Czech J. Food Sci., 2009, 27(10):S99-S101 | DOI: 10.17221/938-CJFS

Studies on Enzymatic Crosslinking of Casein Micelles

C. Partschefeld^*, J. Schreiner, U. Schwarzenbolz, T. Henle

Institute of Food Chemistry, Technische Universität Dresden, D-01062 Dresden, Germany *E-mail: claudia.partschefeld@chemie.tu-dresden.de

The aim of our study was to gain insights into the reactions occurring in casein micelles during enzymatic modification with microbial transglutaminase (mTG). Therefore, UHT-treated milk was incubated with varying amounts of mTG and the caseins were analysed using different analytical methods. Regarding the casein species, it was observed that β -casein was crosslinked to a higher extent than the α-caseins. From this it can be suggested that β-casein is mainly located in the outer space of the micellar structure and therefore better accessible to mTG than α-caseins, which are located predominantly in the interior. Furthermore, it was demonstrated by gel-permeation chromatography and RP-HPLC that the caseins are fixed within the micellar structure, by what the ratio of extramicellar casein decreased. We conclude that an isopeptide network in the outer β -casein rich "shell" of the micelle is formed by mTG, which is responsible for the increased micellar stability.

Keywords: microbial trasglutaminase; casein micelle; crosslinking

Published: June 30, 2009  Show citation