Comparative study on antioxidant, antimicrobial, emulsifying and physico-chemical properties of purified bovine and camel β-casein

Emulsifying properties and in vitro antioxidant and antimicrobial activities of the isolated camel and bovine beta-casein (beta-CN) were investigated and compared. Antioxidant assay showed that both beta-CN had significant reducing power, iron chelating and antiradical activities especially for camel beta-CN. Camel beta-CN also exhibited strong antifungal activities against Aspergillus tamarii and Aspergillus sclerotiorum. The maximum emulsion activity was achieved by both beta-CN samples at pH 7.0 and 9.0 than 5.0, with higher values for the camel beta-CN. This behavior was linked to the relative high electronegative charge and interfacial properties of proteins under conditions away from their isoelectric-point as confirmed by the zeta-potential and interfacial tension measurements. Further, the stability of emulsions decreased at pH 5.0 because of the beta-CN precipitation and aggregation despite its high surface hydrophobicity. This study concluded that the camel beta-CN has antimicrobial, antioxidant, and techno-functional properties in agricultural and food industries.