مقایسه میسل‌هایکازئین (Casein Micelles) در شیرخاموپاستوریزهبی چربی درpHهای مختلف با میکروسکوپ‌های الکترونی نگاره و گذاره

In this research some properties of the casein micelles in the raw and pasteurized milk were studied by electron microscopy. SEM and TEM were used to evaluate the differences in acidified casein micelles of raw and pasteurized milk at the Iso Electric Point (pH=4.6). Milk samples were taken from research pilot plant of The College of Agriculture. Milk was pasteurized by the L.T.L.T. method in the same pilot plant. The samples of raw and pasteurized milk were divided into two parts. One part of raw and pasteurized milk was acidified to the Iso Electric Point of caseins (pH=4.6) by lactic acid (9%) and then sample preparation for electron microscopy was done. According to the previous findings, results indicated that in the native pH, specially in fresh raw milk casein micelles were in spherical and individual form with the smooth surface. Aggregated casein micelles were present of acidified samples of the raw and pasteurized milk. Aggregation was the result of neutralization of electric charges in the isoelectric pH of casein and partial removal of micellar calcium phosphate. Results of both electron microscope confirmed each other and effects of heating on increasing of the casein micelle size during pasteurization were seen.