2. Materials and methods
2.1. Preparation of the film forming solutions
Chitosan, with a deacetylation degree of 97%, derived from shrimp
shells were purchased from Fluka Biochemica.
The chitosan solution (1%) was prepared as follows: weigh 1 g
chitosan and put into a 200-mL beaker, then slowly added 100 mL 1%
citric acid solution and meanwhile stirred with a magnetic stirrer until
the mixture solution pH 3.5–4.0 became clear and coating formed. The
solution was vacuumed for 2 h to remove trapped air bubbles introduced
during the mixing. The film forming solution was used for apple slices
fruit coatings.