کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2434252 | 1106998 | 2014 | 5 صفحه PDF | دانلود رایگان |
Acid casein in phosphate buffer was used as a simplified substrate for cross-linking experiments with microbial transglutaminase. The importance of the intensity of enzyme treatment on the rheology of acid gels was evaluated by preparing mixtures of casein that were cross-linked to a different extent and a native reference to obtain samples with a similar polymerisation degree. The stiffness of acid gels from caseins incubated longer then 3 h was always lower at identical polymerisation degree larger than approximately 30%. The quantification of isopeptides formed by the enzyme reveals a substantial increase of bonds at a stage of cross-linking where only 10% of monomers are available. This indicates that cross-linking must occur between and/or within already existing aggregates, which become larger and less flexible, and supports the hypothesis that, starting with a critical aggregate size the network formation is somewhat impaired by the size and reduced flexibility of the proteins.
Journal: International Dairy Journal - Volume 38, Issue 2, October 2014, Pages 174–178