The pH of the solution was adjusted to 5.6 with 1 N NaOH, and 0.1 ml of Tween-80 was added as an emulsifier. An acidic solution (pH 5.6) containing Tween-80, without chitosan, was used as a control. The papaya fruits were washed with chlorinated water (0.01%), prepared from 5% sodium hypochlorite, prior to coating treatments.