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 Morr, C. V. Articles by Frommes, S. P. Search for Related Content PubMed Articles by Morr, C. V. Articles by Frommes, S. P.

Method for Electron Microscopic Examination of Heated Whey and Ultrafiltrate Systems ¹

Department of Dairy Industries

S. P. Frommes

Department of Veterinary Anatomy University of Minnesota, St. Paul

ABSTRACT

Electron microscopy has proven to be a valuable technique for investigation of the size and shape characteristics of calcium caseinate-phosphate micelles in milk and skimmilk systems (3–6, 10–12). It has also been employed for following the effects of heat treatments upon the state of aggregation of the micellar proteins of skimmilk (6, 7, 9).

This investigation involved the application of electron microscopy to heated whey and ultrafiltrate systems. Specifically, this paper describes a procedure for a) preparing and heating whey and ultrafiltrate systems, b) dilution of the samples for electron microscopic examination, c) application of supporting and sample films to the electron microscopic grids, and d) direct electron microscopic examination of samples without use of staining, fixing, embedding, or shadowing treatments, as customarily done.

Sample preparation. Two whey systems were prepared from raw milk obtained from the University herd by a modification of previously published procedures (8). The milk was separated at 37 C and the skimmilk given a preliminary centrifugation of 147,000 g for 2 hr at 5 C in an International B-35 preparative ultracentrifuge (A-147 rotor) to sediment the calcium caseinate-phosphate micelles with diameters in excess of approximately 30–35 mµ (14).

¹ Paper no. 5851, Scientific Journal Series, Minnesota Agricultural Experiment Station, St. Paul. This work was supported in part by Public Health Service Grant no. GM-07009.