QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kim, Y. P. Articles by Schweigert, B. S. Search for Related Content PubMed PubMed Citation Articles by Kim, Y. P. Articles by Schweigert, B. S.

Vitamin B₁₂ Distribution in Cow's Milk^1,2,

Department of Food Science, Michigan State University, East Lansing, Michigan

The amounts of free and bound vitamin B₁₂ in cow's milk were determined microbiologically with the use of the test organism, Lactobacillus leichmannii. Bound vitamin B₁₂ was released by autoclaving the samples in the presence of acid and cyanide. Approximately 95% of the total vitamin B₁₂ in milk was in the bound form. Milk proteins were separated into gross fractions by isoelectric precipitation, coagulation with rennin, centrifugation, and salting-out with ammonium sulfate. Bound forms of the vitamin occurred in all protein fractions, although the whey proteins contained more than the casein proteins, based on the amount of bound vitamin B₁₂ per mg of protein. The amount of bound vitamin B₁₂ in the original milk was accounted for by analysis of the casein and whey protein fractions.

² Supported in part by grant no. EF-284 from the Division of Environmental Health and Food Protection, U.S. Public Health Service.

³ Research taken in part from a thesis submitted in partial fulfillment of the requirements of the M.S. degree in Food Science, 1964.

Manuscript received 4 March 1965.