title: Thixotropic properties of normal potato starch depending on the degree of the granules pasting.
abstract: The aim of this paper was the study of the rheological instability (thixotropy and/or antithixotropy) of normal potato starch (NPS) pastes depending on their concentration (2-5%) and degree of pasting. Flow curves with hysteresis loops, apparent viscosity at constant shear rate and in-shear structural recovery tests were carried out. Granule size profiles, the pasting characteristic of corresponding starch suspensions and the transmittance of the pastes, the molecular weights and polydispersity of granular starch and its pastes prepared at 80, 95 and 121°C were also studied. The degree of pasting was dependent on the temperature and the concentration and influenced strongly the rheological behavior of the pastes. All pastes belonged to the non-Newtonian liquids thinned by shear and were rheologically unstable to the various extent. Thixotropic properties were connected to the size and the number of the starch granules in the pastes as well as depended on the measuring method used. In the 2 and 3% samples pasted at 80°C the swelling of the granules prevailed their destruction (thixotropy was observed). In the other samples the destruction predominated the swelling (antithixotropy observed).
authors: University of Agriculture in Krakow, Faculty of Food Technology, Department of Carbohydrates Technology, Balicka Street 122, 30-149 Krakow, Poland. Electronic address: rrsikora@cyf-kr.edu.pl.
authors: Marek
authors: M
authors: Sikora
authors: University of Agriculture in Krakow, Faculty of Food Technology, Department of Carbohydrates Technology, Balicka Street 122, 30-149 Krakow, Poland.
authors: Greta
authors: G
authors: Adamczyk
authors: University of Agriculture in Krakow, Faculty of Food Technology, Department of Carbohydrates Technology, Balicka Street 122, 30-149 Krakow, Poland.
authors: Magdalena
authors: M
authors: Krystyjan
authors: University of Agriculture in Krakow, Faculty of Food Technology, Department of Carbohydrates Technology, Balicka Street 122, 30-149 Krakow, Poland.
authors: Anna
authors: A
authors: Dobosz
authors: Krakow College of Health Promotion, Krowoderska Street 73, 31-158 Krakow, Poland.
authors: Piotr
authors: P
authors: Tomasik
authors: University of Agriculture in Krakow, Faculty of Food Technology, Department of Carbohydrates Technology, Balicka Street 122, 30-149 Krakow, Poland.
authors: Wiktor
authors: W
authors: Berski
authors: University of Agriculture in Krakow, Faculty of Food Technology, Department of Carbohydrates Technology, Balicka Street 122, 30-149 Krakow, Poland.
authors: Marcin
authors: M
authors: Lukasiewicz
authors: University of Science and Technology, Faculty of Materials Science and Ceramics, Mickiewicza Street 30, 30-059 Krakow, Poland.
authors: Piotr
authors: P
authors: Izak
mesh_terms: D012212:Rheology; D011198:Solanum tuberosum / Q000737:chemistry*; D013213:Starch / Q000737:chemistry*; D014783:Viscosity
chemical_list: D013213:Starch
keywords: Antithixotropy; Degree of structure recovery; Rheological instability; Thixotropy