Effect of Esterification Conditions on the Physicochemical Properties of Phosphorylated Potato Starch

The aim of this study was to evaluate the effect of the temperature (15 or 45 degrees C) and the duration (15-120 min) of the modification process on the selected physicochemical, thermal, and rheological properties of phosphorylated potato starch. The modified starches contained 93.6-98.2 mg P/100 g (dry weight basis, d.w.b.). Phosphorylation caused color changes with a total color difference between the starches below 0.55, but these changes were less than those that were recognizable by the human eye. The thermal analysis showed two opposite processes appearing during the modification: the loosening of the structure (dominant among starches obtained at 15 degrees C) and the strengthening of the structure (dominant among starches obtained at 45 degrees C). The higher phosphorylation temperature reduced native starch recovery from 140% to 87-116% and increased the hysteresis loop area from -169 to 1040. All of the pastes made from the modified starches showed a weaker tendency for retrogradation (during 21 days of storage) than native starches. The results of the regression analysis conducted between the properties of the starch pastes obtained at 45 degrees C indicated that the modification time appeared to be a better indicator of the rate of modification progress than the phosphorus content. The PCA (principal component analysis) results made it possible to distinguish starch phosphates obtained at 15 degrees C from those obtained at 45 degrees C and those from natural starch.

Automated summary

This study aimed to evaluate the effects of temperature and duration on phosphorylated potato starch. Phosphorylation caused minor color changes and affected the structure and recovery rate of starch. The modified starches showed lower retrogradation tendency and modification time was a better indicator of progress than phosphorus content.