Optimization by a Response Surface Methodology for Extraction of Essential Oil from Ginger (Zingiber rubens) in Vietnam

Using response surface methodology (RSM), this study sought to improve the hydrodistillation process for extracting Zingiber rubens essential oil. To get the best production of essential oils, tests were carried out utilizing a three-factor central mixture design (CCD) with the following parameters: grinding duration 30 - 50 seconds, material-to-water ratio 1/3 - 1/5 g/ml, and distillation time 240 - 360 minutes. A second-order polynomial regression model, reflecting total extraction efficiency as a function of the key hydro-distillation variables, fit strongly (p<0.05) and had a high coefficient of determination (R2 = 0.9628). The highest extraction efficiency (1.456%) was achieved at 43 seconds, 1/4.3 g/ml, and 316 minutes. The chemical makeup of essential oils was evaluated using gas chromatography-mass spectrometry (GC-MS). The predominant component (concentration > 5.0%) in Zingiber rubens essential oil produced by hydro-distillation was discovered to be 7-epi-Sesquithujene (18.71%), which had a high content. The most common compounds were ?-Sesquiphellandrene (9.92%), Citral (9.88%), ?-Curcumene (9.46%), ?-Bisabolene (5.39%), and Camphene (5.08%).