Stability of Milk Fat Emulsions. I. Preparation of Model Oil-in-Water Emulsions and Evaluation of Their Stability

Abstract

A technique was developed for preparing model emulsions with a Branson Sonifier Cell Disruptor. Variables included sonication intensity and time, amounts of oil and emulsifier, and length of storage after sonication. Stability of the emulsions was determined by holding them in a special viewer for 24 h at 23 C. Stability was expressed as percent upper phase separation, or as a "stability index" based on percent total solids in the bottom half of the sample at 24 h, relative to percent total solids in the entire sample at 0 h. There was a high correlation between the two methods of determining stability. Standard conditions for the laboratory preparation and evaluation of emulsions are recommended. These procedures should be useful in studying the influence of different emulsifiers and emulsifying conditions on the stability of oil-in-water emulsions.