Molecular forces driving protein complexation of lentil and whey proteins: Structure-function relationships of trehalose-conjugated protein complexes on protein digestibility and solubility.

Plant-based proteins are often associated with a range of health benefits. Most research primarily investigates pea and soy proteins, while lentil proteins received minimal attention. This study evaluates the effect of protein complexation (using the pH-shifting technique) coupled with trehalose conjugation on lentil and whey proteins. The protein structures after the modification were analysed using spectroscopic methods: Fourier-transform infrared, ultraviolet spectra, and fluorescence spectra. The amide group I, conformation protein, and tertiary structure of the trehalose-conjugated lentil-whey protein complexes (T-LWPs) showed significant changes (P < 0.05). Moreover, the surface properties (surface hydrophobicity and charges) of T-LWPs were significantly modified (P < 0.05), from 457 to 324 a.u and from 36 to -40 mV, respectively. Due to these modifications on the protein structures, the protein digestibility (80-86%) and water solubility (90-94.5%) of T-LWPs increased significantly (P < 0.05) with the increase in the trehalose concentration, from 0 (control) to 5% (w/w), respectively. This study suggested that coupling protein complexation and trehalose conjugation can enhance the overall properties of lentil-based protein complexes. With this enhancement, more opportunities in the utilisation of lentils are to be expected.

Pulse Spray Drying for Bovine Skimmed Milk Powder Production.

Pulse Spray Drying (PSD) has potential as a sustainable means of skimmed milk powder (SMP) production. In this study, powders were obtained from PSD using different drying outlet temperatures (70, 80, 90 and 100 °C), and their characteristics were compared to those of traditional Spray Drying (SD). Native whey proteins were well preserved and Solubility Indexes were over 98% in all cases, despite powders obtained by PSD displaying lower solubility than the SD ones. No visual difference was observable in the powders (ΔE < 2); however, PSD powders were found to be yellower with a higher Browning Index. The drying technology did not have a significant effect on powder moisture content and bulk density. Particle size distribution and scanning electron microscopy images confirmed the presence of fine particles (<10 µm) in all samples that might have provided poor flowability and wetting behavior (overall Carr Index and Hausner ratio were 33.86 ± 3.25% and 1.52 ± 0.07, respectively). Higher amounts of agglomerated particles were found at low temperatures in the products processed with both technologies, but PSD samples showed a narrower particle size distribution and hollow particles with more wrinkles on the surface (probably due to the fast evaporation rate in PSD). Overall, PSD provided SMP with comparable physicochemical characteristics to SD and, once optimized at the industrial level, could offer significant advantages in terms of thermal efficiency without significant modification of the final product quality.

Milk Bioactive Compounds and Gut Microbiota Modulation: The Role of Whey Proteins and Milk Oligosaccharides.

A strong correlation between the occurrence of various pathological conditions and intestinal dysbiosis is supported by a range of strong evidence. Vice versa, many pathologies have been shown, in turn, to be responsible for alterations in the gut microbiota, a condition that can worsen illness outcomes and response to therapies. For these reasons, great efforts have been made, and studies are still ongoing, to elucidate the mechanisms underlying gut microbiota alterations and to search for pharmacologic or other strategies that can effectively restore the gut microbiota. In this narrative review, we examined the most significant literature on the role of some milk bioactive compounds, such as milk oligosaccharides and whey proteins, in modulating the composition of the gut microbiota and the underlying mechanisms of action, with the aim of investigating the impact of the microbiota changes mediated by these milk bioactive molecules on human health, and their potential use as therapeutics to treat or adjuvate the treatment of gut dysbiosis and associated pathologies.

Sustainable whey proteins-nanostructured zinc oxide-based films for the treatment of chronic wounds: New insights from biopharmaceutical studies.

Chronic wounds represent silent epidemic affecting a large portion of the world population, especially the elders; in this context, the development of advanced bioactive dressings is imperative to accelerate wound healing process, while contrasting or preventing infections. The aim of the present work was to provide a deep characterization of the functional and biopharmaceutical properties of a sustainable thin and flexible films, composed of whey proteins alone (WPI) and added with nanostructured zinc oxide (WPZ) and intended for the management of chronic wounds. The potential of whey proteins-based films as wound dressings has been confirmed by their wettability, hydration properties, elastic behavior upon hydration, biodegradation propensity and, when added with nanostructured zinc oxide, antibacterial efficacy against both Gram-positive and Gram-negative pathogens, i.e. Staphylococcus aureus and Escherichia coli. In-vitro experiments, performed on normal human dermal fibroblasts, confirmed film cytocompatibility, also revealing the possible role of Zn2+ ions in promoting fibroblast proliferation. Finally, in-vivo studies on rat model confirmed film suitability to act as wound dressing, since able to ensure a regular healing process while providing effective protection from infections. In particular, both films WPI and WPZ are responsible for the formation in the wound bed of a continuous collagen layer similar to that of healthy skin.

Preferential Binding of Polyphenols in Blackcurrant Extracts with Milk Proteins and the Effects on the Bioaccessibility and Antioxidant Activity of Polyphenols.

Milk proteins are well-known delivery agents; however, there is no clear understanding of the competitive interactions of milk proteins with polyphenols in mixed complex systems. Here, we investigate the preferential competitive interactions of different polyphenols present in blackcurrant extract with milk proteins by quantifying the protein-bound polyphenols and comparing the factors affecting these interactions. In addition, bioaccessibility and antioxidant activity were studied after in vitro gastric digestion. Our results indicated that polyphenols from blackcurrant extracts were preferentially bound to caseins more than whey proteins, with noncovalent interactions causing secondary structural changes in the protein. The hydrophobicity and the charge of the polyphenols were negatively and positively related to the number of polyphenols bound to casein and whey proteins, respectively. Moreover, the bioaccessibility and antioxidant activity of polyphenols were enhanced in the presence of milk proteins in milk-based blackcurrant samples when compared to polyphenol and protein-alone samples in the in vitro gastric phase. These findings underscore the critical role of milk proteins in encapsulating or delivering polyphenols. This will pave the way for boosting the bioavailability of polyphenols by complexing them with milk proteins and formulating functional dairy foods, integrating the beneficial effects of these compounds.

Experimental and in silico approaches for the buffalo whey protein-folic acid complexation elucidation. Molecular changes impacting on protein structure and functionality.

Using a buffalo whey proteins concentrate (BWPC) as a nanocarrier of labile bioactive compounds as vitamins constitutes a very innovative approach with potential application in the food and nutraceutical industries. This work aims to deepen the knowledge of the phenomena occurring in the complexation process of vitamin B9 with BWPC, providing valuable information on the molecular and functional properties of complexes and intervening substances. For such purpose, analytical (SEC-FPLC, Fluorescence spectroscopy, FTIR, DLS, UV-vis spectroscopy) and in-silico methods (molecular docking) were performed to get complementary data. Five types of proteins were identified in the BWPC. Folic acid (FA) interacted with BWPC in buffer pH 7 through H-bonds and hydrophobic interactions, inducing conformational changes and modifying the secondary and tertiary protein structure. The resultant BWPC-FA complexes showed a size distribution in the nanoscale (100-150 nm) with no aggregation. Molecular docking showed that lactoferrin had the highest FA binding affinity. Complexation did not reduce the antioxidant activity of intervening substances. Indeed, the radical scavenging capacity of BWPC-FA was 20 % higher than single BWPC. The obtained results provide relevant data enabling the adding value of the main effluent of buffalo dairy industries.

Thermal characterization and separation of whey proteins by differential scanning calorimetry.

Most commercially available whey products contain a mixture of 6-7 whey proteins; however, there is an increased focus on using the individual whey proteins for their unique biological activities. Before extracting individual whey proteins for use, it is important to quantify how much of a particular protein is present in whey mixtures as well as if the protein is still structurally folded. We first characterized the denaturation temperature and enthalpy values for the six purified whey proteins at six pHs (3-9) and under ion chelation using a nano-differential scanning calorimeter (DSC). From the individual protein scans, we determined the optimal condition for detecting all 6 proteins on a single DSC scan was whey in an EDTA MOPs pH 6.7 buffer.

SVR Chemometrics to Quantify ß-Lactoglobulin and α-Lactalbumin in Milk Using MIR.

Protein content variation in milk can impact the quality and consistency of dairy products, necessitating access to in-line real time monitoring. Here, we present a chemometric approach for the qualitative and quantitative monitoring of ß-lactoglobulin and α-lactalbumin, using mid-infrared spectroscopy (MIR). In this study, we employed Hotelling T2 and Q-residual for outlier detection, automated preprocessing using nippy, conducted wavenumber selection with genetic algorithms, and evaluated four chemometric models, including partial least squares, support vector regression (SVR), ridge, and logistic regression to accurately predict the concentrations of ß-lactoglobulin and α-lactalbumin in milk. For the quantitative analysis of these two whey proteins, SVR performed the best to interpret protein concentration from 197 MIR spectra originating from 42 Cornell University samples of preserved pasteurized modified milk. The R2 values obtained for ß-lactoglobulin and α-lactalbumin using leave one out cross-validation (LOOCV) are 92.8% and 92.7%, respectively, which is the highest correlation reported to date. Our approach introduced a combination of preprocessing automation, genetic algorithm-based wavenumber selection, and used Optuna to optimize the framework for tuning hyperparameters of the chemometric models, resulting in the best chemometric analysis of MIR data to quantitate ß-lactoglobulin and α-lactalbumin to date.

Label-free-based proteomic analysis reveals differential whey proteins of porcine milk during lactation.

In this study, label-free proteomic technology was applied to analyze and compare the whey proteomes of porcine colostrum and mature milk. In total, 2993 and 2906 whey proteins were detected in porcine colostrum and mature milk, respectively. A total of 2745 common proteins were identified in the two milk samples, and 280 proteins were found to be significantly differentially expressed whey proteins in porcine milk. Gene Ontology analysis demonstrated that the differentially expressed whey proteins were primarily enriched in lipid homeostasis, oxidoreductase activity, and the collagen trimer. Kyoto Encyclopedia of Genes and Genomes analysis suggested that the phagosome and endocytosis were the crucial pathways. This study provides systematic and in-depth insight into the compositions and functional properties of whey proteins in porcine milk during different periods of lactation, which may be beneficial for the development of porcine whey proteins in the future.

Whey Protein, Vitamins C and E Decrease Interleukin-10 in Chronic Hemodialysis Patients: A Pioneer, Randomized, Double-Blind Pilot Trial.

OBJECTIVE: To evaluate the effects of supplementation with whey protein combined with vitamins C and E on inflammatory markers in hemodialysis (HD) patients. DESIGN AND METHODS: This was a pioneer, randomized and double-blinded study. Patients were randomized into two groups and stratified by HD frequency. The supplementation group received 20 g of whey protein, 250 mg of vitamin C, and 600 IU of vitamin E; the placebo group, 20 g of rice flour, and microcrystalline cellulose capsules. The interventions were given after HD, 3 times a week, for 8 weeks. The inflammatory markers were assessed: interleukin (IL) IL-12p70, IL-10, IL-6, IL-8, and tumor necrosis factor alpha. For statistical analysis, the χ2 test, Student's t-test, Mann-Whitney test, analysis of variance for repeated two-way measurements, paired t test, and Wilcoxon test were performed. P < .05 was considered statistically significant. RESULTS: Twenty-three patients completed the study. No significant differences were found in inflammatory markers when comparing the groups postintervention. In the intragroup was a decrease in IL-10 in the supplementation group after 8 weeks (P = .0382). IL-6 tended to decrease by 810.95% in the supplementation group and increased by 732.8% (nonsignificant) in the placebo group. CONCLUSION: Whey protein combined with vitamins C and E significantly reduced IL-10 in the supplementation group and could be beneficial to reduce IL-6 in HD patients. Future studies are suggested with a larger sample size, different supplementation doses, and longer interventions.

Effects of whey protein complex combined with low-intensity exercise in elderly inpatients with COPD at a stable stage.

BACKGROUND AND OBJECTIVES: Previous literature mostly has demonstrated the efficacy of pulmonary rehabilitation (PR) combined with whole nutrition powder in patients with chronic obstructive pulmonary disease (COPD). However, the benefits of whey protein as an oral nutritional supplement (ONS) during PR are not clear. METHODS AND STUDY DESIGN: It took 12 weeks to complete the trial, we divided 90 elderly patients with stable-stage COPD into a low-intensity exercise group (n= 30, PR group), PR plus whey proteins complex group (n= 30, PRWP group), and a control group (n= 30) randomly, and assessed index such as exercise capacity, mental health status, lung function, and body composition. Eventually, 84 people persisted until the end of the trial. RESULTS: Compared with the control group, hand grip strength (HGS)(1.4 ± 0.6 kg, and 1.0 ± 0.2 kg respectively, p< 0.05) in the PRWP and PR group, 6 minutes of walking distance (6MWD)(14.1 ± 3.8m, p< 0.05) in PRWP group improved. Furthermore, compared with the PR group, Medical Research Council Dyspnea Scale (MRC)(-0.2 ± 0.1, p< 0.01), anxiety score (-1.2 ± 0.4, p< 0.01), and body weight (2.0 ± 0.8kg, p< 0.05) improved in the PRWP group. There were no inter-group differences in a fat-free mass index or appendicular skeletal muscle mass index. CONCLUSIONS: Muscle strength could be enhanced in both intervention models. Adding whey protein complex was additionally successful in rectifying dyspnea, anxiety, and weight loss caused by exercise. This rehabilitation pattern might be valuable in elderly patients with COPD.

Conformational and Structural Changes in Chickpea Proteins Caused by Simulated Salivary Alterations in the Elderly.

The impact of salivary alterations on chickpea protein structure in the elderly has not been well documented. This study aimed to understand the role of simulated salivary alterations in the conformational properties and secondary structure of the chickpea protein isolate (CPI). Whey protein isolate (WPI) was used as the reference. Protein dispersions (10%) were subjected to in vitro oral processing under simulated salivary conditions in both the elderly and adult subjects. Proteins and their oral counterparts were characterized in terms of their composition, charge, size, solubility, water absorption, molecular weight (MW), and secondary structure (Circular Dichroism and Raman spectroscopy). Under condition of simulated oral digestion in the elderly population, the ordered secondary protein structure was significantly affected, decreasing α-helix by ~36% and ~29% in CPI and WPI compared to the control (adult) population, respectively. An increase in the unordered random coil state was observed. These results could be attributed to an increase in electrolytes in the salivary composition. The structure of CPI is more stable than that of WPI because of its higher MW, more rigid structure, less charged surface, and different amino acid compositions. This study is meaningful in understanding how alterations in the elderly oral system affect protein conformation and is expected to improve the understanding of plant-based protein digestibility.

Acute or Short-term Effects of Whey Protein Alone or Along with Carbohydrate on Inflammation: A Systematic Review of Clinical Trials:.

BACKGROUND: Excessive inflammatory response is associated with several diseases. Recently, there has been an increasing trend for investigation of the acute or short-term effects of whey protein alone or in combination with carbohydrates on inflammatory status, especially in athletes. This systematic review aimed to clarify these effects. MATERIALS AND METHODS: PubMed, Scopus, and Web of Science databases were searched from January 1990 to September 2021, without language restriction. Adult studies examining the effects of whey protein alone or together with carbohydrates on interleukin-6, tumor necrosis factor-α, and C-reactive protein levels with a maximum duration of 15 days and with at least one comparison group were included. The quality of studies was analyzed using the Cochrane risk of bias tool. RESULTS: Twenty-five studies met the inclusion criteria. Significant reductions in inflammatory markers was observed in seven out of 25 studies (28%). However, one out of 25 studies (4%) reported a significant increase in inflammatory status. Among those studies comparing the effects of whey protein alone with non-protein or protein-containing groups, 18.18% (two out of 11) and 10% (one out of ten) of the trials revealed a significant decrease in the markers, respectively. Moreover, of those studies comparing whey protein plus carbohydrate with non-protein or protein-containing groups, 33.33% (two out of six) and 40% (two out of five) of them showed a significant reduction in the inflammatory response, respectively. The quality of the majority of studies (84%) was poor. CONCLUSION: It seems that whey protein alone or the combination of it with carbohydrates may not affect the inflammatory markers in the short run (PROSPERO registration number: CRD42021273915).[GMJ.2023;12:e2441].

The Effect of a High-Protein Diet Supplemented with Blackthorn Flower Extract on Polyphenol Bioavailability and Antioxidant Status in the Organs of C57BL/6 Mice.

The health benefits of polyphenols are based on their bioavailability, which is why a significant portion of research focuses on factors that affect their bioavailability. Previous studies suggest that the intake of polyphenols along with macronutrients in food represents one of the key factors influencing the bioavailability of polyphenols and, consequently, their biological activity in the organism. Since polyphenols in the human diet are mainly consumed in food together with macronutrients, this study investigated the in vivo absorption, metabolism, and distribution of polyphenolic compounds from the water extract of blackthorn flower (Prunus spinosa L.) in combination with a protein-enriched diet in the organs (small intestine, liver, kidney) of C57BL/6 mice. The bioaccumulation of polyphenol molecules, biologically available maximum concentrations of individual groups of polyphenol molecules, and their effect on the oxidative/antioxidative status of organs were also examined. The results of this study indicate increased bioabsorption and bioavailability of flavan-3-ols (EC, EGCG) and reduced absorption kinetics of certain polyphenols from the groups of flavonols, flavones, and phenolic acids in the organs of C57BL/6 mice after intragastric administration of the water extract of blackthorn flower (Prunus spinosa L.) in combination with a diet enriched with whey proteins. Furthermore, subchronic intake of polyphenols from the water extract of blackthorn flower (Prunus spinosa L.) in combination with a diet enriched with whey proteins induces the synthesis of total glutathione (tGSH) in the liver and superoxide dismutase (SOD) in the liver and small intestine. The results of this study suggest potential applications in the development of functional foods aimed at achieving the optimal health status of the organism and the possibility of reducing the risk of oxidative stress-related disease.

Comparison of Whey Proteome and Glycoproteome in Bovine Colostrum and Mature Milk.

Milk samples were collected from 10 cows, in the colostrum (3-4 days) and mature (90 days) lactation stage, to assess the differential expression of all whey proteins and N-glycoproteins. In total, 240 whey proteins and 315 N-glycosylation sites on 214 glycoproteins were quantified. GO annotations, KEGG pathway analysis, and protein classification were performed to understand the similarities and differences of the biological functions of whey proteins and N-glycoproteins among different lactation stages in bovine milk. Furthermore, differential expression of whey proteins and whey N-glycosylated proteins was found between different lactation stages. The related changes of biological functions in differentially expressed proteins were discussed. For example, the increased frequency of glycosylation on lactoferrin and folate receptor alpha occurring in bovine colostrum may provide protection and stimulate development of the newborn calf. Our study thereby improves understanding of variations of glycosylation sites on milk glycoproteins among lactation stages.

Impact of Combined Thermal Pressure Treatments on Physical Properties and Stability of Whey Protein Gel Emulsions.

Emulsion gels are gaining interest as fat replacers due to their benefits associated with calorie reduction and their versatility in a wide range of products. Their production process needs to be tailored to obtain the desired stability and physicochemical properties. This study investigated the effect of heat (70, 80, and 90 °C) and pressure (5, 10, and 15 MPa) to produce whey protein emulsion gels using a pilot-scale tubular heat exchanger equipped with a homogenization valve. Both temperature and pressure determined a significant effect (p < 0.05) on the rheological moduli, with the treated samples displaying a predominant elastic behavior. The treatments also showed an improved pseudoplasticity due to the significant reduction in the flow behavior index (p < 0.05). All the samples showed a bimodal particle size distribution; by increasing the temperature up to 80 °C, a reduction in Dv50 (50th percentile) values compared to the control samples was observed. At 90 °C, the Dv50 value increased because of coalescence and flocculation phenomena occurring during or immediately after processing. The greater aggregation and structural development obtained with stronger process conditions improved the stability of the emulsions. The results show the capability to produce gel emulsions with good physical properties that could be proposed as food ingredients to substitute fats in food products.

Development of Value-Added Butter by Incorporating Whey Protein Hydrolysate-Encapsulated Probiotics.

The probiotic foods market is growing exponentially; however, probiotics' survivability and interaction with product attributes pose major challenges. A previous study of our lab developed a spray-dried encapsulant utilizing whey protein hydrolysate-maltodextrin and probiotics with high viable counts and enhanced bioactive properties. Viscous products such as butter could be suitable carriers for such encapsulated probiotics. The objective of the current study was to standardize this encapsulant in salted and unsalted butter, followed by storage stability studies at 4 °C. Butter was prepared at a lab-scale level, and the encapsulant was added at 0.1% and 1%, followed by physiochemical and microbiological characterization. Analyses were conducted in triplicates, and means were differentiated (p < 0.05). The viability of probiotic bacteria and the physicochemical characteristics of the butter samples with 1% encapsulant were significantly higher as compared to 0.1%. Furthermore, the 1% encapsulated probiotics butter variant showed a relatively higher stability of probiotics ratio (LA5 and BB12) than the control with unencapsulated probiotics during storage conditions. Although the acid values increased along with a mixed trend of hardness, the difference was insignificant. This study thus provided a proof of concept for incorporating encapsulated probiotics in salted and unsalted butter samples.

Utilization of different by-products to produce nutritionally rich gelled products.

Yellow corn cooking water with yerba mate (Ilex paraguariensis) extract, obtained as a by-product of snack manufacture, was combined with whey protein concentrate (7 g/100 g), flaxseed (Linum usitatissimum L.) flour (2 g/100 g), and honey (8 g/100 g) to obtain different gelled products. The effect of the composition on the physicochemical parameters was analyzed. Flaxseed flour was added directly or with a previous pre-heating, and, in both cases, it increased the solid behavior of gels. On the contrary, honey increased the gel liquid-like behavior, and both ingredients modified the color of the gels. Elastic and loss modulus decreased after storage for 7 and 14 days. Some of the textural parameters also changed during storage. Principal component analysis and cluster analysis revealed three groups of formulations according to their composition, and those samples containing only flaxseed flour were best described with the textural and rheological parameters. Yerba mate extract, mainly, flaxseed flour, and honey increased the phenolic composition of gels but decreased the sensory acceptability, despite the sweetness of honey. A variety of gelled products with different textures and flavors was obtained using by-products of the food industry. These gels could be used either for dessert formulations or as a matrix for gelled products.

Protocatechuic acid and gallic acid improve the emulsion and thermal stability of whey protein by covalent binding.

This study aimed to explore the impacts of gallic acid (GA)/protocatechuic acid (PA) on the structural and functional characteristics of whey proteins (WP) through covalent binding. To this purpose, the covalent complexes of WP-PA and WP-GA at different concentration gradients were prepared by the alkaline method. SDS-PAGE indicated that PA/GA was cross-linked by covalent bonds. The decreased contents of free amino and sulfhydryl groups suggested that WP formed covalent bonds with PA/GA by amino and sulfhydryl groups, and the structure of WP became slightly looser after covalent modification by PA/GA. When the concentration of GA was added up to 10 mM, the structure of WP was slightly loosened with a reduction of α-helix content by 2.3% and an increase in random coil content by 3.0%. The emulsion stability index of WP increased by 14.9 min after interaction with GA. Moreover, the binding of WP and 2-10 mM PA/GA increased the denaturation temperature by 1.95 to 19.87 °C, indicating the improved thermal stability of the PA/GA-WP covalent complex. Additionally, the antioxidant capacity of WP was increased with increasing GA/PA concentration. This work may offer worthful information for enhancing the functional properties of WP and the application of the PA/GA-WP covalent complexes in food emulsifiers.

Sensory analysis of formulations containing whey protein to individuals undergoing bariatric and metabolic surgery.

BACKGROUND: Individuals undergoing bariatric surgery often have inadequate protein intake, which can cause loss of lean body mass, low level of physical activity and sarcopenia. The whey protein supplement is the most suitable in this situation, however there is a low adherence to long-term use due to the palatability and monotony of the recipes. The aim this study was to analyze the acceptability of recipes containing whey-based protein supplements in individuals undergoing bariatric and metabolic surgery. METHODS: An on-demand sampling was performed, through a prospective, experimental study, with individuals undergoing bariatric surgery, treated by a multidisciplinary team, in a clinic located in São Paulo, Brazil. The study excluded: individuals with possible changes in taste during the sensory testing period. The study was divided into selection of recipes containing whey proteins, recruitment of tasters, sensory and chemical analysis of the recipes. RESULTS: The sample consisted of 40 tasters, adults, and elderly, who underwent bariatric and metabolic surgery, with a median of eight years of surgery, who had previously consumed a supplement. These individuals were subjected to sensory analysis of six recipes with fresh and minimally processed foods, plus protein supplement. All recipes had food acceptance above 78% and the chemical analysis of the recipes showed an average of 13 g of protein per serving. CONCLUSION: There was favorable acceptance of recipes with whey proteins, which places them as good dietary alternatives for the prevention of sarcopenia and weight relapse in individuals undergoing bariatric and metabolic surgery.