Studies on Enzymatic Crosslinking of Casein Micelles

https://doi.org/10.17221/938-CJFSCitation:Partschefeld C., Schreiner J., Schwarzenbolz U., Henle T. (2009): Studies on Enzymatic Crosslinking of Casein Micelles. Czech J. Food Sci., 27: S99-S101.
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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.
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