258 Carotene and Vitamin-A Contents of butter-fat in cows

Effect of clarification, storage, etc. on the various characteristics of butter-fats

Clarification affects the carotene and vitamin-A contents of butter-fats
only to a small extent. Continuous heating (e.g., indigenous method of
preparing butter from curdled boiled milk or dahi) might lead to a serious
destruction of them. Storage for a short time (up to one month) does not
impair the contents to any appreciable extent but if preserved for longer
periods, a considerable loss might occur. In one or two cases the carotene
and vitamin-A contents were found to be destroyed within a few days. It
may be noted here that the carotene and vitamin-A do not appear to be
affected by pasteurisation and whatever has been found by some is insignifi-
cant [ Davies, 1936 ].

In some of the butter-fats giving low and high Reichert-Wollny values,
the Polenske values and Refractive index by the Butyro-Refractometer were
determined. The values, however, found to be perfectly normal as will be
seen from Table IV. The increase in the Iodine values with storage in Table
VIII appears to be rather unusual.

                                        TABLE IV

Relation of Reichert-value, Iodine number, Polenske value and Refractive
                                     Index of butter-fats