1H n.m.r. study of geletin gels

Low resolution NMR spectroscopy: a tool to study protein denaturation: I. Application to diamagnetic whey proteins

“…T 2 relaxation of the non-equilibrium water proton magnetization in whey protein aqueous solution is purely exponential. This has been already reported for most of the protein-water systems studied (Lambelet et al 1988;Maquet et al 1984;Oakes, 1976a, b;Goldsmith & Toledo, 1985;Lelievre & Creamer, 1978;Rydzy & Skrzyriski, 1980, 1982Blicharska & Rydzy, 1979;Mahdi, 1980;Pumpernik et al 1975;Richardson et al 1986) and has been interpreted (Oakes, 1976a, 6;Lelievre & Creamer, 1978;Mahdi, 1980;Richardson et al 1986) in terms of a two-state model with rapid exchange occurring between bulk water molecules and those bound to proteins. According to this model, transverse relaxation rate, T 2~\ is given by:…”

“…Pulsed NMR spectroscopy has been applied to study the state of water in protein-water systems. In all homogeneous protein samples (Lambelet et al 1988;Maquet et al 1984;Oakes, 1976a, 6;Goldsmith & Toledo, 1985;Lelievre & Creamer, 1978;Rydzy & Skrzyriski, 1980, 1982Blicharska & Rydzy, 1979;Mahdi, 1980;Pumpernik et al 1975;Richardson et al 1986) except myosin-containing samples Yasui et al 1979), the water proton transverse (T 2 ) and longitudinal (T x ) relaxations have been reported to be single exponential processes. Such relaxations were interpreted in terms of a two-state model (Zimmerman & Brittin, 1957) with a rapid exchange between a small number of water molecules tightly bound to the protein and normal bulk water (Lambelet et al 1988;Oakes, 1976a, 6;Richardson et al 1986).…”

Pulsed Low‐Resolution NMR Investigations of Protein Sols and Gels

“…As the transverse relaxation is sensitive to the low frequency of molecular motion, it might, however, be expected to be a more sensitive indicator of the state of gelation than longitudinal relaxation, the latter depending on the higher frequency of molecular motion. Effectively, T, relaxation has been experimentally found to be a better probe than T, relaxation for studying polysaccharides (Child and Pryce, 1972) and protein (Maquet et al, 1984;James and Gillen, 1972;Oakes, 1976a) gels. Accordingly, protein sols and gels were studied using the T, relaxation probe exclusively.…”

“…Previous works have described the use of NMR spectroscopy to study the state of water in food systems containing gelatin (Labuza and Busk, 1979;Odeblad, 1960;Mrevlishvili and Sharimanov, 1978;Maquet et al, 1984), egg (Daszkiewicz et al, 1963;James and Gillen, 1972;Goldsmith and Toledo, 1985), milk (Oakes, 1976a;Lelievre and Creamer, 1978), meat (Nakano and Yasui, 1979;Yasui et al, 1979) and soybean (Mahdi, 1979) proteins. Some of these studies (Mrevlishvili and Sharimanov, 1978;Lelievre and Creamer, 1978;Yasui et al, 1979;Maquet et al, 1984;Goldsmith and Toledo, 1985) describe changes in NMR data on gelation. The present work examines the possibility of applying NMR spectroscopy for characterizing a number of protein-(milk, egg, soy, and gelatin) based food systems and for analyzing sol-to-gel transitions in these systems.…”

Inhibition of hydroxyapatite formation in collagen gels by chondroitin sulphate

“…13 days is necessary for complete equilibration of calcium between the solution and gel phases, indicating that diffusion into the gel is very slow. This is apparently due to 'structuring' of solvent molecules in semi-solid media (Maquet et al, 1984). Precipitation of calcium phosphate commences between 18 and 24 h, and reaches a plateau level after 6 days.…”