Margarines Margarines must have some crystalline structure to maintain a semisolid consistency at refrigerator and room temperatures. Sharp melting at body temperature is needed so that the margarine will melt rapidly in the mouth leaving no waxy feeling. Oleic acid melts at 16 C, whereas elaidic acid melts at 44 C, so that the presence of some bans isomers may vastly raise the melting point and stability of a product. In addition to partial hydrogenation, the correct consistency of a margarine can be obtained by blending soft and hard fats. Another important feature in solidifying oil for margarines is the type of crystal formed.
Fats are polymorphic, that is, they are capable of forming several different types of crystals.
The a crystals are the tiniest, forming a smooth but unstable crystal. The b ' crystals are medium in size, still they are generally desirable in margarines because they impart a smooth texture, are fairly stable, and ensure plasticity of the product. The largest crystals are the b type which are stable and grainy, and generally undesirable. Also, the , b form is readily converted to a hard and brittle structure. Products such as liquid shortenings and coating fats sometimes require the , b crystal.