Effects of mixing ratio on physicochemical, structural properties and application in lycopene-loaded emulsions of blends of whey protein and pea protein.

Physicochemical, structural properties and application in lycopene-loaded emulsions of blends of whey protein isolate (WPI) and pea protein isolate (PPI) at varying mass ratios (100/0, 75/25, 50/50, 25/75, 0/100) were investigated. Data indicated that the mass ratios affected the physical, chemical and storage stability of the emulsion by influencing the particle size, zeta-potential, surface hydrophobicity, free sulfhydryl content, and secondary structure of the blends. Particularly, emulsion with a mixing ratio of 75/25 exhibited superior physical stability against salt concentrations (200 and 500 mM), better chemical stability against UV light and heat, and maintained stability over a 30-day storage period. Emulsions stabilized by blends of different ratios exhibited similar digestion behavior, with no significant differences observed in lycopene's transformation stability and bio-accessibility. Data indicated that substitution of whey protein by pea protein is effective in term of emulsifier application and replacement ratio is an important factor need to be considered.

Functional pH-sensitive film based on pectin and whey protein for grape preservation and shrimp freshness monitoring.

A pH-sensitive film was prepared from pectin (P) and whey protein (W), incorporating anthocyanin-rich purple sweet potato extract (PPE) as the pH indicator. The effect of PPE content on the structure and properties of the films and the pH indicating function were determined and evaluated for shrimp freshness and grape preservation. The solubility (60.23 ± 7.36 %) and water vapor permeability (0.15 ± 0.04 × 10-11 g·cm/(cm2·s·Pa)) of the pectin/whey protein/PPE (PW-PPE) film with 500 mg/100 mL PPE were the lowest of the films tested and much lower than PW films without PPE. PW-PPE films were non-cytotoxic and had excellent biodegradability in soil. Grapes coated with PW-PPE film had reduced weight loss from water evaporation, and decay during storage was inhibited. The total color change (ΔE) of the PW-PPE films had a strong linear correlation with the pH of shrimps during storage. PW-PPE films have application potential to monitor the real-time freshness of meat and extend the shelf life of fruit.

Comparative study of the oligosaccharide profile in goat, bovine, sheep, and human milk whey.

Milk oligosaccharides are high added value compounds that could be obtained by exploiting cheese whey, a byproduct of dairy industry. The objective was to compare the abundance and diversity of oligosaccharides in whey samples from domestic animals and humans. During fresh cheese making, whey samples were collected and analyzed by untargeted and targeted small molecule analysis using high-resolution mass-spectrometry. A great similarity in the metabolite profile between goat and sheep was observed. Up to 11 oligosaccharides were observed in the sheep whey from those typically found in humans. The concentration of 2'-Fucosyllactose (0.136 ± 0.055 g/L) and 3-Fucosyllactose (0.079 ± 0.009 g/L) were significantly higher (p-value <0.01) in sheep whey, while the concentration of 3'-Sialyllactose (0.826 ± 0.638 g/L) was higher in goat whey. No significant differences were observed between goat and sheep whey for the other oligosaccharides (p-value >0.05). Therefore, sheep and goat whey could become an important source of oligosaccharides through their revalorization.

Mechanistic insights into the interaction of Lycium barbarum polysaccharide with whey protein isolate: Functional and structural characterization.

Protein-polysaccharide interactions are crucial for food system structure and stability. This study investigates the interaction of Lycium barbarum polysaccharide (LBP) at 0-2.00 % concentrations with whey protein isolate (WPI), focusing on functionality and structural changes. LBP covalently grafted onto WPI, as confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), forming WPI-LBP complexes with a maximum degree of grafting (DG) of 44.58 % at 2.00 % LBP. This grafting reduced WPI's surface hydrophobicity (H0) and improved solubility, emulsifying properties, and digestibility under certain conditions, with optimal antioxidant activity at 1.00 % LBP. Multispectral analysis and microscopy showed LBP grafting alters WPI's secondary, tertiary, crystalline, and micro/nanostructures. The comprehensive analysis indicates that the interaction between LBP and WPI involves covalent bonding, hydrogen bonding, hydrophobic interactions, and electrostatic forces, as supported by zeta potential and chemical forces results. These findings suggest LBP-protein complexes as promising food materials for enhancing functionality and stability in the food industry.

Heat-induced interactions between microfluidized hemp protein particles and caseins or whey proteins.

The rising demand for sustainable proteins leads to increased interest in plant proteins like hemp protein (HP). However, commercial HP's poor functionality, including heat aggregation, limit its use. This study explored the heat-induced interactions of hemp protein particles (HPPs) with milk proteins, specifically whey proteins and caseins. Using various analysis techniques-static light scattering, TEM, SDS electrophoresis, surface hydrophobicity, and free sulfhydryl content-results showed that co-heating HPPs with whey protein isolate (WPI) or sodium caseinate (NaCN) at 95 °C for 20 min reduced HPPs aggregation. HPPs/WPI particles had a d4,3 of ∼3.8 µm, while HPPs/NaCN were ∼1.9 µm, compared to ∼27.5 µm for HPPs alone. SDS-PAGE indicated that whey proteins irreversibly bound to HPPs, through disulfide bonds, whereas casein bound reversibly, possibly involving the chaperone-like property of casein. This study proposes possible mechanisms by which HPPs interact with milk proteins and impact protein aggregation. This may provide opportunities for developing hybrid protein microparticles.

Regulation in protein hydrophobicity via whey protein-zein self-assembly for improving the techno-functional properties of protein.

This work aims to verify the feasibility of improving protein function by regulating its hydrophobicity and reveal the relationship between structure and function. Whey protein (WP) and zein were the source of hydrophilic and hydrophobic polypeptide chains to prepare complex proteins (CPs) with much different structure and function. The results showed that the water- and oil-holding capacities, emulsifying properties and gel properties of CPs can be significantly improved via changing WP-zein ratio. All these can be attributed to the changes in protein hydrophobicity, which not only regulated the binding strength of protein to water and oil, but also modified their molecular structure (surface characteristics, availability of free thiols, α-helix, ß-sheet, random coil and the formation of disulfide bonds). Notably, optimal protein hydrophobicity varies greatly among different functional properties. Overall, the techno-functional properties of protein can be improved via tuning its hydrophobicity, which may provide novel sights in protein modification.

Reduction of Total Phenols in Virgin Olive Oil as a Preservation Medium during Cold Storage of Whey Cheese and Tofu.

Research background: Virgin olive oil, known as a good source of health-promoting hydrophilic phenols, is traditionally used as a medium for preserving various foods. Phenols in general can form complexes with proteins, but there is little information on the direct contact of virgin olive oil with protein-rich food during long-term storage. In this study, the dynamics of the decline of total phenols in oil used as preservation medium for a traditional (whey cheese skuta) and a modern product (tofu) were compared. Experimental approach: Pieces of skuta or tofu immersed in virgin olive oil at different food-to-oil mass ratios were stored in the refrigerator for up to 21 days. The oil quality indices, water content and the total count of aerobic mesophilic bacteria in the immersed materials were monitored. To determine the total phenols in the oil, the optimal conditions of the Fast Blue BB test, which is a suitable alternative to the standard method, were tested and selected. Results and conclusions: The effect of both materials on the indicators of hydrolytic and oxidative deterioration of the oil is almost identical (a gradual decrease), which is most likely due to the continuous release of water from the immersed food. A sharp decrease in total phenols in the oil (by about 50 %) after seven days of storage in contact with both materials indicates a combination of causes (water-to-oil migration and phenol-protein interactions). The form of the rational function is highly representative of the decrease in total phenols during the first seven days of tofu/oil storage, indicating a very rapid interaction with tofu proteins. The preservative effect of virgin olive oil in terms of microbiological spoilage was not observed. Novelty and scientific contribution: The results of this study contribute to the knowledge on the dynamics of phenol-protein interactions and emphasise the need for further investigations on traditional or newly used protein-rich foods preserved in direct contact with virgin olive oil, taking into account possible changes in the functional, nutritional and sensory properties of phenols and proteins.

Unveiling the slow digestion and peptide profiles of polymerised whey gel via heat and TGase crosslinking: An in vitro/vivo perspective.

Polymerised whey is widely used in dairy products and can affect digestibility when its high-molecular-weight aggregates and gel structure are modified. This study investigated the digestibility, peptide profiles and satiety of modified whey protein isolate (MWPI) pre-heated with transglutaminase. Results showed that 43.06 % of MWPI was digested during the 4-h in vitro digestion, indicating a slow digestion rate. Compared with whey protein isolate (WPI), MWPI yielded 103 peptides with higher abundance following in vitro digestion, including 17 angiotensin-converting enzyme inhibitors and 1 dipeptidyl peptidase-4 inhibitor. Visual analytics indicated differential peptides located at distinct α-helix and ß-sheet of ß-lactoglobulin, α-lactalbumin and bovine serum albumin. MWPI gavage extended stomach retention time, decreased intestinal propulsion rate from 75.60 % (WPI group) to 33.72 % in 30 min and enhanced satiety within 120 min compared with WPI. Overall, whey polymerisation modulates protein-enzyme interactions, releasing different peptides and enhancing satiety.

Differential binding of gallic acid and epigallocatechin gallate to whey protein affects the interfacial adsorption and gastric digestion of O/W emulsion.

Whey protein isolate (WPI) was reacted with 20, 120, and 240 µmol/g gallic acid (GA) or epigallocatechin gallate (EGCG) at 21 °C. Equilibrium dialysis testing indicated a stronger binding capacity of whey proteins with EGCG compared to GA. Both phenolics, especially EGCG, tended to reduce the adsorption of WPI at the oil-water interface and decreased the elasticity modulus (Ed) of the interfacial film. Yet, binding with 20 µmol/g of EGCG and GA (less so) resulted in significantly improved emulsifying activity of WPI, but the emulsion stability was decreased at all phenolic concentrations (except at 240 µmol/g). There was an overall improvement of pepsinolysis of both α-lactalbumin and ß-lactoglobulin. In comparison with GA, EGCG yielded more pronounced effects on WPI interfacial adsorption, dilatational rheology, and peptic digestion.

Polymerized whey protein-SDS interactions at their high concentrations.

Protein-surfactant interactions have been an ongoing topic of interest for many decades. Applications involving complexes of proteins and surfactants are relevant in food, pharmaceuticals, hygiene, molecular characterization, and other fields. In this study, the interactions of polymerized whey proteins (PWP) and sodium dodecyl sulfate (SDS) at high concentrations are investigated. Different characterization techniques are used, including electrical conductivity, turbidity, isothermal titration calorimetry, dynamic light scattering, dilute solution viscometry, rheology, and surface hydrophobicity to elucidate information on the modes and extent of interactions. Results indicate that PWP-SDS interactions produce highly extended, worm like micelles, with SDS decorating PWP chains and covering non-polar residues. PWP can host SDS up to quite high surfactant to protein ratios (SPR), producing solutions that are highly viscous with shear thickening properties, yet with no networking or gelation. Interestingly, dilution of high viscosity PWP-SDS solutions leads to even smaller size of PWP-SDS molecular complex as compared with PWP without SDS. The current study extends the vision of protein surfactant interactions by examining concentration range beyond that found in literature. The results reveal insights that can help expand studies on other systems and find applications in various fields including coatings, cosmetics, food ingredients, drug transport, and disease treatment.

Novel Antioxidant Peptides from Fermented Whey Protein by Lactobacillus rhamnosus B2-1: Separation and Identification by in Vitro and in Silico Approaches.

Whey is a byproduct of the dairy industry and is rich in protein. To enhance the significance of such byproducts and find efficacious antioxidants for combating oxidative stress, this study reported on the preparation, purification, and identification of novel peptides with antioxidant activities from whey protein metabolites following fermentation by Lactobacillus rhamnosus B2-1. The isolation and identification processes involved macroporous adsorption resin column chromatography, gel filtration column chromatography, and liquid chromatography-tandem mass spectrometry. Therein, three novel antioxidant peptides (PKYPVEPF, LEASPEVI, and YPFPGPIHNS) were selected to be synthesized, and they demonstrated remarkable antioxidant activities in vitro chemical assays. PKYPVEPF, LEASPEVI, and YPFPGPIHNS (100 µg/mL) displayed a notable cytoprotective impact on HepG2 cells under oxidative stress induced by H2O2, increasing the cell viability from 49.02 ± 3.05% to 88.59 ± 10.49%, 82.38 ± 19.16%, and 85.15 ± 7.19%, respectively. Moreover, the peptides boosted the activities of catalase and superoxide dismutase in damaged cells and reduced reactive oxygen species levels. The molecular docking studies highlighted that these antioxidant peptides efficiently bound to key amino acids in the Kelch domain of Keap1, thereby preventing the interaction between Keap1 and Nrf2. In conclusion, PKYPVEPF, LEASPEVI, and YPFPGPIHNS demonstrated substantial antioxidant activity, suggesting their potential for widespread application as functional food additives and ingredients.

Sustainable detergent-disinfectant agent based on whey mineralizate and silver nanoparticles for cleaner production in dairy industry.

Detergents and disinfectants for dairy industry must meet a variety of characteristics, including low toxicity, high antibacterial activity, and excellent rinsing of pollutants from working surfaces. This work presents an innovative detergent-disinfectant agent based on whey mineralizate and silver nanoparticles (Ag NPs), which allows reducing production costs and ensuring high cleanliness of treated surfaces compared to analogues. For this purpose, a method for obtaining sols of Ag NPs stabilized with didecyldimethylammonium bromide (Ag NPs-DDAB) was developed and optimized using neural network algorithms. Characterization of Ag NPs-DDAB showed particles with a radius of 4.5 nm and 20 nm, stable in the pH range from 2 to 11. An acute toxicity study of Ag NPs in mice showed LD50 = 4230 µg/kg. Based on the degree of accumulation and inhalation toxicity, Ag NPs-DDAB are classified as low-hazard chemicals. The developed detergent-disinfectant had a washability of about 90%, high antimicrobial activity (0.005 mg/mL) against Penicillium roqueforti and a sanitary and hygienic effect on coliforms, general contamination and pathogenic microorganisms, a low-corrosive effect and low toxicity (315 mg/mL) to Danio rerio. It was concluded that the use of detergent-disinfectant agent will completely eliminate the consumption of water for the equipment cleaning process and can be used to clean an electrodialysis unit's circuits, enabling the utilization of secondary waste from membrane milk processing and promoting resource efficiency and cleaner production in the dairy industry.

Probiotic Milk Enriched with Protein Isolates: Physicochemical, Organoleptic, and Microbiological Properties.

Incorporating plant protein isolates into milk can enhance probiotic culture growth by providing essential nutrients and altering the physicochemical properties of fermented milk. This study investigated the effects of adding 1.5% or 3.0% soy, pea, and whey protein isolates on the growth of Lacticaseibacillus casei and Lactobacillus johnsonii monocultures, as well as the physicochemical (acidity, syneresis, color) and organoleptic properties of fermented milk during 21 days of refrigerated storage. The results showed that 1.5% SPI and WPI did not significantly alter milk acidity compared to controls. Still, pH increased with 1.5% and 3.0% PPI. Storage time significantly affected pH in L. casei fermented milk. The initial addition of WPI at 1.5% and 3.0% reduced syneresis in L. casei fermented milk compared to other samples. Color components were significantly influenced by isolates. Initial L. casei cell counts were lower with SPI (LCS1.5 and LCS3) and 1.5% PPI (LCP1.5) compared to controls. Increasing isolate concentration from 1.5% to 3% enhanced L. johnsonii growth in WPI-milk but reduced L. casei in LCW3 compared to LCW1.5. Only increased pea protein concentration significantly increased L. casei growth. Probiotic populations generally were reduced during extended storage. Moreover, isolates impacted milk organoleptic evaluation. This research demonstrates the potential of protein isolates in creating health-promoting and diverse fermented products and offers insights into their interaction with probiotic cultures to advance functional food technologies.

Microwave-sonication synergistic extraction of dairy waste proteins: A review of green approach for dairy waste proteins valorization.

Ultrasonic and microwave extraction process has great prospects to convert food and agricultural waste from food industries to value-added goods. Also, this review extensively elaborates the utilization of ultrasonication and microwave extraction (US-MW) process for valorization of dairy waste extracted proteins into novel foods. Both of these extraction and processing techniques are considered as green technologies when compared with the other conventional or chemical extraction and processing techniques. Further, this review also explains the impact of US-MW alone and in combination on the dairy waste proteins extraction, nutritional and techno-functional attributes of these dairy-waste proteins. The review also highlights the economic and cost-effective benefits of US-MW processes for extracting the proteins from dairy waste, indicating their feasibility and sustainability. The review also elucidated the synergistic utilization of US-MW extraction as a viable processing technique in extraction or production of bioactive compounds like dairy proteins. In conclusion, this review elucidates the US-MW, both individually and in synergy as a viable source of dairy waste proteins extraction and their application in functional foods. Moreover, in accordance to the latest developments and future prospects at pilot and commercial level to assess the practicability of synergistic use of US-MW extraction in bioenergy production from food wastes other than dairy waste for extraction and production of biodiesel, hydrogen, green methane, and ethanol.

Novel high-protein dairy product based on fresh white cheese and whey protein isolate.

The aim of the study was to obtain hard cheese similar to the rennet hard cheese starting from the fresh white cheese (low and full-fat). This was accomplished with adding a powdered whey protein isolate to the fresh white cheese and heating. Fresh white cheese was produced from full or skim milk and ground with the whey protein isolate powder. The obtained mixture was heated at different temperatures. The increased heating temperature resulted in a more compact product characterized by higher hardness and elasticity compared with the full-fat product. The product approved by the organoleptic analysis panel was obtained by heating the mixed fat white cheese and the powdered whey protein isolate at 80°C for 30 min. The most significant achievement was to obtain in ca. one hour a product similar to that produced in ca. one year that is the hard rennet cheese. It contained ca. 39% wt/wt of protein and can be an interesting offer for dairy industry.

The effect of home-based neuromuscular electrical stimulation-resistance training and protein supplementation on lean mass in persons with spinal cord injury: A pilot study.

In persons with a spinal cord injury (SCI), resistance training using neuromuscular electrical stimulation (NMES-RT) increases lean mass in the lower limbs. However, whether protein supplementation in conjunction with NMES-RT further enhances this training effect is unknown. In this randomized controlled pilot trial, 15 individuals with chronic SCI engaged in 3 times/week NMES-RT, with (NMES+PRO, n = 8) or without protein supplementation (NMES, n = 7), for 12 weeks. Before and after the intervention, whole body and regional body composition (DXA) and fasting glucose and insulin concentrations were assessed in plasma. Adherence to the intervention components was ≥96%. Thigh lean mass was increased to a greater extent after NMES+PRO compared to NMES (0.3 (0.2, 0.4) kg; p < 0.001). Furthermore, fasting insulin concentration and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) were decreased similarly in both groups (fasting insulin: 1 [-9, 11] pmol∙L-1; HOMA-IR: 0.1 [-0.3, 0.5] AU; both p ≥ 0.617). Twelve weeks of home-based NMES-RT increased thigh lean mass, an effect that was potentiated by protein supplementation. In combination with the excellent adherence and apparent improvement in cardiometabolic health outcomes, these findings support further investigation through a full-scale randomized controlled trial.

Optimization and Preparation of Ultrasound-Treated Whey Protein Isolate Pickering Emulsions.

This study aimed to create Pickering emulsions with varying oil fractions and assess the impact of ultrasonic treatment on the properties of Whey Protein Isolates (WPIs). At 640 W for 30 min, ultrasound reduced WPI aggregate size, raised zeta potential, and improved foaming, emulsifying, and water-holding capacities. FTIR analysis showed structural changes, while fluorescence and hydrophobicity increased, indicating tertiary structure alterations. This suggests that sonication efficiently modifies WPI functionality. Under ideal conditions, φ = 80 emulsions were most stable, with no foaming or phase separation. Laser scanning revealed well-organized emulsions at φ = 80. This study provides a reference for modifying and utilizing WPI.

Comparison of the Stability of a Camu Camu Extract Dried and Encapsulated by Means of High-Throughput Electrospraying Assisted by Pressurized Gas.

This study explores the impact on the stability of drying and the encapsulation of a camu camu extract (CCX) using the non-thermal, high-throughput electrospraying assisted by pressurized gas (EAPG) technique. The dried and encapsulated products by the EAPG processing techniques were compared in terms of total soluble phenolic compounds, antioxidant activity, and storage stability. Whey protein concentrate (WPC) and zein (ZN) were selected as the protective excipients for encapsulation. Dried and encapsulated products were obtained in the form of microparticles, which were smaller and more spherical in the case of the encapsulates. No significant differences were observed in the total polyphenolic content (TSP), and only relatively small differences in the antioxidant capacity were measured among samples. The generated products were subjected to various storage conditions to assess their stability and the preservation of the TSP and the antioxidant properties, i.e., 0% relative humidity (RH) and 4 °C; 0% RH and 21 °C; 23% RH and 21 °C; 56% RH and 21 °C; and UV light exposure. The results indicated that ZN encapsulation notably enhanced the retention of total soluble polyphenols and the antioxidant activity compared to WPC and dried CCX, especially in the ratio of 2:1 (encapsulating polymer: dried CCX). This study demonstrates the potential of protein-based encapsulation, particularly using ZN, for stabilizing bioactive compounds against degradation mechanisms induced by humidity, temperature, or ultraviolet radiation exposure.

Biohydrogen production from co-substrates through dark fermentation by bacterial consortium.

Hydrogen is a clean energy carrier that can be used as fuel for fuel cells. Dark fermentative biohydrogen production with other waste biomass needs to be explored as an alternative for sustainable biohydrogen production in future. In this study, lab-scale bioreactor were carried out to produce biohydrogen from co-substrates using bacterial consortium at 37 â„ƒ. For the experimental setup, a 1-L-working-volume reactor was used for biohydrogen production by bacterial monocultures and consortium on co-substrates. A batch experiment was performed at 37 °C with an initial pH of 7.0 and a mixing ratio of 600:300 between dairy whey and sugarcane bagasse. Total solids (TS), volatile solids (VS), total chemical oxygen demand (TCOD), soluble chemical oxygen demand (SCOD), and hydrogen production rate (HPR) were determined from co-substrates during the dark fermentation process. Morphologic changes of biohydrogen producing bacteria binds on co-substrates after the fermentation process were determined using SEM imaging. The bacteria can degrade the substrate when they attach to it causing hole formation and cracked the surface area. The level of biohydrogen production by bacterial consortium was observed and the results revealed a hydrogen production rate of 35.9 mL H2/L/h. In fermentative H2 production, it is quite similar to that of most H2-producing bacteria previously studied, especially that of the bacterial consortium, and this indicates that the attempt to find an outstanding bacterial strain for fermentative H2 production might be very difficult if not impossible.

Comparison of Whey N-Glycoproteins in Yak Colostrum and Mature Milk Based on 4D Label-Free Technology.

Whey proteins are N-glycosylated proteins that play important roles in a variety of biological processes including immune defense. However, the N-glycosylation of yak colostrum (YC) and mature milk (YM) whey proteins is unknown. Therefore, this study systematically compared and analyzed YC and YM whey N-glycoproteomes using the 4D label-free technique. We identified 162 glycoproteins, 222 glycosylated peptides, and 234 glycosylation sites in YC and YM, of which 59 glycoproteins were differentially expressed in YC and YM. According to gene ontology annotation and KEGG pathway metabolism analysis, the differentially expressed N-glycoproteins were highly enriched in "cell adhesion", "extracellular region", and "calcium binding", and were mainly involved in the extracellular matrix (ECM)-receptor interaction pathway. The immunity-related N-glycoproteins, such as platelet glycoprotein 4 (CD36) and polymeric immunoglobulin receptor (PIGR), were observed to be different between YC and YM. The results revealed the glycosylation sites, composition, and biological functions of YC and YM whey N-glycoprotein, which supplemented our understanding of the N-glycosylation of yak whey proteins.