This study explored the ability of apple pectin AU-701 to change the freezing point of water in cryoprotectant solutions with different penetrating abilities using glycerol, dimethyl sulfoxide (DMSO), 1,2-propanediol (1,2-PD), dimethyl acetamide (DMAC), hydroxyethyl starch (HES), hexamethylenebistetraoxyethylurea (or substance A-378), and in biological fluid (human venous blood). An effective interaction was used to protect human blood leukocytes at ultrafreezer temperature (-80°C). Apple pectin affects the freezing temperature of water in different ways and it depends on the medium in which it is dissolved, as it either slows down the freezing process (in glycerol) or accelerates it (venous blood). The addition of apple pectin to the cryosolution increases the activity of the base cryoprotector (glycerol) even at low concentrations. Therefore, the combination of these substances can be effective in freezing biological substances, which is proved by indicators of safety of leukocytes during the freezing process at low temperature (-80°C) for 14 days.
Keywords: apple pectin; cell viability; cryoprotectants; crystallization; leukocytes.