The effect of storage of milk at 25 degrees C upon the major human milk proteins was investigated. Milk samples (n - 8) were collected and stored at 25 degrees C for 72 h. The degree of proteolysis in the skim milk and fat globule protein fractions, protein oxidation and milk lipase activity were measured at regular time intervals. beta-casein was rapidly hydrolyzed, with 38 +/- 5% (mean +/- SEM) remaining after 72 h. The immunological proteins, secretory IgA and lactoferrin, appeared to be resistant to proteolysis. The lipase activity was reduced after 2 h of storage (p <0.001). Protein oxidation was not observed. These results highlight the importance of appropriate milk handling when analyzing the protein composition of milk in a laboratory. Further investigation is required to determine whether the observed effects of storage upon milk proteins are of clinical importance. (C) 2011 Elsevier Ltd. All rights reserved.
Molinari, C., Casadio, Y., Arthur, P., & Hartmann, P. (2011). The effect of storage at 25 degrees C on proteins in human milk. International Dairy Journal, 21, 286-293. https://doi.org/10.1016/j.idairyj.2010.12.001