2.12 Determination of sucrose content
Sucrose content was measured using the method of Shao et al. (2012). Briefly, 5 g of frozen peach tissue was finely ground in a mixture of 0.5 mL of solution I (5.48% (m/v) zinc acetate:glacial acetic acid (97:3)) and 0.5 mL of solution II (potassium ferrocyanide 2.65% (m/v)). The resulting homogenate was diluted with deionized water to 25 mL and then passed through a 0.22 µm membrane filter. The sucrose content in a 20 µL aliquot of the filtrate was measured using an HPLC system (model 2695, Waters, USA), equipped with an X BrigeTM amide column (3.5mm, 4.6250 mm, USA,) and a refractive index detector (model 2414) Waters). The mobile phase composition was acetonitrile/water (80:20 v/v), the total flow rate was 1 mL/min, and the column temperature was 35 ℃.