Changes in the milk serum proteome after thermal and non-thermal treatment

摘要

Milk serum contains many immune-active proteins that are sensitive to heat treatment. This study compared the effects of thermal (63 degrees C, 30 min; 72 degrees C, 15 s; 85 degrees C, 5 min) and non-thermal (ultraviolet-C, UV-C; thermoultrasonication, TUS) treatments on bovine milk serum proteins by using label-free LC-MS/MS-based proteomics. UV-C (4500 J/L) and TUS (60 W, 6 min) treatments achieved a 5log microbial reduction as determined by plate counting. Proteomics showed that e.g., complement proteins, xanthine dehydrogenase/oxidase, and fatty acidbinding protein decreased significantly (p(<)0.05, vertical bar fold change vertical bar(>)1) after thermal treatments, and almost no lactoferrin, immunoglobulin, and lactoperoxidase was retained after heating at 85 degrees C for 5 min, whereas these proteins were mostly retained after non-thermal treatments. Most of these heat-sensitive proteins were located in membrane and extracellular regions and were involved in cellular and metabolic processes, response to stimulus, binding, immune process and catalytic functions. Finally, part of the proteomics results were verified by ELISA. This study thus provided insights for the development of optimized thermal and novel non-thermal treatments for dairy processing.