Response surface methodology for optimization studies of hydro-distillation of essential oil from pixie mandarin (Citrus reticulata Blanco) peels

Essential oil extraction technique from mandarin pixie peels by hydro-distillation is optimized by respon-se surface methodology (RSM). Mathematical techniques were used in experimental design to evaluate the impacts of factors that affect the extraction process and improve the yield of the extraction process. A central mixed design based on infl uencing variables such as water ratio (3–5 mL/g), temperature (110–130° C) and extraction time (90–150 min) was adopted with essential oil yield as the target func-tion. Correlation analysis of the mathematical regression model showed that the quadratic polynomial model can be used to optimize hydro-distillation of pixie mandarin oil. The results showed that under the optimum extraction conditions, the highest quantity of essential oils was achieved (7.28 mL/100 g materials). In terms of statistical analysis, the signifi cance levels (p-value <0.05) of the model showed that the experimental results had a good impact between factors. The coeffi cient of determination indicating the match between the experimental value and the predicted value of the model was high (R2>0.9). The chemical composition of the essential oil was analyzed by Gas Chromatography-Mass Spectrometry, revealing the dominance of limonene content (97.667%), which implies that the essential oil of pixie mandarin could be an alternative source of limonene.