High hydrostatic pressure enhances whey protein digestibility to generate whey peptides that improve glutathione status in CFTR-deficient lung epithelial cells

Flaking of millets and its impact on bioactivity, pasting, digestibility, structural and thermal properties

Five different millets (foxtail, little, barnyard, kodo and browntop) with and without sprouting were subjected to flaking. Phytic acid and phenolic content tends to decrease significantly, whereas antioxidant activity increased up to 77.32% on flaking of millets. A significant decrease in peak and final viscosity was observed in millet flakes. A-type diffraction pattern was predominant for unsprouted millets whereas the flaked millets showed V-type crystallinity. The protein digestibility significantly increased up to 37.77% in flakes made from sprouted millets. The mineral bioavailability upon flaking of millets increased, especially Ca (88.22% for little), Fe (43.04% for barnyard) and Zn (61.77% for kodo), which is attributed to the reduction in phytic acid. Flaking, however, led to an increase in rapidly and slowly digestible starch with a corresponding decrease in resistant starch. Among the unsprouted and sprouted millet flakes, foxtail received the highest sensory scores for overall acceptability.

Tilapia-soybean protein co-precipitates: Focus on physicochemical properties, nutritional quality, and proteomics profile

The development of binary protein systems featuring superior nutritional properties and applied range is an interesting and challenging task in the food industry. In this study, the tilapia-soybean protein co-precipitates (TSPCs) with different mass ratios of tilapia meat and soybean meal were constructed. Results of physicochemical properties showed that the highest solubility and thermal stability values of TSPCs were 81.90 % and 90.30 °C, respectively. TSPCs have the full complement of amino acids and enhanced nutritional quality compared to tilapia protein isolate (TPI) and soybean protein isolate (SPI). TSPC2:1 and TSPC1:1 contained the highest levels of tryptophan, aspartic acid, glycine, histidine, and arginine relative to TPI and SPI. The in vitro protein digestibility and protein digestibility corrected amino acid scores of TSPCs were also higher than that of SPI. SDS-PAGE revealed that TSPCs contained protein subunits from TPI and SPI. Moreover, the lysine-to-arginine ratio and β subunit were greatly correlated with protein digestibility with correlation coefficients of -0.962 (P < 0.01) and -0.971 (P < 0.01), respectively. Compared to SPI, TSPCs displayed a lower lysine-to-arginine ratio and β-conglycinin content, which improved its digestibility. Proteomic analysis indicated that TSPC1:1 had 989 unique proteins, which gives TSPCs enhanced biological properties compared to TPI and SPI, allowing them to participate in a broad range of biochemical metabolic and signal transduction pathways. The study would advance the utilization of mixed proteins toward exceptional food industry applications.

Mechanism Insights of Antibacterial Surfaces Coated with Dead Probiotics

To understand the antimicrobial effect of surfaces fabricated with dead probiotics, we prepared surfaces decorated with dead probiotics Lactobacillus rhamnosus GG (LGG) with varied inactivation methods and explored their inhibitory interactions with Pseudomonas aeruginosa (PAO1). By combining several techniques, i.e., digital holographic microscopy (DHM), atomic force microscopy (AFM), RNA sequencing, and metabolomic analysis, we studied the three-dimensional (3D) swimming behaviors, surface adhesion, biofilm formation, and adaptive responses of PAO1 near such surfaces. The results show that planktonic PAO1 decreases their flick and reverse motions by downregulating the chemotaxis pathway and accelerates with less accumulation near dead LGG surfaces by upregulating the flagellar assembly pathway and decreasing cyclic adenosine monophosphate. Distinct from live siblings, the surfaces decorated with dead LGG show a significant reduction in adhesion strength with PAO1 and inhibit biofilm formation with more downregulated genes in the Pseudomonas quinolone signal and biofilm formation pathway. We demonstrate that the antibacterial ability of such surfaces stems from the gradually released lysate from the dead LGG that is unfavorable to PAO1 in close proximity. The releasing rate and order depend on the cell membrane integrity, which closely relates to the inactivation methods.

Potential Application of High Hydrostatic Pressure on the Production of Hydrolyzed Proteins with Antioxidant and Antihypertensive Properties and Low Allergenicity: A Review

The high hydrostatic pressure (HHP) process has been studied for several applications in food technology and has been commercially implemented in several countries, mainly for non-thermal pasteurization and shelf-life extension of food products. HHP processing has been demonstrated to accelerate proteolytic hydrolysis at a specific combination of pressure and pressure-holding time for a given protein source and enzyme. The enzymatic hydrolysis of proteins is a well-known alternative to producing biologically active peptides, with antioxidant and antihypertensive capacity, from different food protein sources. However, some of these protein sources contain allergenic epitopes which are often not degraded by traditional hydrolysis. Moreover, the peptide profile and related biological activity of a hydrolysate depend on the protein source, the enzymes used, the parameters of the proteolysis process (pH, temperature, time of hydrolysis), and the use of other technologies such as HHP. The present review aims to provide an update on the use of HHP for improving enzymatic hydrolysis, with a particular focus on studies which evaluated hydrolysate antihypertensive and antioxidant capacity, as well as residual allergenicity. Overall, HHP has been shown to improve the biological properties of hydrolysates. While protein allergenicity can be reduced with traditional hydrolysis, HHP can further reduce the allergenicity. Compared with traditional hydrolysis methods, HHP-assisted protein hydrolysis offers a greater opportunity to add value to protein-rich products through conversion into high-end hydrolysate products with enhanced nutritional and functional properties.

Effects of Microwaves, Ultrasonication, and Thermosonication on the Secondary Structure and Digestibility of Bovine Milk Protein

Cow’s milk is considered an excellent protein source. However, the digestibility of milk proteins needs to be improved. This study aimed to evaluate the relationship between the functional properties of milk proteins and their structure upon microwave, ultrasound, and thermosonication treatments. The protein content, digestibility, and secondary-structure changes of milk proteins were determined. The results demonstrated that almost 35% of the proteins in the untreated samples had a α-helix structure and approximately 29% a β-sheet and turns structure. Regarding the untreated samples, the three treatments increased the α-helices and correspondingly decreased the β-sheets and turns. Moreover, the highest milk protein digestibility was observed for the ultrasound-treated samples (90.20–94.41%), followed by the microwave-treated samples (72.56–93.4%), whereas thermosonication resulted in a lower digestibility (68.76–78.81%). The milk protein content was reduced as the microwave processing time and the temperature increased. The final milk protein available in the sample was lower when microwave processing was conducted at 75 °C and 90 °C compared to 60 °C, whereas the ultrasound treatment significantly improved the protein content, and no particular trend was observed for the thermosonicated samples. Thus, ultrasound processing shows a potential application in improving the protein quality of cow’s milk.

Use of UHPH to Obtain Juices With Better Nutritional Quality and Healthier Wines With Low Levels of SO2

Ultra-high pressure homogenization (UHPH) is a high pressure technique in which a fluid is pressurized by pumping at higher than 200 MPa and instantaneously depressurized at atmospheric pressure across a special valve. The full process takes <0.2 s and the in-valve time is <0.02 s. In the valve, extremely intense impacts and shear forces produce the nanofragmentation of biological tissue at a range of 100-300 nm. The antimicrobial effect is highly effective, reaching easily inactivation levels higher than 6-log cycles even at low in-valve temperatures. At in-valve temperatures of 140-150°C (0.02 s) the destruction of thermoresistant spores is possible. Even when the temperature in-valve can be elevated (70-150°C), it can be considered a gentle technology because of the tremendously short processing time. It is easy to get outlet temperatures after valve of 20-25°C by the expansion and assisted by heat exchangers. Thermal markers as hydroxymethylfurfural (HMF) are not formed, nor are deleterious effects observed in sensitive compounds as terpenes or anthocyanins, probably because of the low effect in covalent bonds of small molecules of the high-pressure techniques compared with thermal technologies. Additionally, intense inactivation of oxidative enzymes is observed, therefore protecting the sensory and nutritional quality of fruit juices and avoiding or reducing the use of antioxidants as sulphites. UHPH can be consider a powerful and highly effective continuous and sterilizing technology without thermal repercussions, able to keep fresh juices with most of their initial sensory and nutritional quality and allowing high-quality and natural fermented derivatives as wine.

Production of Antioxidant Hydrolyzates from a Lupinus mutabilis (Tarwi) Protein Concentrate with Alcalase: Optimization by Response Surface Methodology

Lupinus mutabilis (tarwi) is a cultivated legume used principally as a protein source in human and animal nutrition. In this study, protein concentrate was obtained from debittered and defatted tarwi seed flour. SDS-PAGE analysis revealed the presence of highly intense bands ranged between 35 and 60 kDa. Tarwi protein concentrate was subjected to the action of alcalase to produce hydrolyzates with antioxidant activity. A central composite design was employed to study the effect of the experimental variables, enzyme/substrate ratio and incubation time, on the degree of hydrolysis and the radical scavenging capacity. The influence of both variables on the variable responses was demonstrated. The optimal conditions to obtain the highest degree of hydrolysis were enzyme/substrate ratio of 1.72% and 133 min of incubation. The highest radical scavenging activity (TEAC value of 2.7 ± 0.1 μmol Trolox equivalents/mg protein and ORAC value of 3.8 ± 0.1 μmol Trolox equivalents/mg protein) was found in hydrolyzates with alcalase after 138 min and an enzyme/substrate ratio of 1.87%. Peptides released by the action of alcalase and containing hydrophobic and aromatic amino acids could contribute to the antioxidant effects observed. Tarwi proteins could be a new alternative as a food additive with antioxidant properties or as an ingredient of functional foods for health promotion and prevention of free radical-induced chronic diseases.

Invited review: Whey proteins as antioxidants and promoters of cellular antioxidant pathways

Oxidative stress contributes to cell injury and aggravates several chronic diseases. Dietary antioxidants help the body to fight against free radicals and, therefore, avoid or reduce oxidative stress. Recently, proteins from milk whey liquid have been described as antioxidants. This review summarizes the evidence that whey products exhibit radical scavenging activity and reducing power. It examines the processing and treatment attempts to increase the antioxidant bioactivity and identifies 1 enzyme, subtilisin, which consistently produces the most potent whey fractions. The review compares whey from different milk sources and puts whey proteins in the context of other known food antioxidants. However, for efficacy, the antioxidant activity of whey proteins must not only survive processing, but also upper gut transit and arrival in the bloodstream, if whey products are to promote antioxidant levels in target organs. Studies reveal that direct cell exposure to whey samples increases intracellular antioxidants such as glutathione. However, the physiological relevance of these in vitro assays is questionable, and evidence is conflicting from dietary intervention trials, with both rats and humans, that whey products can boost cellular antioxidant biomarkers.

Effect of heating and ionic strength on the interaction of bovine serum albumin and the antinutrients tannic and phytic acids, and its influence on in vitro protein digestibility

Bioavailability of food nutrients can be reduced in the presence of antinutrients such as phytates and tannins. This work aimed to study bovine serum albumin binding to phytic acid and tannic acid, and its influence on in vitro protein digestibility. The effect of autoclaving and boiling on protein digestibility and the microstructure of complexes was also evaluated. Results showed that high ionic strength promotes greater affinity between tannic acid and bovine serum albumin, and decreases in vitro protein digestibility. For phytic acid and bovine serum albumin, the opposite behavior is observed because interactions are governed by electrostatic forces. A rise in temperature above that causing denaturation of the protein favors its interaction with phytic acid, and disfavors that with tannic acid, probably due to different protein binding site exposure. For both antinutrients, heating treatment increased protein hydrolysis, the size of complexes and their fragility.

Effect of high hydrostatic pressure on the enzymatic hydrolysis of bovine serum albumin

BACKGROUND

The extent of enzymatic proteolysis mainly depends on accessibility of the peptide bonds, which stabilize the protein structure. The high hydrostatic pressure (HHP) process is able to induce, at certain operating conditions, protein displacement, thus suggesting that this technology can be used to modify protein resistance to the enzymatic attack. This work aims at investigating the mechanism of enzymatic hydrolysis assisted by HHP performed under different processing conditions (pressure level, treatment time). Bovine serum albumin was selected for the experiments, solubilized in sodium phosphate buffer (25 mg mL^-1 , pH 7.5) with α-chymotrypsin or trypsin (E/S ratio = 1/10) and HPP treatment (100-500 MPa, 15-25 min).

RESULTS

HHP treatment enhanced the extent of the hydrolysis reaction of globular proteins, being more effective than conventional hydrolysis. At HHP treatment conditions maximizing the protein unfolding, the hydrolysis degree of proteins was increased as a consequence of the increased exposure of peptide bonds to the attack of proteolytic enzymes. The maximum hydrolysis degree (10% and 7% respectively for the samples hydrolyzed with α-chymotrypsin and trypsin) was observed for the samples processed at 400 MPa for 25 min. At pressure levels higher than 400 MPa the formation of aggregates was likely to occur; thus the degree of hydrolysis decreased.

CONCLUSION

Protein unfolding represents the key factor controlling the efficiency of HHP-assisted hydrolysis treatments. The peptide produced under high pressure showed lower dimensions and a different structure with respect to those of the hydrolysates obtained when the hydrolysis was carried out at atmospheric pressure, thus opening new frontiers of application in food science and nutrition. © 2016 Society of Chemical Industry.

Pulmonary Pseudomonas aeruginosa infection induces autophagy and proteasome proteolytic pathways in skeletal muscles: effects of a pressurized whey protein-based diet in mice

Background: Pulmonary Pseudomonas aeruginosa infection in cystic fibrosis patients is associated with skeletal muscle atrophy. In this study, we investigated the effects of P. aeurginosa infection and a whey protein-rich diet on skeletal muscle proteolytic pathways.

Design: An agar bead model of pulmonary P. aeurginosa infection was established in adult C57/Bl6 mice. Protein ubiquitinaiton, lipidation of LC3B protein and expressions of autophagy-related genes and ubiquitin E3 ligases were quantified using immunoblotting and qPCR. The effects of pressure-treated whey protein diet on muscle proteolysis were also evaluated.

Results: Pulmonary P. aeurginosa infection reduced diaphragm, tibialis anterior, and soleus muscle weights and increased protein ubiquitination, LC3B protein lipidation, and the expressions of Lc3b, Gabarapl1, Bnip3, Parkin, Atrogin-1, and MuRF1 genes in each muscle. These changes were greater in the tibialis as compared to soleus and diaphragm. Proteolysis indicators increased within one day of infection but were not evident after seven days of infection. A pressurized whey diet attenuated LC3B protein lipidation, expressions of autophagy-related genes (BNIP3), pro-inflammatory cytokines, and protein ubiquitination.

Conclusions: We conclude that pulmonary P. aeruginosa infection activates the autophagy, and the proteasome pathways in skeletal muscles and that a pressurized whey protein diet attenuates muscle proteolysis in this model.

Malting process optimization for protein digestibility enhancement in finger millet grain

Finger millet (Eleusine coracana) is a nutritious, gluten-free, and drought resistant cereal containing high amounts of protein, carbohydrate, and minerals. However, bio-availability of these nutrients is restricted due to the presence of an excessive level of anti-nutrient components, mainly phytic acid, tannin, and oxalate. It has been shown that a well-designed malting/germination process can significantly reduce these anti-nutrients and consequently enhance the nutrient availability. In the present study, the effects of two important germination factors, duration and temperature, on the enhancement of in-vitro protein digestibility of finger millet were thoroughly investigated and optimized. Based on a central composite design, the grains were germinated for 24, 36, and 48 h at 22, 26, and 30 °C. For all factor combinations, protein, peptide, phytic acid, tannin, and oxalate contents were evaluated and digestibility was assessed. It was shown that during the malting/germinating process, both temperature and duration factors significantly influenced the investigated quantities. Germination of finger millet for 48 h at 30 °C increased protein digestibility from 74 % (for native grain) up to 91 %. Besides, it notably decreased phytic acid, tannin, and oxalate contents by 45 %, 46 %, and 29 %, respectively. Linear correlations between protein digestibility and these anti-nutrients were observed.

Clinical Potential of Hyperbaric Pressure-Treated Whey Protein

Whey protein (WP) from cow's milk is a rich source of essential and branched chain amino acids. Whey protein isolates (WPI) has been demonstrated to support muscle accretion, antioxidant activity, and immune modulation. However, whey is not readily digestible due to its tight conformational structure. Treatment of WPI with hyperbaric pressure results in protein unfolding. This enhances protein digestion, and results in an altered spectrum of released peptides, and greater release of essential and branched chain amino acids. Pressurized whey protein isolates (pWPI), through a series of cell culture, animal models and clinical studies, have been demonstrated to enhance muscle accretion, reduce inflammation, improve immunity, and decrease fatigue. It is also conceivable that pWPI would be more accessible to digestive enzymes, which would allow for a more rapid proteolysis of the proteins and an increased or altered release of small bioactive peptides. The altered profile of peptides released from WP digestion could thus play a role in the modulation of the immune response and tissue glutathione (GSH) concentrations. The research to date presents potentially interesting applications for the development of new functional foods based on hyperbaric treatment of WPI to produce products with more potent nutritional and nutraceutical properties.

High Hydrostatic Pressure Pretreatment of Whey Protein Isolates Improves Their Digestibility and Antioxidant Capacity

Whey proteins have well-established antioxidant and anti-inflammatory bioactivities. High hydrostatic pressure processing of whey protein isolates increases their in vitro digestibility resulting in enhanced antioxidant and anti-inflammatory effects. This study compared the effects of different digestion protocols on the digestibility of pressurized (pWPI) and native (nWPI) whey protein isolates and the antioxidant and anti-inflammatory properties of the hydrolysates. The pepsin-pancreatin digestion protocol was modified to better simulate human digestion by adjusting temperature and pH conditions, incubation times, enzymes utilized, enzyme-to-substrate ratio and ultrafiltration membrane molecular weight cut-off. pWPI showed a significantly greater proteolysis rate and rate of peptide appearance regardless of digestion protocol. Both digestion methods generated a greater relative abundance of eluting peptides and the appearance of new peptide peaks in association with pWPI digestion in comparison to nWPI hydrolysates. Hydrolysates of pWPI from both digestion conditions showed enhanced ferric-reducing antioxidant power relative to nWPI hydrolysates. Likewise, pWPI hydrolysates from both digestion protocols showed similar enhanced antioxidant and anti-inflammatory effects in a respiratory epithelial cell line as compared to nWPI hydrolysates. These findings indicate that regardless of considerable variations of in vitro digestion protocols, pressurization of WPI leads to more efficient digestion that improves its antioxidant and anti-inflammatory properties.

Digestibility and structural properties of thermal and high hydrostatic pressure treated sweet potato (Ipomoea batatas L.) protein

This study assessed the effects of thermal (40, 60, 80, 100 and 127 °C) and high hydrostatic pressure (HHP, 200, 400 and 600 MPa) treatments on the in vitro digestibility and structural properties of sweet potato protein (SPP). The results showed that the in vitro digestibility of SPP increased significantly with increasing heating temperature and heating time (0-60 min), while HHP treatment had little or no effect. Native SPP denaturation temperature (T d ) and enthalpy change (ΔH) were 89.0 °C and 9.6 J/g, respectively. Thermal and HHP treated SPP had T d of 84.6-88.9 °C and 86.4-87.6 °C, respectively. ΔH of thermal treated SPP was 3.6-6.4 J/g, while that of HHP treated SPP was 5.9-7.8 J/g. The differential scanning calorimetry (DSC) results demonstrated that HHP and thermal treatments both significantly reduced SPP thermodynamic stability. Circular dichroism analyses revealed that native SPP contains α-helixes, β-sheets and random coils (4.3, 48.0 and 47.7%, respectively). After thermal treatment at 127 °C for 20 min, the content of α-helixes and turns increased significantly (13.2 and 27.6%, respectively), whereas the content of β-sheets decreased significantly (12.3%). In contrast, HHP treatment increased the content of β-sheets, but decreased the content of random coils. This study suggested that the SPP structure changes might be the main reason affecting the in vitro digestibility of SPP, and thermal treatment was more effective at changing SPP secondary structures and improving in vitro SPP digestibility than HHP treatment.

Pressurized whey protein can limit bacterial burden and protein oxidation in Pseudomonas aeruginosa lung infection

BACKGROUND

Lung infection caused by Pseudomonas aeruginosa is associated with an exuberant inflammatory response, oxidative stress, and lung damage. Whey protein is a rich source of cysteine, and anti-inflammatory and immune-enhancing peptides. Anti-inflammatory and antioxidant properties of whey are augmented by hyperbaric pressure treatment. In this study, we tested whether dietary supplementation with pressurized whey protein enhances the host ability to clear P. aeruginosa infection compared with native (i.e., unpressurized) whey.

METHODS

Using a minimally invasive, non-lethal model of murine (female C57Bl/6) model of P. aeruginosa infection (mucoid strain embedded in agar beads), we studied kinetics of infection, inflammation, and oxidative stress at d 1, 3, and 7 postinfection. A parallel set of mice were fed for 4 wk a semipurified diet containing either native or pressurized whey and subsequently infected with P. aeruginosa. In these mice, the parameters mentioned previously were studied at d 1 and 3 postinfection.

RESULTS

Infection with P. aeruginosa resulted in inflammation and protein oxidation sustained beyond bacterial clearance. Animals that were fed pressurized whey had fewer bacteria at day 3 than mice on native whey. Weight loss or broncho-alveolar lavage cell content were comparable. Airway protein oxidation was attenuated, whereas airway leukocyte bacterial killing ability and oxidative burst in response to opsonized bacteria were increased in the pressurized whey-fed animals.

CONCLUSIONS

Use of nutritionally derived substances with anti-inflammatory and antioxidant properties, such as pressurized whey, aids in limiting airway bacterial infection, particularly, under conditions of ongoing oxidative stress.

A new strategy for improved glutathione production from Saccharomyces cerevisiae: use of cysteine- and glycine-rich chicken feather protein hydrolysate as a new cheap substrate

BACKGROUND

Glutathione (GSH) is composed of the amino acids glutamic acid, cysteine and glycine. This study investigated the usability of chicken feather protein hydrolysate (chicken feather peptone, CFP) as a substrate for GSH production from Saccharomyces cerevisiae.

RESULTS

CFP was found to be rich in ash (36.7 g per 100 g), protein (61.1 g per 100 g) and minerals (S, P, K, Ca, Fe, Na and Mg). It also had high contents of cysteine and glycine. CFP augmented biomass and GSH production by 53 and 115% respectively compared with the control medium. The highest biomass (17.4 g l(-1)) and GSH (271 mg L(-1)) concentrations were attained in CFP medium. The second highest biomass (16.8 g l(-1)) and GSH (255 mg L(-1)) concentrations were obtained in fish peptone medium. It was assumed that the high mineral, cysteine and glycine contents of CFP were related to cell growth and GSH synthesis in S. cerevisiae.

CONCLUSION

This is the first report on the effect of cysteine- and glycine-rich protein hydrolysates on GSH production from S. cerevisiae. In this regard, CFP was tested for the first time as a GSH production substrate. As an additional contribution, a new hydrolysis process was developed for the preparation of protein hydrolysates.

Whey protein hydrolysates decrease IL-8 secretion in lipopolysaccharide (LPS)-stimulated respiratory epithelial cells by affecting LPS binding to Toll-like receptor 4

Whey proteins (WP) exert anti-inflammatory and antioxidant effects. Hyperbaric pressurisation of whey increases its digestibility and changes the spectrum of peptides released during digestion. We have shown that dietary supplementation with pressurised whey improves nutritional status and systemic inflammation in patients with cystic fibrosis (CF). Both clinical indices are largely affected by airway processes, to which respiratory epithelial cells actively contribute. Here, we tested whether peptides released from the digestion of pressurised whey can attenuate the inflammatory responses of CF respiratory epithelial cells. Hydrolysates of pressurised WP (pWP) and native WP (nWP, control) were generated in vitro and tested for anti-inflammatory properties judged by the suppression of IL-8 production in CF and non-CF respiratory epithelial cell lines (CFTE29o- and 1HAEo-, respectively). We observed that, in both cell lines, pWP hydrolysate suppressed IL-8 production stimulated by lipopolysaccharide (LPS) to a greater magnitude compared with nWP hydrolysate. Neither hydrolysate suppressed IL-8 production induced by TNF-α or IL-1β, suggesting an effect on the Toll-like receptor (TLR) 4 pathway, the cellular sensor for LPS. Further, neither hydrolysate affected TLR4 expression or neutralised LPS. Both pWP and nWP hydrolysates similarly reduced LPS binding to surface TLR4, while pWP tended to more potently increase extracellular antioxidant capacity.

IN CONCLUSION

(1) anti-inflammatory properties of whey are enhanced by pressurisation; (2) suppression of IL-8 production may contribute to the clinical effects of pressurised whey supplementation on CF; (3) this effect may be partly explained by a combination of reduced LPS binding to TLR4 and enhanced extracellular antioxidant capacity.

Casein protein results in higher prandial and exercise induced whole body protein anabolism than whey protein in chronic obstructive pulmonary disease

Exercise is known to improve physical functioning and health status in Chronic Obstructive Pulmonary Disease (COPD). Recently, disturbances in protein turnover and amino acid kinetics have been observed after exercise in COPD. The objective was to investigate which dairy protein is able to positively influence the protein metabolic response to exercise in COPD. 8 COPD patients and 8 healthy subjects performed a cycle test on two days while ingesting casein or whey protein. Whole body protein breakdown (WbPB), synthesis (WbPS), splanchnic amino acid extraction (SPE), and NetWbPS (=WbPS-WbPB) were measured using stable isotope methodology during 20 min of exercise (at 50% peak work load of COPD group). The controls performed a second exercise test at the same relative workload. Exercise was followed by 1 h of recovery. In the healthy group, WbPS, SPE, and NetPS were higher during casein than during whey feeding (P<.01). WbPS and NetPS were higher during exercise, independent of exercise intensity (P<.01). NetPS was higher during casein feeding in COPD due to lower WbPB (P<.05). Higher SPE was found during exercise during casein and whey feeding in COPD (P<.05). Lactate levels during exercise were higher in COPD (P<.05) independent of the protein. Post-exercise, lower NetPS values were found independent of protein type in both groups. Casein resulted in more protein anabolism than whey protein which was maintained during and following exercise in COPD. Optimizing protein intake might be of importance for muscle maintenance during daily physical activities in COPD.

High hydrostatic pressure pre-treatment of whey proteins enhances whey protein hydrolysate inhibition of oxidative stress and IL-8 secretion in intestinal epithelial cells

BACKGROUND

High hyperbaric pressure treatment of whey protein isolate (WPI) causes changes in the protein structure that enhances the anti-oxidant and anti-inflammatory effects of WPI.

OBJECTIVE

The aim of this study was to compare the anti-oxidant and anti-inflammatory effects of pressurized whey protein isolate (pWPI) vs. native WPI (nWPI) hydrolysates in Caco-2 cells exposed to hydrogen peroxide (H(2)O(2)).

DESIGN

Cells were cultured with different concentrations of pWPI or nWPI hydrolysates either 1 h before or 1 h after H(2)O(2). Cell viability, IL-8 secretion, intracellular reactive oxygen species (ROS), and the medium anti-oxidant capacity (FRAP assay) were measured.

RESULTS

Prior to and after H(2)O(2) exposure, pWPI and nWPI hydrolysates inhibited IL-8 secretion and ROS generation, and increased FRAP activity in a dose-dependent manner. The maximal inhibition of H(2)O(2)-induced IL-8 secretion was greater with 2000 µg mL(-1) of pWPI (50%) vs. nWPI (30%) hydrolysates. At the latter concentration, inhibition of H(2)O(2)-induced ROS formation reached 76% for pWPI, which was greater than for nWPI hydrolysates (32.5%).

CONCLUSIONS

These results suggest that WPI hydrolysates can alleviate inflammation and oxidative stress in intestinal cells exposed to oxidative injury, which is further enhanced by hyperbaric pressure pre-treatment of WPI.

Dietary supplementation with pressurized whey in patients with cystic fibrosis

Cystic fibrosis (CF) is characterized by malnutrition, chronic pulmonary inflammation, and oxidative stress. Whey protein is rich in sulfhydryl groups and is recognized for its ability to increase glutathione and reduce oxidative stress. Previously, we have shown that supplementation with whey increased intracellular glutathione levels in patients with CF. We have subsequently shown that hyperbaric pressure treatment of whey protein promotes the release of novel peptides for absorption, increases intracellular glutathione in healthy subjects, and reduces in vitro production of interleukin (IL)-8. We hypothesized that pressurized whey supplementation in children and adults with CF could have significant nutritional and anti-inflammatory benefits. A pilot open-label study of 1-month dietary supplementation with pressurized whey in CF patients was undertaken to assess the effects. Twenty-seven patients with CF (nine children, 18 adults) were enrolled. The dose of pressurized whey was 20 g/day in patients less than 18 years of age and 40 g/day in older patients. Anthropometric measures, pulmonary function, serum C-reactive protein (CRP), whole blood glutathione, and whole blood IL-8 and IL-6 responses to phytohemagglutinin (PHA) stimulation were measured at baseline and at 1 month. Three adults withdrew (one with gastrointestinal side effects, two with acute infection). Both children and adults showed enhancements in nutritional status, as assessed by body mass index. Children showed improvement in lung function (forced expiratory volume in 1 second). The majority of patients with an initially elevated CRP showed a decrease. PHA-stimulated IL-8 responses tended to decrease in the adults. Whole blood glutathione levels did not change. Thus, oral supplementation with pressurized whey improves nutritional status and can have additional beneficial effects on inflammation in patients with CF.

An open-label dose-response study of lymphocyte glutathione levels in healthy men and women receiving pressurized whey protein isolate supplements

BACKGROUND

High-pressure treatment of whey protein may increase digestibility and bioavailability of cysteine. The purpose of the study was to determine whether total lymphocyte glutathione (gamma-glutamyl-cysteinyl-glycine [GSH]) levels (oxidized+reduced) can be augmented from three different doses of pressurized whey protein supplements in a dose-dependent manner over a 2-week period.

METHODS

Eighteen healthy males and 18 healthy females were randomized into three different groups, with 31 finishing the study. Each group ingested 15, 30, or 45 g/day pressurized whey protein in the morning in bar format for 14 days. Each group was blinded to the amount of whey protein they were ingesting. Ten millilitres of blood was withdrawn before and after the 2-week period to assess blood lymphocyte levels pre and post supplementation.

RESULTS

There was no change in body weight or reported physical activity levels pre and post supplementation. Pre-lymphocyte GSH levels were not significantly different between groups (3.7+/-0.7 micromol/l). Least-squares linear regression showed that the change in lymphocyte GSH levels from pre to post supplementation was affected by the amount of whey protein ingested daily (P=0.037). The group that ingested 45 g/day pressurized whey protein augmented GSH levels the most (by approximately 24%), and the group that ingested 15 g/day did not increase lymphocyte GSH levels.

CONCLUSIONS

We conclude that there is a significant relationship between the dosage of supplementation and the change in lymphocyte GSH levels. Furthermore, the increase in GSH was linear with the amount of whey protein ingested. Pressurized whey protein supplementation of 45 g/day for 2 weeks can increase lymphocyte GSH by 24%.

Nutrition in pediatric lung disease

The respiratory system exists in an oxygenated milieu and is recurrently exposed to both endogenous and exogenous oxidants and irritants. A variety of dietary-dependent defenses have evolved to protect the lungs. These comprise vitamins, proteins, polyphenols, fatty acids and co-factors. This is a brief review of oxidant sources and the antioxidant system, as pertains to the respiratory system. The challenge to both clinicians and investigators is to understand how defenses are integrated and coordinated so that enhanced protection can be delivered.