Interbreed variation of dairy cow milk in terms of specific proteome and lipidome for establishing criteria of milk selection.

Background: Ruminant milk is a very complex table food and naturally encrypted with different components possessing various health-promoting characteristics.

Aim: In the present study, we focused on breed-wise compositional difference in milk including various components and release of fatty acids and peptides during digestion.

Methods: First, milk samples were analysed using lactoscan LW milk analyser, MALDI-TOF and gas chromatography. In addition, in vitro simulated gastrointestinal digestion of milk was performed to determine the fatty acid and peptide concentration.

Results: Percentage fat was significantly less in Karan Fries (KF) and Holstein Friesian (HF) milk compared to Sahiwal (SW), Tharparkar (TP), Gir (GIR) and Karan Swiss (KS). The mean conductivity displayed the healthy status in SW, TP, GIR, KF and HF milk. The protein was significantly higher in KF milk compared to SW, TP, GIR and HF milk. KS milk possessed the highest number of peptides followed by HF, SW, TP, GIR and KF milk. The fatty acid compositional difference was primarily observed in saturated fatty acids including the C4:0, C21:0 and also w6 linoleic acid. On the basis of peptide number of MALDI-TOF, milk from SW and KS was selected for digestion in in vitro to check the availability of fatty acids and peptides in the intestine. There was more release of fatty acids in SW milk and more peptide from KS milk in intestinal conditions. Therefore, the difference in composition exists based on protein and fat components in indigenous and crossbred cows' milk.

Conclusions: The breed-wise difference in composition of milk is important to study as it not only reflected the nutritional value and various biological activities, but also emphasis on specific proteomic and lipidomic of milk that eventually can be used as criteria for selection of milk.