Pulsed Low‐Resolution NMR Investigations of Protein Sols and Gels

Abstract

Water proton transverse (T,) relaxation measurements in whey, egg, gelatin, and soybean sols and gels were determined. TZ relaxation in protein sols and gels was a single exponential process, except for oil containing sols which showed a two-phase behavior. The relaxation rates (l/r,) increased linearly with concentration of either protein or oil. For samples containing protein which underwent an irreversible denaturation upon heating, T, relaxation times were longer in the sols than in the gels. In gels, the variation of the Ta relaxation times with temperature was interpreted in terms of an exchange between labile protein protons and water protons.

Assessment of water diffusivity in gelatine gel from moisture profiles. I––Non-destructive measurement of 1D moisture profiles during drying from 2D nuclear magnetic resonance images

“…8 groups all the independent measurements of T 2 carried out for three pH values (4.6, 6 and 7.7) and two temperatures (10 and 27°C). The T 2 values decreased exponentially with the decrease in moisture content as already observed by Oakes (1976) in aqueous solutions of native bovine serum albumin and by Lambelet, Berrocal, Desarzens, Froehlicher, and Ducret (1988) in gelatine gels. The measurements were therefore fitted with Eq.…”

Evaluating the solubility of powdered food ingredients using dynamic nuclear magnetic resonance (NMR) relaxometry

“…This was shown by the decrease in T 2 values that corresponds to an increase in 'restricted' water associated with the solutes, and results were consistent with the hypothesis that water in the solution falls into one of two categories, 'free' and 'restricted' water (Davenel et al, 1997). Others have reported the influence of the type of ingredient on the existence of multiple water phases (Davenel et al, 2002;Lambelet, Berrocal, Desarzens, Froehlicher, & Ducret, 1988;Le Dean, Mariette, Lucas, & Marin, 2001;Mariette, Tellier, Brule, & Marchal, 1993;McBrierty, Martin, & Karasz, 1999;Padua, Richardson, & Steinberg, 1991;Ruan & Chen, 1998).…”

Prediction of hydrogel pore size by pulse NMR and neural networks

“…This decaying signal is analyzed to give structural information about the sample. This NMR technique has been used to study the state of water in food systems and the microstructure of food materials (Ruan, 1992;Labuza, 1979;Lambelet, 1988). Similarly, the relaxation characteristics of water in hydrogel pores can be used to explore the pore size distribution of the hydrogel.…”