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 Garnot, P. Articles by Olson, N. F. Search for Related Content PubMed Articles by Garnot, P. Articles by Olson, N. F.

Influence of Protein and Fat Contents of Ultrafiltered Milk on Rheological Properties of Gels Formed by Chymosin¹

Department of Food Science and Walter V. Price Cheese Research Institute, University of Wisconsin, Madison 53706

³ Reprint requests.

ABSTRACT

Enzymatically induced gelation of milk and milk concentrated by ultrafiltration was studied with a curd firmness tester which measured transmission of oscillatory deformations through the product. Scott Blair's relationship between pseudo modulus of rigidity (G) and time after clotting (t), G = G e^—/t described the gelation of ultrafiltered retentates satisfactorily. Maximum gel firmness G, and , which is the time to reach a firmness of G/e, were affected substantially by protein content. The effect of protein content on rates of firming of gels were evaluated at different stages of gel formation. At the onset of gelation, rates increased up to protein content 90 g kg^—1 but decreased at higher protein concentrations. At a later stage, this decrease disappeared and rates correlated with protein content. Those observations are discussed relative to effects of protein content on proteolytic and aggregation phases of milk clotting.

Times from clotting to point of cutting curd were affected significantly by slight increases in protein above that in unconcentrated milk, but clotting times were not affected. Variations in fat content had inconsequential effects on test measures.

¹ Research supported by the College of Agricultural and Life Sciences, Hatch project M661 and by the Walter V. Price Cheese Research Institute.

² Institut National de la Recherche Agronomique, Laboratoire de Recherches de Technologie Laitière, 65, Rue de St. Brieuc, — 35042 Rennes-Cedex, France.