Optimizing the Preparation Process and Antioxidant Activity of α-Glucosidase Inhibitory Peptide from Cinnamomum camphora Seed Kernel

To achieve high-value development and use of the abundant Cinnamomum camphora seed resources in China and screen the α-glucosidase inhibitor peptides derived from Cinnamomum camphora seed kernel (CCSK), the aim of this study was to produce α-glucosidase inhibitory peptides from CCSK by optimizing CCSK protein enzymatic hydrolysis conditions through single-factor experiments and orthogonal tests. Degree of hydrolysis (DH) and α-glucosidase inhibitory activity were used as evaluation indexes. Subsequently, the amino acid composition and in vitro antioxidant activity of the obtained α-glucosidase inhibitory peptides were analyzed. The results revealed that the following were the optimal conditions of CCSK protein enzymatic hydrolysis: papain as the hydrolase; hydrolysis temperature of 55 ℃, pH of 6.0, hydrolysis duration of 2.0 h, and an enzyme addition of 16000 U/g. At these conditions, the DH value of the obtained CCSK α-glucosidase inhibitory peptides was 26.81%, while their median inhibition rates (IC₅₀ values) on α-glucosidase, DPPH free radicals, and ABTS⁺ free radicals were 11.52, 5.42, and 0.64 mg/mL, respectively. This study provides a theoretical basis for production of α-glucosidase inhibitory peptides from CCSK.