Enhancement of the Anti-diabetic Activities of Tea Protein Hydrolysate (TPH) through the Conjugation of TPH with EGCG: Characterization of Conjugate
DOI:
https://doi.org/10.17721/fujcV14I1P123-140Keywords:
Tea protein hydrolysate (TPH), EGCG-TPH conjugate, EGCG, Antidiabetic activity, FTIRAbstract
This study produced a tea protein hydrolysate (TPH) from Fujian white tea residue at pH 9, with a solid-to-liquid (S/L) ratio of 1:20 (w/v), an enzyme-to-substrate (E/S) ratio of 1.188%, a temperature of 60 ℃, and a reaction time of 3 hours. After free-radical grafting, EGCG and TPH formed conjugates. The functional properties of the conjugate and its main components, including solubility, were evaluated. Additionally, UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to confirm the formation of the conjugate. EGCG and TPH formed conjugates, as suggested by FTIR, UV-visible spectroscopy, and SEM analyses, thereby enhancing in vitro anti-diabetic enzyme-inhibitory activity. The conjugation of EGCG and TPH increased the inhibition rates of α-amylase and α-glucosidase by 8.1% and 25.4%, respectively, compared to EGCG alone, and by 28.7% and 55.7% compared to TPH alone. Moreover, EGCG-TPH showed improved functional performance over each sample. The synergistic enhancement of the complex's anti-diabetic properties, through free radical scavenging and enzyme inhibition, confirms the structural integrity of the EGCG-TPH conjugate. This mechanism of synergistic activity provides a new approach to developing anti-diabetic compounds from natural sources. It highlights the potential to utilize high-value tea-processing byproducts and support the development of functional dietary strategies for diabetes.
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