Effect of different drying methods combined with fermentation and enzymolysis on nutritional composition and flavor of chicken bone powder

Chicken bone powder was dried by using spray drying (SD), hot air drying (AD), freeze drying (FD), and infrared freeze drying (IFD) in this study. Nutritional composition, antioxidant property, physical property, energy consumption, and flavor were compared, respectively. The results demonstrated that IFD powder had the highest content of amino acid nitrogen (49 mg/100 g). And in terms of polypeptide content, IFD and FD powder showed no significant difference, were obviously higher than AD and SD powder. As for antioxidant property, IFD and FD powder had higher DPPH and ·OH scavenging capacity than AD and SD powder. In addition, IFD powder had the highest L* value (74.59) and SD powder had the lowest L* value (65.35), which was consistence with the result of appearance score. Concerning flavor and sensory evaluation, IFD powder showed the highest umami value (11.85) and acceptability score (52.52) among four drying methods. Besides, the typical E-nose sensors response values of the IFD powder were closest to those of the enzymatic hydrolysate before drying and SD powder had the highest response value in all sensors. Finally on the basis of energy consumption, SD showed the minimum drying time and energy consumption.