چکیده :

The antimicrobial activity of lysozyme against Gram positive bacteria is well known. Application of this enzyme as a natural antimicrobial or preservative agent in food and pharmaceutical industry is under consideration in many laboratories. The antimicrobial effect of lysozyme can be extended towards Gram negative bacteria by chemical modification including conjugation with carbohydrates. The purpose of this investigation was to find the optimum experimental conditions for glycation of lysozyme with polysaccharides dextran, galactomannan and mannan and to evaluate some functional properties of the modified enzyme. Lysozyme was allowed to react with dextran under Maillard reaction condition at different pH and temperatures and in the presence of 50 mmol/L sodium bisulfite or cysteine and the extent of glycation was determined by ion exchange chromatography and SDS-PAGE. The optimum condition for glycation was pH 8.5 and 60 °C with a protein to derxtran molar ratio of 1:5. Same results were obtained for galactomannan but mannan did not react. Under these condition three moles dextran was attached to one mole lysozyme. Sodium bisulfite inhibited glycation at pH 8.5 and temperatures above 40 °C while cysteine prevented glycation at all pH and temperatures. Dextran-conjugated lysozyme exhibited improved heat stability, pH and heat solubility and better emulsifying property as compared with the unmodified lysozyme. These results suggest that it is possible to improve the properties of this enzyme in order to make it more suitable for application in foods and pharmaceuticals.

کلید واژگان :

LysozymeDextranGalactomannanMannanGlycationAntimicrobialFunctional properties



ارزش ریالی : 300000 ریال
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