Immunochemical quantification of heat denaturation of camel ( Camelus dromedarius ) whey proteins
Résumé
The major whey proteins IgG, serum albumin and alpha-lactalbumin were purified from camel milk using gel permeation and ion-exchange chromatography. Specific antisera against each of them were raised and used to quantify their heat denaturation in early or mature milk over a range of 60-90 degrees C for 10-60 min using the single radial immunodiffusion technique. The heat denaturation midpoints for the mature milk heated 30 min were 67(.)2, 73(.)0 and 77(.)5 degrees C for IgG, albumin and alpha-lactalbumin respectively. The early milk was more sensitive to heat treatment with coagulation at low temperature and heat denaturation midpoints of 64(.)8, 71(.)6 and 72(.)6 degrees C respectively. This difference was related to the high IgG content of the early milk (12(.)6 mg/ml v. 0(.)5 mg/ml for the mature milk) and stresses the importance of monitoring the IgG level of milk to assess the absence of colostrum.