2. Materials and methods
2.1. Sample preparation
Samples of strawberry were used from the Kordestan area in the west of Iran. This kind of strawberry was selected by its popularity and vast area of cultivation. Samples were directly harvested from Chenareh farm of Sanandaj and were transferred and cold-stored in the university laboratory in suitable panniers. To prepare samples for freezing, they were initially washed in cold water of 5 °C and medium-sized strawberries, with clear red colour, suitable degree of ripeness and lack of any apparent damage, were selected. Then, their sepals were separated manually and after straining were packed in 450 g of 70 μm polyethylene packing (Mallett, 1993). All chemical reagents were of analytical grade and obtained from Merck Company.