HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sanmann, F. P. Articles by Ruehe, H. A. Search for Related Content PubMed Articles by Sanmann, F. P. Articles by Ruehe, H. A.

Some Factors Influencing the Volume of Foam on Milk^*

Department of Dairy Husbandry, University of Illinois, Urbana, Illinois

ABSTRACT

A number of the factors influencing the volume of foam appearing on milk were studied. As a measure of the foaming ability of a sample, the "percentage increase in volume due to foam" was determined. The foaming ability of milk varies widely under different conditions. It is necessary, therefore, to specify the conditions under which the measurements are made.

Low temperatures favor the production of the largest volume of foam. With increasing temperature, the volume of foam decreases to a minimum, then rises again with increasing temperature to a second maximum point, lower than the first maximum; this is followed by a decrease in the volume of foam as the temperature rises.

Freshly drawn milk does not exhibit so low a minimum foaming ability as previously cooled and aged milk. The effect of age on the foaming ability of milk seems to be dependent in part on the changes taking place in the fat globules during the aging period. These changes, in turn, are partly dependent on the temperature at which the milk is held.

Agitation of milk at a low temperature reduces its subsequent ability to foam. Agitation at a temperature which is high enough to cause the fat globules to be in a liquid condition increases the subsequent foaming ability of the milk.

There seems to be no definite relationship between the composition and the foaming ability of milk from individual cows. When the influence of the individual characteristics is standardized, increases in the fat content generally decrease the foaming ability of milk, and increases in the milk solids not fat content generally increase the foaming ability.

Moderate amounts of developed acidity increase the foaming ability of milk, as measured at 40°F.; when there is enough developed acidity to cause a curdling of the milk in the cold, the foaming ability decreases. When the measurements are made at 80°F., no significant changes in the foaming ability appear until there is a considerable amount of developed acidity; then a slight increase occurs. When the measurements are made at 140°F., a decrease in the foaming ability is evident as soon as there is enough developed acidity to bring about a slight curdling of the milk during the tempering process.

When the measurements are made at 40°F., added calcium lactate decreases the foaming ability of milk; added primary magnesium phosphate increases the foaming ability. When the measurements are made at 80°F., none of the added salts as used in this study bring about any change in the foaming ability of milk. When the measurements are made at 140°F., added calcium lactate and primary magnesium phosphate each cause a decrease in the foaming ability; this decrease accompanies a slight curdling of the milk during the tempering process. Added sodium citrate causes a slight decrease in the foaming ability of milk, when the measurements are made at 140°F. Added sodium bicarbonate or disodium phosphate as used in this study have no effect on the foaming ability of milk.

^* An abstract of a thesis submitted by F. P. Sanmann in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Dairy Husbandry in the Graduate School of the University of Illinois, 1929.