With a view to develope novel functional properties of food proteins, biological, chemical and physical modification was carried out. Differences of nucleotide sequence found in cDNA of soybean glycinin A1aB1b subunit prepared from Glycin max var. Shirotsurunoko and Bonminori suggest that oligonucleotide site-directed mutagenesis is useful to develope novel functional properties. Formation of n-hexanal, undesirable flavor, was depressed in soybean by the deletion of lipoxygenase 2. In addition, n-hexanal was proved to be produced enzymatically from 13-hydroperoxy-linoleic acid by hydroperoxidelyase. Soy glycinin and αs1-casein were lipophilized by chemically attaching naturally occurring fatty acids to them. The covalent attachment of fatty acid residues to these proteins caused an increase in their emulsification activity. The binding of orthophosphate to soy proteins increased gel forming and emulsification activities even at acidic environment. Soy proteins and maize protein, zein, were associated with soy lecithin and phosphatidate by sonication, respectively. The emulsiffication activity of phospholipid-protein complex was highly increased after they were treated with 50% alcohol or pro tease digestion.
Polystyrene particles adhered to a glass plate was set in an ultra-centrifuge equipped with an angle rotor of which the angle being changed from 20° to 40°, were removed in various experimental conditions; i.e. washing time, rpm of centrifuge, and particle size. Correlation between the removal force Fc (horizontal component Fh and vertical component Fv) vs. particle size has been observed, and the following results were obtained. 1) The removal percentage increased with increasing washing time, and particle size, and were proportional to rpm of the centrifuge. 2) The ratio of Fh and Fv were adjusted by changing rotor angle at constant Fc. The removal percentage increased with increasing Fh (i.e. decreasing θ). 3) The value of Fc necessery for the removal percentage of 50% were 80.5×10-5 dyn, 12.6×10-4 dyn for the particle diameter of 5μm, 15μm respectively at θ=30°.
Rheological measurement and microscopic observation were carried out to understand the shearing rate (D) dependence of the shape of multilamellar structure which is made up of dialkyl (C1618) dimethylammonium chloride (DADMAC). Five percent DADMAC dispersion exhibited a pseudoplastic flow indicating reduction of apparent volume fraction of the DADMAC aggregate. Viscosity curve of the dispersion at 50°C (above the transition temperature of DADMAC : 37°C) was lower by 1 to 2 orders than that at 25°C when no remarkable shearing rate was applied. On the other hand, there was no significant difference between the viscosity at 25°C and that at 50°C after the dispersion was treated with D of more than 105s-1. By an electron microscopy using a freeze-fracture replica method, a mixture of multilamellar vesicles with different numbers of bimolecular layers were observed in the dispersion not treated with remarkable D. Both the number of bimolecular layers and the size of multilamellar vesicles were found to be reduced with an increase of an applied D. Almost every vesicle became an aggregate with a few layers, especially when the dispersion was treated with D of more than 105s-1. Consequently a network structure was formed spontaneously among each vesicle which led to a slight increase of viscosity in relatively low D region during storage period over a month. This phenomenon can be attributed to an electrostatic interaction between the small aggregates.
To establish a standard method for measuring the consistency of fats, the compression method was collaboratively tested by members of the solid fat committee of Japan Oil Chemists' Society. The types of adapters for the instrument (Fig.-1) and conditions for sample preparations were studied. Better reproducibility was possible using an adapter of φ; 30mm for shortenings and margarines and φ=3mm for hydrogenated fats. In both cases, the repeatability and reproducibility coefficients of variation were less than 5% and 12%, respectively. These results were better than those for corn penetration which was examined at the same time.
Single bilayer liposomes (SUV type) were obtained from an ethanol solution of egg licithin. Co-enzyme Q10 (CoQ10), used for treating heart disease, was incorporated into the liposomes. Liposome stability and effects of various additives (Polyethyleneglycol and Soybean oil) were evaluated on the basis of average particle size as measured by AUTOSIZER. This stability increased by the incorporation of CoQ10 and the addition of Soybean oil. The increase in liposome particle size was greater by the addition of Polyethyleneglycol than that of liposomes only incorporated by CoQ10.