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Background: Gels of potato starches with varying amylose content were prepared and the degree of pasting and the course of retrogradation were studied. The average molar masses of granular and pasted starches were estimated. Determination of the degree of pasting involved use of optical microscopy and the study of pasting characteristics. The studies of susceptibility to retrogradation considered mechanical spectra, hardness, syneresis, resistant starch content, and X‐ray measurements. Results: Heating of the starch suspensions at 95 °C resulted in almost complete deterioration of granules. Changes in storage modulus (G') exceeded these of loss modulus (G"). Values of G' and G", hardness and syneresis increased with the period of the sample storage and, simultaneously, the relevant tangent of the phase shift angle (tg (G"/G')) decreased. A tendency was observed for the resistant starch (RS) content to increase on prolonged storage of gels. The patterns of diffractograms for the pasted and lyophilized samples only differed slightly. Conclusion: The pastes of all the studied potato starches were characterized by a similar degree of pasting. The most essential changes in the physicochemical properties of the gels were observed between the 30th and 90th days of storage. The susceptibility of potato starch gels to retrogradation, especially within the first 2 h, was controlled, mainly by the amylose content. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Materials used in this research were residual oat flour and starch isolated from it, and wheat flour and starch were used as reference. Pasting temperature of the starch present in flour or isolated starch increased with increasing syrup concentration, depending on material and syrup concentration. The maximum values of oat flour and starch paste viscosity were achieved at 30–40% syrup concentration, and at 50% for wheat pastes. Oat flour and starch pastes were pseudoplastic shear thinning fluids. In presence of syrup they revealed lesser deviation from Newtonian properties. Mechanical spectrum analysis of oat flour and starch pastes revealed stronger elastic than viscous properties. The hardness of flour gels prepared in syrup was higher than aqueous ones, and was increasing with increasing syrup concentration. It was stable during 7 days of storage. Adhesiveness of oat flour gels with syrup were lower than aqueous ones, reverse situation was observed for wheat flour gels. During storage, oat gels showed an increase of adhesiveness, in contrast to wheat gels, that were characterized by only initial increase of adhesiveness. [ABSTRACT FROM AUTHOR]