Abstract: The optimum condition of chitosan-coating treatment was determined through orthogonal test, with citrus Tian-cao as material. In the study the changes of water content,deoxidizing sugar, total scid, VC in the pulp, SOD activity, POD activity, membrane permeability in the peel of Citrus Tian-cao during storage were determined. The results showed that nutrition component is always in a tendency to decrease, also fresh-keeping coated by chitosan is higher than control, SOD activity increases and relatival membrane permeability of peel is lower than control in the whole storage time. Therefore, citrus Tian-cao fresh-keeping by chitosan can delay senescence of fruit so that it has better effect.

Key words: citrus Tian-cao, coated by chitosan, fresh-keeping, storage result