Vitamin Xanthan

In addition to the necessary protection of the contents of the emulsion droplets, effective encapsulation technology requires that the release of the active matter be controlled at a specified rate. Benichou et aL (2004) have demonstrated that a mixture of whey protein isolate (WPI) and xanthan gum can be successfully used for the controlled release of vitamin Bi entrapped within the inner aqueous phase of a multiple emulsion. The release profile, as a function of the pH of the external aqueous phase, is plotted in Figure 7.25. We can observe that the external interface appears more effectively sealed against release of the entrapped vitamin at pH = 2 than at pH = 4 or 7. It was reported that an increase in the protein-to-potysaccharide ratio reduced the release rate at pH = 3.5 (Benichou et aL, 2004). More broadly, the authors suggest that compatible blends of biopolymers (hydrocolloids and proteins) should be considered excellent amphiphilic candidates to serve as release controllers and stability7 enhancers in future formulations of double emulsions. So perhaps mixed compatible biopolymers wall at last allow researchers to... 

Vitamin Bi was entrapped in an inner aqueous phase of a double emulsion stabilized by a mixture of whey protein isolate and xanthan as the external gum. The release of the vitamin was modulated by altering the pH or the ratio of the two biopolymers. The increased rate of release of the vitamin as pH was increased from 2 to 7 has been attributed to the decreased electrostatic interaction between whey protein isolate and xanthan. Increasing the rigidity of the external interface by increasing the amount of xanthan also decreased the rate of release of the vitamin (Benichou et al. 2004). 

Solvents, e.g., ethanol, acetone Cells, e.g., bakers yeast, brewers yeast Crude cellular extracts, e.g., yeast extract Organic acids, e.g., citric acid, lactic acid Vitamins and amino acids, e.g., lysine, ascorbic acid Gums and polymers, e.g., xanthan, geUan Antibiotics, e.g., peniciUins, rifampicin... 

Vitamin activity in foods and food products serves as an example where typical problems arise with traditional liquid solvent extraction and then where SFE has been used to address these concerns [30]. In addition to the routine assay of food products, there is a considerable amount of research being conducted on the role of carotenoids and xanthans as antioxidants in the human body. This antioxidant-role may address many health concerns such as aging and various diseases. The "friendly-extracting-environment" of SFE has some merit of consideration for such studies, particularly with regard to the lesser possibility of oxidation of the analytes during the sample preparation step. 

Large scale fermenters are used to make such products as yeast, vitamin C, xanthan gum, citric acid, aud penicillin, for example. Fermentations are usually carried out in tall vessels with multiple-impeUer systems. Air is sparged in at the bottom to provide the microorganisms in the vessel with a supply of oxygen. It is important that the mixer disperse the gas into fine bubbles, a condition that is required to ensure good mass transfer from the air to the broth. See Chapter 11... 

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