title: Dielectric spectroscopy study of water dynamics in frozen bovine milk.
abstract: Bovine milk is a complex colloidal liquid exhibiting a multi-scaled structure. It is of particular importance, both commercially and scientifically, to investigate both its dynamic and structural properties. In the current study we have employed the broadband dielectric spectroscopy (BDS) technique in the frequency range of 10(-1)-10(6)Hz and the temperature range of 176-230 K in order to examine the molecular structure and dynamics of quenched bovine milk. Four dielectric relaxation processes were identified. Three of them are associated with water in its different forms: water-lactose complexes, bulk hexagonal and cubic ices. The fourth process is attributed to domain wall relaxations linked to the presence of micro-cracks in the ice structures. In addition, the first process, attributed to water-lactose complexes, obeys the Meyer-Neldel compensation law and can be taken as evidence of differing interfaces of these complexes with the bulk water of the milk, mediated by the lactose concentration. Furthermore, an intriguing structural-dynamic transition around 200K was observed. Considering the mentioned above, we conclude that our results emphasize the structural and dynamical significance of water in bovine milk.
authors.affiliation: The Hebrew University of Jerusalem, Department of Applied Physics, Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Agranovich
authors.affiliation: The Hebrew University of Jerusalem, Department of Applied Physics, Israel.
authors.forename: Paul
authors.initials: P
authors.lastname: Ben Ishai
authors.affiliation: Afimilk, Kibbutz Afikim, Israel.
authors.forename: Gil
authors.initials: G
authors.lastname: Katz
authors.affiliation: Afimilk, Kibbutz Afikim, Israel.
authors.forename: Dror
authors.initials: D
authors.lastname: Bezman
authors.affiliation: The Hebrew University of Jerusalem, Department of Applied Physics, Israel. Electronic address: yurif@mail.huji.ac.il.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Feldman
mesh_terms: D000465:Algorithms; D000818:Animals; D002364:Caseins / Q000737:chemistry; D002417:Cattle; D003102:Colloids / Q000737:chemistry; D058266:Dielectric Spectroscopy / Q000379:methods*; D019277:Entropy; D005615:Freezing; D006358:Hot Temperature; D007700:Kinetics; D007785:Lactose / Q000737:chemistry; D008892:Milk / Q000737:chemistry*; D044366:Transition Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D002364:Caseins; D003102:Colloids; D014867:Water; D007785:Lactose
keywords: Bovine milk; Dielectric relaxation; Dielectric spectroscopy; Ice; Lactose; Water