Influence of milk protein concentrates with modified calcium content on enteral dairy beverage formulations: Storage stability

Control of calcium-mediated storage defects, such as age gelation and sedimentation, were evaluated in enteral high-protein dairy beverages during storage. To investigate the effects of reduced-calcium ingredients on storage stability, 2 batches each of milk protein concentrates (MPC) with 3 levels of calcium content were acquired [control, 20% calcium-reduced (MPC-20), and 30% calcium-reduced (MPC-30)]. Control and calcium-reduced MPC were used to formulate 8% (wt/wt) protein enteral dairy beverages. The formulation also consisted of other ingredients, such as gums, maltodextrin, potassium citrate, and sucrose. The pH-adjusted formulation was divided into 2 parts, one with 0.15% sodium hexametaphosphate (SHMP) and the other with 0% SHMP. The formulations were homogenized and retort sterilized at 121°C for 15 min. The retort-sterilized beverages were stored at room temperature for up to 90 d and particle size and apparent viscosity were measured on d 0, 7, 30, 60, and 90. Beverages formulated using control MPC with 0 and 0.15% SHMP exhibited sedimentation, causing a decrease in apparent viscosity by approximately 10 cP and clear phase separation by d 90. The MPC-20 beverages with 0% SHMP exhibited stable particle size and apparent viscosities during storage. In the presence of 0.15% SHMP, particle size increased rapidly by 40 nm on d 90, implying the start of progressive gelation. On the other hand, highest apparent viscosities leading to gelation were observed in MPC-30 beverages at both concentrations of SHMP studied. These results suggested that beverages formulated with MPC-20 and 0% SHMP would have better storage stability by maintaining lower apparent viscosities. Further reduction of calcium using MPC-30 resulted in rapid gelation of beverages during storage.     

Removal of milk fat globules from whey protein concentrate 34% to prepare clear and heat-stable protein dispersions

Whey protein concentrates (WPC) are low-cost protein ingredients, but their application in transparent ready-to-drink beverages is limited due to turbidity caused by fat globules and heat instability. In this work, fat globules were removed from WPC 34% (WPC-34) to prepare heat-stable ingredients via the Maillard reaction. The removal of fat globules by acid precipitation and centrifugation was observed to be the most complete at pH 4.0, and the loss of protein was caused by micrometer-sized fat globules and protein aggregates. Spray-dried powder prepared from the transparent supernatant was glycated at 130°C for 20 and 30 min or 60°C for 24 and 48 h. The 2 groups of samples had comparable heat stability and degree of glycation, evaluated by free amino content and analytical ultracentrifugation, but high-temperature, short-time treatment reduced the color formation during glycation. Therefore, WPC-34 can be processed for application in transparent beverages.     

Effect of dipotassium phosphate and heat on milk protein beverage viscosity and color

Our objective was to determine the effect of addition of dipotassium phosphate (DKP) at 3 different thermal treatments on color, viscosity, and sensory properties of 7.5% milk protein-based beverages during 15 d of storage at 4°C. Micellar casein concentrate (MCC) and milk protein concentrate (MPC) containing about 7.5% protein were produced from pasteurized skim milk using a 3×, 3-stage ceramic microfiltration process and a 3×, 3-stage polymeric ultrafiltration membrane process, respectively. The MCC and MPC were each split into 6 batches, based on thermal process and addition of DKP. The 6 batches were no postfiltration heat treatment with added DKP (0.15%), no postfiltration heat without added DKP (0%), postfiltration high-temperature, short time (HTST) with DKP, postfiltration HTST without DKP, postfiltration direct steam injection with DKP, and postfiltration direct steam injection without DKP. The 6 MCC milk-based beverages and the 6 MPC milk-based beverages were stored at 4°C. Viscosity, color, and sensory properties were determined over 15 d of refrigerated storage. MCC- and MPC-based beverages at 7.5% protein with and without 0.15% added dipotassium phosphate were successfully run through an HTST and direct steam injection thermal process. The 7.5% protein MCC-based beverage contained a higher calcium and phosphorus content (2,425 and 1,583 mg/L, respectively) than the 7.5% protein MPC-based beverages (2,141 and 1,338 mg/L, respectively). Pasteurization (HTST) had very little effect on beverage particle size distribution, whereas direct steam injection thermal processing produced protein aggregates with medians in the range of 10 and 175 μm for MPC beverages. A population of casein micelles at about 0.15 μm was found in both MCC- and MPC-based beverages. Larger particles in the 175-μm range were not detected in the MCC beverages. In general, the apparent viscosity (AV) of MCC beverages was higher than MPC beverages. Added DKP increased the AV of both MCC- and MPC-based beverages, while increasing heat treatment decreased AV. The AV of beverages with DKP increased during 15 d of 4°C of storage for both MCC and MPC, whereas there was very little change in AV during storage without DKP and a similar effect was observed for sensory viscosity scores. The L value of beverages was higher with higher heat treatment, but DKP addition decreased L value and sensory opacity greatly. Sulfur-eggy flavors were detected in MPC beverages, but not MCC-based beverages.     

The effect of the duration of infusion,temperature, and water volume on the rutin content in the preparation of mate tea beverages: An optimization study

The consumption of tea beverages has increased 30% over the last decade, mainly due to the presence of bioactive compounds. Mate tea, produced by infusing the leaves and stems of Ilex paraguariensis, is the most widely consumed beverage in Brazil. The present study employed a central composite experimental design to optimize the transfer of rutin from the leaves and stems to the beverage during the infusion process. The optimum condition was applied to three batches of mate tea beverages from five commercial samples. Analysis of the rutin content was performed by high performance liquid chromatography coupled to a photo diodo array detector. The maximum rutin content in the beverage was obtained when the infusion was performed using 2 g of mate tea added to 100 mL of water at 72 °C and infused for 9 min. The commercial tea beverages prepared under these conditions contained from 0.16 to 1.1 mg of rutin in the ready-to-drink product.     

A comparison of pilot-scale supersonic direct steam injection to conventional steam infusion and tubular heating systems for the heat treatment of protein-enriched skim milk-based beverages

Direct supersonic steam injection, direct steam infusion, and indirect tubular heating were each applied to protein-enriched skim milk-based beverages with 4, 6 and 8% (w/w) total protein, and the effect of final heat temperature on the physical properties of these beverages was investigated. Supersonic steam injection resulted in significantly lower levels of denaturation of β-lactoglobulin (34.5%), compared to both infusion (76.3%) and tubular (97.1%) heating technologies. Viscosity, particle size and accelerated physical stability of formulations did not differ significantly between the heating technologies, while noticeable colour differences due to heat treatment (mainly attributed to increasing b* value) were observed, particularly for tubular heating. Overall, the extent of protein denaturation in high-protein dairy products was significantly influenced by the particular heating technology applied. The application of supersonic steam injection technology, with rapid heating and high shear characteristics, may enable differenciated product characteristics for ready-to-drink ambient-delivery high-protein dairy beverages.Industrial relevanceThe design and application of novel direct supersonic steam injection technology was comprehensively studied and found to provide significant benefits over direct steam infusion and indirect tubular heating technologies for skim milk-based protein beverages. This type of injection heating system resulted in heat-treated formulations with lower levels of denatured whey proteins, compared to tubular and infusion heating, offering an alternative opportunity to the industry in terms of producing shelf-stable dairy protein beverages.     

Ready-to-drink protein beverages: Effects of milk protein concentration and type on flavor

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.     

Absorption of folic acid and ascorbic acid from nutrient comparable beverages

One hundred percent fruit juices can help consumers increase the nutrient content of the diet since these beverages can be naturally rich in micronutrients. Micronutrient-fortified low-calorie beverages are an important alternative to those wishing to minimize their calorie intakes. However, little is known about the bioavailability of nutrients from fortified beverages relative to 100% fruit juices. The present study examined the bioavailability of ascorbic acid (AA) and folic acid (FA) in 100% orange juice (OJ) and a low-calorie beverage fortified with these nutrients. In a within-subjects, cross-over design, 12 adult men consumed a 591 mL serving of OJ, a low-calorie beverage fortified with AA and FA, and 1% low fat milk. Participants were aged 20 to 35 y, with body mass indexes between 20 and 30 kg/m(2). Blood plasma concentrations of AA and serum concentrations of FA were assayed by serial blood draws, made at 30 min intervals for 4.5 h. Blood plasma concentration of AA was significantly greater after ingestion of the fortified beverage compared to after OJ ingestion. However, the bioavailability of AA did not significantly differ from that of OJ. Analyses of FA indicated no significant difference between fortified beverage and OJ. Consumption of both vitamin containing beverages led to higher concentrations of AA and FA than the milk control. This study showed that similar levels of AA and FA bioavailability can be attained through ingestion of 100% OJ and a fortified beverage.     

Comparing the Effects of Ultra‐High‐Pressure Homogenization and Conventional Thermal Treatments on the Microbiological,Physical, and Chemical Quality of Almond Beverages

The effects of ultra‐high‐pressure homogenization (UHPH) at 200 and 300 MPa, in combination with different inlet temperatures (55, 65, and 75 °C) on almond beverages with lecithin (AML) and without lecithin (AM), were studied. UHPH‐treated samples were compared with the base product (untreated), pasteurized (90 °C, 90 s), and ultra‐high‐temperature (UHT, 142 °C, 6 s) samples. Microbiological analysis, physical (dispersion stability, particle size distribution, and hydrophobicity), and chemical (hydroperoxide index) parameters of special relevance in almond beverages were studied. Microbiological results showed that pressure and inlet temperature combination had a significant impact on the lethal effect of UHPH treatment. While most UHPH treatments applied produced a higher quality of almond beverage than the pasteurized samples, the combination of 300 MPa and 65 and/or 75 °C corresponded to a maximum temperature after high pressure valve of 127.7 ± 9.7 and 129.3 ± 12.6 °C, respectively. This temperature acted during less than 0.7 s and produced no bacterial growth in almond beverages after incubation at 30 °C for 20 d. UHPH treatments of AML samples caused a significant decrease in particle size, resulting in a high physical stability of products compared to conventional heat treatments. UHPH treatment produced higher values of hydroperoxide index at day 1 of production than heat‐treated almond beverage. Hydrophobicity increased in AML‐UHPH‐treated samples compared to AM and conventional treatments. Practical Application: Ultra‐high‐pressure‐homogenization (UHPH) is an emerging technology, a potential alternative to conventional heat treatments. It is a simple process consisting of single step. When liquid food (almond beverage in this study) passes through the high‐pressure valve, a very good stability and reduction of microorganisms is achieved, both effects due to the particle breakdown. Specific UHPH conditions could produce commercial sterilization of almond beverage.     

EFFECTS OF ADDED WEIGHTING AGENT AND XANTHAN GUM ON STABILITY AND RHEOLOGICAL PROPERTIES OF BEVERAGE CLOUD EMULSIONS FORMULATED USING MODIFIED STARCH

Stability of beverage emulsion is measured by the rate at which the emulsion creams, flocculates or coalesces, and is generally dependent on rheology of water phase, difference in specific gravities of the two phases and droplet size/distribution of the emulsion. The effects of weighting agents (sucrose acetate isobutyrate and brominated vegetable oil) and xanthan gum on modified starch‐based emulsions were evaluated in this study. Emulsion was formed by addition of 9% coconut oil, in the presence or absence of weighting agents, into the water phase containing modified starch at 10, 12 or 14% without or with the addition of 0.3% xanthan gum. Stabilities of emulsions were evaluated both in the concentrated form used for storage and dilute form used in beverages. The addition of xanthan gum into the water phase decreased the flow behavior index (n) from 0.88 down to 0.31 and increased elastic modulus (G′) over 20 times at elevated frequency (ω = 50 rad/s) and elevated the stability of the emulsion. The xanthan gum‐added emulsion had smaller particle size and demonstrated 14 and 5 times slower phase separation compared to the emulsions without or with the addition of weighting agents, respectively. When the elastic modulus was larger than the viscous modulus (G′ > G″), the emulsions demonstrated greater stability. In dilute beverage solutions, creaming was observed in the absence of xanthan gum.     

Effect of pre- and post-heat treatments on the physicochemical,microstructural and rheological properties of milk protein concentrate-stabilised oil-in-water emulsions

The effect of heat treatment on the physical stability of milk protein concentrate (MPC) stabilised emulsions was investigated; 3% (w/w) MPC dispersions were preheated at 90 °C for 5 min at neutral pH prior to emulsification. Heat-treated (120 °C, 10 min) emulsions stabilised by preheated MPC had slightly fewer droplet–droplet interactions than that stabilised by unheated MPC because the whey proteins were pre-denatured (∼90% denaturation of the total whey proteins), which led to a reduction in subsequent heat-induced droplet–droplet and droplet–protein interactions. Emulsions stabilised by calcium-depleted MPC were also investigated. The presence of some non-micellar casein fractions gave better emulsification and may have conferred a protective stabilising effect on whey protein aggregation, in both the dispersed phase and the continuous phase during the secondary heat treatment. It was concluded that calcium manipulation and thermal modification of MPC can be utilised to control the functionality in oil-in-water emulsions.     

UHT-Sterilized Peanut Beverages: Kinetics of Physicochemical Changes during Storage and Shelf-Life Prediction Modeling

Strawberry-flavored (S04) and chocolate-flavored (C04 and C20) peanut beverages UHT-sterilized (137 °C, 4 sec or 20 sec) and aseptically filled in Tetra Briks were stored for 6 mo at 5, 20 and 35 °C. Sensory characteristics and kinetics of physicochemical changes were studied. The changes were of zero (pH of S04, and sedimentation and homogenization indices of all beverages) and first (pH of C04 and C20, viscosity and color lightness of all beverages) order. Reaction rate constant and Gibb's free energy increased with temperature. Activation energy followed Arrhenius equation. Deterioration in beverage sensory qualities highly correlated with increase in sedimentation index and decrease in pH and emulsion stability. Shelf-life prediction models were constructed based on sensory and kinetics data. The shelf-life was estimated to be 4–7 mo for beverages stored at 30–35 °C.     

无均质工艺的果肉型果汁饮料非生物稳定性的研究

在无均质机的条件下,清汁型和浊汁型果肉饮料分别采用不同型号的结冷胶等构成其稳定体系.通过设计出合理的产品配方和工艺流程,控制好饮料的pH,可以获得较理想的稳定效果,从而解决了长期困扰在小型饮料企业的技术难题.     

Influence of high hydrostatic pressure processing on physicochemical characteristics of a fermented pomegranate (Punica granatum L.) beverage

The effect of high hydrostatic pressure at 500 MPa/10 min (HHP1), 550 MPa/10 min (HHP2) and 600 MPa/5 min (HHP3) on the microbiological, physicochemical, antioxidant and sensory characteristics of a fermented pomegranate (FP) beverage, stored for 42 days (4 ± 1 °C), was evaluated. The FP beverage was also pasteurized at 63 °C/30 min (VAT) and 72 °C/15 s (HTST). The high hydrostatic pressure (HHP) and VAT pasteurized beverages did not show microbial growth (<10 CFU/mL) throughout 42 days of storage. The physicochemical characteristics were not affected (p > 0.05) by HHP or pasteurization. Color of the samples showed significant differences (p ≤ 0.05) in all HHP processed and pasteurized beverages. Antioxidant activity, total phenolic compounds, flavonoids and anthocyanins increased slightly after HHP processing. Antioxidants decreased throughout the storage in all treatments. Both HHP processed and pasteurized beverages were well accepted by average consumers when evaluated using a 9-points hedonic scale.Industrial relevanceThe high hydrostatic pressure (HHP) improves the microbiological, antioxidant and sensorial stability of fermented pomegranate beverages during storage. The HHP is more common for processing fruit juices than for fermented beverages; therefore, it can be expanded to the fermented beverages industry, which could modify the today usual thermal processing methods and, or the addition of preservatives, that are not natural, for delivering high quality and healthier pomegranate fermented beverages to consumers.     

Microemulsions as nanoreactors to produce whey protein nanoparticles with enhanced heat stability by thermal pretreatment

Native whey proteins (NWPs) may form gels or aggregates after thermal processing. The goal of this work was to improve heat stability of NWPs by incorporating protein solutions in nanoscalar micelles of water/oil microemulsions to form whey protein nanoparticles (WPNs) by thermal pretreatment at 90 °C for 20 min. The produced WPNs smaller than 100 nm corresponded to a transparent dispersion. The WPNs produced at NWP solution pH of 6.8 had a better heat stability than those produced at pH 3.5. The salt concentration (0–400 mM NaCl) in NWP solutions did not significantly change the size of corresponding WPNs. Compared to NWPs, the 5% (w/v) dispersion of WPNs at pH 6.8, 100 mM NaCl did not form a gel after heating at 80 °C for 20 min. The improved heat stability and reduced turbidity of WPNs may enable novel applications of whey proteins in beverages.     

Effects of calcium chelating agents on the solubility of milk protein concentrate

The aim of this study was to determine the effects of calcium chelating agents on the dissolution and functionality of 10% (w/w) milk protein concentrate (MPC) powder. MPC powder dissolution rate and solubility significantly (P > 0.05) increased with addition of sodium phosphate, trisodium citrate (TSC) and sodium hexametaphosphate (SHMP), compared to MPC dispersions alone. Trisodium citrate and SHMP addition increased viscosity as a result of micelle swelling. However, dispersions containing SHMP showed a decrease in viscosity after prolonged time due to micelle dissociation. Overall, MPC powder dissolution was aided by the addition of calcium chelating agents.     

Effects of Calcium Addition on Stability and Sensory Properties of Soy Beverage

Pasteurized or thermally processed soy beverages (6% soy solids) were fortified to a comparable level of cow's milk with 25 mM (or 30 mM) calcium using mixtures of calcium citrate and tricalcium phosphate. These fortified pasteurized products had acceptable sensory properties. Addition of these calcium salts did not adversely affect protein stability of the beverage. Calcium citrate addition caused a decrease in beverage pH and viscosity. Thermally processed (still retort and agitort) canned beverages containing calcium salts were stable for 6 months when stored at 1°C or at room temperature.     

A low-calorie beverage supplemented with low-viscosity pectin reduces energy intake at a subsequent meal

The addition of fiber to foods and beverages has been linked with greater satiety and reduced energy intakes at the next meal. However, measures of satiety can be influenced by the time interval between beverage consumption and the next meal. The objective of this study was to determine how the time interval between consumption and a subsequent test meal impacts the satiating power of a low-calorie beverage supplemented with low-viscosity pectin fiber. Forty-two participants (20 men, 22 women) each participated in 4 study sessions. Study preloads were 2 low-calorie beverages (355 mL, 8 kcal) containing either 0 g fiber (no fiber) or 8 g low-viscosity fiber (added fiber). These preloads were consumed either 90 min before lunch or 15 min before lunch. Every 15 min, participants rated hunger, desire to eat, fullness, and thirst using 100-mm visual analogue scales. A test lunch was served and plate waste was measured. Beverages with added fiber reduced energy intakes at lunch relative to those without fiber. A short delay (15 min) between beverage consumption and a subsequent meal was associated with higher satiety ratings and reduced energy intakes, regardless of fiber content. The addition of low-viscosity pectin to low-calorie beverages reduced energy intakes at the next meal, presenting a possible tool for intake regulation. A short time interval between consumption of a low-calorie beverage and a meal also increased satiety and decreased food intake, reflecting the short-lived effect of volume.     

A natural clouding agent from orange peels obtained using polygalacturonase and cellulase

Clouding agents (CAs) provide high cloud stability when they are diluted and added to fruit beverages. Natural CA could also give the visual appearance and sensorial aspect of a natural cloudy fruit juice beverage. In addition, natural CAs are preferred over the synthetic ones by consumers. Therefore, the main objective of this study was to obtain a natural CA from orange peel that provided high cloud stability of fruit beverages. The treatment included the use of polygalacturonase (PG) and cellulase (C) to hydrolyze most of the peel components. Orange peels treated with 69 mg/kg of C and 90 μl/kg of PG during 80 min at 48 °C led to a CA that provided a cloudy stable solution on a fruit beverage. This CA presented a cloud stability of 94.7 days that represented a turbidity reduction of 9.1% after 9 days under fridge temperatures. Otherwise, the treatment conditions to get the highest cloud stability were not coincident to those necessary to preserve the color or to obtain the greatest extraction yield of the CA.     

On the heat stability of whey protein: Effect of sodium hexametaphosphate

Despite a growing demand for whey protein‐based drinks, their instability and lack of solubility during thermal processing is a major challenge for food product formulators. In the present study, the effects of different hydrocolloids and sodium hexametaphosphate (SHMP) on the heat stability, rheological properties, microstructure and sensory characteristics of whey protein concentrate (WPC) dispersions were evaluated. The results indicated that at pH 4, xanthan, k‐carrageenan, low methoxyl pectin (LMP) and guar stabilised WPC dispersion without heat treatment, all maintained stability during pasteurisation but not sterilisation. For pH 7, for the same set of hydrocolloids, a similar trend was also observed, albeit at different concentrations. However, by adding optimum ratios of SHMP protein denaturation was retarded, particularly in the case of LMP and i‐carrageenan. The highest and lowest apparent viscosities were exhibited by samples containing 0.01% and 0.15% w/w SHMP, respectively. This study highlights the potential capability of SHMP in the prevention of protein denaturation. An exact plausible stability mechanism still needs further more detailed investigation.     

Stability of milk protein concentrate suspensions to in-container sterilisation heating conditions

Milk protein concentrate (MPC) powders, ranging from 35 (MPC35) to 87 (MPC90)% protein, were reconstituted to 8.5% protein and assessed for heat stability at 120 °C, Ca-ion activity, heat-induced dissociation of κ-casein, and heat-induced gelation of serum-phase proteins in ultracentrifugal supernatants of unheated MPC suspensions. Heat stability of MPC suspensions depended on the protein content of the powder from which the suspensions were prepared. MPC70 had excellent heat stability compared with MPC35; however, MPC80, MPC85 and MPC90 were highly unstable to heating. Ca-ion activity increased with increasing protein content of the MPCs, whereas the extent of heat-induced dissociation of κ-casein and gelation of serum-phase proteins decreased. Increased heat stability with increasing protein content from MPC35 to MPC70 was attributed to decreased κ-casein dissociation and reduced gelation of serum-phase proteins. Despite these stabilising factors, excessively high Ca-ion activity caused MPC80, MPC85 and MPC90 to have very poor heat stability at pH 6.3–6.8, 6.3–7.1 and 6.3–7.3, respectively.