Edible adsorption

Hydrogels are used ia the refining of edible oils to adsorb phosphohpids, trace metals, and soaps (103). The adsorption capacity depends on the ease of hydration of the adsorbates, so best performance demands careful control of moisture content ia the system (104). Sihca hydrogel ia combination with alumiaa has beea fouad to be useful for purifyiag used cooking oils ia order to extead their life and enhance the quahty of the fried food (105). 

Plant uptake is one of several routes by which an organic contaminant can enter man s food chain. The amount of uptake depends on plant species, concentration, depth of placement, soil type, temperature, moisture, and many other parameters. Translocation of the absorbed material into various plant parts will determine the degree of man s exposure—i.e., whether the material moves to an edible portion of the plant. Past experience with nonpolar chlorinated pesticides suggested optimal uptake conditions are achieved when the chemical is placed in a soil with low adsorptive capacity e.g., a sand), evenly distributed throughout the soil profile, and with oil producing plants. Plant experiments were conducted with one set of parameters that would be optimal for uptake and translocation. The uptake of two dioxins and one phenol (2,4-dichlorophenol (DCP)) from one soil was measured in soybean and oats (7). The application rates were DCP = 0.07 ppm, DCDD 0.10 ppm, and TCDD = 0.06 ppm. The specific activity of the com-... 

Adsorption from solutions onto solid surfaces is important in many industrial practices, such as dye or organic contaminant removal, edible oil clarification by activated carbon, and ion exchange, where the adsorption of ions from electrolyte solutions is carried out. Adsorption from solution is also used in analytical chemistry in various chromatography applications. On the other hand, surfactant, polymer and biological material adsorption on solids, to modify the surface of solid particles in stabilizing dispersions, are also very important industrial fields. 

Hastert, R.C. Adsorptive treatment of edible oils. Introduction to Fats and Oik Technology P.J. Wan, Ed. AOCS Press Champaign, IL, 1991 p. 96. 

Silica gels are applied for the stabilisation of beer, using the selective adsorption properties of gel products. Another adsorption application is the use of silica hydrogels in edible oil refining, where the gel acts as an adsorbent for phospholipids and color. 

Silica hydrogels are used in the refining of edible oils to adsorb phospholipids, trace metals, and soaps [18]. The adsorption capacity depends on the ease of hydration of... 

This effect of adsorption between hexane and the surface of zirconia may decrease the effective size of the pores and, consequently, lead to a decrease in the flow of hexane. Additionally, the surface of zirconia may be able to catalyze the isomerization of cyclohexane and decomposition reactions, which could also explain the reduction in permeate flux observed. These authors concluded then that the membranes of polyethersulfone submitted to pretreatment showed high flow with hexane, was stable over time, and increased linearly with pressure, following the usual behavior for pure solvents. The stability of these membranes pretreated to hexane allows a full potential of applications in edible oils. In ceramic membranes, however, the decline in the flow of hexane observed as a function of time indicated that the solvent interacted with the membrane, being adsorbed on its surface. As a result, the flow of hexane through ceramic membranes was much lower than those obtained with polyethersulfone membrane with similar values of molar weight cutoff The results are not explained by simple models used to predict conventional solvent flow, as the equation of Hagen-Poiseuille therefore, parameters other than viscosity must be taken into account, such as surface tension and hydrophilicity of the membrane. 

Vegetable Oils. Triglycerides form the principal component of most edible oils obtained from seeds and fruits small amoimts of free fatty acids and sterols occur also. As shown in Fig. 130, i, olive oil, a typical example, can be easily separated by adsorption TLC into these three fractions. Oils containing triglycerides of epoxy- and hydroxy-acids as well as those of the ordinary fatty acids show very characteristic... 

Edible fats NDGA, quercin Silica gel phenolic acids Silica gel CHClj-CftHe- MeOH-LP (60 20 15 5) Exposure to air Adsorption 18 Sensitive for detection of the compounds in fats... 

Edible Metal-Organic Frameworks Metal-Organic Frameworks for Removal of Harmful Gases Postsynthetic Modification of Metal-Organic Frameworks Open Metal Sites in Metal-Organic-Frameworks Adsorption of Hydrocarbons and Alcohols in Metal-Organic Framework Materials. 

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