Concentration Of Sodium Hexametaphosphate Research Articles

Influence of calcium sequestering salt type and concentration on the characteristics of processed cheese made from Gouda cheese of different ages

The effect of 90, 180 and 270 mEq/kg of the calcium sequestering salts (CSS) disodium phosphate (DSP), trisodium citrate (TSC) and sodium hexametaphosphate (SHMP) on the solubilisation of proteins and minerals and the rheological and textural properties of processed cheese (PC) prepared from Gouda cheese ripened for 30–150 d at 8°C was studied. The solubilisation of individual caseins and Ca and the maximum loss tangent during temperature sweeps of PC made from Gouda cheese increased, while hardness of PC decreased with ripening duration of the Gouda cheese. Levels of soluble Ca in PC increased with increasing concentration of TSC and SHMP, but decreased with increasing concentration of DSP. The solubilisation of casein and Ca due to ripening of Gouda cheese used for manufacturing PC could explain the changes in texture and loss tangent of PC. The results suggest that DSP, TSC or SHMP in PC formulation can form insoluble Ca-phosphate, soluble Ca-citrate or insoluble casein-Ca-HMP complexes, respectively, that influence casein solubilisation differently and together with levels of residual intact casein determine the functional attributes of PC.

Formation and Application of Polymer Spherulite-like Patterns of Halloysite Nanotubes by Evaporation-Induced Self-Assembly.

Halloysite nanotubes (HNTs) are one-dimensional clay nanomaterials featuring distinct tubular structures and unique surface charges. HNTs can readily form ordered assembly structures under specific conditions, which shows significant potential applications in optical and biological fields. In this study, sodium hexametaphosphate (SHMP) was employed as a stabilizer to prepare polymer spherulite-like patterns via the evaporation-induced self-assembly (EISA) technique. The incorporation of SHMP enhanced the repulsion force among the nanotubes and the surface potential, which facilitated the orderly deposition of HNTs. The influence of HNT concentration, SHMP concentration, drying temperature, and substrate on the polymer spherulites-like pattern has been investigated in detail. The optimal conditions were 10 wt % HNT dispersion, 0.6 wt % SHMP concentration, 30 °C as drying temperature, and glass substrates. In addition, by changing the droplet volume and shape of the three-phase contact line, patterns of different sizes and shapes can be achieved. Bovine serum albumin or metal salt compounds were incorporated into the dispersion of SHMP-modified HNTs, which altered the charge and the self-assembled patterns with different area ratios. Thus, this technology can be utilized for the analysis and comparison of protein and metal ion concentration accurately. This study creates the correlation between the structural parameters and the preparation process involved in creating polymer spherulite-like patterns of modified HNTs and offers fresh insights into potential applications for the self-assembly of HNT droplets in the realms of anticounterfeiting and solution concentration analysis.

Influence of citrate- and phosphate-based calcium sequestering salts on the disruption of casein micelles

The disruption of casein micelles through the addition of calcium sequestering salts (CSS) disodium phosphate (DSP), disodium pyrophosphate (DSPP) and tetrasodium pyrophosphate (TSPP), sodium tripolyphosphate (STPP), sodium hexametaphosphate (SHMP) and trisodium citrate (TSC) at 10, 15, 20 and 30 mEq/L levels was investigated in 5% micellar casein isolate (MCI) solution. All the CSS, except DSPP and TSPP, showed a decrease in particle size and viscosity with increasing concentration. The addition of 10–30 mEq/L of CSS to MCI decreased the protein-bound sedimentable Ca and P at pH 6.5 10 kDa-permeable Ca decreased with increasing concentration of DSP, DSPP, TSPP, STPP and SHMP. These results indicate that orthophosphates, pyrophosphates and polyphosphates combined with Ca to form insoluble Ca phosphate complexes together with casein. Higher amount of 10 kDa permeable Ca for MCI samples with TSC confirms the formation of soluble Ca-citrate complexes.

A common food additive (E452), hexametaphosphate, denatures the digestive enzyme trypsin

Phosphate additions in processed foods are a health risk that has been overlooked. This study examined the effects of a permitted food additive (E452; Sodium Hexametaphosphate (SHMP)) on trypsin solubility, structure, and stability at the intestinal physiological pH of 6.0. SHMP-treated trypsin samples were assessed for conformational changes and aggregation propensity using various spectroscopic and microscopic methods. Far-UV CD spectroscopy and intrinsic tryptophan fluorescence showed a rise in fluorescence intensity and alpha-helical structure up to 10 μM SHMP (∼1:1 M ratio). Secondary structure loss, tryptophan quenching, and solubility decrease with an increase in SHMP concentration (>10 μM). SHMP-treated trypsin aggregates showed poor ThT fluorescence. According to kinetics, SHMP leads to trypsin aggregation instantly. All spectroscopic studies showed trypsin denatured at above 10 μM SHMP. Thus, digestive enzyme structure and solubility loss will impair food digestion and health. Therefore, SHMP should be avoided as a food additive.

Flotation separation influenced by the rheological properties of diaspore-pyrite mixed pulp

The effects of pyrite and diaspore with different particle sizes on the rheological properties of pulp with butyl xanthate added as a collector were studied, and the mechanism for rheological pyrite separation from diaspore by flotation was probed. The apparent viscosity of the diaspore pulp with different particle sizes was higher than that of pyrite, especially for -30 μm diaspore. Microfine diaspore was an important component affecting the apparent viscosity and yield stress of the diaspore-pyrite mixed pulp, and the pulp became a non-Newtonian fluid when the mass fraction of fine-grained diaspore in the mixed pulp was high. In this study, sodium hexametaphosphate (SHMP) was used to control the rheology of the mixed pulp and improve the pyrite flotation, and the S (sulfur) recovery rate first increased and then decreased with increasing SHMP concentration. The apparent viscosity of the pulp decreased by 3.01% and the S recovery rate increased by 34.83% when the amount of added SHMP was 0.05 mg/kg. The apparent viscosity with 0.50 mg/kg SHMP was 21.76% lower than that seen with the addition of 0.05 mg/kg SHMP, but the S recovery rate was also reduced by 14.94%. Further research showed that the increased SHMP concentration led to increases in the electronegativities of the particle surface and the repulsive force between particles, which prevented agglomeration of the particles, reduced the apparent viscosity and yield stress of the mixed pulp, promoted collisions between the pyrite particles and the bubbles, and reduced the resistance of the air bubbles to flotation.

Investigations on capping-induced changes in structural, optical, and thermal properties of Zn0.96Ni0.04S nanoparticles

We present the chemical precipitation technique for producing several quantities of sodium hexametaphosphate (SHMP) capped zinc sulphide nanoparticles doped with Ni2+ in an ambient environment. The average grain size of the nanoparticles generated was tuned by using SHMP concentration. SEM with EDAX, HRTEM, and SAED patterns was used to confirm the particle size, crystallinity, and composition. Compared to bulk ZnS, UV–Vis spectra of both capped and uncapped samples reveal a blue shift in the absorption edge. FTIR studies confirmed the capping of SHMP on the surface of Ni-doped ZnS. PL spectra of ZnS:Ni2+ nanoparticles exhibit intense and sustained visible-light emissions. The intensity of the blue emission centered at 468 nm increased with increasing SHMP concentration up to 0.75 wt percent but decreased with higher concentrations of SHMP. TG – DTA results show that SHMP – ZnS (Ni-doped) nanoparticles have excellent thermal stability due to improved shape and compactness.

Role of sodium hexametaphosphate in ultra-fine grinding of alumina-doped titanium dioxide

In wet stirred milling of Al-doped TiO2, sodium hexametaphosphate (SHMP) is used as a small molecule dispersant to improve milling performance. In both acidic and basic conditions, SHMP interacts strongly with Al-doped TiO2 and remains stable during milling. Considering the apparent and true particle breakage performance, at pH 10.3, the optimal dosing concentration was 0.16 wt% (0.33θ, sub-monolayer coverage), which is consistent for both dilute (5 vol%) and concentrated (≥ 19.1 vol%) suspensions. At higher SHMP concentration (0.77θ), the increased solution conductivity compromised milling performance by weakly destabilizing the Al-doped TiO2 particles. At the optimal dose concentration of 0.33θ SHMP, particle dispersion is maintained through electrostatic and steric forces which contribute to moderating changes in suspension viscosity (~10% increase) as the particle size is reduced.

Evaluation of the Remineralizing Effect of Fluoridated Toothpaste with Sodium Hexametaphosphate on Demineralized Primary Teeth Enamel

Background: A primary aim of pediatric dentists is to repair the early demineralized enamel without intervention through remineralization. Sodium hexametaphosphate (SHMP) is a remineralizing material that has been reported to have promising results for caries management. Aim of the study: Evaluation of the remineralization potential of fluoridated toothpaste with SHMP on demineralized enamel of primary teeth. Materials and Methods: Fifty six freshly extracted anterior deciduous teeth were collected and divided into four groups regarding the concentrations of SHMP added to 400 ppm F containing tooth paste. Three groups contained (0.25%, 0.5%, 1%) respectively and a control group without SHMP. Specimens were treated with the tooth pastes and exposed to pH cycling for 5 days then a remineralizing solution for additional 2 days. Specimens were evaluated using Digital Radiographic Density Analysis at baseline, after demineralization and after remineralization. Results: Teeth treated with SHMP showed marked remineralization effect than those treated with fluoride alone. Increasing the concentration of SHMP from 0.25, 0.5 to 1%, associated with increased the remineralizing effect. Conclusion: SHMP has a superior remineralizing effect over fluoride alone. 1% SHMP concentration added to 400F ppm toothpaste provided the best results.

Preparation and Characterization of Carboxymethylated and Cross-Linked Enset Starch as a Disintegrant in Tablets

Starch and modified starches have been commonly employed as excipient in pharmaceutical industry. The use of non-modified or “native” starch, However, is mostly confined due to limitation in several physicochemical properties. Cross-linked sodium carboxymethyl starch which is also known as sodium starch glycolate is extensively used in fast dissolving tablets to disperse the drugs within short span of time. In this study, enset starch was carboxymethylated and subsequently cross-linked. Carboxymethyl enset starch (CMES) was obtained by reacting enset starch and monochloroacetic acid (MCA) in the presence of sodium hydroxide. CMESs having different degree of substitution (DS) were cross-linked at variousconcentrations (2.5, 5 and 10% w/w) of sodium hexametaphosphate (SHMP) to provide sodium starch glycolate of enset starch (SSG-E). The fourier transform infrared (FTIR) spectra confirmed the presence of carboxymethylated group in the modified starch granules with new band at 1608.52 cm-1. This dually modified enset starch (SSG-E) was evaluated as a potential disintegrant in paracetamol tablets in comparison with commercially available sodium starch glycolate, Disegel. Carboxymethylation was significantly influenced by reaction medium, reaction temperature and reaction time (p < 0.05). CMES with higher DS (0.437 ± 0.03) exhibited higher peak viscosity than CMES with lower DS (0.224 ± 0.01). Despite exhibiting greater swelling power, CMES showed significantly lower pasting viscosity compared to the native starch (p < 0.05). At 2.5% SHMP, the dually modified starch (SSG-E) exhibited significant increase in swelling but its rate of water-uptake was lower than that of Disegel. As the SHMP concentration wasincreased from 2.5 to 5%, the swelling power decreased significantly (p < 0.05). When the concentration was increased to 10% the swelling power increased significantly (p < 0.05). At 2.5% SHMP concentration SSG-E showed a viscosity comparable to that of CMES. As the concentration of SHMP increased to 5 and to 10% w/w, significant decrease in viscosity (p < 0.05) was observed. Compared to the native enset starch (NES), the solubility of SSG-E was more than 4-fold, but its viscosity was much lower than that of CMESs. The SSG-E exhibited lower moisture sorption than CMES but higher sorption than NES. SSG-E showed good flowability, superior swelling power and solubility than NES. The disintegration time (DT) of paracetamol tablets containing SSG-E as a disintegrant was comparable to those tablets with similar concentration of Disegel. At 4% SSG-E, paracetamol tablets exhibited DT less than 1 min.
 Keywords: carboxymethylation, degree of cross-linking, enset starch, paracetamol tablets, sodium starch glycolate

Effect of pH on the efficiency of sodium hexametaphosphate as calcium carbonate scale inhibitor at high temperature and high pressure

Calcium carbonate (CaCO3) scale deposition causes serious issues in industries which deal with water, and its formation reaction is pH-depending. This study investigated the efficiency of sodium hexametaphosphate (SHMP) as scale inhibitor for calcium carbonate, as a function of pH and SHMP concentration, under drastic conditions of temperature, scaling ions concentration and pressure. The relationship between pH and CaCO3 formation parameters was evaluated by static and dynamic tube blocking tests and scanning electron microscopy (SEM) images. Quantum chemistry calculations were performed to evaluate thermodynamic values related to interactions between the inhibitor and CaCO3. At pH 6.5, excellent results were found with complete inhibition of CaCO3 deposition on capillary with just 2.5 mg L−1 of SHMP and deformed structures for CaCO3 crystals were observed by SEM images. Results also showed a reversal behavior of SHMP as inhibitor at pH neutral and slightly alkaline, with a decrease on inhibition efficiency even raising SHMP concentration, related to the fast precipitation of CaCO3 in the drastic conditions evaluated.

The mechanochemical route of vaterite synthesis using sodium hexametaphosphate as an inorganic additive

AbstractVaterite is a metastable phase of CaCO3 and was prepared mechanochemically for the first time with the assistance of sodium hexametaphosphate (SHMP). First, CaCO3 was prepared without SHMP and was characterized using X‐ray diffraction (XRD) to study the effect of milling times and speeds on the polymorphs of product. The results indicate that the reaction is complete at 60 minutes producing only calcite. Additionally, amorphous CaCO3 (ACC) was obtained at a milling speed of 300 rpm, while calcite was obtained at 600 and 1000 rpm. Then, the effect of SHMP concentration on the fraction of vaterite was investigated, and the vaterite fraction increased with increasing SHMP amount. Subsequently, the effect of milling speed in the presence of 0.8 g of SHMP was studied, and the vaterite fraction increased with decreasing milling speed. Finally, gentler manual milling was employed, and the effect of the amount of added SHMP on vaterite formation was evaluated. The results confirmed that vaterite increased with increasing amounts of SHMP, and that vaterite formed more readily via manual milling than via mechanical milling. Observations with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that calcite and vaterite particles formed by mechanical milling were irregular agglomerates composed of primary nanoparticles while calcite particles formed by manual milling were irregular microparticles. Moreover, vaterite readily aggregated into spherical particles as the amount of SHMP increased. To investigate the reaction process and mechanism, the ethanol‐washed product was characterized using XRD, SEM/EDS and TEM/SAED. The results demonstrate that ACC and calcite were concomitant during the milling process, and ACC transformed into vaterite during subsequent water washing.

Influence of milk protein concentrates with modified calcium content on enteral dairy beverage formulations: Physicochemical properties

Because of their high protein and low lactose content, milk protein concentrates (MPC) are typically used in the formulation of ready-to-drink beverages. Calcium-mediated aggregation of proteins during storage is one of the main reasons for loss of storage stability of these beverages. Control and calcium-reduced MPC [20% calcium-reduced (MPC-20) and 30% calcium-reduced (MPC-30)] were used to evaluate the physicochemical properties in this study. This study was conducted in 2 phases. In phase I, 8% protein solutions were prepared by reconstituting the 3 MPC and adjusting the pH to 7. These solutions were divided into 3 equal parts, 0, 0.15, or 0.25% sodium hexametaphosphate (SHMP) was added, and the solutions were homogenized. In phase II, enteral dairy beverage formulations containing MPC and a mixture of gums, maltodextrin, and sugar were evaluated following the same procedure used in phase I. In both phases, heat stability, apparent viscosity, and particle size were compared before and after heat treatment at 140°C for 15 s. In the absence of SHMP, MPC-20 and MPC-30 exhibited the highest heat coagulation time at 30.9 and 32.8 min, respectively, compared with the control (20.9 min). In phase II, without any addition of SHMP, MPC-20 exhibited the highest heat coagulation time of 9.3 min compared with 7.1 min for control and 6.2 min for MPC-30. An increase in apparent viscosity and a decrease in particle size of reconstituted MPC solutions in phases I and II with an increase in SHMP concentration was attributed to casein micelle dissociation caused by calcium chelation. This study highlights the potential for application of calcium-reduced MPC in dairy-based ready-to-drink and enteral nutrition beverage formulations to improve their heat stability.

Sodium hexa meta phosphate impact as electrolyte additive on electrochemical behavior of lead-acid battery

Sodium hexa meta phosphate (SHMP) is an inorganic salt with a polymeric structure which produces massive branches of hexa meta phosphate anions (HMP−) in an acidic environment. The main goal of the presented work is to investigate the influence of SHMP as an electrolyte additive on the performance of the lead-acid batteries. To achieve the point, the examinations are done in two separate ways: i) Investigation electrochemical behavior of lead alloy electrode, by studying Hydrogen and Oxygen Evolution Reaction (HER and OER) with electrochemical techniques including; Cyclic Voltammetry and Linear Sweep Voltammetry. Then, Scan of Electron Microscopy (SEM performed to study the surface of the electrode after electrochemical treatments. By increasing SHMP concentration, overpotential of hydrogen and oxygen evolution is increased due to improving particle size of PbSO4 which consequently lessens water loss. ii) Real battery tests including; water consumption test, capacity measurements and High Rate Partial State of Charge (HRPSoC) as a cycle-life examination. Also, Scan of Electron Microscopy from the surface of the negative electrode and X-Ray Diffraction (XRD) analysis of negative electrode plate at the charge and discharge state after cycle-life test are prepared for study the PbSO4 particles size and quantity or the morphology of sulfating layer. Addition of SHMP to the electrolyte of the lead-acid battery increases cycle-life numbers and accordingly prolongs battery life. Therefore, SHMP is a promising electrolyte additive and it would be used with a combination of additives to increase the overall performance of a lead-acid battery.

The Influences of Sodium Hexametaphosphate (SHMP) and Methyl Orange (MO) on Enzyme Hydrolysis of Excess Sludge

The effect of Sodium Hexametaphosphate (SHMP) and Methyl Orange (MO) on the hydrolysis of sludge were investigated under the optimum condition of alkaline protease hydrolysis. The results showed that as the concentration of SHMP was increased, the content of Soluble Chemical Oxygen Demand (SCOD), protein, and polysaccharide in the sludge hydrolysate gradually raised. When the concentration of SHMP was 0.1g/g·tss, the contents of SCOD, protein, and polysaccharide increased by 17.16%, 50%, and 9.72% respectively. With the increase of MO concentration, SCOD decreased gradually. When the concentration of SHMP was 0.02g/g·tss, the SCOD decreased by 10.3%. An increase of 13% in the protein content was noted, when the concentration was 0.02g/g·tss. On the contrary, there was a slight reduction of the polysaccharide content i.e. 2.4%. The concentration of the polysaccharide was found to be the lowest at the concentration of 0.002g/g·tss. From the aforementioned results combined with three-dimensional fluorescence map of sludge EPS, it was found that SHMP promoted the hydrolysis of sludge by alkaline protease and accelerated the dissolution of intracellular organic matter. Herein, the MO inhibited alkaline protease hydrolysis of sludge, which hindered the dissolution of intracellular organics.

Effect of residence time on the degree of CaCO3 precipitation in the presence of an anti-scalant

The present work examines the effect of residence time on the degree of CaCO3 precipitation in a continuous flow stirred tank reactor in the presence of the inhibiting additive sodium hexametaphosphate (SHMP). The degree of CaCO3 precipitation and the degree of SHMP adsorption on the crystallizing particles were both measured in a series of experiments performed with solutions at the same initial supersaturation level residing in the reaction vessel at various retention times in the range of 20 to 150min. Variation of the SHMP concentration in the feed gave the anticipated trend of a decrease in the degree of CaCO3 precipitation with an increase in inhibitor concentration. However, surprisingly, increase of the residence time at a constant SHMP dosage level led to a diminished degree of CaCO3 precipitation. The rate of SHMP adsorption on the crystallizing CaCO3 particles was found to vary inversely with the square root of residence time. This result suggests that adsorption of the SHMP inhibitor on the crystallizing CaCO3 particles is a slow, diffusion-controlled process. Precipitation is increasingly inhibited at an increased residence time due to the augmented level of the adsorbed SHMP inhibitor. A diffusion-controlled adsorption model enabled successful correlation of all kinetic data.

Determination of Sodium Hexametaphosphate in Beverages Based on the Fluorescence Quenching of Acridine Orange

Sodium hexametaphosphate was shown to form a complex with acridine orange by electrostatic interactions that induce fluorescence quenching. Analysis of fluorescence intensity showed that the process was dominated by static quenching, which was confirmed by absorption spectra and lifetime of the excited state. The decreased fluorescence intensity was directly proportional to the concentration of sodium hexametaphosphate between 8.0 × 10−7 and 1.1 × 10−5 mol L−1 with a limit of detection of 5.3 × 10−7 mol L−1. Beverages were analyzed for sodium hexametaphosphate with recoveries between 91.7% and 108.3%.

基于钙黄绿素-臧红T荧光共振能量转移检测六偏磷酸钠

In a medium of tris-HCl buffer (pH 8.5), calcein (donor) can react with safranine T (acceptor) efficiently to produce fluorescence resonance energy transfer (FRET). However, the addition of sodium hexametaphosphate (SHMP)destroyed the FRET system because of the electrostatic interaction between SHMP and the acceptor, which makes fluorescence change ratio between the increased fluorescence intensity of calcein and the reduced fluorescence of ST ( FD/ FA) has a good linear correlated with the concentration of SHMP. Based on the phenomena, a novel rapid FRET method for determination of sodium hexametaphosphate was developed. Under the optimized conditions, the linear range is 3.0×10 6–1.0×10 5mol/L, and the relative standard deviation (RSD) is 3.1% for determination of sodium hexametaphosphat (c = 6.0×10 6, n=11). The proposed method is of high selectivity, simple to operate and rapid detection, and is successfully applied to determine the concentration of SHMP in drink samples.

Effect of sodium hexametaphosphate concentration and cooking time on the physicochemical properties of pasteurized process cheese

Sodium hexametaphosphate (SHMP) is commonly used as an emulsifying salt (ES) in process cheese, although rarely as the sole ES. It appears that no published studies exist on the effect of SHMP concentration on the properties of process cheese when pH is kept constant; pH is well known to affect process cheese functionality. The detailed interactions between the added phosphate, casein (CN), and indigenous Ca phosphate are poorly understood. We studied the effect of the concentration of SHMP (0.25–2.75%) and holding time (0–20min) on the textural and rheological properties of pasteurized process Cheddar cheese using a central composite rotatable design. All cheeses were adjusted to pH 5.6. The meltability of process cheese (as indicated by the decrease in loss tangent parameter from small amplitude oscillatory rheology, degree of flow, and melt area from the Schreiber test) decreased with an increase in the concentration of SHMP. Holding time also led to a slight reduction in meltability. Hardness of process cheese increased as the concentration of SHMP increased. Acid-base titration curves indicated that the buffering peak at pH 4.8, which is attributable to residual colloidal Ca phosphate, was shifted to lower pH values with increasing concentration of SHMP. The insoluble Ca and total and insoluble P contents increased as concentration of SHMP increased. The proportion of insoluble P as a percentage of total (indigenous and added) P decreased with an increase in ES concentration because of some of the (added) SHMP formed soluble salts. The results of this study suggest that SHMP chelated the residual colloidal Ca phosphate content and dispersed CN; the newly formed Ca-phosphate complex remained trapped within the process cheese matrix, probably by cross-linking CN. Increasing the concentration of SHMP helped to improve fat emulsification and CN dispersion during cooking, both of which probably helped to reinforce the structure of process cheese.

Rheology of pyrite slurry and its dispersant for the biooxidation process

Rheology of slurry significantly influenced the grindability, fine grinding performance and energy consumption of industrial minerals in wet grinding. The solid concentration, particle size, temperature and the dispersant, which affected the rheological characteristics of pyrite slurry and the biooxidation process were investigated in this study. This research aimed at the wet grinding process improved by the control of slurry rheology and getting a biocompatible dispersant. The results revealed that the viscosity increased with the solid concentration, which was in agreement with the Chong model. There was a critical concentration (40 wt.%) that led to the flow behavior of slurry transformed from Newtonian fluids to shear-thinning non-Newtonian fluids which fitted to the Casson model. It was also found that the apparent viscosity of slurry increased with the decrease of the particle size and the temperature at high solid concentration. Sodium Hexametaphosphate (SH) was selected experimentally as an effective dispersant for the mineral slurry. The appropriate concentration of SH was also determined at the range from 0.005 wt.% to 0.05 wt.%. The addition of dispersants could reduce the viscosity and yield stress, increase the zeta potential ( ζ) of suspension pronouncedly. No negative effects on the growth rate of microorganisms and the pyrite biooxidation were observed. Therefore, dispersant separation and recovery process could be avoided.

Effects of Calcium Chloride and Sodium Hexametaphosphate on Certain Chemical and Physical Properties of Soymilk

Soymilks with sodium hexametaphosphate (SHMP) (0% to 1.2%) and calcium chloride (12.50, 18.75, and 25.00 mM Ca) were analyzed for total Ca, Ca ion concentration, pH, kinematic viscosity, particle diameter, and sediment after pasteurization. Higher added Ca led to significant (P</= 0.05) increases in Ca ion concentration and significant (P</= 0.05) decreases in pH. At certain levels of SHMP, higher concentrations of added Ca significantly increased (P</= 0.05) kinematic viscosity, particle diameter, and sediment. Increasing SHMP concentration reduced Ca ion concentration, particle diameter, and dry sediment content, but reduced kinematic viscosity of samples (P</= 0.05). Adding SHMP up to 0.7% influenced pH of soymilk in different ways, depending on the level of Ca addition. When the pH of Ca-fortified soymilk was adjusted to a higher level, ionic Ca decreased as pH increased. There was a negative linear relationship between the logarithm of ionic Ca concentration and the adjusted pH of the soymilk. Ionic Ca appeared to be a good indicator of thermally induced sediment formation, with little sediment being produced if ionic Ca was maintained below 0.4 mM.