Whilst the emulsifying properties of the protein fraction of vicia fabu are almost independent on the acetylation degree, the shear modulus of the gels produced by heat denaturation increases at first with increasing acetylation degree, decreases with further increase of the acetylation, and comes finally to zero for very high acetylation degrees.By changes of pH and by influence of added NaC1, CaCI,, AICI,, and starch, the shear modulus of gels of acetylated protein fractions of vicia f u h can be increased, by addition of sunflower oil it can be decreased.On the base of studies on the fraction p d i l e and on the changes of the content of sulthydryl and disulfide groups of the protein fractions of vicia fabo and the corresponding gels in dependence on the acetylation degree, an interpretation of the results is given, As a continuation of our already published results on the modification of the functional properties of vicia faba proteins by acetylation [l] this paper contains results on emulsifying and gel properties of vicia faba proteins in dependence on the degree of acetylation and on other influencing factors. Material and methodsThe acetylated fractions of viciajiaba protein which are very soluble in water (I) (degree of acetylation: 42, 78.92, and 97 :d) and the corresponding non-acetylated fraction of vicia faha protein (11) were prepared as described previously [I] from an viciafaba protein isolate (111).The acetylation degree of the proteins is given as the percentage of the blocked lysine and has been determined according to [2,3].The determination of the content of sulfhydryl and disulfide groups has been carried out by an amperometric technique described in [4].The gel chromatographic investigations were accomplished using Sepharose 6 B (Pharmacia, Sweden) in a 9/50 column with glass filter, combined with a 21 15 type Multiperpex peristaltic pump (LKB, Sweden) and an Uvicord I1 spectrophotometer (LKB, Sweden); 5.0 mg protein in 1.0 ml solution were given on the column. The flow rate was 6 ml/h and the fraction size 2 ml. To estimate the molecular masses a calibration was carried out with cytochrom C, chymotrypsinogen A, ovalbumin (SERVA, Heidelberg) and bovine serum albumin (FERAK, Berlin-West). The proteins were separated in borate buffer (pH 8.4; p = 0.25), in borate buffer (pH 8.4: p = 0.25 + 0.1 % sodium dodecylsulfate), and in borate buffer (pH 8.4 p = 0.25 + 0. I 7; sodium dodecylsulfate -4-0.1 % 2-mercaptoethanol).

Alkaline solutions of a mixture from rapeseed globulin and casein show plastic flow, which is influenced by protein concentration, relation of rapeseed globulin and casein, temperature and time of storage of the protein solution. The sodium hydroxide concentration with a great variability doesn't take effect on the rheological properties. With increasing content of casein in such alkaline solutions of rapeseed globuline and casein results an approach to NEWTONian flow. The spinnability of alkaline solutions of a mixture from rapeseed globulin and casein and the properties of the corresponding spun protein fibers are influenced by protein concentration, relation of rapeseed globulin and casein of the spinning solution and temperature of coagulating bath. The sodium hydroxide content of the spinning solution and the hydrochloric acid concentration of the coagulating bath with a great variability don't take effect. The spinnability of alkaline solutions of a mixture from rapeseed albumin starchsulphate and casein and the properties of the corresponding spun protein fibers compared to rapeseed globulin-casein mixtures are influenced additionally by sodium hydroxide concentration of the spinning solution and hydrochloric acid content of coagulating bath. The favourable influence on the properties of spun rapeseed albuminstarchsulphate-casein fibers isn't increased by a growth of the rapeseed albumin starchsulphate content more then 4% of the protein concentration of the spinning solution.

No abstract

No abstract

Using the method of mathematical planning of experiments and taking thc shear modulus of the gels as an equivalent ofthegelationdegree. theconditionsofthethermaldenaturation at the maximum shear modulus were found to be TD 2 I00 C and fD o 60 min for the non-acetylated C'icio fnbo protein and TD =z 100 'C and to 4 40 min for the acetylated Viciafiha protein. On these conditions the dependence of the shear modulus ( G ) on the protein concentration ( C ) is expressed by exponential functions G = K . C" and 6' = z . c4 ". respectively.By an increasing acetylation of the Viciofaba protein the shear modulus, the thickness of the many-line chains, and the net density of gels are increased; the same is \slid for the shear modulus and the masking of disulfde groups hy an increasing concentration of non-acetylated and acetylated Vicia fnha proteins.

The specific demand of sodium hydroxide is determined for the dissolution of sunflower seed globulin, casein and a mixture of them to equal parts. In low protein-containing solutions it depends for sunflower seed globulin very much on the sodium chloride concentration. From sunflower seed globulin, casein and a mixture of them to equal parts are prepared with sodium hydroxide high protein-containing alkaline solutions. Sunflower seed globulin forms temporally a gel phase. After this phase the solution of sunflower seed globulin shows like casein and a mixture of sunflower seed globulin/casein (I:I) pseudoplastic flow. The flow curves of the pseudoplastic solutions are described mathematically with the OSWALDian power statement. By alkaline solutions of casein and sunflower seed globulin/casein (I:I) the flow exponent n is distributed statistically about 0.9, by solutions of sunflower seed globulin a distribution exists about the mean values n = 0.85 and n = 0.50. lg k depends in all protein solutions on the concentration of protein, sodium chloride, sodium hydroxide and on the temperature and time. For all protein solutions exists a linear relation between the logarithm of viscosity and the reciprocal temperature for lg k and I/T, which is derived normally for NEWTONian flow behaviour. In a suitable scope of spinning for all protein solutions are carried out complete factorial experiment, which guide to regression equations of lg k; in the case of sunflower seed globulin are calculated also a regression equation of the flow exponent n. Going out from the parameters of the spinning process the properties of the spun sunflower seed globulin/casein (I:I) fibers are described.

From field bean protein and a mixture of field bean protein with casein to equal parts are prepared with sodium hydroxide high protein-containing alkaline solutions, which show pseudoplastic flow. The flow curves of the pseudoplastic field bean protein-casein (I:I)-solutions are described mathematically with the Ostwaldian power statement. In a suitable scope of spinning of this solutions are carried out complete factorial experiments, which guide to regression equations of lg k and n. g k depends on the concentration of protein; an effect of the sodium hydroxide concentration exists lonly about interactions. On the other hand the flow exponent n depends on the hydroxide concentration. The properties of the spun field bean protein/casein (I:I) fibres are described.

No abstract