1H nuclear magnetic resonance relaxometry study of water state in milk protein mixtures.
1H NMR signal was used to characterize highly hydrated milk protein dispersions (3-20% dry matter) with various micellar casein concentrations (3-15%), whey protein concentrations (0-3%), lactose concentrations (0-7.5%), CaCl(2) concentrations (0-2 mM), and pH (6.2-6.6). The results showed the predominant effect of micellar casein concentration on water state and were consistent with the three-site relaxation model in the absence of lactose. The relaxation rates observed for these dispersions were explained by the free water relaxation rate, the hydration water relaxation rate, and the exchangeable proton relaxation rate. Hydration water was found to be mainly influenced by casein micelle concentration and structure. The variations in hydration with pH were consistent with those observed for classical measurement of voluminosity observed at this range of pH. The effects of lactose and whey protein content are discussed.
Cemagref, UR Technologie des équipements Agro-alimentaires, 17 avenue de Cucillé, CS 64427, 35044 Rennes Cedex, France.
Anne
A
Le Dean
François
F
Mariette
Michèle
M
Marin
D002122:Calcium Chloride / Q000032:analysis; D002364:Caseins / Q000032:analysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006863:Hydrogen-Ion Concentration; D007785:Lactose / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008894:Milk Proteins / Q000032:analysis / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D000067816:Whey Proteins
D002364:Caseins; D008823:Micelles; D008894:Milk Proteins; D000067816:Whey Proteins; D014867:Water; D007785:Lactose; D002122:Calcium Chloride