Whey Protein Concentrates and Isolates

Background: Whey protein is a popular supplement in sports nutrition. Soy protein is an alternative to whey protein, often marketed to individuals following a plant-based diet. Evaluating whey and soy protein supplementation's role in resistance exercise is essential for providing evidence-based nutrition guidance. Objective: The study aim was to conduct a systematic literature review and meta-analysis on randomized control trials (RCTs) on the effectiveness of whey and soy protein supplementation on outcomes of lean body mass (LBM), squat, bench press, and plasma essential plasma amino acid (EAA) levels in young adult men and women. Methods: The databases searched included: Cochrane, EBSCO Host, PubMed, and Scopus. Inclusion criteria were interventions that included whey or soy protein concentrate or isolate and participants aged 18 to 30 years who engage in resistance exercise. Exclusion criteria were randomized control trials (RCTs), protein supplements with additives, and unspecified protein supplements. Two reviewers independently evaluated 1813 studies based on the inclusion and exclusion criteria. Studies that met these criteria underwent data extraction for LBM, squat, bench press, and circulating EAA. The studies were assessed for risk of bias was assessed using the Cochrane RoB 2 tool for RCTs. A meta-analysis was performed using a random-effects model. Results: The review included a total of 12 studies with 261 participants. There was no significant effect of supplementing whey or soy protein intervention on LBM mean difference (MD) (1.13; 95% CI: -0.76, 3.02; p=0.22, I2 =55.7%), squat performance (MD 4.06; 95% CI:-5.46, 13.57; p=0.34, I2 =77.5%). However, whey protein supplementation had a significant effect on bench press (MD 5.72; 95% CI:1.30, 10.15; p=0.02, I2 =61.2%). Conclusion: These findings suggest that while both whey and soy proteins can be part of a resistance training regimen, whey protein may offer a specific advantage in enhancing upper body strength in young adults engaging in resistance training. Due to the small number of studies and sample size, these findings should be interpreted with caution. Further research with larger-powered randomized controlled trials is necessary to provide more definitive conclusions regarding the effectiveness of protein supplements for enhancing strength performance.

This study compared the effects of dietary whey protein with dietary casein or soy protein on glycogen storage and glycoregulatory enzyme activities in the liver of sedentary and exercise-trained rats. Male Sprague-Dawley rats (ca. 130 g) were divided into one sedentary and three exercise-trained groups, with eight animals in each group. Casein was provided as the source of dietary protein in the sedentary group while the exercise-trained groups were fed casein, whey, or soy protein. Rats in the exercise-trained groups ran for 30 mins/day, 4 days/week on a motor-driven treadmill. In the exercise-trained rats, animals fed whey protein had higher liver glycogen content than animals in the other two diet groups. Glucokinase activity was significantly higher in rats fed whey protein compared to that in rats fed soy protein, while glucose 6-phosphatase activity was significantly decreased in animals on the whey protein diet compared with those the other two diets. Although 6-phospho-fructokinase activity was significantly lower in the whey protein group than in the soy protein group, we found that fructose 1,6-bisphosphatase activity was significantly higher in the whey group compared with either the casein or soy groups. Pyruvate kinase activity in rats fed the casein diet was significantly higher than in rats fed either the whey or soy protein diets. In addition, hepatic alanine aminotransferase activity and serum alanine level were also increased in the whey protein group compared with the casein or soy protein groups. Taken together, these results demonstrate that the whey protein diet in exercise-trained rats results in significantly higher levels of liver glycogen, because of the combined effects of regulation of rate limiting glycolytic and gluconeogenic enzyme activities and activation of glycogenesis from alanine via alanine amino-transferase.

Whey and soy proteins have a variety of applications. Previous work has documented flavors of rehydrated whey and soy proteins. It is necessary to understand what flavors whey and soy proteins contribute to product applications to optimize protein performance in desired applications. This research was conducted to characterize sensory properties of meal replacement products containing whey and soy proteins. Flavor and texture lexicons were developed for meal replacement bars and beverages. Commercial peanut butter-flavored meal replacement bars and vanilla meal replacement shakes were evaluated by an experienced, trained descriptive panel (n= 9). Prototypes of bars and beverages were developed with 3 levels of whey and soy protein and subsequently evaluated. Consumer acceptance testing (n= 85) was conducted on the prototype bars and beverages. Protein type as well as product-specific formulation contributed differences in flavor and texture of commercial bars and beverages (P < 0.05). Sensory properties of prototype bars and beverages fell within the spectrum of commercial products. Prototype bars made with whey protein were characterized by sweet aromatic and vanillin flavor notes while the texture was characterized by adhesiveness and cohesiveness. Prototype bars made with soy protein were characterized by nutty flavor while the texture was characterized by tooth-pack and denseness. Whey protein contributed to sweet aromatic and vanillin flavors in prototype beverages while soy protein contributed cereal/grainy flavors. Consumer acceptance scores were higher for prototype bars and beverages containing whey protein or a mixture of whey/soy protein than for products made with soy protein alone (P < 0.05). These results will aid researchers and product developers in optimizing sensory quality in meal replacement products.

Guanzhong goat and Holstein cow milks are the major milk supply for the Chinese dairy industry. Whey proteins and milk fat globule membrane (MFGM) proteins of both milk were characterized and compared using proteomic techniques. A total of 283, 159, 593, and 349 proteins were identified, respectively, in whey and MFGM for the two species using Liquid Chromatography combined with Tandem Mass Spectrometry (LC-MS/MS). Functional categories analyses showed that both goat and cow MFGM proteins had three most abundant proteins of phosphoproteins, membrane-related and acetylation-related proteins. Gene ontology (GO) annotation revealed that whey proteins in goat and cow milk exhibited different biological processes and molecular functions while both enriched in extracellular exosome for cellular components. Both goat and cow MFGM proteins showed main biological process of oxidation-reduction, cellular component of extracellular exosome, and molecular function of poly(A) RNA binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that large number of both goat and cow whey proteins were involved in disease, metabolism, and immune pathways with different number and types. The most general pathways for goat and cow MFGM proteins were metabolism pathways and disease pathways, respectively. The results indicated that Guanzhong goat and Holstein cow milk were different in varieties of whey proteins and MFGM proteins and their functions and pathways. PRACTICAL APPLICATION: Guanzhong goat and Holstein cow milks are the major milk sources for the Chinese consumers. However, information about proteomics of whey and MFGM proteins of Guanzhong goat and Holstein cow milk is limited. Our study characterized and compared both whey and MFGM proteins using proteomic techniques. The results provide useful information for infant formula and milk protein products in the Chinese dairy industry.

Whey protein (WP) is characterized as a “fast” protein and caseinate (CA) as a “slow” protein according to their digestion and absorption rates. We hypothesized that co-ingestion of milk proteins (WP and CA) may be effective for prolonging the muscle protein synthesis response compared to either protein alone. We therefore compared the effect of ingesting milk protein (MP) to either WP or CA alone on muscle protein synthesis after exercise in rats. We also compared the effects of these milk-derived proteins to a control, soy protein (SP). Male Sprague-Dawley rats swam for two hours. Immediately after exercise, one of the following four solutions was administered: WP, CA, MP, or SP. Individual rats were euthanized at designated postprandial time points and triceps muscle samples collected for measurement of the protein fractional synthesis rate (FSR). FSR tended to increase in all groups post-ingestion, although the initial peaks of FSR occurred at different times (WP, peak time = 60 min, FSR = 7.76%/day; MP, peak time = 90 min, FSR = 8.34%/day; CA, peak time = 120 min, FSR = 7.85%/day). Milk-derived proteins caused significantly greater increases (p < 0.05) in FSR compared with SP at different times (WP, 60 min; MP, 90 and 120 min; CA, 120 min). Although statistical analysis could not be performed, the calculated the area under the curve (AUC) values for FSR following this trend were: MP, 534.61; CA, 498.22; WP, 473.46; and SP, 406.18. We conclude that ingestion of MP, CA or WP causes the initial peak time in muscle protein synthesis to occur at different times (WP, fast; MP, intermediate; CA, slow) and the dairy proteins have a superior effect on muscle protein synthesis after exercise compared with SP.

BackgroundSoccer-specific speed-endurance training induces short-term neuromuscular fatigue and performance deterioration over a 72-h recovery period, associated with elevated markers of exercise-induced muscle damage. We compared the effects of whey vs. soy protein supplementation on field activity, performance, muscle damage and redox responses following speed-endurance training in soccer players.MethodsTen well-trained, male soccer players completed three speed-endurance training trials, receiving whey protein (WP), soy protein (SP) or an isoenergetic placebo (PL; maltodextrin) according to a randomized, double-blind, crossover, repeated-measures design. A pre-loading period was applied in each trial during which protein supplementation was individually adjusted to reach a total protein intake of 1.5 g/kg/day, whereas in PL protein intake was adjusted at 0.8–1 g/kg/day. Following pre-loading, two speed-endurance training sessions (1 and 2) were performed 1 day apart, over a 3-day experimental period. During each session, field activity and heart rate were continuously monitored using global positioning system and heart rate monitors, respectively. Performance (isokinetic strength of knee extensors and flexors, maximal voluntary isometric contraction, speed, repeated sprint ability, countermovement jump), muscle damage (delayed-onset of muscle soreness, creatine kinase activity) and redox status (glutathione, total antioxidant capacity, protein carbonyls) were evaluated at baseline (pre), following pre-loading (post-load), and during recovery from speed-endurance training.ResultsHigh-intensity and high-speed running decreased (P ≤ 0.05) during speed-endurance training in all trials, but WP and SP mitigated this response. Isokinetic strength, maximal voluntary isometric contraction, 30-m speed, repeated sprint ability and countermovement jump performance were similarly deteriorated during recovery following speed-endurance training in all trials (P ≤ 0.05). 10 m speed was impaired at 24 h only in PL. Delayed-onset of muscle soreness, creatine kinase, total antioxidant capacity and protein carbonyls increased and glutathione decreased equally among trials following speed-endurance training (P ≤ 0.05), with SP inducing a faster recovery of protein carbonyls only at 48 h (P ≤ 0.05) compared to WP and PL.ConclusionsIn conclusion, increasing daily protein intake to 1.5 g/kg through ingestion of either whey or soy protein supplements mitigates field performance deterioration during successive speed-endurance training sessions without affecting exercise-induced muscle damage and redox status markers.Trial registrationName of the registry: clinicaltrials.gov. Trial registration: NCT03753321. Date of registration: 12/10/2018.

4 - Whey proteins

The corticosterone-binding protein present in rat whey was further characterized by determining, with the aid of a dextran-coated charcoal procedure, the apparent rate of dissociation of the corticosterone.protein complex. The half-time values for the dissociation of the corticosterone.protein complexes in rat whey and serum were compared and found to be identical, i.e. 23 min at 0 C, when the measurements were made over a period of 40 min. The possible presence in small amounts of a corticosterone.protein complex in whey with the much slower dissociation rate characteristic of mammary glucocorticoid receptor could not be detected even when the dissociation was followed over a much longer period. The charcoal adsorption method also provided independent estimates of the molar concentrations of the corticosterone-binding proteins in rat serum and whey. The mean concentration of corticosterone-binding protein in whey was found to be 15% of that in coincidental serum during early lactation. The serum levels of corticosterone-binding protein decline markedly at parturition and then rise from day 2 to day 6 of lactation in rats with small litters. The results of this and a previous study suggest that the corticosterone-binding protein in whey is probably derived from that in serum. The mode of transport of the corticosterone-binding protein from the bloodstream across the mammary epithelium into milk as well as the concentrations of the corticosterone-binding proteins in serum and whey may be factors influencing the uptake of the glucocorticoid by its target cells.

0159 The depletion of glycogen storages has been associated with fatigue during constantload exercise. Therefore, it is important to examine some regulatory enzyme activities of the carbohydrate metabolism and determine the reasons for the glycogen accumulation in the liver. PURPOSE: We investigated whether dietary whey protein, as compared with dietary casein or soy protein, affected the storage of glycogen and glycoregulatory enzymes activity in sedentary or exercised rats liver. METHODS: 32 male Sprague-Dawley rats (ca. 130 g) were used. After acclimation, all rats were divided into one sedentary or three exercised groups (n = 8). In the sedentary group, casein was the source of dietary protein, while the three exercised groups were fed either casein, whey protein or soy protein. All experimental diets contained 20% protein. Rats were allowed free access to food and water for 4 weeks. Rats in the exercised groups were trained using a motor-driven treadmill for 30 min/day, 4 days/week. The running speed was 20 m/min, 7o inclination during the first 5 min, and 25 m/min, 7o inclination during the last 25 min. At end of the training period, all the rats were sacrificed after 12 h starvation in the resting state and 24 h after the end of the last training. Under ether anesthesia, arteriovenous blood was collected. Liver was quickly removed, washed and frozen at−80o C until assay. RESULTS: The whey protein group showed a significant increase of hepatic glycogen as compared with the other two exercised groups. The activities of 6-phosphofructokinase and pyruvate kinase (glycolysis limiting enzymes) were significantly lower in rats fed whey protein compared to those in rats fed casein. On the other hand, hepatic fructose 1, 6-bisphosphatase activity (gluconeogenesis limiting enzyme) was significantly increased in rats fed whey protein as compared with those fed casein or soy protein. Furthermore, a significant decrease in liver lipogenic enzyme activities (malic enzyme, glucose 6-phosphate dehydrogenase, acetyl-CoA carboxylase and fatty acid synthase) was observed in rats fed whey or soy protein compared with those fed casein diet. Besides, hepatic alanine aminotransferase activity and the level of alanine in serum were increased in the whey protein group as compared with the casein or soy protein group. CONCLUSION: We demonstrated that a whey protein diet favored the increase of the liver glycogen, due to a decrease of glycolysis and lipogenic limiting enzyme activities, as well as to the activation of gluconeogenesis from alanine via alanine aminotransferase.

0159 The depletion of glycogen storages has been associated with fatigue during constantload exercise. Therefore, it is important to examine some regulatory enzyme activities of the carbohydrate metabolism and determine the reasons for the glycogen accumulation in the liver. PURPOSE: We investigated whether dietary whey protein, as compared with dietary casein or soy protein, affected the storage of glycogen and glycoregulatory enzymes activity in sedentary or exercised rats liver. METHODS: 32 male Sprague-Dawley rats (ca. 130 g) were used. After acclimation, all rats were divided into one sedentary or three exercised groups (n = 8). In the sedentary group, casein was the source of dietary protein, while the three exercised groups were fed either casein, whey protein or soy protein. All experimental diets contained 20% protein. Rats were allowed free access to food and water for 4 weeks. Rats in the exercised groups were trained using a motor-driven treadmill for 30 min/day, 4 days/week. The running speed was 20 m/min, 7o inclination during the first 5 min, and 25 m/min, 7o inclination during the last 25 min. At end of the training period, all the rats were sacrificed after 12 h starvation in the resting state and 24 h after the end of the last training. Under ether anesthesia, arteriovenous blood was collected. Liver was quickly removed, washed and frozen at−80o C until assay. RESULTS: The whey protein group showed a significant increase of hepatic glycogen as compared with the other two exercised groups. The activities of 6-phosphofructokinase and pyruvate kinase (glycolysis limiting enzymes) were significantly lower in rats fed whey protein compared to those in rats fed casein. On the other hand, hepatic fructose 1, 6-bisphosphatase activity (gluconeogenesis limiting enzyme) was significantly increased in rats fed whey protein as compared with those fed casein or soy protein. Furthermore, a significant decrease in liver lipogenic enzyme activities (malic enzyme, glucose 6-phosphate dehydrogenase, acetyl-CoA carboxylase and fatty acid synthase) was observed in rats fed whey or soy protein compared with those fed casein diet. Besides, hepatic alanine aminotransferase activity and the level of alanine in serum were increased in the whey protein group as compared with the casein or soy protein group. CONCLUSION: We demonstrated that a whey protein diet favored the increase of the liver glycogen, due to a decrease of glycolysis and lipogenic limiting enzyme activities, as well as to the activation of gluconeogenesis from alanine via alanine aminotransferase.

This randomized trial compared pea protein, whey protein, and water-only supplementation on muscle damage, inflammation, delayed onset of muscle soreness (DOMS), and physical fitness test performance during a 5-day period after a 90-min eccentric exercise bout in non-athletic non-obese males (n = 92, ages 18–55 years). The two protein sources (0.9 g protein/kg divided into three doses/day) were administered under double blind procedures. The eccentric exercise protocol induced significant muscle damage and soreness, and reduced bench press and 30-s Wingate performance. Whey protein supplementation significantly attenuated post-exercise blood levels for biomarkers of muscle damage compared to water-only, with large effect sizes for creatine kinase and myoglobin during the fourth and fifth days of recovery (Cohen’s d > 0.80); pea protein versus water supplementation had an intermediate non-significant effect (Cohen’s d < 0.50); and no significant differences between whey and pea protein were found. Whey and pea protein compared to water supplementation had no significant effects on post-exercise DOMS and the fitness tests. In conclusion, high intake of whey protein for 5 days after intensive eccentric exercise mitigated the efflux of muscle damage biomarkers, with the intake of pea protein having an intermediate effect.

Protein supplementation, particularly whey and soy protein, are widely used by individuals engaged in resistance exercise training (RET) to enhance lean body mass (LBM) and muscle strength. However, their effectiveness remain unclear due to conflicting study results. This systematic review and meta-analysis evaluated the effect of whey and soy protein supplementation on amino acid bioavailability, LBM, and strength performance in healthy young adults engaged in RET. Database searches were conducted in Cochrane, EBSCO Host, PubMed, and Scopus from inception to October 19, 2024 using a pre-defined search strategy. Initial screening resulted in a total of 1,813 studies that met the eligibility criteria. The inclusion criteria required participants to be trained or untrained young adults aged 18–30 years engaged in RET and taking either whey or soy protein in the form of concentrate or isolate with the primary outcome of LBM and secondary outcomes of bench press, squat, or plasma essential amino acid (EAA). The studies were assessed for risk of bias using the Cochrane RoB 2 tool, and a meta-analysis was conducted using a random-effects model. A total of 12 studies with 261 participants were included after full-text screening with the main reason for exclusion being wrong population. The analysis found no significant effect of either whey or soy protein supplementation on LBM. However, protein supplement increased peak plasma total EAA with whey protein significantly improved bench press (mean difference [MD] 8.87; 95% CI: 5.95–11.79) and squat performance (MD 9.60; 95% CI: 5.61–13.60), with low to no heterogeneity. These findings suggest whey protein supplementation can enhance strength without significantly altering LBM in young adults. However, further large-scale, high-quality randomized controlled trials are needed to establish definitive conclusions on the effects of protein supplementation RET. The review was registered August 30, 2024 in PROSPERO (CRD42024598070).

ABSTRACT: Whey and soy proteins are valuable dried ingredients with applications in numerous foods. Characterization and comparison of the flavor properties of these value‐added ingredients are needed to interpret analytical flavor chemistry results and to identify specific ingredient applications and marketing strategies. The goals of this study were to develop a sensory lexicon for whey and soy proteins, and to subsequently identify and compare the descriptive sensory properties of whey and soy proteins. Consumers also filled out a survey to probe their opinions and attitudes to dairy and soy products. Twenty‐four descriptive sensory attributes were identified to evaluate appearance, flavor, and texture/mouthfeel of rehydrated proteins. Twenty‐two samples (14 whey proteins and 8 soy proteins) were selected for descriptive sensory analysis. Proteins were rehydrated (10% solids, [w/v]) and evaluated in triplicate by a highly trained sensory panel (n= 10) trained to use the developed language. Both whey and soy proteins were differentiated using the identified language (P&lt; 0.05). Each protein type displayed sensory variability, but different sensory attributes distinguished whey proteins from soy proteins. Consumers (n= 147) perceived distinct health benefits associated with dairy and soy products, respectively. These results will enhance ongoing research and product development with these nutritional and functional ingredients.

Different dietary protein sources can promote different renal statuses. We examined the effects of whey protein (WP) and soy protein (SP) intake on plasma, urinary, and morphological renal parameters in rats. One hundred and twenty Wistar rats were randomly distributed into 2 experimental groups fed with either WP or SP diets over 12 weeks. These diets were based on commercial WP or SP isolates. The urinary calcium content was higher in the WP diet compared to the SP diet group (P<.001) whereas the urinary citrate level was lower (P<.001). The urinary pH was more acidic in the WP diet group compared to the SP diet group (P<.001); however, no differences were observed between the groups for any of the renal morphological parameters analyzed (all, P>.05) or other plasma renal markers such as albumin or urea concentrations. The increase of acid and urinary calcium and the lower urinary citrate level observed in the WP diet group could increase the incidence of nephrolithiasis compared to the SP diet group. Despite the WP showed poorer acid-base profile, no significant morphological renal changes were observed. These results suggest that the use of SP instead of WP appears to promote a more alkaline plasma and urinary profile, with their consequent renal advantages.

RuBisCO was extracted from sugar beet leaves using soft and food-compatible technologies. Proximate composition, solubility, emulsifying, foaming and gelling properties of the protein isolate were determined. All these properties were systematically benchmarked against commercial whey and soy protein isolates used in food applications. RuBisCO protein isolate (RPI) contained 930 g kg-1 of crude protein. Protein solubility was higher than 80% at pH values lower than 4.0 or higher than 5.5. Foaming capacity of RPI was better at pH 4.0 than at pH 7.0. Interestingly, 10 g kg-1 protein foams were more stable (pH 7.0 and 4.0) than foams obtained with whey or soy protein. Moreover, 10 g kg-1 RPI emulsions at pH 4.0 or 7.0 exhibited good stability, being similar to whey protein isolate. Remarkable gelling properties were observed at pH 7.0, where 50 g kg-1 protein solutions of RPI formed self-supporting gels while more concentrated solutions were needed for whey or soy protein. RuBisCO showed comparable or superior functional properties to those of currently used whey and soy protein isolates. These results highlight the high potential of sugar beet leaf protein isolate as a nutritious and functional food ingredient to face global food security and protein supply. © 2018 Society of Chemical Industry.