Uptake ability

Water uptake ability, water Measure of the amount of liquid a solid Water uptake ability Advantages Used for solid or dry foods. Regenstein et al. 

Figure B5.3.1 A comparison of water retention properties expressible moisture versus water uptake ability. Reprinted from Regenstein (1984) with permission from the American Meat Science Association.

Water uptake ability is a measure of the amount of water that a sample can imbibe under specified centrifugation conditions. The amount and composition of the sample need to be known. Samples need to be blended in the presence of excess liquid. After centrifugation, the amount of protein in the supernatant (i.e., protein lost from the sample) and the volume of supernatant can be measured to accurately determine water uptake ability. Alternatively, WUAcan be measured from the pellet itself. Both calculation methods are presented here. 

Water uptake ability. Excess additional water that a material can imbibe. (The author recognizes the contribution of the USDA Regional Hatch Project NE-123 for this term.)... 

The other type of water retention measurement is water uptake ability. The basic question that this test tries to answer is, what is the amount of water a material can retain in the presence of an excess of solution One might consider this measurement as the sponge capacity of a food material. This property depends mainly on the properties of the insoluble phase and on the physical state of the food, i.e., the degree of particle disintegration. It is thus a question that can only be asked of an insoluble or partially insoluble material. 

As the water uptake ability is partly structural, it is dependent on particle size, and thus the blending process must be standardized. For this purpose, the author has found the Omnimixer (Dupont s Sorvall Division) to be a particularly useful device. It is an upside-down blender that, most importantly, with the appropriate adapter, can be used to blend samples in centrifuge tubes, avoiding the need for quantitative transfer of some very sticky and viscous materials. Again, all the details of the method need to be standardized, even if this is done in an arbitrary fashion. 

Although the conditions used for the measurement of both expressible moisture and water uptake ability are arbitrary, the two can be performed under similar conditions. One of the real benefits of the two tests, with arbitrarily defined working parameters, is that they can, in theory, be done in parallel, e.g., by placing four samples for expressible moisture and four samples for water uptake ability in the same eight-cell centrifuge. In this case, the differences observed reflect the differences between... 

Drip loss, cooking or processing loss, and thaw loss are similar to expressible moisture. In most cases, however, the moisture is lost without the need to apply a force. Thus, the liquid that is expelled can simply be collected by carefully pouring off the excess liquid. The drip loss test is a very quick and easy test that can be used with many samples. Drip loss measurements are slower than expressible moisture or water uptake ability measurements because they must include time for significant losses to occur. 

Expressible moisture and water uptake ability measure different properties. Figure B5.3.2 shows the very different cation and anion dependencies of these methods using fish samples. Figure B5.3.3 shows that the pH profiles are also different. It is also apparent that WUA is often >100%, while expressible moisture must, of necessity, be <100%. Figure B5.3.4 shows an example where expressible moisture was actually correlated with a separate and independent functional measurement. In this case, the binding of cooked fish muscle as determined by a subjective sensory panel pulling samples of fish apparently paralleled the moisture retention of the raw fish (moisture retention = 1 - expressible moisture). Ideally, functional properties should show such correlations with other properties of interest in food systems. 

Measurement of expressible moisture and water uptake ability both require <1 hr. Drip... 

Presents the method for measuring water uptake ability. 

Uptake ability, see Water retention Water uptake ability... 

Water slurrying, in starch isolation, 675 Water uptake ability (WUA) see also Water retention WHC... 

Western blot, see Immunoblot Wet grinding, starch isolation, 674-676 Wheat and wheat starch enzymatic quantification, 682 isolation, 676 moisture content, 22 Whole-grain wheat, enzymatic quantification, 682 Wijs reagent, 467-468, 475 Wine, see also Grapes WUA. see Water uptake ability... 

In nature, the top Vj of a plant s roots are specialized for nutrient uptake, while the lower Vs of the roots are specialized for water uptake. My "dual root" totally organic growing system enhances the natural specialization of the root systems to maximize their dual nutrient and water uptake abilities. 

Whatever constraints exist on the biogeochemical composition of phyto-plankters, uptake abilities ought to be potentially more variable. It should be possible for the transport sites for one nutrient in the cell wall to be increased at the expense of sites for other nutrients. However, this does not seem to occur in the case of iron (Sunda Huntsman, 1995), perhaps because of... 

In one study with 200 strains of P. aeruginosa the majority of resistant strains were low level (MIC < 500 ig/ml). These were shown to have a decreased uptake ability for SM, yet their ribosomes were sensitive to the drug. One strain, however, was highly resistant (MIC > 20,000 pg/ml). Its ribosomes had no binding affinity for the drug. 

The uptake ability of nanoparticles with different surface charges were determined on two different cell lines, namely rat alveolar macrophages (NR8383) and human colonic adenocarcinoma (Caco-2) cell lines. The cationic nanoparticles showed the highest cellular uptake and nanoparticles... 

Very recently, TSILs having a bis-imidazolium motif linked with various organic groups may allow for the synthesis of hierarchical nanoporous nitrogen-doped carbons (Fig. 1.5). Microporous-mesoporous carbon with the specific surface area up to 1,300 m g was facilely obtained through the ionothermal synthesis process as well [34], Besides the potential good CO2 uptake abilities of these N-doped mesoporous carbons, they may also be considered as the baskets for polyamines-derived CO2 adsorbents based on their good mesoporous architectures. 

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