Texture of cooked potatoes: The effect of ions and ph on the compressive strength of cooked potatoes

Abstract

Abstract It was shown from experiments on disks cooked in solutions of calcium chloride and calcium acetate, and in buffered solutions of calcium chloride at various pHs (sodium concentration constant) and from experiments where the ratios of disks to calcium chloride were varied, that the effect of calcium in increasing the compressive strength of the disks was small compared to the effect of reduced pH. The interaction of sodium and calcium was investigated at pH 6 (≈︁ the pH of cooked potato tissue). The effect of sodium in reducing compressive strength of the disks outweighed the effect of calcium in increasing compressive strength. Sodium and potassium chloride had a similar effect on loss of compressive strength on cooking. Increased compressive strength due to pH or the presence of calcium was overcome by extending the length of cooking. It is suggested that transelimination, ion exchange and hydrogen bond breakage may be more important factors than the chelation of calcium by naturally occurring phytin, in the breakdown of pectic substances and loss of intercellular adhesion during normal cooking of toes.