Abstract: In this study, we comparatively investigated the emulsifying activity index (EAI) and emulsion stability index (ESI) of camel whey protein (CWP) and bovine whey protein (BWP) at different water/oil phase ratios (8:2, 7:3, 5:5, 3:7, and 2:8). The results showed that with the increase in oil phase volume fraction, the EAI and ESI of both proteins were significantly increased. When oil phase volume fraction was higher than 70%, the emulsions were no longer separated into layers. At the same water/oil phase ratio, the EAI and ESI of Pickering emulsion stabilized with CWP were higher than those with BWP. The Pickering emulsion stabilized by CWP showed smaller droplet size of (722.41 ± 77.91) nm at an oil phase volume fraction of 30%, and the absolute value of the zeta potential was higher than 30 mV ((33.58 ± 0.15) mV) at an oil phase volume fraction of 20%. Compared with BWP Pickering emulsion, the ESI of CWP was improved by about 200%. This study showed that CWP could be used as a high-quality emulsifier to stabilize Pickering emulsions and be applied in the development of functional camel milk food products.

Key words: camel milk; whey protein; Pickering emulsion; emulsifying activity; emulsion stability