The pH of the solution was adjusted to pH 5.0 with 0.1 M NaOH and the solution was made up to 1.0 L. An acid solution at pH 5.0, without chitosan was used as a control. After they had been air-dried for 30 min at 25 °C, the sliced fruit were placed into plastic trays, and over-wrapped with 30 × 20 cm PVDC film (Wu-Yu Chimistry Co., Japan). They were then stored at 6 °C to be later assessed. Mango fruit pulp stored at 6 °C had the best quality (unpublished data), so this temperature was used in this work.
All other chemicals were obtained from commercial sources and were of analytical grade.