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Emodin (E), the main active ingredient in rhubarb, is a hydrophobic molecule. Micellar casein (MC) is the natural state of caseins in milk. In this study, the interaction between MC and E was calculated by fluorescence analysis with the addition of pectin (P). The average size and structure of P-MC@ E complexes were analyzed, as well as their DPPH free radical and ABTS cationic radical scavenging activities. In addition, the release profiles of emodin from the complexes were evaluated by a simulated gastrointestinal digestion experiment. Results showed that the major interaction between MC and emodin was hydrophobic forces in the P-MC system with the ratio of P to MC in the range of 0:10 - 5:5, the binding constant of which was greater than 103. With the increase of pectin content, the particle size of P-MC@ E complexes increased gradually, but its infrared spectra did not change significantly. Furthermore, the DPPH free radical and ABTS cationic radical scavenging activities of the complexes were significantly higher than those of free emodin, which increased with the increase of pectin content. After binding with P-MC, the release rate of emodin during simulated gastrointestinal digestion decreased. The results could provide basic references for the loading and delivery of emodin. [ABSTRACT FROM AUTHOR]

In this work, oil-in-water (O/W) emulsion gels with 70% oil phase were prepared using micellar casein (MC) and sodium alginate (SA) as substrates with the addition of gluconate-δ-lactone (GDL) as acidifying agent. The effects of GDL addition on the microstructure, stability and rheological properties of emulsion gels were studied, and the release characteristics of emulsion gels loaded with proanthocyanidins (PC) were analyzed. The results showed that with increasing GDL concentration, the average size of oil droplets in emulsion gels decreased, and it gradually decreased during the storage period. GDL acidification improved the apparent viscosity and storage modulus of emulsion gels, and this effect increased with GDL concentration. The microstructure of emulsion gels did not change significantly after heat treatment at 65 or 80 ℃ for 30 min. Meanwhile, the emulsion gels were stable to acidic and basic conditions as well as storage. In addition, the release rate of PC-loaded emulsion gels was higher than that of free PC during simulated intestinal digestion, and the cumulative release rate at 10 h increased with GDL concentration. The results of this study could provide a reference for the preparation of emulsion gels based on MC and the improvement of PC stability.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRACT: High protein levels in yogurt, as well as the presence of denatured whey proteins in the milk, lead to the development of firm gels that can make it difficult to formulate a fluid beverage. We wanted to prepare high-protein yogurts and explore the effects of using micellar casein isolate (MCI), which was significantly depleted in whey protein by microfiltration. Little is known about the use of whey protein-depleted milk protein powders for high-protein yogurt products. Microfiltration also depletes soluble ions, in addition to whey proteins, and so alterations to the ionic strength of rehydrated MCI dispersions were also explored, to understand their effects on a high-protein yogurt gel system. Yogurts were prepared at 8% protein (wt/wt) from MCI or nonfat dry milk (NDM). The NDM was dispersed in water, and MCI powders were dispersed in water (with either low levels of added lactose to allow fermentation to achieve the target pH, or a high level to match the lactose content of the NDM sample) or in ultrafiltered (UF) milk permeate to align its ionic strength with that of the NDM dispersion. Dispersions were then heated at 85°C for 30 min while stirring, cooled to 40°C in an ice bath, and fermented with yogurt cultures to a final pH of 4.3. The stiffness of set-style yogurt gels, as determined by the storage modulus, was lowest in whey protein-depleted milk (i.e., MCI) prepared with a high ionic strength (UF permeate). Confocal laser scanning microscopy and permeability measurements revealed no large differences in the gel microstructure of MCI samples prepared in various dispersants. Stirred yogurt made from MCI that was prepared with low ionic strength showed slow rates of elastic bond reformation after stirring, as well as slower increases in cluster particle size throughout the ambient storage period. Both the presence of denatured whey proteins and the ionic strength of milk dispersions significantly affected the properties of set and stirred-style yogurt gels. Results from this study showed that the ionic strength of the heated milk dispersion before fermentation had a large influence on the gelation pH and strength of acid milk gels, but only when prepared at high (8%) protein levels. Results also showed that depleting milk of whey proteins before fermentation led to the development of weak yogurt gels, which were slow to rebody and may be better suited for preparing cultured milk beverages where low viscosities are desirable.

The modern food industry sees raw milk as a source of functional ingredients. Technologies of protein ingredients have a great scientific and practical importance because membrane fractionation methods preserve the native structure and properties of protein components. The resulting proteins have good fat profile, moisture retention, and emulsification characteristics, as well as perform some useful technological functions in food systems. They have no status of food additives and can be applied in various branches of food production. Unfortunately, the Russian food industry has no such technologies of its own. This article introduces some technological recommendations for the p roduction of domestic micellar casein concentrate. The research involved skim milk, commercial micellar casein concentrates from various manufacturers, curd samples with 9.0% of fat in dry matter, and Rossiysky cheese produced according to traditional formulation and technology. The experiment relied on standard research methods of physical and chemical analysis to establish the chemical composition of the samples, e.g., fractional composition of skim milk proteins, grain-size distribution, amino acid profile, etc. The study involved a comparative analysis of the chemical composition, as well as functional and technological properties of commercial micellar casein concentrates from various manufacturers. A set of experiments made it possible to define the thermal effect on raw material and to predict the prospects for usage of the new technology. Samples with a high ratio of casein:whey proteins and a moderately high heat treatment increased the curd and cheese yield by 10–12% in comparison with the traditional formulation. Samples with the maximal concentration of undenatured milk-serum protein nitrogen increased the yield of protein dairy products by 2–3% in comparison with other samples of micellar casein concentrates. The ratio of casein:whey proteins was 80:20 in skim milk obtained at PJSC Dairy “Voronezhsky”. The optimal pore diameter was ≥ 15 nm. As for the microbiological properties, QMA and OAMO was 6×104 CFU/dm3, and no pathogenic microorganisms were detected. Therefore, low-temperature pasteurization proved feasible at ≤ 76 ± 2°C and 10–15 s of hold time. The micellar casein concentrate added certain functional and technological properties to the finished product, depending on the specific application scope. The new technology will enable the domestic food industry to ov ercome the existing import dependence.

Drying characteristics of milk whey protein concentrate (WPC) and micellar caseins (MC) were investigated through a custom-designed mobile thin-film dryer. Several mixtures containing different WPC to MC ratios were tested in drying experiments. Both the constant drying period and falling rate period were identified. It was noticed the initial drying rates at constant drying period were slightly hindered by the presence of protein even at low concentrations. The drying kinetics was investigated by the characteristic drying curve (CDC) method and the drying behavior at the falling rate period was evaluated by a specific parameter n. As the result, while WPC exhibited a uniform master characteristic drying curve through different drying conditions, samples with certain amount of MC showed the more "scattered" curves, which lead to a wide distribution of n. Besides, it was observed that a thin layer of crust formed during the drying process. The analysis of the drying characteristics of MC led to a meaningful correlation with the morphology and structural properties. As the morphology of the crust was determined by the velocity and temperature of the impinging air, it became an inherent limitation for this thin film drying method to investigate materials with such crust formation phenomena. [ABSTRACT FROM AUTHOR]

High protein levels in yogurt, as well as the presence of denatured whey proteins in the milk, lead to the development of firm gels that can make it difficult to formulate a fluid beverage. We wanted to prepare high-protein yogurts and explore the effects of using micellar casein isolate (MCI), which was significantly depleted in whey protein by microfiltration. Little is known about the use of whey protein-depleted milk protein powders for high-protein yogurt products. Microfiltration also depletes soluble ions, in addition to whey proteins, and so alterations to the ionic strength of rehydrated MCI dispersions were also explored, to understand their effects on a high-protein yogurt gel system. Yogurts were prepared at 8% protein (wt/wt) from MCI or nonfat dry milk (NDM). The NDM was dispersed in water, and MCI powders were dispersed in water (with either low levels of added lactose to allow fermentation to achieve the target pH, or a high level to match the lactose content of the NDM sample) or in ultrafiltered (UF) milk permeate to align its ionic strength with that of the NDM dispersion. Dispersions were then heated at 85°C for 30 min while stirring, cooled to 40°C in an ice bath, and fermented with yogurt cultures to a final pH of 4.3. The stiffness of set-style yogurt gels, as determined by the storage modulus, was lowest in whey protein-depleted milk (i.e., MCI) prepared with a high ionic strength (UF permeate). Confocal laser scanning microscopy and permeability measurements revealed no large differences in the gel microstructure of MCI samples prepared in various dispersants. Stirred yogurt made from MCI that was prepared with low ionic strength showed slow rates of elastic bond reformation after stirring, as well as slower increases in cluster particle size throughout the ambient storage period. Both the presence of denatured whey proteins and the ionic strength of milk dispersions significantly affected the properties of set and stirred-style yogurt gels. Results from this study showed that the ionic strength of the heated milk dispersion before fermentation had a large influence on the gelation pH and strength of acid milk gels, but only when prepared at high (8%) protein levels. Results also showed that depleting milk of whey proteins before fermentation led to the development of weak yogurt gels, which were slow to rebody and may be better suited for preparing cultured milk beverages where low viscosities are desirable. [ABSTRACT FROM AUTHOR]

Milk protein concentrates (MPCs), which are produced from skim milk following a series of manufacturing steps including pasteurization, membrane filtration, evaporation and spray drying, represent a relatively new category of dairy ingredients. MPC powders mainly comprise caseins and whey proteins in the same ratio of occurrence as in milk. While bovine MPCs have applications as an ingredient in several protein enriched food products, technofunctional concerns, e.g., reduced solubility and emulsification properties, especially after long-term storage, limit their widespread and consistent utilization in many food products. Changes in the surface and internal structure of MPC powder particles during manufacture and storage occur via casein-casein and casein-whey protein interactions and also via the formation of casein crosslinks in the presence of calcium ions which are associated with diminishment of MPCs functional properties. The aggregation of micellar caseins as a result of these interactions has been considered as the main cause of insolubility in MPCs. In addition, the occurrence of lactose-protein interactions as a result of the promotion of the Maillard reaction mainly during storage of MPC may lead to greater insolubility. This review focuses on the solubility of MPC with an emphasis on understanding the factors involved in its insolubility along with approaches which may be employed to overcome MPC insolubility. Several strategies have been developed based on manipulation of the manufacturing process, along with composition, physical, chemical and enzymatic modifications to overcome MPC insolubility. Despite many advances, dairy ingredient manufacturers are still investigating technical solutions to resolve the insolubility issues associated with the large-scale manufacture of MPC. [ABSTRACT FROM AUTHOR]

ABSTRACT: Concentrated micellar casein (CMC) is a high-protein ingredient that can be used in process cheese product formulations. The objectives of this study were to develop a process to produce CMC and to evaluate the effect of sodium chloride and sodium citrate on its storage stability. Skim milk was pasteurized at 76°C for 16 s and cooled to ≤4°C. The skim milk was heated to 50°C using a plate heat exchanger and microfiltered with a graded permeability (GP) ceramic microfiltration (MF) membrane system (0.1 μm) in a continuous feed-and-bleed mode (flux of 71.43 L/m2 per hour) using a 3× concentration factor (CF) to produce a 3× MF retentate. Subsequently, the retentate of the first stage was diluted 2× with soft water (2 kg of water: 1 kg of retentate) and again MF at 50°C using a 3× CF. The retentate of the second stage was then cooled to 4°C and stored overnight. The following day, the retentate was heated to 63°C and MF in a recirculation mode until the total solids (TS) reached approximately 22% (wt/wt). Subsequently, the MF system temperature was increased to 74°C and MF until the permeate flux was 25% TS and >95% casein as percentage of TP can be manufactured using GP MF ceramic membranes and could be stored up to 60 d at 4°C. The effects of the small increase in NCN and NPN, as well as the addition of sodium chloride or sodium citrate in CMC during 60 d of storage on process cheese characteristics, will be evaluated in subsequent studies.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Natural casein is a highly structured protein and the characteristic of self-assembly makes the formation of micelles, thus negatively limiting the applications. High hydrostatic pressure (HHP), as a novel non-thermal process, can modify the structures of protein and improve the related functionalities. In this study, micellar casein was subjected to HHP treatment from 100 to 500 MPa, which then loaded quercetin and formed the nanoemulsion. The thermal, pH, ions and physical stability of nanoemulsion were comprehensively investigated. The results showed 300–500 MPa could effectively disintegrate the micellar structures of natural casein by dissociating colloidal calcium phosphate, which significantly improved the emulsifying activity and encapsulation efficiency. However, 500 MPa caused the nanoemulsion loading most quercetin and subsequently showed the better physical and ions stability in comparison with control and 100–400 MPa. Therefore, HHP is expected to modify the high-order structure of casein, which becomes the ideal nano-vehicles for hydrophobic bioactive substances.

[Display omitted] • Fluid FM is a direct analysis of interfacial properties of multiphase systems. • Interfacial protein composition determines RDC physical properties. • Micellar casein layer is less strong but increases adherence of fat globules. • Multi-protein synergy was key to the stabilization and aeration of whipped creams. • Micellar casein contributed to the thixotropy of aerated foams. In this study, whipped cream with blends of micellar casein (MCN) and whey protein (WPI) in different ratios were prepared to investigate the role of protein interfacial behavior in determining foam properties at multiple scales, using theoretical modeling, and microscopic and macroscopic analysis. Fluid force microscopy has been used for the first time as a more realistic and direct means of analyzing interfaces properties in multiphase systems. The adsorption kinetics showed that the interfacial permeability constant of WPI (4.24 × 10-4 s−1) was significantly higher than that of the MCN (2.97 × 10-4 s−1), and the WPI interfacial layer had a higher modulus of elasticity (71.38 mN/m) than that of the MCN (47.89 mN/m). This model was validated via the mechanical analysis of the fat globules in real emulsions. The WPI-stabilized fat globule was found to have a higher Young's modulus (219.67 Pa), which contributes to the integrity of its fat globule morphology. As the ratio of MCN was increased in the sample, however, both the interfacial modulus and Young's modulus decreased. Moreover, the rate of partial coalescence was found to increase, a phenomenon that decreased the stability of the emulsion and increased the rate of aeration. The mechanical analysis also revealed a higher level of adhesion between MCN-stabilized fat globule (25.16 nN), which increased fat globule aggregation and emulsion viscosity, while improving thixotropic recovery. The synergistic effect of the blended MCN and WPI provided the highest overrun, at 194.53 %. These studies elucidate the role of the interfacial behavior of proteins in determining the quality of whipped cream and provide ideas for the application of proteins in multiphase systems. [ABSTRACT FROM AUTHOR]

Concentrated micellar casein (CMC) is a high-protein ingredient that can be used in process cheese product formulations. The objectives of this study were to develop a process to produce CMC and to evaluate the effect of sodium chloride and sodium citrate on its storage stability. Skim milk was pasteurized at 76°C for 16 s and cooled to ≤4°C. The skim milk was heated to 50°C using a plate heat exchanger and microfiltered with a graded permeability (GP) ceramic microfiltration (MF) membrane system (0.1 μm) in a continuous feed-and-bleed mode (flux of 71.43 L/m2 per hour) using a 3× concentration factor (CF) to produce a 3× MF retentate. Subsequently, the retentate of the first stage was diluted 2× with soft water (2 kg of water: 1 kg of retentate) and again MF at 50°C using a 3× CF. The retentate of the second stage was then cooled to 4°C and stored overnight. The following day, the retentate was heated to 63°C and MF in a recirculation mode until the total solids (TS) reached approximately 22% (wt/wt). Subsequently, the MF system temperature was increased to 74°C and MF until the permeate flux was <3 L/m2 per hour. The CMC was then divided into 3 aliquots (approximately 10 kg each) at 74°C. The first portion was a control, whereas 1% of sodium chloride was added to the second portion (T1), and 1% of sodium chloride plus 1% of sodium citrate were added to the third portion (T2). The CMC retentates were transferred hot to sterilized vials and stored at 4°C. This trial was repeated 3 times using separate lots of skim milk. The CMC at d 0 (immediately after manufacturing) contained 25.41% TS, 21.65% true protein (TP), 0.09% nonprotein nitrogen (NPN), and 0.55% noncasein nitrogen (NCN). Mean total aerobic bacterial counts (TBC) in control, T1, and T2 at d 0 were 2.6, 2.5, and 2.8 log cfu/mL, respectively. The level of proteolysis (NCN and NPN values) increased with increasing TBC during 60 d of storage at 4°C. This study determined that CMC with >25% TS and >95% casein as percentage of TP can be manufactured using GP MF ceramic membranes and could be stored up to 60 d at 4°C. The effects of the small increase in NCN and NPN, as well as the addition of sodium chloride or sodium citrate in CMC during 60 d of storage on process cheese characteristics, will be evaluated in subsequent studies. [ABSTRACT FROM AUTHOR]

Puerarin (PUE) and daidzein (DAI) are polyphenols with extensive biological activities. In the present study, the interactions between PUE/DAI and micellar casein (MC) were investigated, and the physicochemical properties of their complexes were analyzed. The results of fluorescence spectrum analysis and molecular docking revealed that the main interactions between DAI and MC were hydrophobic forces, while that between PUE and MC was hydrogen bonding. The FTIR and XRD analyses confirmed the formation of complexes between MC and PUE/DAI. After binding to PUE/DAI, the size of MC increased. The weight loss rate of MC decreased after complexing with PUE/DAI, but its morphology was not extensively modified. The DPPH radical scavenging capacities of PUE‐MC and DAI‐MC complexes were higher than those of free PUE/DAI in both water and ethanol. In vitro release experiments showed that the release rate of PUE/DAI was inhibited by MC under simulated intestinal conditions. Practical applications: The low water solubility and poor bioavailability of PUE and DAI limit their application. Micellar casein has high affinity for PUE and DAI. After encapsulated by micellar casein, the release rates of PUE and DAI were prolonged during simulated intestinal digestion. The results would provide useful information for improving the solubility and bioavailability of PUE and DAI, and broadening the use of them in the food and pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Background: Stabilization of freeze-dried lactic acid bacteria during long-term storage is challenging for the food industry. Water activity of the lyophilizates is clearly related to the water availability and maintaining a low aw during storage allows to increase bacteria viability. The aim of this study was to achieve a low water activity after freeze-drying and subsequently during long-term storage through the design of a lyoprotectant. Indeed, for the same water content as sucrose (commonly used lyoprotectant), water activity is lower for some components such as whey, micellar casein or inulin. We hypothesized that the addition of these components in a lyoprotectant, with a higher bound water content than sucrose would improve lactobacilli strains survival to long-term storage. Therefore, in this study, 5% whey (w/v), 5% micellar casein (w/v) or 5% inulin (w/v) were added to a 5% sucrose solution (w/v) and compared with a lyoprotectant only composed of 5% sucrose (w/v). Protective effect of the four lyoprotectants was assessed measuring Lactiplantibacillus plantarum CNCM I-4459 survival and water activity after freeze-drying and during 9 months storage at 25 °C. Results: The addition whey and inulin were not effective in increasing Lactiplantibacillus plantarum CNCM I-4459 survival to long-term-storage (4 log reduction at 9 months storage). However, the addition of micellar casein to sucrose increased drastically the protective effect of the lyoprotectant (3.6 log i.e. 0.4 log reduction at 9 months storage). Comparing to a lyoprotectant containing whey or inulin, a lyoprotectant containing micellar casein resulted in a lower water activity after freeze-drying and its maintenance during storage (0.13 ± 0.05). Conclusions: The addition of micellar casein to a sucrose solution, contrary to the addition of whey and inulin, resulted in a higher bacterial viability to long-term storage. Indeed, for the same water content as the others lyoprotectants, a significant lower water activity was obtained with micellar casein during storage. Probably due to high bound water content of micellar casein, less water could be available for chemical degradation reactions, responsible for bacterial damages during long-term storage. Therefore, the addition of this component to a sucrose solution could be an effective strategy for dried bacteria stabilization during long-term storage. [ABSTRACT FROM AUTHOR]

During overnight sleep, the longest postabsorptive and inactive phase of the day causes protein catabolism and loss. However, the daytime ingestion of dairy proteins has been shown to stimulate muscle protein synthesis and growth. This study compared the effects of pre-sleep supplementation of a protein blend (PB) composed of micellar casein (MCa) and whey protein (1:1) versus isolate MCa on the plasma levels of branched-chain amino acids (BCAAs) and the activation of the mechanistic target of rapamycin (mTOR) signaling, a critical intracellular pathway involved in the regulation of muscle protein synthesis. After 10 h of fasting during the active phase, rats were fed with a single dose of PB or MCa (5.6 g protein/kg of body mass) by gavage, and samples of blood and gastrocnemius muscle were collected at 30, 90, and 450 min. PB and MCa supplementations induced an increase (~3-fold, P < 0.001) of plasma BCAAs at 30 and 90 min. Most importantly, the stimulatory phosphorylation levels of mTOR and its downstream target p70 ribosomal protein S6 kinase (p70S6K) were similarly higher (~2.5-fold, P < 0.001) 30 and 90 min after MCa and PB. Plasma levels of leucine, isoleucine, valine, and overall BCAAs were correlated with the activation of mTOR (P < 0.001) and p70S6K (P < 0.001). MCa and PB supplementations before the inactive phase of rats resulted in an anabolic milieu in the skeletal muscle by inducing a transient increase in plasma BCAAs and a similar activation of the mTOR/p70S6K axis.

This study evaluated the role of protein concentration and milk protein ingredient [serum protein isolate (SPI), micellar casein concentrate (MCC), or milk protein concentrate (MPC)] on sensory properties of vanilla ready-to-drink (RTD) protein beverages. The RTD beverages were manufactured from 5 different liquid milk protein blends: 100% MCC, 100% MPC, 18:82 SPI:MCC, 50:50 SPI:MCC, and 50:50 SPI:MPC, at 2 different protein concentrations: 6.3% and 10.5% (wt/wt) protein (15 or 25 g of protein per 237 mL) with 0.5% (wt/wt) fat and 0.7% (wt/wt) lactose. Dipotassium phosphate, carrageenan, cellulose gum, sucralose, and vanilla flavor were included. Blended beverages were preheated to 60°C, homogenized (20.7 MPa), and cooled to 8°C. The beverages were then preheated to 90°C and ultrapasteurized (141°C, 3 s) by direct steam injection followed by vacuum cooling to 86°C and homogenized again (17.2 MPa first stage, 3.5 MPa second stage). Beverages were cooled to 8°C, filled into sanitized bottles, and stored at 4°C. Initial testing of RTD beverages included proximate analyses and aerobic plate count and coliform count. Volatile sulfur compounds and sensory properties were evaluated through 8-wk storage at 4°C. Astringency and sensory viscosity were higher and vanillin flavor was lower in beverages containing 10.5% protein compared with 6.3% protein, and sulfur/eggy flavor, astringency, and viscosity were higher, and sweet aromatic/vanillin flavor was lower in beverages with higher serum protein as a percentage of true protein within each protein content. Volatile compound analysis of headspace vanillin and sulfur compounds was consistent with sensory results: beverages with 50% serum protein as a percentage of true protein and 10.5% protein had the highest concentrations of sulfur volatiles and lower vanillin compared with other beverages. Sulfur volatiles and vanillin, as well as sulfur/eggy and sweet aromatic/vanillin flavors, decreased in all beverages with storage time. These results will enable manufacturers to select or optimize protein blends to better formulate RTD beverages to provide consumers with a protein beverage with high protein content and desired flavor and functional properties. [ABSTRACT FROM AUTHOR]

The data in this article are related to the research publication “Digestion of micellar casein in duodenum cannulated pigs. Correlation between in vitro simulated gastric digestion and in vivo data” (Miralles et al., Food Chemistry, 2021, 343, 128428). Pig duodenum effluents were collected with a T-shaped cannula 15 min before and during digestion over 150 min after casein intake. The casein degradation profile of individual pigs during digestion is presented. All identified peptide sequences at different digestion times for six subjects are provided. The peptide profile of digests in the form of heat maps is shown for αs1-, αs2-, β- and κ-casein. The sum of amino acids belonging to peptides released from β- and αs1-casein has been used to determine correlation coefficients and range the inter-individual variability. Finally, the global amino acid composition, isoelectric point and sequence length of all released peptides has been determined.

Milk, a rich source of nutrients, can be fractionated into a wide range of components for use in foods and beverages. With advancements in filtration technologies, micellar caseins and milk-derived whey proteins are now produced from skim milk using microfiltration. Microfiltered ingredients offer unique functional and nutritional benefits that can be exploited in new product development. Microfiltration offers promise in cheesemaking, where microfiltered milk can be used for protein standardization to improve the yield and consistency of cheese and help with operation throughputs. Micellar casein concentrates and milk whey proteins could offer unique functional and flavor properties in various food applications. Consumer desires for safe, nutritious, and clean-label foods could be potential growth opportunities for these new ingredients. The application of micellar casein concentrates in protein standardization could offer a window of opportunity to US cheese makers by improving yields and throughputs in manufacturing plants. [ABSTRACT FROM AUTHOR]

The effect of casein on the quality of ice cream with different fat content was studied. According to functional and technological characteristics, micellar casein was selected for the enrichment of ice cream. Using mathematical modeling in the environment of the MathCad-15 package, the mass fraction of micellar casein in the composition of ice cream with a fat content of 0 to 15 % was optimized in order to obtain a high-quality product. At the first stage, the response surface methodology was used to optimize the response functions (overrun, melting resistance, organoleptic characteristics) for the varied fat and protein content. In the second stage, a comprehensive quality score of ice cream was used for modeling as a function of estimates of individual quality indicators, converted into scalable values using weights. The inverse relationship between the values of the optimal protein content and the fat content of ice cream was determined. To achieve the maximum technological effect, in the composition of ice cream with a fat content of 0-5 %, 6-10 % and 11-15 %, the need for micellar casein is 6-5 %, 4-3 % and 2.5-1 %, respectively. According to the results of calculating the percentage of energy value introduced by total protein (more than 20 %), it was concluded that ice cream with a fat content of 0-5 % with mass fractions of micellar casein of 6-5 % and total protein of 9.7-8.7 % can be attributed to the category of products with high protein content. Ice cream with a fat content of 10-15 % with mass fractions of casein micellar of 3-1 % and total protein of 6.7-4.7 % can be attributed to a product with high protein content. The results of the study allow expanding the range of protein-containing ice cream to meet the needs of consumers of different groups [ABSTRACT FROM AUTHOR]

Anthocyanins (ACNs) possess the natural advantage of gastric stabilization and has the potential to be adopted for the delivery system design for prolonged gastric release to enhance its bioavailability. In this study, micellar casein treated with high hydrostatic pressure (100, 300, and 500 MPa) was applied to load ACNs, and exogenous serum Ca2+ (0.15, 2, and 5 mM) controlled the gastric aggregation behavior of casein during in vitro digestion. The results showed that the high level of pressure dissociated the micellar structure and provided more cross-linking possibilities for serum Ca2+. Furthermore, the high serum Ca2+ level enhanced gastric aggregation of casein subunits and submicelles leading to delayed gastric emptying, and controlled the slow release of ACNs, which contributed to prolong the ACN retention in the stomach. The application of high hydrostatic pressure (HHP) in food sterilization has been relatively mature, and there is an urgent need to expand it toward the nutritional and health field in search of high added value. Herein, HHP was applied to solve the problem of low bioavailability of ACNs based on the ingenious relationship between HHP and casein micelles. The research data can help to develop nutraceuticals or high satiety foods with ACNs as the main functional component at low cost. [Display omitted] • HHP dissociated casein micelles and increased the EE of ACNs. • High level of pressure provided more cross-linking possibilities for serum Ca2+. • High level of serum Ca2+ enhanced gastric aggregation and ACNs slow release. • HHP-induced subunits and submicelles were cross-linked by serum Ca2+ in the stomach. [ABSTRACT FROM AUTHOR]

We investigated the effect of different phosphate salts on the structural integrity of micellar casein (MC) at pH 7.0. With the increase of salt concentration, a reduction in turbidity was observed for the MC solutions, and it was modeled using an exponential decay function. The inflection point of the model was defined as the first critical salt concentration (C*), and it is suggested that the salt concentration initiates the disintegration of MC. For linear polyphosphates, C* decreased with the number of phosphate groups. Apparent viscosity (η app) of MC solutions increased with the increase of salt concentration, and they recorded a peak while the turbidity decreased to a minimum. The salt concentration that resulted in the highest η app was identified as the second critical salt concentration (C**). It is hypothesized that the interactions among protein species present in the mixtures are at an optimum state at C**. Both C* and C** were found to be dependent on the MC concentration. The work presented herein supports an understanding of the concentration effect of phosphate salts on MC for structuring dairy products. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The heat-induced gelation of oil-in-water emulsions stabilised by mixtures of micellar caseins (MC) and plant proteins (PLP) was investigated in order to assess the potential of PLP to replace milk proteins for the development of novel food products. The aim of this work was to investigate how the heat-induced gelation of MC/PLP oil-in-water emulsions is affected by sunflower oil content (0, 5, 10 and 15% w/w) and total protein content in the aqueous phase (C; from 1 to 4% w/w) at different protein compositions (MC/PLP = 100/0 to 0/100) and pH 5.8. Two types of PLP were used: soy proteins (SP) and pea proteins (PP). Storage moduli (G') were measured during heating ramps from 20 to 90 °C and heat-induced gelation was characterised by an increase in G' at a gelation temperature (T g). The gel stiffness (G el) was determined after 1 h at 90 °C and the microstructure of the emulsion gels was observed by confocal laser scanning microscopy (CLSM). T g increased when an increasing fraction of MC was replaced by SP or PP, due to binding of calcium to PLP. T g decreased with increasing oil content in the MC/PLP emulsions mainly up to 10% w/w oil, explained by protein interactions at the oil-water interface. Generally, MC could be successfully replaced by PLP while maintaining the same G el. G el increased with increasing oil content, suggesting that oil droplets acted as active fillers in the emulsion gels, which was confirmed by CLSM images. G el slightly increased with increasing C from 1 to 4% w/w. It was also shown that PLP can be used instead of whey proteins in MC/whey protein oil-in-water emulsions while maintaining the same G el. [ABSTRACT FROM AUTHOR]

Background: Whey and micellar casein are high-quality dairy proteins that can stimulate postprandial muscle protein synthesis rates. How whey and casein compare with milk protein in their capacity to stimulate postprandial myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis rates during postexercise recovery is currently unknown.Objective: The objective of this study was to compare postprandial MyoPS and MitoPS rates after protein-carbohydrate co-ingestion with milk protein, whey, or micellar casein during recovery from a single bout of concurrent resistance- and endurance-type exercise in young healthy men.Methods: In a randomized, double-blind, parallel-group design, 48 healthy, young, recreationally active men (mean ± SEM age: 23 ± 0.3 y) received a primed continuous infusion of L-[ring-13C6]-phenylalanine and L-[ring-3,5-2H2]-tyrosine and ingested 45 g carbohydrate with 0 g protein (CHO), 20 g milk protein (MILK), 20 g whey protein (WHEY), or 20 g micellar casein protein (CASEIN) after a sequential bout of resistance- and endurance-type exercise (i.e., concurrent exercise). Blood and muscle biopsies were collected over 360 min during recovery from exercise to assess MyoPS and MitoPS rates and signaling through mammalian target of rapamycin complex 1 (mTORC1).Results: Despite temporal differences in postprandial plasma leucine concentrations between treatments (P < 0.001), MyoPS rates over 360 min of recovery did not differ between treatments (CHO: 0.049% ± 0.003%/h; MILK: 0.059% ± 0.003%/h; WHEY: 0.054% ± 0.002%/h; CASEIN: 0.059% ± 0.005%/h; P = 0.11). When MILK, WHEY, and CASEIN were pooled into a single group (PROTEIN), protein co-ingestion resulted in greater MyoPS rates compared with CHO (PROTEIN: 0.057% ± 0.002%/h; CHO: 0.049% ± 0.003%/h; P = 0.04). MitoPS rates and signaling through the mTORC1 pathway were similar between treatments.Conclusion: MyoPS and MitoPS rates do not differ after co-ingestion of either milk protein, whey protein, or micellar casein protein with carbohydrate during recovery from a single bout of concurrent resistance- and endurance-type exercise in recreationally active young men. Co-ingestion of protein with carbohydrate results in greater MyoPS, but not MitoPS rates, when compared with the ingestion of carbohydrate only during recovery from concurrent exercise. This trial was registered at Nederlands Trial Register: NTR5098. [ABSTRACT FROM AUTHOR]

Highlights • Sodium hexametaphosphate increases the viscosity of milk protein concentrate. • Dephosphorylating milk protein altered its viscosity profile. • NMR can be utilised to observe protein dephosphorylation. • NMR showed sodium hexametaphosphate to interact with calcium-phosphoserine. • Phosphoserine peaks were absent in dephosphorylated milk protein. Abstract This study investigated the effects of dephosphorylation and sodium hexametaphosphate (SHMP) salt addition on the viscosity of milk protein concentrate (MPC) solutions. Dephosphorylation (DP) of casein was performed using bovine alkaline phosphatase. Nuclear magnetic resonance (NMR) spectra showed that dephosphorylation depleted the casein-bound phosphate region (CNP). SHMP addition (5 mM) had no impact on the 31P NMR spectra of DP-MPC; addition of 5 mM SHMP to control MPC (C-MPC) resulted in a shift in peaks associated with the CNP region, possibly caused by SHMP sequestering calcium, leading to swelling of micelles. DP-MPC exhibited a lower viscosity compared to C-MPC, with SHMP addition at 12.5 and 25 mM causing gelation of C-MPC and DP-MPC solutions. This work confirmed the role that phosphate residues have in maintaining micelle structural stability and provides new insights into controlling viscosity of MPC solutions. [ABSTRACT FROM AUTHOR]

Emulsion gels have numerous practical applications in the pharmaceutical and food industries, the preparation of which involves multiple processing steps including the production of emulsions and transition of emulsions into gels. Improving the stability of emulsion gels and simplifying their preparation process are key issues. By exploiting the properties of micellar casein (MC), pectin (P) and sodium alginate (SA), a highly stable emulsion gel with 70% oil was created through one-pot homogenization based on the jamming transition. Emulsion gels prepared with an SA-MC ratio of 3:7 exhibited high stability during acidification, heating and with addition of Ca2+, maintained their stability after more than 810 days of storage. It also prolonged the release rate of caffeic acid phenethyl (CAPE) while protecting proanthocyanidin (PC) from degradation during simulated gastrointestinal digestion. Interestingly, P/SA-MC (3:7) emulsion gels containing PC and CAPE prevented the cytotoxic effects of PC and CAPE on human colon epithelial NCM-460 cells, but still allowed PC and CAPE to exert a strong anticancer effect on Caco-2 colon cancer cells. Our approach not only eliminates additional pre- and/or post-treatments used to prepare or stabilize the emulsion gel, but also provides a promising carrier for bioactive molecules. [Display omitted] • Emulsion gels with pectin/sodium alginate and micellar casein (P/SA-MC) were created. • P/SA strengthened the network and enhanced viscoelasticity of MC emulsion gels. • SA-MC emulsion gels at 2:8 and 3:7 kept stable with acidification and 810 d storage. • PC-CAPE in emulsion gels promoted NCM-460 cells' growth while inhibiting Caco-2. • SA-MC emulsion gels showed controlled-release of CAPE and protection for PC. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate how the heat-induced gelation of micellar casein (MC) suspensions (6% w/w MC) is affected by the addition of three globular proteins (GP) (whey proteins (WP), pea proteins (PP) and soy proteins (SP); from 0 to 6% w/w) at pH ≤ 6.0. Storage moduli (G′) were measured as a function of temperature from 20 °C to 90 °C. Heat-induced gelation was characterised by a sharp increase in G′ at a critical temperature (T c ). The suspensions were then held at 90 °C for 1h to determine the stiffness of the gels. Regardless of the pH, T c of MC suspensions increased with the addition of GP. Interestingly, this increase depended on the type of GP and was stronger in the order SP > PP > WP. This effect was mainly explained by differences in calcium binding efficiency between the different GP (SP > PP >> WP) and/or the mineral composition of the ingredients. Native GP influence gelation of MC by binding calcium, thus reducing the amount available for MC to bridge, leading to an increase in T c . T c of the suspensions decreased with decreasing pH due to both decrease in the net charge density of MC and release of Ca 2+ that in turn favoured heat-induced gelation of MC. Gel stiffness was not influenced much by PP or SP addition. However, it increased significantly in the presence of WP, due to co-aggregation of denatured WP with MC above 70 °C, which reinforced the MC network. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Synchrotron radiation circular dichroism (SRCD) and Fourier transform infrared (FTIR) spectroscopy were used to examine the conformation evolution of micellar casein (MC) powder during storage and to determine whether the spectral changes could be related to their solubility evolution. RESULTS: A loss in intensity of SRCD spectra as a function of storage time has been observed. Quantification of secondary structures revealed losses of α‐helix content during storage. Moreover, a redshift of the amide I band in the FTIR spectrum was demonstrated during the storage and was interpreted as a rearrangement of the secondary structure of the protein, which is in line with the SRCD results. The qualitative results obtained by FTIR clearly support the quantitative evolution of the secondary structure obtained by the analysis of SRCD spectra. Principal component analysis (PCA) of FTIR spectra permits a good separation of samples according to the storage time. PCA shows that the evolution of secondary structures and solubility loss are closely linked. CONCLUSION: With the quantitative data provided by SRCD spectra, it was established that, whatever the storage conditions, a unique curve exists between loss of α‐helix content and loss in solubility, showing that loss of α‐helix content is a marker of solubility loss for the MC powders studied. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Highly concentrated micellar casein concentrate (HC-MCC) contains ~18% casein with ~70% of whey proteins removed by microfiltration and diafiltration of skim milk, followed by vacuum evaporation for further concentration. When blended with cream, HC-MCC forms recombined concentrated milk (RCM), which could be used as a starting material in cheese making. Our objective was to investigate the rennet coagulation properties of RCM while varying parameters such as casein level, pH, rennet level, and coagulation temperature. The HC-MCC was mixed with cream using low shear at 50°C for 10 min, followed by cooling to 31, 28, or 25°C and adding rennet, and rheological properties were determined. Rennet coagulation time [RCT, the time at which storage modulus (G′) = loss modulus (G″)] decreased from 8.7 to 7.4 min as casein level increased from 3.2 to 5.7%, without a significant additional difference in RCT at casein levels >5.7%. The initial G″ (G″0) increased about 10-fold when casein levels were increased from 3.2 to 10.9%, whereas no change in initial G′ (G′0) was observed. When G′ was measured relative to RCT (i.e., 1, 1.5, or 2 times RCT after RCT was reached, and expressed as G′1, G′1.5, and G′2), log relationship was found between relative G′ and casein level (R2 > 0.94). Lowering coagulation temperature from 31 to 25°C increased G″0 by 6 fold and extended RCT from 7.4 to 9.5 min. After coagulation, relative G′ was initially higher at the lower temperature with G′1 of 3.6 Pa at 25°C and 2.0 Pa at 31°C, but delayed in further development with G′2 of 0.8 kPa at 25°C and 1.1 kPa at 31°C. Lowering pH of RCM from 6.6 to 6.2 resulted in reduced RCT from 11.9 to 6.5 min with increased relative G′ after coagulation. When less rennet was used, RCT increased in a linear inverse relationship without changes in relative G′ or G″. The microstructure of RCM coagulum (~11% casein), observed using transmission electron microscopy, confirmed that RCM curd had a rigid protein matrix containing extensively cross-linked protein strands. [ABSTRACT FROM AUTHOR]

We aimed to assess if casein structure affects its digestion and its subsequent amino acid delivery kinetic. Higher nitrogen levels were recovered in dialysates after in vitro digestions of sodium caseinate (SC, formed of small aggregates) compared to micellar casein (MC, native form of casein) and calcium caseinate (CC, intermediate structure). Likewise, plasma indispensable amino-acid concentration peak was higher after SC compared to MC or CC ingestion in healthy volunteers in a randomized, double blind, cross-over study. In pigs, gamma-scintigraphy using labelled meals revealed that SC was mainly localized in the proximal part of the stomach whereas MC was distributed in the whole gastric cavity. Caseins were found in both solid and liquid phases and partly hydrolyzed casein in the solid phase shortly after SC drink ingestion. These data support the concept of slow (MC) and rapid (SC) casein depending of casein structure, likely due to their intra-gastric clotting properties., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Gaelle BOUDRY reports financial support and equipment, drugs, or supplies were provided by Ingredia SA. Audrey BOULIER reports a relationship with Ingredia SA that includes: employment. Alain BANIEL reports a relationship with Ingredia SA that includes: employment. Gaelle BOUDRY reports a relationship with Ingredia SA that includes: travel reimbursement., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Casein micelle is known to be a CCP-mediated tight structure that often shows unique stomach curd behavior and rapid intestinal hydrolysis. These inherent properties make it difficult for casein micelles-formed powders called micellar casein (MC) to achieve high loading capacity and controlled release of loaded bioactive compounds. In this study, dextran sulfate (DS) was used as a calcium chelator to combine with MC, and spray-dried microparticles were prepared to load blueberry anthocyanins (ACNs). In vitro gastrointestinal digestion was carried out to investigate the relationship between the structural changes of MC induced by DS as well as the dynamic release process of ACNs. The results indicated that the encapsulation efficiency of microparticles increased from 52.76% ± 2.36%–91.86% ± 0.87% with the addition of DS. During in vitro digestion, the different CCP dissociation degrees induced by DS resulted in different dissolution and curdling abilities of microparticles in the stomach, which thus precisely controlled the release process of ACNs. Simultaneously, the combination with DS could delay the disintegration of the structures of microparticles in the small intestine, thereby hindering the degradation of ACNs. This study will contribute to the design of casein-based delivery systems and the development of related functional products. [Display omitted] • MC formed curds in the stomach and hydrolyzed quickly in the small intestine. • The digestion properties made MC fail to achieve controlled release of ACNs. • DS with calcium chelating ability could adjust the digestion properties of MC. • The less release of ACNs was achieved by the structure barrier of DS. [ABSTRACT FROM AUTHOR]

Highly concentrated micellar casein concentrate (HC-MCC), a potential ingredient for cheese making, contains ~20% casein with ~70% of serum proteins removed by microfiltration and diafiltration of skim milk, followed by vacuum evaporation. Our objective was to investigate cold gelation properties of recombined concentrated milk (RCM) by mixing thawed frozen HC-MCC and cream under different casein levels, pH, and protein-to-fat ratios, and with addition of sodium citrate or calcium. The HC-MCC was recombined with cream using low shear at 50°C for 30 min, and rheological measurements were conducted. Cold-gelling temperature [the temperature at which storage modulus (G') = loss modulus (G")] was linearly correlated with casein levels from 8.6 to 11.5% (R2 = 0.71), pH from 6.6 to 7.0 (R2 = 0.96), and addition of sodium citrate from 0 to 0.36 mmol/g of casein (R2 = 0.80). At pH 7.0, gelation occurred at 12, 26, and 38°C with 9, 10, and 11% casein, respectively. At pH 6.6, 6.8, and 7.0, RCM with 12% casein gelled at a mean temperature of 12, 26, and 37°C, respectively. Adding calcium chloride at 0.17 mmol/g of casein significantly increased cold-gelling temperature from 18 to ≥50°C, whereas no significant change was observed at levels up to 0.12 mmol/g of casein. Different protein to fat ratios ranging from 0.8 to 1.2 did not significantly influence gelling temperature. In transmission electron micrographs of RCM with 12% casein, casein micelles were nonspherical and partially dissociated into small protein strands. Upon addition of calcium chloride at 0.21 mmol/g of casein, casein micelles were more spherical and retained colloidal structure with the presence of aggregated casein micelles. These gelation processes of RCM with or without addition of trisodium citrate were both reversible. We propose that cold gelation of RCM occurs when protein strands that have been partially released from the casein micelles entangle, restrict their mobility, and form a fine-stranded gel network. Upon addition of high levels of calcium, cold gelation was promoted presumably through direct aggregation of casein micelles. Understanding cold gelation properties can facilitate potential use of RCM in cheese making. [ABSTRACT FROM AUTHOR]

The influence of different globular protein sources (soy, pea and whey proteins), casein-to-globular protein ratios (6:4 and 4:6), and initial heating pH values (6.6, 6.9 and 7.2) on the heat stability, creaming stability, and flow behavior of mixed protein stabilized emulsions (10% w/w protein and 10% w/w oil) was studied. Fine emulsions in the nanometric range (<300 nm) were formed and the emulsification was not significantly affected by the globular protein sources and mixed micellar casein–globular protein ratios. Flocculation was observed after homogenization when whey proteins were present in the micellar casein–globular protein mixtures, which may have been caused by a bridging-type droplet flocculation with a mean particle size of up to 10 μm. Furthermore, the higher the whey protein content, the more extensive the droplet flocculation. Heat treatment at 90 °C for 15 min generally decreased the heat stability and resulted in more shear-thinning behaviors of the mixed protein-stabilized emulsions. Those changes were mainly attributed to the denaturation and aggregation of globular proteins. Of the three globular proteins, the soy proteins gave the highest heat stability in combination with micellar caseins. This work also showed that the extent of heat-induced destabilization was dependent on the pH value during initial heating, denaturation temperature, concentration and inherent mineral contents of the globular proteins. Particle size distribution, microstructure and rheological measurements showed strong correlations with heat stability. [ABSTRACT FROM AUTHOR]

The aim of this work was to determine the effect and magnitude of matrix inhomogeneity on the rheological properties of emulsion-filled gels. To this end, we have investigated the rheological properties in casein gels containing different volume fractions of dispersed fat droplets with varying hardness. Rheological properties of the filled gels were investigated by uniaxial compression. Matrix inhomogeneity was controlled by changing the casein concentration, and was quantified by confocal laser scanning microscopy (CLSM) and image analysis. CLSM images showed that the matrix becomes more inhomogeneous when the protein concentration decreases and image analysis was used to quantify this inhomogeneity. As the dispersed fat droplets bind to the proteins (active droplets), the droplets are located more in the casein-rich areas. The inhomogeneous distribution of the casein micelles led to an accumulation of the dispersed fat droplets in the gelled micellar casein regions, thereby increasing the effective volume fraction of the droplets. This increase in the effective volume fraction of the droplets was higher for lower casein concentrations, due to a higher degree of inhomogeneity, resulting in a larger effect in reinforcing the gel compared to more homogeneous systems. These results may be used for designing structures to decrease the fat content or replace solid fat by liquid oil. [ABSTRACT FROM AUTHOR]