Concept: Whey protein
BACKGROUND: Consumption of moderate amounts of animal-derived protein has been shown to differently influence skeletal muscle hypertrophy during resistance training when compared with nitrogenous and isoenergetic amounts of plant-based protein administered in small to moderate doses. Therefore, the purpose of the study was to determine if the post-exercise consumption of rice protein isolate could increase recovery and elicit adequate changes in body composition compared to equally dosed whey protein isolate if given in large, isocaloric doses. METHODS: 24 college-aged, resistance trained males were recruited for this study. Subjects were randomly and equally divided into two groups, either consuming 48 g of rice or whey protein isolate (isocaloric and isonitrogenous) on training days. Subjects trained 3 days per week for 8 weeks as a part of a daily undulating periodized resistance-training program. The rice and whey protein supplements were consumed immediately following exercise. Ratings of perceived recovery, soreness, and readiness to train were recorded prior to and following the first training session. Ultrasonography determined muscle thickness, dual emission x-ray absorptiometry determined body composition, and bench press and leg press for upper and lower body strength were recorded during weeks 0, 4, and 8. An ANOVA model was used to measure group, time, and group by time interactions. If any main effects were observed, a Tukey post-hoc was employed to locate where differences occurred. RESULTS: No detectable differences were present in psychometric scores of perceived recovery, soreness, or readiness to train (p > 0.05). Significant time effects were observed in which lean body mass, muscle mass, strength and power all increased and fat mass decreased; however, no condition by time interactions were observed (p > 0.05). CONCLUSION: Both whey and rice protein isolate administration post resistance exercise improved indices of body composition and exercise performance; however, there were no differences between the two groups.
BACKGROUND: The pattern of protein intake following exercise may impact whole-body protein turnover and net protein retention. We determined the effects of different protein feeding strategies on protein metabolism in resistance-trained young men. METHODS: Participants were randomly assigned to ingest either 80g of whey protein as 8x10g every 1.5h (PULSE; n=8), 4x20g every 3h (intermediate, INT; n=7), or 2x40g every 6h (BOLUS; n=8) after an acute bout of bilateral knee extension exercise (4x10 repetitions at 80% maximal strength). Whole-body protein turnover (Q), synthesis (S), breakdown (B), and net balance (NB) were measured throughout 12h of recovery by a bolus ingestion of [15N]glycine with urinary [15N]ammonia enrichment as the collected end-product. RESULTS: PULSE Q rates were greater than BOLUS (~19%, P<0.05) with a trend towards being greater than INT (~9%, P=0.08). Rates of S were 32% and 19% greater and rates of B were 51% and 57% greater for PULSE as compared to INT and BOLUS, respectively (P<0.05), with no difference between INT and BOLUS. There were no statistical differences in NB between groups (P=0.23); however, magnitude-based inferential statistics revealed likely small (mean effect+/-90%CI; 0.59+/-0.87) and moderate (0.80+/-0.91) increases in NB for PULSE and INT compared to BOLUS and possible small increase (0.42+/-1.00) for INT vs. PULSE. CONCLUSION: We conclude that the pattern of ingested protein, and not only the total daily amount, can impact whole-body protein metabolism. Individuals aiming to maximize NB would likely benefit from repeated ingestion of moderate amounts of protein (~20g) at regular intervals (~3h) throughout the day.
In this paper, the extracts of three-part beggarticks (Bidens tripartita) were prepared using ultrasonic assisted micelle-mediated extraction method (UAMME). Different kind of surfactants and WPC (whey protein concentrate) were applied. In the B. tripartita extracts twenty polyphenols were identified by UPLC-DAD-MS. Both aqueous and UAMME extracts mainly contained chlorogenic acid, caftaric acid and its derivatives as well as luteolin 7-O-glucoside. The luteolin was extracted with Rokanol B2 and Triton X-100. Furthermore, antioxidative properties of the extracts were analyzed with two methods: reactions with di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH) reagent and Follin’s method. The DPPH radical scavenging by micellar extracts was in general comparable with the antioxidant activity of conventional extracts. The most active was sample with Tego Care CG90, reducing about 73% of the radical. Obtained results confirmed that the UAMME might be an alternative method, to the liquid-liquid or solid-liquid extraction, of obtaining specified extracts rich in active compounds. Selecting a suitable surfactant may thus provide the expected composition of the extract.
Previous work demonstrated that a soy-dairy protein blend (PB) prolongs hyperaminoacidemia and muscle protein synthesis in young adults after resistance exercise.
The differential ability of various milk protein fractions to stimulate muscle protein synthesis (MPS) has been previously described, with whey protein generally considered to be superior to other fractions. However, the relative ability of a whole milk protein to stimulate MPS has not been compared to whey. Sixteen healthy middle-aged males ingested either 20 g of milk protein (n = 8) or whey protein (n = 8) while undergoing a primed constant infusion of ring (13)C₆ phenylalanine. Muscle biopsies were obtained 120 min prior to consumption of the protein and 90 and 210 min afterwards. Resting myofibrillar fractional synthetic rates (FSR) were 0.019% ± 0.009% and 0.021% ± 0.018% h(-1) in the milk and whey groups respectively. For the first 90 min after protein ingestion the FSR increased (p < 0.001) to 0.057% ± 0.018% and 0.052% ± 0.024% h(-1) in the milk and whey groups respectively with no difference between groups (p = 0.810). FSR returned to baseline in both groups between 90 and 210 min after protein ingestion. Despite evidence of increased rate of digestion and leucine availability following the ingestion of whey protein, there was similar activation of MPS in middle-aged men with either 20 g of milk protein or whey protein.
A RP-HPLC method, developed for the separation and quantification of the most common genetic variants of bovine milk proteins, was successfully applied to the analysis of water buffalo milk. All the most common buffalo casein and whey proteins fractions, as well as their genetic variants, were detected and separated simultaneously in 40 min. Purified buffalo proteins were used as calibration standards and a total of 536 individual milk samples were analysed for protein composition. α(S1)-, α(S2)-, βγ-, and κ-casein were 32.2%, 15.8%, 36.5%, and 15.5%, respectively, of total casein content, whereas content of β-Lactoglobulin was approximately 1.3 times as high as that of α-Lactalbumin. The existence of a polymorphism of κ-casein was demonstrated in Mediterranean water buffalo and α(S1)- and κ-casein genetic variants were successfully detected by RP-HPLC.
The aim of this study is to prepare whey protein (WP)-based microparticles (MP) using the Encapsulator(®) device. The viscosity dependence of the extrusion device required to mix WP with a food-grade and less viscous polymer. Mixed WP/ALG MP were obtained with the optimized WP/alginate (ALG) ratio (62/38). These particles were further coated with WP or ALG using non-traumatic and solvent-free coating process developed in this study. Size and morphology of coated and uncoated MP were determined. Then, swelling and degradation (WP release) of formulations were investigated in pH 1.2 and 7.5 buffers and in simulated gastric and intestinal fluids (SGF, SIF) and compared to pure ALG and pure WP particle behaviours. At pH 1.2, pure ALG shrank and pure WP swelled, whereas the sizes of mixed WP/ALG matrix were stable. In SGF, WP/ALG MP resisted to pepsin degradation compare to pure WP particles due to ALG shrinkage which limited pepsin diffusion within particles. Coating addition with WP or ALG slowed down pepsin degradation. At pH 7.5, WP/ALG particles were rapidly degraded due to ALG sensitivity but the addition of a WP coating limited effectively the swelling and the degradation of MP. In SIF, pancreatin accelerated MP degradation but ALG-coated MP exhibited interesting robustness. These results confirmed the interest and the feasibility to produce coated WP-based MP which could be a potential orally controlled release drug delivery system.
Samples of fresh skim milk, reconstituted micellar casein, and casein powder were sonicated at 20kHz to investigate the effect of ultrasonication. For fresh skim milk, the average size of the remaining fat globules was reduced by approximately 10nm after 60min of sonication; however, the size of the casein micelles was determined to be unchanged. A small increase in soluble whey protein and a corresponding decrease in viscosity also occurred within the first few minutes of sonication, which could be attributed to the breakup of casein-whey protein aggregates. No measurable changes in free casein content could be detected in ultracentrifuged skim milk samples sonicated for up to 60min. A small, temporary decrease in pH resulted from sonication; however, no measurable change in soluble calcium concentration was observed. Therefore, casein micelles in fresh skim milk were stable during the exposure to ultrasonication. Similar results were obtained for reconstituted micellar casein, whereas larger viscosity changes were observed as whey protein content was increased. Controlled application of ultrasound can be usefully applied to reverse process-induced protein aggregation without affecting the native state of casein micelles.
Whey protein isolate (WPI) nanoparticles were prepared using ethanol desolvation, and their capacity to incorporate ZnCl(2) was analysed. Desolvation was carried out at pH 9 and the volume of added ethanol was 0-3 times the volume of protein solution. The desolvated solutions were dispersed in acidified water (pH 3) immediately after desolvation. The size of the WPI nanoparticles increased with the volume ratio of ethanol:water used, as well as with the amount of ZnCl(2). The nanoparticles showed high incorporation efficiencies, and remained stable after 30 days of storage at 22 °C. The amount of zinc incorporated in the WPI particle suspensions was within the range of daily zinc requirements for healthy adults.
Insect-resistant films containing a microencapsulated insect-repelling agent were developed to protect food products from the Indian meal moth (Plodia interpunctella). Cinnamon oil (CO), an insect repelling agent, was encapsulated with gum arabic, whey protein isolate (WPI)/maltodextrin (MD), or poly(vinyl alcohol) (PVA). A low-density polyethylene (LDPE) film was coated with an ink or a polypropylene (PP) solution that incorporated the microcapsules. The encapsulation efficiency values obtained with gum arabic, WPI/MD, and PVA were 90.4%, 94.6%, and 80.7%, respectively. The films containing a microcapsule emulsion of PVA and CO or incorporating a microcapsule powder of WPI/MD and CO were the most effective (P < 0.05) at repelling moth larvae. The release rate of cinnamaldehyde, an active repellent of cinnamaldehyde, in the PP was 23 times lower when cinnamaldehyde was microencapsulated. Coating with the microcapsules did not alter the tensile properties of the films. The invasion of larvae into cookies was prevented by the insect-repellent films, demonstrating potential for the films in insect-resistant packaging for food products.