Stability and structural properties of bee pollen protein hydrolysate microencapsulated using maltodextrin and whey protein concentrate

In this research, the bee pollen protein hydrolysate was microencapsulated by spray drying using maltodextrin (MD), whey protein concentrate (WPC) and a mixture of both compounds. For this purpose, the bee pollen was hydrolysed by alcalase (enzyme concentration of 1.5%) at 50 °C and pH 8 during 3.95 h, and then freeze-dried. The hydrolysed protein and wall materials were used in ratio of 1:10 (w/w). The wall materials included maltodextrin 2%, WPC 2%, as well as maltodextrin and WPC mixtures with 3:1 ratio. The resulting capsules were exposed to UV radiation for 48 h to accelerate the oxidation. The results showed that the capsule prepared using maltodextrin and WPC mixture showed the highest DPPH radical scavenging during exposure to UV radiation. Based on the FTIR spectroscopy results, the wall containing maltodextrin and WPC mixture showed the best performance in maintaining the chemical structure of hydrolysed protein. The SEM results indicated that the microcapsules prepared with WPC and maltodextrin mixture as wall material showed uniform and smoother wall than those prepared with maltodextrin alone. Finally, it was found that the maltodextrin and WPC mixture was the best wall with an appropriate protective capability for the microencapsulation of hydrolysed proteins and their protection against UV radiation.