Weight loss rate determination
Using an analytical balance we determined the weight of 10 strawberries. The weight was registered. The weight loss rate was calculated using the following formula:
Weight loss rate = (The weight of fruit before storage - the weight of fruit during storage)/The weight of fruit before storage x 100%.
Ascorbic acid determination
The ascorbic acid was measured by 2, 6-dichlorophenolindo- phenol titration . Briefly, tissue (50g) from six fruits was immediately homogenized in 50mL of 0.02g/mL oxalic acid solution and then centrifuged at 15000xg at 4oC for 15 min. Afterwards, 10 mL of supernatant was titrated to a permanent pink colour by 0.1% 2, 6-dichlorophenolindophe- nol titration. Ascorbic acid concentration was calculated according to the titration volume of 2, 6-dichlorophenolindo- phenol and expressed as mg/100g fresh weight.
Respiration rate determination
Respiration rate was measured by sealing each jar, and sampling the headspace (0.5mL) using gas-tight glass syringes . Gas samples were analyzed using a gas chromatograph with a thermal conductivity detector