In recent years, food-derived hypoglycemic peptides have received a lot of attention in the study of active peptides, but their anti-diabetic mechanism of action is not yet clear. In this study, camellia seed cake protein (CSCP) was used to prepare active peptides with α-glucosidase inhibition. The optimization of the preparation of camellia seed cake protein hydrolyzed peptides (CSCPH) was conducted via response surface methodology (RSM) using a protamex with α-glucosidase inhibition as an indicator. The optimal hydrolysis conditions were pH 7.11, 4300 U/g enzyme concentration, 50 °C hydrolysis temperature, and 3.95 h hydrolysis time. Under these conditions, the α-glucosidase inhibition rate of CSCPH was 58.70% (IC₅₀ 8.442 ± 0.33 mg/mL). The peptides with high α-glucosidase inhibitory activity were isolated from CSCPH by ultrafiltration and Sephadex G25. Leu-Leu-Val-Leu-Tyr-Tyr-Glu-Tyr (LLVLYYEY) and Leu-Leu-Leu-Leu-Pro-Ser-Tyr-Ser-Glu-Phe (LLLLPSYSEF) were identified and synthesized for the first time by Liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) analysis and virtual screening with IC₅₀ values of 0.33 and 1.11 mM, respectively. Lineweaver-Burk analysis and molecular docking demonstrated that LLVLYYEY was a non-competitive inhibitor of α-glucosidase, whereas LLLLPSYSEF inhibited α-glucosidase, which displayed a mixed inhibition mechanism. The study suggests the possibility of using peptides from Camellia seed cake as hypoglycaemic compounds for the prevention and treatment of diabetes.

Numerous studies indicate that tea has versatile health benefits, and attempts are being made to use it as a food additive. In this study, three types of tea powder (TP) [matcha tea powder (MTP), green tea powder (GTP), and black tea powder (BTP)] were used in noodle processing, and the cooking properties, antioxidant potential, and volatile profiles of dried tea noodles (DTN) were investigated. Between 0.5% and 2% TP addition decreased the cooking time, cooking loss, and water absorption of DTN, regardless of concentrations. TP decreased the brightness (L*) of the DTN while increasing the greenness (|−a*|) and yellowness (b*) values of matcha tea noodles (MTN) and green tea noodles (GTN), as well as the redness (a*) and yellowness (b*) values of black tea noodles (BTN). The results of the 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) scavenging activity (10.84–95%), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free scavenging activity (2.03–92.23%), and total phenolic content (TPC) (97.32–540.97 mg/g) of the noodles increased as the TP addition increased. Besides, TP also enriched the flavor of the DTN, with alcohol, aldehydes, and ethers being the main components. In conclusion, the addition of TP positively improved the quality of the DTN and increased its antioxidative potential.