Phytochemical Profiles and Anti-Diabetic Potential of the Extract of Pueraria lobata Compound Teabags: Preparation and Optimization Infusion Conditions

A Pueraria lobata root compound teabag using Pueraria lobate root, Stigma maydis, and Prunus mume as the main material was prepared in this study, and the brewing technology was optimized using Response Surface Methodology (RSM). The sensory evaluation, total polysaccharide, and phenolic compound content were used as evaluation indicators and the effect of the compound ratio of raw material was studied. As a result, the compound ratio of Pueraria lobate root, Prunus mume, and Stigma maydis was determined to be 2:2:1 (m:m:m). To obtain the best brewing conditions for high inhibition rates of α-amylase and α-glucosidase, the teabag brewing process was optimized using RSM equipped with a 3-factor-3-level Box-Behnken (BBD) experimental design. Three independent variables were assigned to brewing water temperature (80-100℃), amount of water addition (150-200 mL), and soaking time (3-9 min) to design an empirical model best fit in the inhibition rates of α-amylase and α-glucosidase. The range of values for each variable was based on the previous one-factor experiment (results not shown). The optimal brewing process for the preparation of the Pueraria lobata root compound tea was a brewing water temperature of 90.8℃, an amount of water addition of 155 mL, and a soaking time of 5.9 min. The inhibition rate of α-amylase and α-glucosidase could reach 45.09±1.13 and 60.52±2.47%, respectively. These findings suggested that a Pueraria lobata root compound teabag was established, with a unique aroma, a slightly bitter and sweet taste, high polysaccharides and phenolic content, and excellent in vitro hypoglycemic activity.