title: Physicochemical, thermal and rheological properties of starches isolated from malting barley varieties.
abstract: The aim of this work was to characterize physicochemical, thermal and rheological properties of starches isolated from malting barley varieties. The analyzed starches contained 19.6-25.2 g of amylose, 42.47-70.67 mg of phosphorus, 0.50-1.26 g of protein and 0.10-0.61 g of fat per 100 g of starch dry mass. The clarity of the 1 % (w/w) starch pastes ranged from 5.4 to 9.8 %. Values of the characteristic gelatinization temperatures were in the ranges of 56.5-58.5 °C, 61.2-63.0 °C and 66.7-68.7 °C, respectively for TO, TP and TE, whereas values of gelatinization enthalpy were from 6.49 to 9.61 J/g. The barley starches showed various tendency to retrogradation, from 24.52 to 44.22 %, measured as R = ∆HR/∆HG value. The pasting curves showed differences in pasting characteristics of the barley starches, where values of peak (PV) and final (FV) viscosities were 133-230 mPa·s and 224-411 mPa·s, respectively. The barley starch pastes exhibited non-Newtonian, shear thinning flow behaviour and thixotropy phenomenon. After cooling the starch gels showed different viscoelastic properties, however, most of them behaved like weak gels (tan δ = G″/G' > 0.1). Significant linear correlations between the parameters of pasting characteristic and some rheological parameters were found.
authors.affiliation: Department of Analysis and Evaluation of Food Quality, University of Agriculture in Krakow, Balicka 122, 30-149 Kraków, Poland.
authors.forename: Karolina
authors.initials: K
authors.lastname: Pycia
authors.affiliation: Department of Analysis and Evaluation of Food Quality, University of Agriculture in Krakow, Balicka 122, 30-149 Kraków, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Gałkowska
authors.affiliation: Department of Analysis and Evaluation of Food Quality, University of Agriculture in Krakow, Balicka 122, 30-149 Kraków, Poland.
authors.forename: Lesław
authors.initials: L
authors.lastname: Juszczak
authors.affiliation: Department of Analysis and Evaluation of Food Quality, University of Agriculture in Krakow, Balicka 122, 30-149 Kraków, Poland.
authors.forename: Teresa
authors.initials: T
authors.lastname: Fortuna
authors.affiliation: Department of Engineering and Machinery in Food Industry, University of Agriculture in Krakow, Balicka 122, 30-149 Kraków, Poland.
authors.forename: Teresa
authors.initials: T
authors.lastname: Witczak
keywords: Malting barley; Physicochemical properties; Starch