Metabolomic and volatilome profiling of milk to assess the application of infrared radiation processing

The use of Infrared (IR) in milk sanitation shows potential for reducing microorganisms while preserving quality. However, its use in milk and dairy products is still limited. Thermal processes are evaluated based on the thermal inactivation kinetics of the milk enzyme, alkaline phosphatase, which is not applicable to IR treatment because it remains active. The metabolomic and volatilome approach was used to compare the milk treated with IR radiation at 2 different energies with the starting raw milk, to identify possible treatment markers that can potentially be adopted at an inspection level. IR-treated milk samples showed by metabolomic only one up-regulated compound compared to raw: hypoxanthine. Moreover, we noted a statistically significant increase of some vitamins, amino acids and unsaturated fatty acids in IR-treated samples. From volatilome analysis, 2-propanone, 1,1-dichloro-propanone, dimethyl sulphide, 3-methyl-3-buten-1-ol and 2-ethoxy-2-methyl-propane, significantly increased after treatment, could serve as markers for the use of IR radiation.