Water barrel analogy

Calcium caseinate and butter oil have been extruded directly at 50-60% moisture levels to obtain a cheese analog with no surface water or fat (Cheftel et ah, 1992). The fat emulsification and melting ability increased with screw speed or barrel temperature. The texture of the extmded analogs was similar to those obtained by batch cooking and was affected by pH (Cheftel et ah, 1992) and emulsifying salts (Cavalier-Salou and Cheftel, 1991). The product can be used as adjimcts for hamburger, pizza, and sauces. 

Aspects of sample preparation have been reviewed. Phenols and aromatic amines, although amenable to EC oxidation detection, tend to be relatively water soluble and thus polar extraction solvents such as ethyl acetate may have to be used if liquid-liquid extraction (LLE) is to be employed. Solid-phase extraction (SPE), using disposable cartridges or plastic syringe barrels packed usually with chemically-modified silica materials (Table 4.2) analogous to those used in HPLC columns, but with greater porosity, provides an alternative and may be more effective in extracting relatively hydrophilic analytes. On-line sample preparation procedures such as prior to EC detection have also been described. 

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