Caseinate Concentration Research Articles

A Method for Isolating β-Casein

A new method was developed for obtaining pure β-CN. Calcium caseinate (3%) was reconstituted, renneted to form a gel, cooled (4°C) to allow β-CN dissociation from the caseinate gel, and centrifuged. The supernatant was warmed to 30°C, precipitating pure β-CN from solution. Large quantities of β-CN were recovered by scaling-up this procedure, but these β-CN preparations were less pure than the β-CN that was prepared on a smaller scale. Chromatography (FPLC®) and urea-PAGE showed β-CN to be the main component in the precipitate. Chymosin, used to form the caseinate gel, did not extensively hydrolyze β-CN under the conditions of these experiments. Calcium concentration, cooling time, and caseinate concentration influenced the recovery of β-CN. Maximum recovery of β-CN, under the experimental conditions used, occurred at 10mM calcium, 48h of cooling, and 3% caseinate concentration.

Layering of Sodium Caseinate Submicelles in Thin Liquid Films— A New Stability Mechanism for Food Dispersions

Drainage and stability mechanisms of thin foam and emulsion films containing aqueous sodium caseinate solutions were investigated. We found that the films thin stepwise by stratification. The heights of the film step-transitions were in the same range as the effective size of the casein-aggregates, the so-called submicelles (about 20 nm). This showed that microlayering of submicelles takes place in the stratifying film and, at a step-transition, a layer leaves the film. The number of steps increased with increasing caseinate concentration. Increase of temperature accelerated the step-transitions. At a lower temperature the drainage was not only slower but the last transition was inhibited and a final film containing a layer of submicelles formed. The stepwise film thinning process could also be stopped at high film thicknesses by decreasing the film size, i.e., by forming smaller drops or bubbles. The stepwise thickness transition results could be explained by the theory of “vacancy” mechanism. It was found that the film and the emulsion are very stable if the drained emulsion film contains layer(s) of submicelles. This new mechanism of microlayering in foam and emulsion films can be important in the stability of food systems because the concentration (0.1–4 wt%) and temperature (25–80°C) ranges where the phenomenon was observed are similar to those found in practical applications.

Sodium Caseinate-Stabilized Emulsions: Factors Affecting Coverage and Composition of Surface Proteins

As the concentration of caseinate in sodium caseinate-stabilized emulsions increased, the protein surface concentration increased. It plateaued at 1.36 ± 0.05 mg/m2 at a caseinate concentration between 2 and 4% (w/w), but the surface protein concentration markedly increased as caseinate concentration rose from 5 to 7.5%. At caseinate concentration below 2%, β-casein adsorbed at the surface of oil droplets in preference to other caseins. Increasing the oil concentration from 10 to 30% (w/w) decreased the surface protein concentration from 3.7 ± 0.3 to 1.4 ± 0.04 mg/m2, but further increases in oil concentration had much less effect. A decrease in surface protein concentration was observed as the homogenization pressure increased from 34 to 136 bar, but higher pressures had no further effect. β-Casein was adsorbed preferentially at the droplet surface in emulsions homogenized at pressures above 204 bar. Addition of calcium chloride to sodium caseinate solutions above 0.08% w/w resulted in formation of large casein particles/aggregates which adsorbed on to the droplet surface causing higher surface protein concentration. Keywords: Sodium caseinate; oil-in-water emulsions; protein adsorption; surface composition

A rheological comparison between the effects of sodium caseinate on potato and maize starch

The differences in response of 1% potato and 4% maize starch pastes to sodium caseinate inclusion were investigated. Pasting of the starches was performed at 95 °C for l h in a range of concentrations of sodium caseinate. Caseinate levels as low as 0.01% dramatically reduced the swelling volume of potato starch and hence the viscosity of the system. Since sodium chloride addition shows similar effects, it appears that caseinate acts through a non-specific ionic strength effect. The influence of caseinate on maize starch was less clear since it depended on the solvent medium. In distilled, deionized water, there was an increase in viscosity with increasing caseinate concentration, which may simply be explained by a contribution of the caseinate to the viscosity of the continuous phase. However, in 0.1M, pH 7.0 buffer the results suggest that caseinate may inhibit retrogradation as the viscosity of the system after ageing is reduced by its inclusion. It is suggested that phase separation between starch and caseinate is encouraged at high salt concentrations. As a consequence, both starch granule swelling and subsequent retrogradation are discouraged by caseinate in the buffer system, but not when pasting is carried out in distilled, deionized water.

Efeito do caseinato de sódio nas propriedades sensoriais do presunto "cook-in"

Realizou-se o estudo do efeito das diferentes concentrações de caseinato de sódio nos atributos sensoriais do presento "cook-in". Em cada uma das quatro repetições, vinte presuntos foram designados ao acaso num dos cinco tratamentos, nos quais a formulação da salmoura de cura foi injetada a 20% em relação ao peso da carne em todos os tratamentos. A composição básica da salmoura correspondeu a 0,5% fosfato; 2,0% sal; 0,4% sais de cura; 0,66% condimento para presunto e 0,25% ascorbato, as condições de processamento foram as mesmas para todos os tratamentos, mas foram utilizados diferentes concentrações de caseinato de sódio em cada tratamento (0,0%; 0,5%; 1,0% e 1,5%). Foram retiradas amostras para medir o pH. Calculou-se as perdas no tambleamento e no cozimento e o rendimento. As propriedades sensoriais do presunto "cook-in" também foram avaliadas quanto a cor, aroma, coesividade, fatiamento, sabor e textura. O pH não apresentou efeito significativo, devido à salmoura ter sido ajustada para pH 9,0 para todos os tratamentos. Os presuntos com 1,0% caseinato de sódio apresentaram uma ótima aceitabilidade, mas apresentaram também a maior perda no cozimento. Os presuntos com 0,5% de caseinato de sódio apresentaram a menor perda no cozimento e uma razoável aceitabilidade das propriedades sensoriais.

Microfluidization of dairy model emulsions. I. Preparation of emulsions and influence of processing and formulation on the size distribution of milk fat globules

sodium caseinate (0.5-3.9 wt%), butter oil (5.2-14.7 wt%) and monoglyceride (0.08-0.88 wt%) concentrations. These 2 functions account respectively for 93.7 and 81.7% of the variation in the average diameterand in the size distribution width of the microfluidized fat globules and were used to explain certain interactions between the different variables affecting the size of the microfluidized fat globules. They were also used to demonstrate the existence of the optimal conditions that correspond to the extremes of the average particle diameter and of the distribution width of the fat globules. Finally, these 2 functions allowed us to predict fat globule size parameters as a function of process and formulation conditions.

Fractionation of sodium caseinate by ultrafiltration

A method for the fractionation of sodium caseinate into a β-casein-rich permeate and an α s κ- casein-rich retentate has been developed using ultrafiltration through 300 000 dalton cut-off membranes at 4°C. The β-casein fraction was 80% homogeneous, γ-caseins being the principal contaminants; most of the β-casein could be recovered in the permeate by diafiltration or repeated ultrafiltration. For the successful recovery of β-casein, it was essential to dissolve the sodium caseinate in deionized or distilled water but pH in the range 7–9 was not significant. A caseinate concentration of 1% was optimal in terms of yield and ease of operation.

Characterization of Natural and Imitation Mozzarella Cheeses by Differential Scanning Calorimetry

Differential scanning calorimetry was used to distinguish natural Mozzarella cheese from imitation Mozzarella made with calcium caseinate. The enthalpy of the milk fat melting transition at 18°C decreased with increasing caseinate concentration. Scanning electron microscopy studies revealed an agglomeration of lipids in the imitation samples, whereas the natural cheese had a uniform dispersion of fat globules. The addition of the caseinate apparently affected the crystallization of the fat, leading to the enthalpy reduction. Electrophoresis and atomic absorption procedures did not differentiate between natural and imitation samples.

The interaction of sodium caseinate with monoglyceride and diglyceride at the oil-water interface and its effect on interfacial rheological properties

The viscoelasticity at a corn oil-water interface of films of sodium caseinate, and of sodium caseinate plus glyceryl monostearate (GMS) and glyceryl distearate (GDS), have been examined. Caseinate films exhibited little viscoelasticity, but in the presence of GMS and GDS significant viscoelasticity developed. The magnitude of the viscoelasticity parameters was influenced by the GMS/GDS ratio employed at any caseinate concentration. Optimum values of the parameters were obtained at a 5/2 GMS/GDS ratio. This was attributed to association of caseinate with the glycerides, which had themselves entered into some form of association prior to adsorption of caseinate.

Use of Sodium Caseinate and Egg-albumin for the Retention of the Added Artificial Color to Agar Jelly

Effect of sodium caseinate or egg-albumin was examined to improve the retention of artificial color to agar jelly. By increasing the concentration of sodium caseinate to 0.4% or eggalbumin to 0.2%, and by lowering pH of jelly to 4.0, the color retention was improved remarkably, although such treatments resulted in, weakening of jelly strength. The color retention of dyes examined was in the following order; rose bengal>erythrosine>phloxine>eosine>sulfonate dyes such as amaranth, acid red, and new coccine.

Relation of Composition of the Aqueous Phase to Oxidized Flavor Development by Dialyzed Globular Milk Fat

Six per cent dialyzed milk fat and 4ppm copper were incorporated into: 1) salt solutions containing sodium citrate, phosphate buffer, NaCl, KCl, and CaCl2, and mixtures of those solutions; 2) salt solutions containing amounts of sodium caseinate ranging from 0.50 to 5.0%; 3) salt solutions containing 2 to 10% α-lactose; 4) the above model systems in presence of ascorbic acid.After 48 hr at 3-5C, oxidation rates and intensity were measured in terms of the optical density (OD) of the 2-thiobarbituric acid test.Both rates and intensity of oxidized flavor development varied significantly in the various salt solutions and their mixtures. Increasing lactose concentration increased the oxidation rates significantly in all systems, (OD increased from 0.32 to 0.50 in phosphate and 0.14 to 0.21 in citrate). The reverse of this trend was obtained in presence of an increased concentration of sodium caseinate (OD decreased from 0.25 to 0.05 in phosphate and 0.15 to 0.05 in citrate). Homogenized fat showed much lower oxidation rates in presence of casein than did nonhomogenized fat.In a salt-free system (water), ascorbic acid behaved as an antioxidant at concentrations from 0.50-2.0mg and a weak prooxidant at concentrations from 2-10mg per 100ml. This behavior was reversed in presence of salt solutions, with the oxidation intensity varying considerably depending on the composition of the model system.These results clearly demonstrate the importance of the aqueous phase in determining both rate and intensity of oxidized flavor development.