| Popis: |
Summary Twelve modifications of the Babcock test for homogenized milk were studied to determine their accuracy and to ascertain which methods were most effective in eliminating the plugs of curdy or charred material at the base of the fat column. Five series each of lower-fat and higher-fat homogenized milk were tested by each of ten modified methods as well as by the Mojonnier and by the regular Babcock method. No one test Was found consistently to eliminate completely the foreign material at the base of the fat column of tests on homogenized milk although some tests reduced the amount of this material to a negligible quantity. The modified methods, yielding results both on lower-fat and on higher-fat homogenized milk closer to those of the Mojonnier and to those of the regular Babcock test on nonhomogenized milk, had in common (a) the use of the approximate or full amount of normal strength acid required of the Babcock test; (b) the addition of the acid in at least three portions; and (c) the remixing of the acid-serum-water mixture after centrifuging andfollowing the addition of water. Clear, char-free fat columns were obtained by the addition of a water-alcohol mixture (1.4 to 1) to the test as suggested by Brueckner (7) instead of the final addition of water. Apparently in making a good Babcock fat test of homogenized milk, the reaction of the sulphuric acid on the proteins of the milk, particularly on that adsorbed to the fat globules, must be prolonged and be as vigorous as possible without engendering sufficient heat to char the sample. Since this study was completed and the manuscript written, the paper "The Babcock Fat Test on Homogenized Milk" by L. M. Lampert and J. H. Brandon has appeared in the Journal of Milk Technology 8(3) : 140–144, 1944, and hence has not been included in the review of literature. |
