Increasing Protein Concentration (increasing + protein_concentration)

Distribution by Scientific Domains


Selected Abstracts


FILM FORMING MECHANISM AND MECHANICAL AND THERMAL PROPERTIES OF WHEY PROTEIN ISOLATE-BASED EDIBLE FILMS AS AFFECTED BY PROTEIN CONCENTRATION, GLYCEROL RATIO AND PULLULAN CONTENT

JOURNAL OF FOOD BIOCHEMISTRY, Issue 3 2010
MAHAMADOU ELHADJI GOUNGA
ABSTRACT Tensile strength (TS), elongation at break (EAB) and elastic modulus (EM) of edible films prepared from 5, 7 and 9% whey protein isolate (WPI) plasticized with different levels of glycerol (Gly) (WPI : Gly = 3.6:1, 3:1 and 2:1) were investigated in order to completely characterize WPI-Gly films. On increasing protein concentration an increase in TS and EAB was observed. On the other hand, increasing Gly led to a decrease in TS and EM, while EAB increased. The addition of pullulan (Pul) into the film forming solution (FFS) increased EAB while TS, EM and thermal properties were reduced. This suggested that Pul had a similar effect as plasticizers. Films with higher Pul content showed lighter protein bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Fourier transform infrared spectroscopy showed that hydrogen bonding was high in WPI : Pul films as compared with the control. This is attributed to the protein-polysaccharide interactions brought about by the dominance of Pul in the FFS. PRACTICAL APPLICATIONS This work describes some physical properties of films based on blends of whey protein isolate (WPI) and pullulan (Pul), made after a previous study on some characteristics of films based on pure WPI plasticized by glycerol. The most studied proteins in the edible films technology being gluten and WPI, the use of Pul in mixture with WPI is considered as a new investigation to explore the utilization of WPI-Pul in edible film and coating materials applied to food products. Furthermore, the use of WPI-Pul films and coatings could potentially extend the shelf life and improve the stability of the coated products as shown by the resultant properties in this investigation and previous works. [source]


Formation of Soy Protein Isolate Cold-set Gels: Protein and Salt Effects

JOURNAL OF FOOD SCIENCE, Issue 1 2005
Anne Maltais
ABSTRACT: The influence of protein and calcium concentration on soy protein cold-set gel formation and rheology has been investigated. Cold-set gels can be formed at soy protein concentrations from 6% to 9% and calcium concentrations from 10 to 20 mM. Gel properties can be modulated by changing the protein and/or CaCl2 concentrations. An increase in CaCl2 concentration from 10 to 20 mM increased gel opacity while an increase in protein concentration from 6% to 9% decreased opacity. Water-holding capacity improved with increasing protein concentration and decreasing CaCl2 concentration. The elastic modulus (G') increased with protein and calcium chloride concentrations. Microscopy revealed an increase in the diameters of aggregates and pores as CaCl2 concentration increased and as protein concentration decreased. Cold-set gels with a broad range of characteristics can be obtained from soy protein. [source]


TEXTURAL CHARACTERIZATION OF SOY-BASED YOGURT BY THE VANE METHOD

JOURNAL OF TEXTURE STUDIES, Issue 2 2002
IGOR V. KOVALENKO
ABSTRACT The vane method was applied to evaluate failure characteristics of soy-based yogurts prepared from five soybean varieties at Brix values of 6, 8, and 10. Yield stress, yield strain, and water-holding capacity were compared. Yield stress values ranging from 133 to 420 Pa at 2.5% protein and 498 to 1171 Pa at 4.0% protein were dependent on soybean variety and increased with increasing protein concentration. The average yield strain of samples was not affected by protein or variety. Compared to commercial dairy yogurt, soy yogurt had 132 to 445% higher yield stress at similar protein content, and was less deformable based on yield strain measurements. Water-holding capacity of soy yogurts was variety dependent, although this dependence was less pronounced at higher protein concentrations. The vane method may be effectively used as a rapid and inexpensive technique for detecting textural differences of soy-based yogurts. [source]


Protein,Protein Interactions in Complex Cosolvent Solutions,

CHEMPHYSCHEM, Issue 5 2007
Nadeem Javid
Abstract The effects of various kosmotropic and chaotropic cosolvents and salts on the intermolecular interaction potential of positively charged lysozyme is evaluated at varying protein concentrations by using synchrotron small-angle X-ray scattering in combination with liquid-state theoretical approaches. The experimentally derived static structure factors S(Q) obtained without and with added cosolvents and salts are analysed with a statistical mechanical model based on the Derjaguin,Landau,Verwey,Overbeek (DLVO) potential, which accounts for repulsive and attractive interactions between the protein molecules. Different cosolvents and salts influence the interactions between protein molecules differently as a result of changes in the hydration level or solvation, in charge screening, specific adsorption of the additives at the protein surface, or increased hydrophobic interactions. Intermolecular interaction effects are significant above protein concentrations of 1 wt,%, and with increasing protein concentration, the repulsive nature of the intermolecular pair potential V(r) increases markedly. Kosmotropic cosolvents like glycerol and sucrose exhibit strong concentration-dependent effects on the interaction potential, leading to an increase of repulsive forces between the protein molecules at low to medium high osmolyte concentrations. Addition of trifluoroethanol exhibits a multiphasic effect on V(r) when changing its concentration. Salts like sodium chloride and potassium sulfate exhibit strong concentration-dependent changes of the interaction potential due to charge screening of the positively charged protein molecules. Guanidinium chloride (GdmCl) at low concentrations exhibits a similar charge-screening effect, resulting in increased attractive interactions between the protein molecules. At higher GdmCl concentrations, V(r) becomes more repulsive in nature due to the presence of high concentrations of Gdm+ ions binding to the protein molecules. Our findings also imply that in calculations of thermodynamic properties of proteins in solution and cosolvent mixtures, activity coefficients may not generally be neglected in the concentration range above 1 wt,% protein. [source]