Butterfat spreads

The added emulsifiers not only influence stability but also reduce interfacial tension and influence drop-size distribution, hence influencing the creaminess of the product [29]. They can also modify the extent and type of fat crystallization [50]. Mixed gels have also been used [50]. fl-Carotene is often added to produce a yellow colour and provide vitamin A. By varying the amounts of components such as vegetable oils, animal fats and milk fat, a wide range of variations have come into use. Some examples of these spreadable fats include butter, margarine, low-fat spread, vegetable-fat spread, butterfat spread, low-calorie spread, yellow-fat spread, water-continuous spread and so on [50]. The reduced-fat and low-fat spreads tend to have fat contents of 10-79%. Flack [50] provides an illustration of a process plant layout for the manufacture of spreadable fats. 

Rousseau, D., Marangoni, A.G. 1999. The effects of interesterification on physical and sensory attributes of butterfat and butterfat-canola oil spreads. Food Res. Int. 31, 381-388. 

Rousseau, D., and Marangoni, A.G. (1998). The effeets of chemical and enzymatic interesterification on the physical and sensory properties of butterfat-canola oil spreads. Food Research International. 31 381-388. 

A recent development is the production of low-calorie spreads in developed countries to meet demands for a reduced dietary fat intake. These spreads (fat content about 40%) were first introduced in the USA in 1964, and in Europe in Holland and the UK in 1969 and 1968 respectively. Legislation regarding this type of product is less strict with respect to mixing margarine and butterfat. In various countries, such mixtures are already on the market (Sweden, UK, France, Japan). 

Crystal polymorph plays a key role in final product consistency and acceptability. Smaller crystals lead to firmer fat products, whereas larger fats give a sense of sandiness in the mouth. Incorporation of large amounts of liquid oil increases the tendency of the desirable P polymorphic form to convert to the p form (deMan et al., 1995). In the production of butterfat-canola oil spreads, preserving the P form would be essential in order to avoid a sandy mouthfeel. 

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