The relationship between fruit softening and 
β-galactosidase activity, pectin content, and cell wall calcium content in different apple cultivars

To understand the mechanisms of fruit softening, the relationship between apple softening and β-galactosidase activity and the content of pectin and calcium in cell walls was investigated.
The fruit firmness and β-galactosidase activity, as well as the content of pectin and calcium in cell walls were studied in four apple cultivars during storage at room temperature (25°C); ‘Golden Delicious’, ‘Starkrimson’, ‘Qinguan’, and ‘Fuji’. The study showed faster softening, an increased trend in β-galactosidase activity, a concomitant increase in soluble pectin, a faster decrease of cell wall substances and protopectin content, and a minimal change of cell-wall calcium content in ‘Golden Delicious’ and ‘Starkrimson’ compared with ‘Qinguan’, and ‘Fuji’. In contrast, ‘Qinguan’ and ‘Fuji’ apples softened more slowly, had lower β-galactosidase activity, and slower decrease of cell wall substances and protopectin content, while the cell-wall calcium content showed an upward trend during storage.
Thus, it suggested that the increase of β-galactosidase activity and soluble pectin in the cell wall leads to apple softening, while the calcium content in the cell wall has a minimal effect on apple softening.

I International Apple Symposium

YeQing Guan, Feng Zhang, YuDou Cheng, JunFeng Guan

apple fruit, cell wall hydrolase, cell wall substance, firmness, mineral element

https://doi.org/10.17660/ActaHortic.2019.1261.11