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This is a contribution to the #FoodChem Carnival.

One of the stranger things in Henley’s was the obsession with eggs and egg-whites.  An entire section was devoted to egg-white based beverages, and egg dating and preservation were hot topis.  Under proper conditions it is apparently possible to preserve eggs at room temperature for up to one year (water/sodium silicate), though the authors do remark that the taste suffers slightly.

While the yolk of an egg holds most of the delicious fats, the protein rich egg white is of greater use to a chemist.  Fine particles can be very difficult to remove from solvated compounds via simple filtration, as they simply slide through most filters.  This is especially problematic during wine making, when polymerized tannins and yeast proteins will leave a faint haze in the finished product.

The solution is to aggregate these particles into larger molecules that can be easily filtered.  Egg whites are ideal for this purpose, as they can be poured in at room temperature and then denatured by raising the temperature above 70°C.  As the ovalbumin and other egg proteins clump together they will abstract insoluble materials from the solution, leaving behind the soluble compounds as a clear liquid.  In Henley’s the technique is listed under clarification, and is written as a general solution to the filtration problem.  I’ve never heard of the technique in an organic chemistry lab, but given the low price of eggs (and the high price of sub-micron filters) I may have to experiment.

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