Anna Dobosz1, Marek Sikora1, Magdalena Krystyjan1, Piotr Tomasik2, Radosław Lach3, Barbara Borczak4, Wiktor Berski1, Marcin Lukasiewicz1. 1. Department of Carbohydrates Technology, Faculty of Food Technology, University of Agriculture in Krakow, Krakow, Poland. 2. Nantes Nanotechnological Systems, Bolesławiec, Poland. 3. Department of Ceramics and Refractories, Faculty of Materials Science and Ceramics, University of Science and Technology, Krakow, Poland. 4. Department of Human Nutrition, Faculty of Food Technology, University of Agriculture in Krakow, Krakow, Poland.
Abstract
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.
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 potatostarch gels to retrogradation, especially within the first 2 h, was controlled, mainly by the amylose content.
Authors: Magdalena Krystyjan; Anna Dobosz-Kobędza; Marek Sikora; Hanna Maria Baranowska Journal: Polymers (Basel) Date: 2022-01-23 Impact factor: 4.329
Authors: Marek Sikora; Magdalena Krystyjan; Anna Dobosz; Piotr Tomasik; Katarzyna Walkowiak; Łukasz Masewicz; Przemysław Łukasz Kowalczewski; Hanna Maria Baranowska Journal: Polymers (Basel) Date: 2019-10-27 Impact factor: 4.329