Optimization of Three Extraction Factors for Flavonoid Contents in Morus alba var. shalun using Box–Behnken Response Surface Methodology

Abstract

This study aimed to optimize the extraction conditions of total flavonoid content (TFC) using Response Surface Methodology (RSM) based on a Box–Behnken Design (BBD). Three extraction variables were evaluated, namely ethanol concentration (40–80%), extraction temperature (40–70 °C), and extraction time (30–90 min). The experimental results showed that all extraction parameters and their interactions influenced flavonoid recovery. Contour plots, desirability analysis, and cube plot visualization demonstrated that moderate extraction conditions produced better responses compared to extreme conditions. The optimum extraction region was obtained at approximately 60% ethanol concentration, 55 °C extraction temperature, and 60 min extraction time, resulting in relatively high total flavonoid content with a good desirability value. The interaction among extraction variables indicated that balanced extraction conditions were important for improving extraction efficiency and maintaining compound stability. Overall, the developed RSM model provided useful information for optimizing flavonoid extraction from natural materials.