Effects of Drying Methods on the Physicochemical and Functional Properties of Cinnamomum camphora Seed Kernel Protein Isolate

Cinnamomum camphora seed kernel protein isolate (CPI) has attracted increasing attention due to its sustainability and potential applications. This study aimed to investigate the effects of freeze-drying (FD), vacuum-drying (VD), and spray-drying (SD) on the physicochemical and functional properties of CPI. The morphology observation results showed that the SD-CPI, SD-CPI, and VD-CPI were spherical, lamellar, and massive, respectively. Compared to FD and SD, VD had more impact on the color, surface hydrophobicity, intermolecular disulfide bonds, intrinsic fluorescence, and thermal stability of CPI. Fourier transform infrared spectroscopy (FTIR) analyses showed that among three CPI samples, VD-CPI had the highest content of β-sheet but the lowest contents of α-helix and β-turn. At different pH values, the solubility, emulsification, and foaming properties of VD-CPI were inferior to those of FD-CPI and SD-CPI. These results provide useful information on the changes in the physicochemical and functional properties of CPI subjected to different drying methods, and offer theoretical guidance for the production and use of CPI in the food industry.