Protein Fraction Heterogeneity in Donkey’s Milk Analysed by Proteomic Methods

Donkey’s milk is often well tolerate by patients affected by cow’s milk protein allergy, probably thanks to its protein composition. This empiric evidence, confirmed by some clinical trials, needs to be better inves- tigated. A preliminary survey on the protein fraction of donkey’s milk was carried out: fifty-six individual milk sam- ples have been collected and analysed by IEF and SDS-PAGE. Five different IEF patterns have been identified, showing a marked heterogeneity both in casein and whey protein fractions. A single IEF pattern showed an appar- ent reduced amount of casein fraction highlighted by SDS. Three of the five IEF patterns have been further inves- tigated by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS).