Optimization of nobiletin extraction assisted by microwave from orange byproduct using response surface methodology

Nobiletin (NOB) is a well-known polymethoxylated flavone that has only been found in citrus. The objective of this study is to obtain the optimal conditions for extracting nobiletin from sweet orange residues by microwave-assisted extraction (MAE) using response surface method. By using the Box-Behnken experimental design and SAS software 3 independent variables including solid/solvent ratio, microwave power, and treatment time were examined for the response variable nobiletin extraction yield. The regression Eq. 7 statistically significant (p < 0.001) and R-2 was 0.9189. Based on our regression result and considering the feasibility of experiment conduction, we chose the following independent variable values as the optimized conditions for the extraction of NOB: 1:21.91 (g/mL) for the solid/solvent ratio, 14.16 min for the treatment time, and 693.72 W for the microwave power. Under these conditions, the nobiletin yield of 267.8 mu g/g of byproduct was achieved.