Rehydration and structure of reconstituted casein micelles

Principal Investigator:

Donald J. McMahon, Utah State University



Project Summary:

Microstructure of casein micelles reconstituted from sodium caseinate, calcium caseinate, calcium caseinate formed from acid casein dissolved using calcium hydroxide, and non-fat dried milk (NFDM) were studied using transmission electron microscopy. Solutions of all the dried products were made to a casein concentration of 2.4% and the pH of the solution adjusted to 6.65�0.05. The powders were hydrated at 40 �C, and allowed to stabilize for 4 h. Sodium caseinate did not form any micelles but rather a network very similar to a gel-like structure. Calcium caseinate formed large micellar structures, which were stained heavily. Casein micelles in non-fat dried milk appeared to have lost their perfect spherical shape forming incomplete spherical shapes. When acid casein was dissolved in water by the addition of calcium hydroxide, the structure of the calcium caseinate formed was different from the former. These formed smaller particles with irregular shapes. Similar structures were formed from adjunct starter culture media.





Published Abstract:

Oommen, B. S., D. J. McMahon and W. R. McManus. 2001. A comparitive study of the microstructure of caseins in dried milk. 96th American Dairy Science Association Meeting, J. Dairy Sci. 84(Supp. 1):381