Abstract
We performed extraction and fractionation of pectin from fresh and steamed potatoes with different specific gravities and evaluated the association between changes in the chemical properties of the potatoes and those in their physical characteristics. Concerning physical characteristics, potatoes became soft and less cohesive after steaming but became hard and difficult to mash after a decrease in the food temperature. The former change was more marked in potatoes with a high specific gravity while the latter change was more marked in potatoes with a low specific gravity. The amount of watersoluble pectin in potatoes increased after steaming but decreased after a subsequent decrease in the food temperature. The former change was more marked in potatoes with a high specific gravity while the latter change was more maked in potatoes with a low specific gravity. In watersoluble pectin, the lowmolecular fraction increased after steaming but decreased after a decreased in the food temperature. The behavior of the watersoluble pectin fraction after steaming and a subsequent decrease in the food temperature markedly differed according to the specific gravity.
