Fat crystals influence the stability of food emulsions such as margarine, butter or cream if adsorbed to oil/water interface. During the adsorption process, a new fat crystal/water interface is created while the oil/water interface is lost. The driving force for adsorption is therefore the difference between the interactions fat crystal/water and oil/water. In this work we have estimated this interaction difference and compared it to displacement energy for fat crystals from the oil/water interface to the oil. Our calculations have shown that fat crystal adsorption to the oil/water interface (expressed by contact angle Q) is determined by polar energy, excess fat crystal/water over oil/water (Isw-Iow). The interfacial tension constitutes the resistance force for crystal adsorption to the interface. Polar interaction energy fat crystal/water is stronger than polar interaction energy oil/water in all cases examined (Isw-Iow>0). The difference corresponds to about 104-106 hydrogen bonds for a hypothetical fat crystal with a diameter of 1 µm. Displacement energy for fat crystals to oil, is lower than polar energy excess in most cases examined. Thus, an additional interaction between fat crystals and oil make it easy to displace the crystals to the oil. There is also a relationship between adhesion tension (-gow·cosQ) for the crystals at oil/water interface, and the interfacial tension gow. A straight line of a slope -1 is achieved for systems with low interfacial tensions (gow) and low polar energy excess (Isw-Iow).
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