Cell wall fractions were extracted according to methods previously described by Brummell et al. (2004) with slight modification. The powdered frozen flesh sample (3.0 g) was homogenized in 8 mL of 80% ethanol, stirred for 20 min at 80 °C and then centrifuged. The precipitate was washed with 80% ethanol and pure acetone three times and then sequentially immersed in 95% dimethyl sulfoxide (DMSO) for 12 h before centrifuging to remove the starch in the supernatants. Finally, the residue was dried until it SB 225002 was a constant weight at 45 °C in a ventilated oven, and the dried residue was considered to be the cell wall material (CWM). 50 mg CWM was extracted with distilled water and then centrifuged (15 min at 4000 × g). The supernatant was designated as the water-soluble pectin (WSP) fraction. The precipitate was sequentially dispersed with trans-1,2-diaminocyclohexane-N,N,N9,N9-tetraacetic acid (CDTA) and Na2CO3 containing 0.1% NaBH4 for 24 h to obtain CDTA-soluble pectin (CSP) fraction and Na2CO3-soluble pectin (NSP) fraction, respectively.. These three pectin fractions were quantified as uronic acid content using the carbazole method (Bitter and Muir, 1962) with three replications per sample.