2.6. Sample collecting
For analysis of enzymes and metabolites,the fruit exocarp (peel) tissue around the equatorial region of each fruit was removed with a stainless vegetable peeler and cut into small pieces every 2 d during storage. Each treatment replicate at each sampling time contained 3 fruit, with 3 replicates for each treatment. The tissue samples were rapidly frozen in liquid nitrogen and stored at −80 ◦C until use.