Study on physicochemical characteristics of lutein nanoemulsions stabilized by chickpea protein isolate‐stevioside complex

BACKGROUND: Chickpea protein isolate (CPI) originating from chickpeas has the advantages of facilitating the stability of food emulsions. Stevioside (STE) exhibits a notable surface activity and can improve the water solubility of numerous hydrophobic nutrients. STE and protein mixtures show great potential as emulsions stabilizers. The present study aimed to prepare a novel nanoemulsion for encapsulating lutein (LUT) by ultrasonic homogenization using chickpea protein isolate‐stevioside complex (CPI‐STE) as a stabilizer and also to investigate the physicochemical characteristics. RESULTS: The results obtained showed that different preparation conditions demonstrated significant influences on the physicochemical properties of CPI‐STE‐LUT nanoemulsions. Under the optimal condition, the average particle size of CPI‐STE‐LUT nanoemulsions was 195.1 nm, and the emulsifying and encapsulation efficiencies of lutein were 91.04% and 87.56%, respectively. CPI‐STE‐LUT nanoemulsions stabilized by CPI‐STE could significantly increase the emulsifying and encapsulation efficiencies of lutein compared to that stabilized by CPI. Fourier transform infrared spectroscopy revealed that hydrogen bond was the main binding force of CPI and lutein, and there was a covalent bond between the two molecules. Furthermore, the stability of CPI‐STE‐LUT nanoemulsions in gastrointestinal phase was higher than that of CPI‐LUT nanoemulsions, which could load lutein more effectively and be more resistant to digestive enzymes. CONCLUSION: The present study reports the physicochemical characterization of CPI‐STE‐LUT nanoemulsions for the first time. CPI‐STE‐LUT nanoemulsions were characterized by a small average particle size lower than 200 nm, as well as high emulsifying and encapsulation efficiencies, and good stability. © 2021 Society of Chemical Industry.