Major whey proteins in donkey’s milk: effect of season and lactation stage. Implications for potential dietary interventions in human diseases

Abstract

According to current literature, donkey’s milk has been suggested as a hypoallergenic substitute in children affected by cow’s milk protein allergy as well as a promising nutraceutical for aged people. However, the biologically active components of donkey’s milk have not yet completely elucidated. In this framework this study is aimed at measuring α-lactalbumin (α-LA), β-lactoglobulin (β-LG), and lysozyme (LYS), the principal whey proteins in donkey’s milk, in relation to lactation stage and production season. Analysis were performed by reversed-phase high-performance liquid chromatography. α-LA, β-LG, and LYS resulted to be affected by lactation stage (P < 0.01) and production season (P < 0.01). Overall, the protein content was higher (0.01 > P < 0.05) during the first four lactation’s months and decreased until the month 8. The β-LG was the major protein (1.75 mg mL⁻¹ as mean; peak 2.24 ± 0.09 mg mL⁻¹), while the α-LA had a mean concentration of 1.32 mg mL⁻¹ and peaked at month 1 (1.57 ± 0.09 mg mL⁻¹) and LYS (0.66 mg mL⁻¹ as mean) showed the highest value equal to 0.76 ± 0.03 mg mL⁻¹. The highest (P < 0.01) concentration of all proteins was recorded at spring (α-LA: 1.69 mL⁻¹; β-LG: 2.07 mL⁻¹; LYS: 0.76 mL⁻¹).

Keywords::

• Donkey milk
• α-lactalbumin
• β-lactoglobulin
• lysozyme
• human health implications

Acknowledgement

The authors thank Dr Marianna La Guardia for her support in the experimental work.

Declaration of interest

Paper supported by a grant from the University of Bari Aldo Moro (Bari, Italy).