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oai:www.ideals.illinois.edu:2142/22996 2023-07-10 col_2142_5131 col_2142_14781 com_2142_5130 com_2142_687 com_2142_397

Steinberg, Marvin P. Padua, Graciela Wild 2011-05-07T13:58:27Z 2011-05-07T13:58:27Z 10000-01-01 1989 The water states associated with the skim milk components whey protein, rennet casein, lactose and with other sugars were characterized and quantitated by pulsed NMR spectroscopy. The relation between the water states and the rheological properties of these materials was also investigated. Proton longitudinal relaxation rates were determined for whey protein powders and suspensions of solids concentrations between 0.01 and 2.90 g solids/g water. These data showed three hydration regions. The application of the two-state model with fast exchange to the dilute suspension data allowed the identification of polymer and free water states in this region. The same model was used to identify polymer and capillary water in the high solids region. For the intermediate solids, a three-state model was developed. These models enabled the calculation of the quantity of each water state in a whey protein-water system. The same approach was used to determine the water states in casein-water mixtures over a concentration range of 0.4 to 6 g casein/g water. A plot of relaxation rate against solids content showed four linear regions which indicated the presence of four water states. The NMR two-state model with fast exchange was applied to Regions III and IV, and two extended forms of this model were developed for Regions I and II. Proton relaxation rates were determined for lactose, sucrose, dextrose and fructose solutions of about 0.5 to 2 g sugar/g water. The log of relaxation rate against concentration was linear throughout the concentration range for all sugars. Each line showed the same intercept but a different slope. Variation of log viscosity with concentration for the same solutions was also linear; and the semi-log plots fell in the same relative order as they did for the relaxation rate. This finding showed that the viscosity of a sugar solution depends on the mobility of the water phase. Viscosity was determined for whey protein suspensions up to 0.48 g solids/g water. Correlation of viscosity data with proton relaxation rate determinations yielded two linear relations. This correlation was interpreted in terms of the effect of water states on the viscosity of the system. Within a hydration region, viscosity was linearly dependent on the amount of free water in the sample. Made available in DSpace on 2011-05-07T13:58:27Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9010976.pdf: 2706458 bytes, checksum: 3ac8c1961a2a948878caa62217a3de64 (MD5) Previous issue date: 1989 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:01:28Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:29:09-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9010976 (UMI)AAI9010976 http://hdl.handle.net/2142/22996 eng Copyright 1989 Padua, Graciela Wild Agriculture, Food Science and Technology Water states associated with skim milk components quantitated by NMR text Food Science Food Science University of Illinois at Urbana-Champaign Dissertation Ph.D.