Foaming capacity determining

Maurer et al. [57] determined the foaming power of octadecyl sulfuric acid and several of its salts, such as sodium, triethylamine, triethanolamine, and some amino acids. Foam capacity, measured by the Ross-Miles test [150] at 60°C, was in the range of 180-210 mm showing comparatively few differences. 

For the studies presented in this chapter, samples of peanut and cottonseed meal suspensions were evaluated for foam capacity, stability, and viscosity measurements as described by Cherry and coworkers (23, 24, 22). Vegetable protein suspensions at the appropriate concentration and pH were whipped in a Waring-type blender. After blending, the whipped products were transferred to a graduated cyclinder. Milliliters of foam were recorded immediately and at various time intervals to determine capacity and stability. A Brookfield viscometer and... 

Multiple r2 values of 0.9346 and 0.9280 were obtained for these equations of capacity and stability, respectively. The relative importance of each respective partial regression coefficient was determined by comparison of B values (32). These evaluations indicate that the most important variables in the two models for foam capacity and stability are soluble protein, soluble and insoluble carbohydrate and ash, and insoluble fiber. 

Measurement of Biodegradation. Numerous studies have documented the aerobic biodegradability of various AS compounds (see ref. 12). Most of these studies used methylene blue active substance (MBAS) and other colorimetric determinations, change in surface tension, foaming capacity, and sulfate formation as an indication of primary AS degradation. 

Conclusions concerning further process studies can be drawn from this simple analysis. (1) There is a need to try to reduce foaming at stage 2 of process A. If the requirement concerning the volume of vessel 2 in process A could be reduced by 40%, tank AE2500 with a capacity of 3.46 m might be sufficient, which would significantly decrease the capital costs. (2) Physical properties of all mixtures should be determined and thermokinetic data for the second steps of both processes provided to make calculations of the schedule more reliable. 

Cheng et al. carried out the impedance study on a foam-type NiMH battery with nonwoven PP separator to determine the main causes of early cycle deterioration. Their data indicated that the decrease in the voltage characteristic of the battery was due to drying out of the separator that increases the ohmic resistance of the battery and that decay of the total discharge capacity is due to an inactive surface that increases the charge-transfer of the battery. 

Solubility is a critical functional characteristic because many functional properties depend on the capacity of proteins to go into solution initially, e.g. gelation, emulsification, foam formation. Data on solubility of a protein under a variety of environmental conditions (pH, ionic strength, temperature) are useful diagnostically in providing information on prior treatment of a protein (i.e. if denaturation has occurred) and as indices of the potential applications of the protein, e.g. a protein with poor solubility is of little use in foams). Determination of solubility is the first test in evaluation of the potential functional properties of proteins and retention of solubility is a useful criterion when selecting methods for isolating and refining protein preparations (1). Several researchers have reported on the solubility of extracted microbial proteins (69,82,83,84). In many instances yeast proteins demonstrate very inferior solubility properties below pH 7.5 because of denaturation. 

A method for expansion ratio determination based on measuring heat capacity of a foam is described by Fokina and Kruglyakov [30] (see also Section 8.5). 

Fig. 8.4. Scheme of the set up used to determine the heat capacity and expansion ratio of a foam 1 -... 

The latter, however, do not have the capacity, once adsorbed, to stabilise the foam, it is well established that pure liquids do not foam. Transient foams are obtained with solutes such as short-chain aliphatic alcohols or acids which lower the surface tension moderately really persistent foams arise only with solutes that lower the surface tension strongly in dilute solution - the highly surface-active materials such as detergents and proteins. The physical chemistry of the surface layers of the solutions is what determines the stability of the system. 

Seeber, G., Bnchmeiser, M. R., Bonn, G. K., and Bertsch, T., Determination of airborne, volatile amines fram polyurethane foams by sorptionan to a high-capacity cation-exchange resin based on polyfsnccinic acid), J. Chromatogr., 809, 121-129, 1998. 

The weight of the low-potential electrode slightly impressed the thin foam samples. Hence, capacity C2 was measured before and after the sample capacity (Cl) and conductance (Gl) measurement. The average sample thickness during the Cl/Gl determination was calculated using both C2 capacity values. These measurements were performed at 22"C 1°C and a relative humidity of 50%. The results of these measurements are collected in the Tables 5.3 and 5.4. 

Values of Cp are used in (13-5) to compute the Souders and Brown capacity parameter C. Because the liquid flows contain a large percentage of absorber oil, a foaming factor, Fp of 0,75 is assumed. Also assume AJAa >0.1 so that Fha is 1.0. The value of Fst is determined from surface tension tr, which can be estimated for mixtures by various methods. For paraffin hydrocarbon mixtures, a suitable estimate in dynes per centimeter, based on densities, can be obtained from the equation... 

Via the determined viscosities, useful information can be obtained about molecular structure and chemical constitution. For example, the knowledge of the viscosity is of crucial importance for the beer brewing process. A beer with a viscosity above 1,7 mPa s is hard to filtrate, which leads to a declining capacity. On the other hand, a higher viscosity has a positive effect on the wholeheartedness and the stability of the foam of the beer. For this reason the main aim of viscosimetric measurements here is the optimization of filtration methods and the quality control of malt, flavor and beer [42]. 

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