Case Study: Optimization of antidiabetic properties of stevia black tea brewing

Abstract: This research was conducted to determine the effect of adding stevia leaf powder on the anti-diabetic properties of stevia-black tea drinks. A design is needed to find the best proportion of stevia black tea to get the best anti-diabetic properties. The research design used was a response surface method completely, with a central composite, 2 factors, and 1 replication. The factor was stevia and black tea, with varying weights according to the design proposed by the RSM program. The combination of stevia and black tea was put into a tea bag, weighing 2 g. Tea was brewed by steeping every 2 g of stevia black tea in 200 mL of hot water at 94 ± 5 °C for 4 ± 1 min. And then cool the infusion to room temperature for 15 min, and the tea was filled in a glass of dark brown color, to be analyzed one hour later. The parameter analyzed for anti-diabetic properties was the inhibition of the alpha-amylase enzyme. The data obtained from testing this parameter was then analyzed using RSM design Minitab 17. The results of the optimization show that stevia has a direct and positive effect on amylase inhibitory ability, while black tea has an inverse and negative effect.

Keywords: optimization, antidiabetic, amylase, black tea, stevia