An NMR relaxation study of the state of water in gelatin gels.
A combination of 1H and 23Na NMR is used to probe the dynamic state of water in gelatine gels as the water content is lowered from 70% to dryness. A sharp increase in the proton and sodium transverse relaxation rates is observed as the water content falls from 20 to 15% while the proton longitudinal and dipolar cross relaxation rates show a maximum at ca. 15%. We show that these observations can be understood if monolayer coverage occurs at 15% and multilayers of less strongly interacting hydration water are formed between 15 and 20%. Above 20% the water appears to behave as an unperturbed bulk phase.
D003890:Desiccation; D005504:Food Analysis; D005519:Food Preservation; D005780:Gelatin; D005782:Gels; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D014867:Water / Q000032:analysis*