Abstract: Yali pears were subjected to short-time high-pressure carbon dioxide (HPCD) treatment in order to explore the relationship between their CO2-induced browning and intracellular calcium. After HPCD treatment, the content of water soluble and membrane-bound calcium decreased, whereas the contents of calcium oxalate, calcium phosphate, calcium pectate and calcium carbonate increased in Yali pears as the HPCD treatment time increased. An increase in the content of carbonate calcium was also confirmed by X-ray diffraction analysis after HPCD treatment. Moreover, the structure of brown Yali pears was destroyed, which was examined by transmission electron microscope (TEM). Therefore, HPCD treatment can change the types and distribution of calcium in Yali pear cells, increase cell permeability, and accelerate the browning of fruits.

Key words: high pressure carbon dioxide, yali pear, browning, cell structure, calcium content