The chemical denaturation of groundnut protein and fibre formation

Physicochemical properties of oilseed proteins

This review attempts to consolidate the information on the physicochemical properties of proteins from groundnut, soybean, sesame seed, mustard seed, rapeseed, sunflower seed, cottonseed, and other oilseeds. It deals with the extraction and characterization of the oilseed proteins and describes the methods for isolation of the various protein fractions and determination of their physicochemical characteristics. Also discussed are the subunit composition of the oligomeric proteins, their hydrodynamic properties, and the effect of denaturants on these proteins. The similarity in the properties of the proteins from various oilseed materials is discussed. The review article aims to indicate the gaps in our knowledge about the physicochemical properties of oilseed proteins and suggests areas for future investigation.

[Rheology and spinning of alkaline solutions of sunflower seed globulin and casein]

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.