Bound Water Associated with 7S and 11S Soy Proteins Determined by Vapor Sorption Isotherms and Pulsed NMR |
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| Authors: | K. TANTEERATARM L. S. WEI M. P. STEINBERG N. YAMASHITA |
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| Affiliation: | Authors Tanteeratarm, Wei and Steinberg are affiliated with the Dept. of Food Science, Univ. of Illinois, 382D Agr. Engr. Sci. Bldg., 1304 W. Pennsylvania Ave., Urbana, IL 61801. Author Yamashita is with the Dept. of Applied Chemistry, Kinki Univ., 3–4–1 Kowakae, Higashi-Osaka, 577 Japan. |
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| Abstract: | Bound water associated with freeze-dried 7S and 11S proteins was characterized by applying both sorption isotherm and proton pulsed NMR techniques. Over the aw range 0.10 to 0.97, the water binding capacity of the 7S protein was superior to that of the US protein. There was no significant difference in sorption capacity between unhealed and heated proteins. The isotherms showed a biphasic linear relation so that two states of bound water, namely polymer and capillary water, were distinguished. NMR data followed isotherm data. The NMR mobility of the polymer water was less than that of the capillary water, as expected. However, high mobility was not related to high moisture content in the capillary water region. |
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