Short- and long-term retrogradation of potato starches of various amylose content.

BACKGROUND

Gels of potato starches ofvariousamylose content were prepared and the degree of pasting and the course of retrogradation were studied. Average molar masses of granular and pasted starches were estimated. Determination of the degree of pasting involved optical microscopy and pasting characteristics. The studies of the susceptibility to retrogradation included mechanical spectra, hardness, syneresis, resistant starch content and X-raymeasurements.

RESULTS

Heating of the starch suspensions at 95o C resulted in almost complete deterioration of granules. changes of G' exceeded these of G". Values of G' and G", hardness and syneresis rose with the time of the sample storage and, simultaneously, relevant tg (G"/G') decreased. The tendency to increasing content of RS on prolonged storage of gels was observed. The pattern of diffractograms for the pasted and lyophilized samples only slightly differed from one another.

CONCLUSIONS

The pastes of all studied potato starches were characterized by the similar degree of pasting. The most essential changes of physicochemical properties of the gels were observed between 30th and 90th day of the storage. The susceptibility of potato starch gels to retrogradation, especially within the first two hours, was controlled, mainly by the amylose content. This article is protected by copyright. All rights reserved.