Margarine

When the milk has reached the desired state of sourness, as determined by analysis, it is churned with the fat, with or with out artificial colouring matter, in specially constructed jacketed churns fitted with beaters for finely incorporating the previously melted fat with the soured milk. This churning process has to be carried out with great skill, care being taken to maintain the correct temperature and to stop the churning at the exact point when the emulsion reaches its maximum thickness, as continued churning causes the mass to become thin again. Various types of continuous emulsifiers other than churns are in use, some of which are very efficient. When the emulsion has reached the de sired state, the product is then finished by either the wet or the dry process.

Wet and Dry Processes.

In the wet process the emulsion is projected against a violent spray of iced water, which causes the emulsified fat to solidify in fine globules; the solidified mass which is produced subsequently floats on a tank of cooled water, from which it is removed and mechanically worked until the de sired consistency is obtained. Salt and preservative, if any, are incorporated into the mass together with more colour. About 3o% of milk is used in the wet process.

The dry process is more economical, and little more than half the amount of milk is then required. In this process the emulsion from the churns is run in a gentle stream on to large rolls cooled inside with brine. The emulsion, as it solidifies on the surface of the rolls, is scraped off by knives and then worked on tables, kneaders and rolls, in the same manner as in the wet process.

Admixture with Butter.

Margarine, like butter, must not contain more than 16% of water. The admixture of butter with margarine to the extent of more than io% of the former is pro hibited. This regulation is still in force, though it seems originally to have been made to dispel the fear of the farmer that butter might be adulterated with small quantities of margarine to make such an excellent product that his trade might suffer, and that the public might be defrauded. Modern methods of analysis are able to determine the percentage of butter fat in margarine to within comparatively narrow limits, which was not the case when margarine was first invented.

Margarine usually contained 0.25% of boron preservative, ex cept the type termed "fresh-roll," in which preservative was not used. For many years up to 0.5% of boron preservative was per mitted, but under British regulations which came into force in 1927, preservatives, other than salt, are not permitted. The nu tritive value of margarine has long been a subject of discussion. The chemical composition of butter is very similar to margarine, which actually gives the same number of calories or heat units as butter, and an average margarine is as digestible as an average butter. The average butter is characterized by considerable vitamin content, whereas margarine is practically devoid of any such characteristic. (See W. Clayton, Margarine, 192o.) (E. R. Bo; R. G. P.)