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Starch is a natural polysaccharide for which the technological quality depends on the genetic basis of the plant and the environmental conditions of the cultivation. Growing plants under cover without soil has many advantages for controlling the above-mentioned conditions. The present research focuses on determining the effect of under cover hydroponic potato cultivation on the physicochemical properties of accumulated potato starch (PS). The plants were grown in the hydroponic system, with (greenhouse, GH) and without recirculation nutrient solution (foil tunnel, FT). The reference sample was PS isolated from plants grown in a tunnel in containers filled with mineral soil (SO). The influence of the cultivation method on the elemental composition of the starch molecules was noted. The cultivation method also influenced the protein and amylose content of the PS. Considering the chromatic parameters, PS-GH and PS-FT were brighter and whiter, with a tinge of blue, than PS-SO. PS-SO was also characterized by the largest average diameters of granules, while PS-GH had the lowest crystallinity. PS-SO showed a better resistance to the combined action of elevated temperature and shear force. There was a slight variation in the gelatinization temperature values. Additionally, significant differences for enthalpy and the retrogradation ratio were observed. The cultivation method did not influence the glass transition and melting. [ABSTRACT FROM AUTHOR]

The aim was to study the rheological, especially thixo- and antithixotropic properties of normal potato starch (NPS) with the addition of locust bean gum (LBG) depending on the pasting temperature, the starch concentration and the amount of LBG. All the pastes under study were rheologically unstable, non-Newtonian, shear thinning fluids. The increase in the LBG content obstructed pasting of the starch granules and increased viscosity of the pastes. In a vast majority of cases obstruction in swelling granules and, hence, higher amount of non-pasted granules evoked thixotropy. In turn, a higher numbers of well swollen granules and, hence pasted granules led to antithixotropy. Apart from the concentration of both polysaccharides and pasting temperature the results depended also on the measuring method applied. [ABSTRACT FROM AUTHOR]