SWELLING BEHAVIOR OF CELL-WALL AND STARCH IN POTATO (SOLANUM-TUBEROSUM L) TUBER CELLS .2. PERMEABILITY AND SWELLING IN MACERATES

The permeability and swelling behaviour in macerates of potato tuber c ells were studied, because of their role in determining the texture of potato products. Chromatography of globular proteins on a column of m acerate of boiled potato cells indicated cell wail (CW) pore dimension s smaller than the protein molecular size of 600 kDa. Swelling of boil ed and dried potato tuber cells, resuspended in various liquids, was d ependent on the dielectric constant of the liquid (2.5-109), indicatin g the presence of an electrical double layer upon fibril surfaces of C W and starch polymers. Solvents of high dielectric constant such as fo rmamide and dimethylsulphoxide showed remarkably high swelling capacit y; this was attributed to the behaviour of the starch which behaves as an inflating agent of the cell owing to its solubility and expansion capability in solvents of high dielectric constant.