mimicking of breast milk have been intensively studied with the objective of narrowing the gap between human milk and infant formulae. The functions of the key nutritional components in infant formulae are examined. This review detailed recent developments in the formulation of different types of special infant formulae and efforts for their humanization, and summarized safety and quality control of infant formulae.

Antioxidant Potential of the Sweet Whey-Based Beverage Colada after the Digestive Process and Relationships with the Lipid and Protein Fractions

Whey-based beverages could be an effective way of reusing a by-product of th cheese industry, mitigating environmental hazards and, at the same time, profiting a useful food with high nutritional and antioxidant properties. In this study, a traditional Ecuadorian beverage (Colada) was prepared combining sweet whey, Maracuyá and barley. Antioxidant properties before and after an in vitro digestion using the INFOGEST method were determined, and relationships with intestinal transformations of the lipid and protein fractions were analyzed. The digestive process had a positive effect on antioxidant properties based on increased values of ABTS and FRAP located in the bioaccessible fraction (BF), together with strong increments of total polyphenols. Moreover, pretreatment of Caco-2 cells with the BF of Colada significantly reduced ROS generation (p < 0.001) measured by the dichlorofluorescein assay. Substantial changes of the fatty acid profile occurred during digestion, such as a fall of saturated fatty acids and a rise of polyunsaturated. The protein profile, examined by SDS-PAGE and exclusion molecular chromatography in the BF, showed that the major part of the proteins were digested in the intestinal phase. Analysis of NanoLC-MS/MS revealed 18 antioxidant peptides originated from whey proteins, but also 16 peptides from barley with potential antioxidant properties. In conclusion, combining sweet whey with Maracuyá and barley constitutes an excellent nutritional beverage with a strong antioxidant potential.

The Influence of Whey Protein Heating Parameters on Their Susceptibility to Digestive Enzymes and the Antidiabetic Activity of Hydrolysates

The inhibition of dipeptidyl peptidase-IV (DPP-IV) and the release of glucagon-like peptide-1 (GLP-1) could normalize blood glucose levels in diabetic patients. This study evaluated the susceptibility of whey proteins to enzyme hydrolysis and the antidiabetic properties of protein hydrolysates from β-lactoglobulin (β-LG) and α-lactalbumin (α-LA) solutions compared with whey protein isolate (WPI) solution treated at different heating temperatures (65, 75, and 85 °C). α-LA hydrolysate provided the lowest degree of hydrolysis (DH). Those heating temperatures did not significantly affect the DH of all protein hydrolysates. α-LA hydrolysate significantly increased GLP-1 levels and DPP-IV inhibitory activity more than β-LG hydrolysate. WPI hydrolysate inhibited DPP-IV activity less than an α-LA hydrolysate, but they were no significant differences for GLP-1 release activity. Heat treatment could affect the antidiabetic properties of all protein hydrolysates. Heating at 75 °C resulted in greater inhibition of the activity of DPP-IV than at 65 and 85 °C. The highest increase in GLP-1 release was also observed by heating at 75 °C. The recently obtained information is useful for the utilization of α-LA, heated at 75 °C for 30 min, in the preparation of antidiabetic food supplements.

Identification and characterization of antioxidant peptides obtained from the bioaccessible fraction of α-lactalbumin hydrolysate

Whey is an abundantand sustainable source of bioactive peptides obtained from cheese making process. Whey proteins such as α-lactalbumin can be biologically active when the bioactive peptides encrypted in the amino acid sequence of the native protein are released by enzymatic hydrolysis. In the present work, the identification, sequence analysis, and antioxidant activity of bioaccessible peptides from α-lactalbumin alcalase-hydrolysate was assessed. Antioxidant activity (ABTS, ORAC, and HORAC) of α-lactalbumin showed a significant increase (p < 0.05) after the enzymatic treatment with alcalase and this capacity increased even more after the simulation of the gastrointestinal digestion process. Peptides contained in the gastrointestinal digest of α-lactalbumin hydrolysate were separated by preparative RP-HPLC (55 fractions), and three peptides were identified by LC-MS/MS analysis from selected fractions: IWCKDDQNPH (MW: 1254.54 Da) f(59-68), KFLDDDLTDDIM (MW: 1439.64 Da) f(79-90), DKFLDDDLTDDIM (MW: 1554.67 Da) f(78-90). Among the chemically synthesized peptides, IWCKDDQNPH showed the highest antioxidant capacity determined by ORAC, ABTS, and HORAC assays (IC₅₀ 0.015 ± 0.002, 0.45 ± 0.02, and 1.30 ± 0.05 mg/ml, respectively) and this activity may be related to the amino acid sequence. This is the first report where these bioaccessible peptides from α-lactalbumin hydrolysate were identified. The α-lactalbumin hydrolysate could be employed as a functional antioxidant ingredient. PRACTICAL APPLICATION: The present work studied the bioaccessibility of antioxidant peptides from an α-lactalbumin alcalase-hydrolysate by identifying three novel bioaccessible peptides responsible for the antioxidant capacity, providing evidence of the hydrolysate potential as an antioxidant ingredient in the formulations of functional foods and/or food supplements.

Bioactive peptide release and the absorption tracking of casein in the gastrointestinal digestion of rats

Bovine casein is considered as an important source of many bioactive peptides (BAPs), which can also be produced via in vitro simulated gastrointestinal hydrolysis. To perform their physiological functions, some active peptides need to pass through the intestinal epithelial barrier and keep their structural integrity after oral administration. Owing to the complexity of in vivo digestion and absorption, there have been few studies in this area. In this study, casein was labeled with FITC to trace its digestion and absorption in Sprague Dawley (SD) rats. Gastric juice, intestinal fluid, blood, and intestinal tissue samples were collected at different time-points for preservation and analysis after intragastric administration. The results showed that CN-FITC exhibited good labeling stability in the gastrointestinal digestive juice both in vivo and in vitro, suggesting its potential to be used for the detection and tracking of casein hydrolysate. After the intra-gastric administration of FITC, the diffusion rates of fluorescent substances in serum were much higher than in the CN-FITC group. The maximum peptide content in the CN-FITC group during intestinal digestion was achieved 2 h after administration, and electrophoretic analysis of the hydrolysate composition suggested that the molecular weights of the peptides were mainly concentrated in the range of 3.4-10 kDa. The hydrolyzed peptides from CN-FITC could be absorbed into the blood just 1 h after administration. Frozen sections of rat duodenal tissue were observed under a confocal laser scanning microscope, and they showed that the CN-FITC digested products were absorbed from villi to mucosa in the rat intestines, and the casein-hydrolyzed polypeptides were accumulated significantly in tissue samples 2 h after administration. The peptides were mainly absorbed in the duodenum on the basis of absorption experiments using an everted gut sac. After intestinal digestion for 2 h, peptides with weights less than 5 kDa were enriched and identified using LC-MS-MS, and they were found to be mainly derived from β-casein, containing potential angiotensin-I-converting enzyme inhibitory, antioxidant, dipeptidyl peptidase IV inhibitory, and morphine-like peptides. The peptides from casein hydrolysate were tracked entering the blood through the intestinal epithelial barrier in the form of complete fragments, and they might exert potential physiological activity in vivo.

Commercial whey products promote intestinal barrier function with glycomacropeptide enhanced activity in downregulating bacterial endotoxin lipopolysaccharides (LPS)-induced inflammation in vitro

Cheese whey contains bioactive compounds which have shown multiple health-promoting benefits. This study aimed to assess the commercial whey products (CWP) whey protein isolate (WPI), galacto-oligosaccharide-whey protein concentrate (GOS-W) and glycomacropeptide (GMP) for their potential to improve intestinal health in vitro using HT29-MTX intestinal goblet and Caco-2 epithelial cells. Results from HT29-MTX culture showed that WPI mitigated reactive oxygen species (ROS) production at a higher extent compared to GOS-W or GMP. However, GMP downregulated the lipopolysaccharide (LPS)-induced TLR-4 inflammatory pathway with the highest potency compared to the other CWP. Biomarkers of epithelial integrity assessed on both cell lines showed tight junction proteins claudin-1, claudin-3, occludin (OCC), and zonula occludens-1 (ZO-1) upregulation by GMP in HT29-MTX (1.33-1.93-fold of control) and in Caco-2 cells (1.56-2.09-fold of control). All CWP increased transepithelial electrical resistance (TEER) in TNF-α challenged Caco-2/HT29-MTX co-culture monolayer (p < 0.05), but only GMP was similar to the positive control TGF-β1, known for its role in promoting epithelial barrier function. The TNF-α-induced co-culture monolayer permeability was prevented at similar levels by all CWP (p < 0.05). In conclusion, CWP may be used as functional food ingredients to protect against intestinal disorders with emphasis on the GMP enhanced anti-inflammatory and intestinal barrier function properties. Further in vivo studies are guaranteed to validate these findings.

Role of Bioactive Peptide Sequences in the Potential Impact of Dairy Protein Intake on Metabolic Health

For years, there has been an increasing move towards elucidating the complexities of how food can interplay with the signalling networks underlying energy homeostasis and glycaemic control. Dairy foods can be regarded as the greatest source of proteins and peptides with various health benefits and are a well-recognized source of bioactive compounds. A number of dairy protein-derived peptide sequences with the ability to modulate functions related to the control of food intake, body weight gain and glucose homeostasis have been isolated and characterized. Their being active in vivo may be questionable mainly due to expected low bioavailability after ingestion, and hence their real contribution to the metabolic impact of dairy protein intake needs to be discussed. Some reports suggest that the differential effects of dairy proteins-in particular whey proteins-on mechanisms underlying energy balance and glucose-homeostasis may be attributed to their unique amino acid composition and hence the release of free amino acid mixtures enriched in essential amino acids (i.e., branched-chain-amino acids) upon digestion. Actually, the research reports reviewed in this article suggest that, among a number of dairy protein-derived peptides isolated and characterized as bioactive compounds in vitro, some peptides can be active in vivo post-oral administration through a local action in the gut, or, alternatively, a systemic action on specific molecular targets after entering the systemic circulation. Moreover, these studies highlight the importance of the enteroendocrine system in the cross talk between food proteins and the neuroendocrine network regulating energy balance.

Glucagon-like peptide-1 response to whey protein is less diminished by dipeptidyl peptidase-4 in comparison with responses to dextrin, a lipid and casein in rats

Although glucose is the best-known nutrient to stimulate glucagon-like peptide-1 (GLP-1) secretion, dietary peptides also potently stimulate GLP-1 secretion. Certain peptide fragments derived from dietary proteins possess dipeptidyl peptidase-4 (DPP-4) inhibitory activity in vitro. Hence, we hypothesised that dietary peptides protect GLP-1 from degradation through attenuating DPP-4 activity in vivo. Here, we compared GLP-1 responses with dietary proteins, a carbohydrate and a lipid (Intralipos) in rats having or not having plasma DPP-4 activity. Plasma GLP-1 concentrations clearly increased by oral administration of whey protein (2-4 g/kg), but not by that of dextrin (2-4 g/kg), in control rats (untreated Sprague-Dawley rats and F344/Jcl rats), having DPP-4 activity. In contrast, dextrin administration increased the plasma GLP-1 concentrations as the whey protein administration did, in rats having reduced or no DPP-4 activity (a DPP-4 inhibitor, sitagliptin-treated Sprague-Dawley rats or DPP-4-deficient F344/DuCrl/Crlj rats). DPP-4 inhibition by sitagliptin treatment also enhanced GLP-1 response to Intralipos, and casein, but the treatment did not further enhance GLP-1 response to whey protein. Intestinal GLP-1 content and gastric emptying rate were not associated with differences in GLP-1 responses to test nutrients. The luminal contents from rats administered whey protein decreased DPP-4 activity in vitro. These results suggest that GLP-1 released by dextrin, Intralipos and casein was immediately degraded by DPP-4, while GLP-1 released by whey protein was less degraded. Our study provides novel in vivo evidence supporting the hypothesis that dietary peptides not only stimulate GLP-1 secretion but also inhibit DPP-4 activity to potentiate GLP-1 response.

Antioxidant and cytoprotective effect of peptides produced by hydrolysis of whey protein concentrate with trypsin

Whey protein is one of the most relevant co-products manufactured by the dairy industry and it is a powerful environmental pollutant. Therefore, the enzymatic hydrolysis of whey protein concentrate (WPC 35) to produce antioxidant peptides is an innovative approach which can provide added value to whey. The WPC 35 hydrolysis with trypsin was carried out for 4.31 h at 41.1 °C with an enzyme/substrate ratio of 0.017. Under such hydrolysis conditions, the peptides produced have the highest radical scavenging activity and cytoprotector effect. The WPC hydrolysate and a permeate ≤3 kDa were characterized by SDS-page, RP-HPLC and MALDI-TOF-MS. Furthermore, O₂^•- and HO^• scavenging activity and the cytoprotective effect against a stress agent in epithelial cells of the rat ileum (IEC-18) were determined. In this study, strong antioxidant and cytoprotective peptides were obtained from a low-cost dairy industry product, which could improve consumers' health when used as functional ingredients.

Whey proteins: targets of oxidation, or mediators of redox protection

Bovine whey proteins are highly valued dairy ingredients. This is primarily due to their amino acid content, digestibility, bioactivities and their processing characteristics. One of the reported bioactivities of whey proteins is antioxidant activity. Numerous dietary intervention trials with humans and animals indicate that consumption of whey products can modulate redox biomarkers to reduce oxidative stress. This bioactivity has in part been assigned to whey peptides using a range of biochemical or cellular assays in vitro. Superimposing whey peptide sequences from gastrointestinal samples, with whey peptides proven to be antioxidant in vitro, allows us to propose peptides from whey likely to exhibit antioxidant activity in the diet. However, whey proteins themselves are targets of oxidation during processing particularly when exposed to high thermal loads and/or extensive processing (e.g. infant formula manufacture). Oxidative damage of whey proteins can be selective with regard to the residues that are modified and are associated with the degree of protein unfolding, with α-Lactalbumin more susceptible than β-Lactoglobulin. Such oxidative damage may have adverse effects on human health. This review summarises how whey proteins can modulate cellular redox pathways and conversely how whey proteins can be oxidised during processing. Given the extensive processing steps that whey proteins are often subjected to, we conclude that oxidation during processing is likely to compromise the positive health attributes associated with whey proteins.

Bovine whey peptides transit the intestinal barrier to reduce oxidative stress in muscle cells

Health benefits are routinely attributed to whey proteins, their hydrolysates and peptides based on in vitro chemical and cellular assays. The objective of this study was to track the fate of whey proteins through the upper gastrointestinal tract, their uptake across the intestinal barrier and then assess the physiological impact to downstream target cells. Simulated gastrointestinal digestion (SGID) released a selection of whey peptides some of which were transported across a Caco-2/HT-29 intestinal barrier, inhibited free radical formation in muscle and liver cells. In addition, SGID of β-lactoglobulin resulted in the highest concentration of free amino acids (176 nM) arriving on the basolateral side of the co-culture with notable levels of branched chain and sulphur-containing amino acids. In vitro results indicate that consumption of whey proteins will deliver bioactive peptides to target cells.