Study On Making Preservative Of Snap Beans By Using N,O-Carboxymethyl Chitosan

This study dealed with making preservative of snap beans that were distinguishing vegetable in Hei Longjiang province by using edible chitosan.The results showed that:(1) When chitosan was mixed with 55%NaOH solution in proportion of 1:10 (w/v g/mL) and the reaction took place at temperature of 105 for 6 hours, chitosan having a deacetyl percentage of 94% and viscosity of >200cps could be available; The degree of substitution of carboxymethyl chitosan was 0.68 while the ratio of chitosan to sodium hydroxide to chloroacetic acide (mass ratio) was 1/1.1/1, The reaction took 2.5h at room temperature, then lifted to 60 and held there for 2.5h.(2) During the storage ,the regularity of quality changing of snap beans was: The content of water, victamin C and reducing sugar decreased constantly, the contents of chlorophyll decreased at first, then increased slowly until a cumulative peak appeared, and decreased finally; The result of Lg9(34) orthogonal experiment showed that the optimum proportion of the preservative was respectively as follow: The quantity of N,O-carboxymethyl chitosan was 2.0%, Sodium dehydroaceate 0.2g/kg, 6-BA 20ng/mL.(3) Among 8 varieties of snap beans used in this test, little snap beans and purple flower snap beans were more storable, so they can be used for long-term storage.