Characterization of milk proteins by MALDI-ToF: influence of different packaging and shelf-life

This chapter deals with the influence evaluation of different packaging on pasteurized milk samples at T=4 °C using the MALDI-Tof (Matrix Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry) technique. Examined packages have been polypaired materials (Tetra-Brik and Tetra-Rex), polyethylene terephtalate (PET) and glass. An evaluation on the protein fraction of lighted pasteurizaed milk samples at T=4 °C over a period of 9 days of preservation has been carried out to relate this parameter with milk qulality. The collected spectra show no protein degradation until the fourth day shelf-life, while at fifth day of preservation proteolysis became more evident although no evident differences between all kind of materials were found. Nevertheless different protein profiles for each packaging were obtained at eight and nine day shelf-life with the presence of several peaks related to the pronunced proteolysis. Spectra obtained show very complicated patterns in the mass range related to proteose peptones fraction mostly coming from the proteolysis of â-casein. At nine day shelf-life milk sample in glass show the the most complex protein spectra, followed by PET and Tetra-Rex and finally by Tetra-Brik. This chapter deals with the influence evaluation of different packaging on pasteurized milk samples at T=4 °C using the MALDI-Tof (Matrix Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry) technique. Examined packages have been polypaired materials (Tetra-Brik and Tetra-Rex), polyethylene terephtalate (PET) and glass. An evaluation on the protein fraction of lighted pasteurizaed milk samples at T=4 °C over a period of 9 days of preservation has been carried out to relate this parameter with milk qulality. The collected spectra show no protein degradation until the fourth day shelf-life, while at fifth day of preservation proteolysis became more evident although no evident differences between all kind of materials were found. Nevertheless different protein profiles for each packaging were obtained at eight and nine day shelf-life with the presence of several peaks related to the pronunced proteolysis. Spectra obtained show very complicated patterns in the mass range related to proteose peptones fraction mostly coming from the proteolysis of â-casein. At nine day shelf-life milk sample in glass show the the most complex protein spectra, followed by PET and Tetra-Rex and finally by Tetra-Brik.