Water hydration capacities

The protein fraction showed low nitrogen solubility and rather low water hydration and oil absorption values relative to those of the proteinates but oil emulsification was quite high. Refined legume fiber had a water hydration capacity of over 20 g/g product. 

Functional property tests were conducted in duplicate. AACC (21) methods were used for the determination of water hydration capacity (Method 88-04) and nitrogen solubility index (NSI) (Method 46-23). Oil absorption capacity was measured by the procedures of Lin et al. (22) and oil emulsification by a modification (22) of the Inklaar and Fortuin (23) method. Pasting characteristics of 12.0% (w/v, db) slurries of the flours and processed products were determined on a Brabender Visco/Amylograph (Method 22-10). The slurries were heated from 30 to 95°C before cooling to 50°C to obtain the cold paste viscosity value. Gelation experiments were conducted by heating 15% (w/v db) slurries in sealed stainless steel containers to 90°C for 45 min in a water bath C3). 

Process and product PH Nitrogen solubility index % Water hydration capacity g/g sample Oil absorption Oil emulsification capacity g/g sample % ... 

Table IV. Water hydration capacity values of various protein...

Functional property terminology is not well defined and is not universally agreed upon. Often, the same term is used to describe a variety of methods measuring different properties. For example, terms such as water hydration capacity, water absorption, water binding, and waterholding capacity are all used interchangeably to describe water bound or retained by a protein. It is therefore necessary to carefully define the terms under study and make sure the methods selected measure the desired parameters. 

Quinn, J.R. and Paton, D. 1979. A practical measurement of water hydration capacity of protein materials. Cereal Chem. 56 38-40. 

Water-Holding Capacity (WHC). AU polysaccharides are hydrophilic and hydrogen bond to variable amounts of water. HydratabUity is a function of the three-dimensional stmcture of the polymer (11) and is kifluenced by other components ki the solvent. Fibrous polymers and porous fiber preparations also absorb water by entrapment. The more highly crystalline fiber components are more difficult to hydrate and have less tendency to sweU. Stmctural features and other factors, including grinding, that decrease crystallinity or alter stmcture, may iacrease hydratioa capacity and solubUity. 

According to El-Mashri et al.,190 the A106 A104 ratio determines the hydration capacity of anodic oxides. Tetrahedral sites are hydrated easily to form a boehmite-like structure, which is known to be composed of double layers of Al-centered octahedra, weakly linked by water molecules to other layers.184 As the oxide formed in H3P04 contains about 70% tetrahedral aluminum bonds, its hydration ability should be higher than that of the oxide formed in tartrate solution. However, this has not been found in practice, which is interpreted by El-Mashri et al. as being due to some reduction of A104 by incorporated phosphate species. 

The behaviors of the Li and Cs resonances for membranes incorporating these counterions are qualitatively similar to that for the samples incorporating the Na probe, d for the Cs+ form undergoes a significant shift at the lowest water content, which is reasonable considering the low hydration capacity of this large cation. 

Both hydrocolloids and emulsifiers increase the water-binding capacity in the mix (increased % of hydrogen atoms with low T2 and decreased T2 values). A synergistic effect is observed when both ingredients are present. From studies described earlier in this chapter, the effect of hydrocolloids is assumed to be due to simple water binding and increased thickness of protein layers around the fat globules, whereas the effect of emulsifiers may be due to the increased hydration of interfacially bound protein as well as increased hydration of polar groups of emulsifier at the oil-water interface. 

Knowing that 1 mg/cm2 of product water is a threshold, how much water can be stored at maximum within each component of the fuel cell, and how much can be removed to the outside For the cathode catalyst layer (CCL) with typical thickness of 10 p,m and 50% pore volume fraction, the CCL water storage capacity is approximately 0.5 mg/cm2. A 30- un-thick membrane can store 1.5 mg/cm2 of water, but its actual water storage capacity depends on the initial water content, A., and therefore is proportional to (ks.where A.sa, denotes the water content of a fully hydrated membrane. The escape of water into the GDL is unlikely due to the very low vapor pressure at cold-start temperatures (Pv>sa, = 40 Pa at —30°C). For reference, the GDL with 300 pm thickness and 50% porosity would store about 15 mg/cm2 of water, if it could be fully utilized. This capacity is too large to be used for cold start. From this simple estimation we can conclude that the CCL water storage capacity alone is not sufficient for successful cold start and that a successful strategy is to store water in the membrane. 

In the case of a structurally inhomogeneous series of antihistamines, the sedative side-effects were found to be much better described by their octanol-water distribution coefficient at pH 7.4, log D, than by Alog P0ct.-aik. or their hydration capacity, Aalkane [b7[. 

Berardesca, E., Fideli, D., Borroni, G., and Maibach, H. In vivo hydration and water-retention capacity of stratum corneum in clinically uninvolved skin in atopic and psoriatic patients. Acfa. Derm. Venereol. (Stockh.) 70 400 104 (1990). 

In a hemiface trial in humans 5% vitamin E reduced rhytides, skin roughness, length of facial lines, and depth of wrinkles more than vehicle.68 Topical tocopherol acetate was also shown to significantly increase stratum corneum hydration in human volunteers with additionally enhancing the water-binding capacity as compared to vehicle. The optimum concentration for these effects was 5% tocopherol acetate.69... 

Sodium starch glycolate, crospovidone, Disintegrant Hydration capacity, water uptake... 

Hydration Solubility, dispersibility, wettability, water absorption, water holding capacity, swelling, thickening... 

In most fuel cell operations, humidified gases are used to ensure proper membrane hydration. Hence, the ability to remove liquid water becomes the primary concern of GDL selection. PTEE is often used to increase the GDL hydrophobic-ity. Contact angle is commonly used to measure the hydrophobicity (typically in the range between 120 and 140°). However, Gurau et al. suggested that external contact angle measurements were more indicative of the GDL surface roughness than the capillary forces in the GDL pores (which reflects the real measurement of water removal capacity). They presented a new method for... 

---