• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.200-204
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• 2000

Protein conjugation of curdlan belonging to $\beta$-1, 3-glucan was carried out to improve it surface functionalities. The glucan was mixed with phosvitin, {TEX}$$\alpha$_{s}${/TEX}-casein, lysozyme or ovalbumin, respectively. The mixture was freeze-dried, and he resulting powder was incubated at 6$0^{\circ}C$ and 79% relative humidity for 12 days in order to generate a controlled Maillard reaction between curdlan and proteins. conjugation with unfolding proteins, i.e., phosvitin and {TEX}$$\alpha$_{s}${/TEX}-casein, drastically increased the solubility of the glucan, whereas lysozyme and ovalbmin did not. The solubility in water of curdlan was 3.44% for the phosvitin conjugate and 1.09% for the {TEX}$$\alpha$_{s}${/TEX}-casein conjugate. SDS-slab polyacrylamide gel electrophoresis showed that curdlan was solubilized due to covalent binding with phosvitin. Emulsifying properties of curdlan were substantially improved by the conjugation with phosvitin and {TEX}$$\alpha$_{s}${/TEX}-casein. Emulsion stability of the curdlan-phosvitin conjugate was about 2.9 times greater than that of the curdlan-phosvitin mixture.

• Preventive Nutrition and Food Science
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• v.7 no.2
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• pp.139-145
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• 2002

Hen egg-white lysozyme, ovalbumin, egg-yolk phosvitin, acid-precipitated soy protein and $\alpha$$_{sl}$ milk casein were covalently linked with galactomannan through a controlled dry-heating at 6$0^{\circ}C$ under 79% relative humidity without any chemical reagent. Neoglycosylation by the covalent binding of polysaccharide chains brought a significant improvement into the surface functionalities of food proteins. Excellent emulsifying properties and foaming properties were observed in all protein-galactomannan conjugates. Bacterial mutagenesis tests and animal dose test were done to evaluate the food safety of the protein-galactomannan conjugates. The neo-glycoproteins were negative for Ames test using Salmonella typhimurium TA100 (hisG46) and TA98 (hisD3052) strains, and rec-assay using Bacillus subtilis Hl7 (rec) and M45 (re $c^{+}$) strains. All substances were also nontoxic for oral administration to rats. L $D_{50}$ 's of these substances were all more than 7.5 g/kg body-weight of rat. No effect was also observed in the weight increases and the concentrations of total cholesterol, triglyceride and phospholipids in blood serum of the administrated rats with 7.5 g/kg conjugates. Thus, Maillard-type protein-polysaccharide conjugates prepared by covalent attachment of galactomannan to food proteins were proposed to be useful as a safe functional biopolymer in this study.y.