Experimental cookery

subsequent addition of oil the dispersed particles become smaller, and the mayonnaise stiffer. This is shown in Figs. 27 to 30, which are photo- micrographs of mayonnaise. If the oil is added to the egg yolk before the vinegar, the first oil particles emulsified are very small and remain small with subsequent additions of oil. When the vinegar is added, the dispersed globules become larger, and the mayonnaise less stiff. Kilgore suggests the following method. The salt, mustard, and other dry seasonings are added at first to fresh egg yolks, for they aid in holding the excess moisture. To this is added just enough vinegar to make a heavy paste. Then run in the oil until half is added, add another portion of vinegar, equal to that at the start, and the remainder at the end of the batch. Corran suggests that the emulsification be carried out in three stages. ( 1 ) The dry ingredients, egg yolk, and part of the aqueous ingredients are mixed thoroughly. (2) All the oil is added, forming a creamy nucleus. (3) The creamy nucleus is diluted with the remainder of the aqueous ingredients. The ingredients used. These include the oil, the salt and seasonings, the vinegar, the egg yolks, and even previously emulsified mayonnaise. Any of the edible oils may be used in mayonnaise. Salt and seasonings. Salt, mustard, paprika, and pepper are usually added to mayonnaise. Small amounts of other seasonings may be used. Pasteurized spice mixtures are also now available to the mayonnaise manu- facturer. The addition of an electrolyte to an emulsion may produce different results, depending upon the electrolyte, the emulsifier, and the type of emulsion. Some electrolytes cause reversal of certain emulsions; others may tend to stabilize the emulsion. Seifriz in his work with emul- sions stabilized with casein found that sodium chloride had no influence on the water-in-oil emulsions, but tended to stabilize oil-in-water emul- sions. The effect of sodium chloride would probably vary with the emul- sifier and the concentration of the salt. Krantz and Gordon found that the concentration of the sodium chloride affected the stability of some emulsions. In mayonnaise, when egg yolk is used as the emulsifier and with the proportion of salt given in Experiment 52, it has been found that the addition of the salt to the egg yolk before the addition of any oil tends to stabilize the emulsion. In these experiments the vinegar was also added to the egg yolk before the oil was added. When the salt is added to the mayonnaise after the oil has been added, the size of the dispersed oil globules is larger and the emulsion breaks more readily while it is being made, indicating a lessened stability. The amount of salt used in the recipe may tend to lessen the solubility of the egg proteins sufficiently so that a more tenacious film is formed. If the concentration of the salt is great enough to "salt out" the egg proteins, then different results would be obtained. Thus it seems preferable to add the salt to the egg yolk and vinegar before adding the oil in making mayonnaise. Calcium salts, since 282 EMULSIONS Fig. 27. — Mayonnaise. Showing the coarse emulsion formed after the addition of one tablespoon of oil. The vinegar and seasonings were added to the egg yolk, before the oil was added. Magnification approximately x 200.