Emulsifying Properties of Salted Yolk After Pasteurization and Storage

Abstract

The emulsifying properties of egg yolk containing 10% sodium chloride pasteurized by two methods were determined: One, a high temperature—short time method involved the use of heat treatments for five min. at 62°, 67°, 73°, and 78° C. The other, a low temperature—long time method involved holding times of 2, 4, 6 and 8 days at 52° C. Samples were evaluated immediately after pasteurization, as well as after storage for one week at 10° and −20° C. Phase inversion titrations with oil and water were used to determine emulsifying capacity. Natural egg yolk contains strongly polar phospholipids and lipoproteins, as well as weakly polar-cholesterol. The former supports o/w emulsions and the latter w/o emulsions. Neither emulsifier system appeared very sensitive to heat damage. Hence, salted egg yolk can be pasteurized at higher temperatures than previously used or investigated without damaging its emulsifying properties. Storing the product after pasteurization tended to reduce the oil needed to invert the emulsion from an o/w to w/o type, which suggests that storage may be more important than pasteurization conditions.