Differences in whey protein content between cow's milk collected in late pasture and early indoor feeding season from conventional and organic farms in Poland.

Background: The aim of the study was to investigate bioactive whey protein concentrations in cow's milk collected in late pasture (LP) and early indoor feeding (EIF) season from conventional and organic farms in Poland.
Results: Results showed that in the LP somatic cell count (SCC) was higher under organic farming conditions. However, percentages of protein and fat were higher under conventional farming conditions. In EIF, milk from conventional dairy farms had a higher percentage of fat and lactose and a lower concentration of protein and SCC in comparison to milk from organic farms. Organic milk in LP had higher concentrations of beneficial whey proteins than conventional milk, including β-lactoglobulin (β-Lg, 4.12 vs. 2.68 g L⁻¹), lactoferrin (Lf, 334.99 vs. 188.02 mg L⁻¹), and lysozyme (Lz, 15.68 vs. 12.56 µg L⁻¹). However, conventional milk in EIF had higher concentrations of bovine serum albumin (146.47 vs. 118.65 mg L⁻¹), Lf (49 vs. 185.27 mg L⁻¹), and Lz (16.63 vs. 13.22 µg L⁻¹).
Conclusions: The results show significant differences in the investigated parameters between organic milk and milk from conventional system during EIF and LP. Moreover, extending the pasture season during EIF in organic farms decreases concentration of bioactive compounds of milk.
(Copyright © 2012 Society of Chemical Industry.)