The proton relaxation times,
T1 and
T2, were determined at 10 and 30°C for six kinds of gelforming substances,
i.e., agar, κ-carrageenan, waxy corn starch, gelatin, egg albumin and curdlan, at several water content levels (70-99%), and the amount of bound water and the correlation time of the bound water were determined. The amount of bound water in agar gel was the highest (0.6-1.0 g of H
2O/g of dry matter (DM)) followed by curdlan, egg albumin, κ-carrageen.an (0.07-0.17 g of H
2O/g of DM) and was the lowest in waxy corn starch and gelatin (0.03-0.1 g of H
2O/g of DM). The values at 10°C were higher than at 30°C for the hydrophilic gels, and lower for the hydrophobic ones. Therefore, the process for forming bound water in curdlan, which is known to retain hydrophobic bonds, is suggested to be much different from that in hydrophilic gels.
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