title: Surface energy analysis (SEA) and rheology of powder milk dairy products.
abstract: Results of inverse gas chromatography adsorption/desorption experiments using selected probes on skimmed milk, whey and demineralised whey powder materials are presented. The dispersive component of surface energy was found to be dominant, indicating a low polarity character. Surface energy profiles of demineralised whey and skimmed milk showed a characteristic steep exponential decrease from approximately 170 mJ/m(2) to 60 mJ/m(2) and 140 mJ/m(2) to 45 mJ/m(2), respectively, whereas whey powder exhibited a constant (non-exponential) surface energy at approximately 45 mJ/m(2). The dispersive surface energy of demineralised whey and skimmed milk powder showed a broad distribution ranging from 40 mJ/m(2) to 120 mJ/m(2) and 175 mJ/m(2), respectively. In contrast, the dispersive surface energy distribution for whey was very narrow, ranging from only 42.8 mJ/m(2) to 45 mJ/m(2). The determined yield locus and Mohr's circles indicated that demineralised whey exhibited free flowing powder characteristics, whereas skimmed milk and whey exhibited cohesive powder flow behaviour.
authors.affiliation: Department of Physical Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic; Tomas Bata University in Zlin, Faculty of Technology, Institute of Foodstuff Technology, nám. T.G. Masaryka 5555, 760 05 Zlín, Czech Republic. Electronic address: lapcikl@seznam.cz.
authors.forename: Lubomír
authors.initials: L
authors.lastname: Lapčík
authors.affiliation: Department of Physical Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic; Tomas Bata University in Zlin, Faculty of Technology, Institute of Foodstuff Technology, nám. T.G. Masaryka 5555, 760 05 Zlín, Czech Republic.
authors.forename: Barbora
authors.initials: B
authors.lastname: Lapčíková
authors.affiliation: Department of Physical Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic.
authors.forename: Eva
authors.initials: E
authors.lastname: Otyepková
authors.affiliation: Department of Physical Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic.
authors.forename: Michal
authors.initials: M
authors.lastname: Otyepka
authors.affiliation: Department of Physical Chemistry, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Vlček
authors.affiliation: Tomas Bata University in Zlin, Faculty of Technology, Institute of Foodstuff Technology, nám. T.G. Masaryka 5555, 760 05 Zlín, Czech Republic.
authors.forename: František
authors.initials: F
authors.lastname: Buňka
authors.affiliation: Tomas Bata University in Zlin, Faculty of Technology, Institute of Foodstuff Technology, nám. T.G. Masaryka 5555, 760 05 Zlín, Czech Republic.
authors.forename: Richardos Nikolaos
authors.initials: RN
authors.lastname: Salek
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D002849:Chromatography, Gas; D003611:Dairy Products / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D011208:Powders / Q000737:chemistry; D012212:Rheology; D013816:Thermodynamics
chemical_list: D011208:Powders
keywords: Demineralised whey powder; Flow index; Inverse gas chromatography; Powder rheology; Scanning electron microscopy; Skimmed milk powder; Surface energy analysis; Surface energy distribution; Thermal analysis; Wetting; Whey powder