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 Ford, T. F. Articles by Alexander, T. G. Search for Related Content PubMed Articles by Ford, T. F. Articles by Alexander, T. G.

Apparent Specific Volume of the Calcium Caseinate-Calcium Phosphate Complex in Milk

Eastern Utilization Research and Development Division, USDA, Washington, D.C.

ABSTRACT

Skimmilks were progressively depleted of casein colloids by centrifuging, supernatant liquids and deposited colloids being thus obtained. The deposits were washed by redispersing in distilled water and recentrifuging. Densities were determined on the supernatant liquids and on water suspensions of the washed colloids. The analysis of the data on supernatant liquids is novel, in that the apparent specific volume is first calculated for the casein complex hydrate and the specific volume of the unhydrated complex derived from this, a procedure required because the solvent is not water but milk serum. Within close limits, the values obtained are the same as those calculated directly from the densities of suspensions of washed deposits, and also agree with values calculated from the separate specific volumes of the components of the complex. The apparent specific volumes found vary slightly with composition, and are to a first approximation linearly related to the calcium content of the complex. For a colloid fraction of milk of average calcium content the apparent specific volume found is 0.697, and the extremes are 0.694 and 0.700, all with probable errors of about 0.4%. Use of these values in calculating the densities of the hydrated and solvated casein colloid particles as they exist in milk is discussed. The data are for Jersey and Holstein milks.

¹ Present address: U. S. Naval Research Laboratory, Washington, D. C.

² Present address: Venice, Florida.

³ Present address: Food and Drug Administration, U.S. Dept. of Health, Education and Welfare, Washington, D. C.