Improving the antioxidant activity of microbial canthaxanthin by its encapsulation with bioactive peptides of soybean protein

In this study, the pH-shifting method was used for the encapsulation of microbial canthaxanthin with soy protein hydrolysates to increase its antioxidant activity. Enzymatic hydrolysis improved the functional and structural properties of soy protein hydrolysates in comparison to native ones. Reducing power and radical quenching activity of hydrolysates were raised respectively from 14.6 and 0.05 to 92.9 and 0.19 and their bioactive loading properties were significantly increased more than five times. Encapsulation parameters, structural attributes, and antioxidant activity were also studied after complexation. Fourier transform infrared spectroscopy findings indicated the formation of hydrogen bonds between canthaxanthin and hydrolysates. The crystalline nature of canthaxanthin was changed to amorphous, according to the X-ray diffraction assay. Reducing power and radical quenching activity increased (respectively 2.3-fold and 1.5-fold). The results showed the positive effects of enzymatic hydrolysis of soy protein and the pH-driven method of encapsulation on improvement in the antioxidant activity of canthaxanthin.