14B-24

H. I. OH, Y. J. KIM, J. H. JANG, and D. H. JO. Dept. of Food Science, Sejong University, Kunja-Dong 98, Kwangjin-Ku, Seoul, 143-747, South Korea

Chitosan is thought to have many biological functions, i.e., anticancer activity, enhancement of immune function and antimicrobial activities, etc. However, most of the chitosan researches are directed toward medical applications. Our objectives was to use 4 different kinds of chitosan to determine whether addition of chitosan could prolong storage stability of mayonnaise. Four different kinds of chitosan were prepared by treating crude chitin with 1N HCl and 1N NaOH under different conditions. Antimicrobial activities of chitosans were tested against Lactobacillus plantarium, Lactobacillus fructivorans and Zygosaccharomyces bailii, spoilage microorganisms of mayonnaise. The effect of addition of chitosan having a high antimicrobial activity on the storage stability of mayonnaise has been studied during storage at 25 and 37^oC. In the antioxidative activity test, all samples did not show any significant differences when mayonnaise samples were stored at 25^oC. However, when the samples were stored at 37^oC, mayonnaise with 100ppm addition of chitosan-50 was more effective in antioxidant activity than that of 500, 1,000 ppm. There was no significant difference of POV values among samples when stored at 25^oC. However, the POV value of mayonnaise with 100 ppm chitosan increased to a less extent as compared to those of others, which increased rapidly after 6 weeks of storage at 37^oC. Although there was no significant difference in the emulsion stability among the samples when stored at 25^oC, mayonnaise with 100ppm chitosan retained over 93% emulsion stability even after 10 weeks storage at 37^oC. In microbial challenge test, addition of 100ppm chitosan-50 to mayonnaise prevented or extinguished the growth of Lactobacillus fructivorans and Zygosaccharomyces bailii. These results suggest that chitosan might have antioxdant activity and maintain emulsion integrity of mayonnaise at elevated storage temperature. Addition of chitosan can also prevent growth of spoilage microorganisms of mayonnaise during marketing in the prolonged hot summer seaseon.