Study on Optimization for Enhancing Extraction by Hydrodistillation of Tea Tree Oil with Surfactant Tween 80

Abstract

In this study the response surface methodology (RSM) was adopted to evaluate the effects of process parameters of hydrodistillation for extraction of tea tree oil (TTO) in presence of a nonionic surfactant - Tween 80 These process parameters include the surfactant concentration the extraction time and the liquid/solid ratio on the extraction yield of TTO were investigated Results showed that the data were adequately fitted into the second-order polynomial model in which the extraction time had a significant effect on the extraction yield of TTO It was predicted that the optimum extraction condition is 2700 ppm as the concentration of Tween 80 in hydro-distill 140 min for extraction time and liquid/solid ratio at 11 6 Under these optimal conditions the extraction yield of tea tee oil was 5 48% The kinetics model of oil extraction comprised two stages of washing and diffusion The surfactant added could increase both kinetic parameters The components of tea tree oil were analyzed with gas chromatography (GC) while HPLC was employed to analyze the quantity of Tween 80 present in the extracted TTO The oil obtained under the optimal extraction condition underwent further tests for the stability of its microemulsion formulation with Tween 80 as well as its antibacterial and antioxidant properties The maximum amount of tea tree oil that could be solubilized within the micelles increased with an increasing concentration of Tween 80 The microemulsion made with TTO in 5 wt% Tween 80 was stable for over 30 days Antioxidant activity of tea tree oil was determined using the DPPH assay The EC50 value was 75 07 mg/g The ?-terpinene one main ingredient of TTO exhibited good antioxidant activity while its EC50 was 45 85 mg/g The antibacterial activity of tea tree oil was evaluated against Escherichia coli and Staphylococcus aureus with the agar disk-diffusion method and the broth dilution Tea tree oil displayed the superior antimicrobial properties evaluated by the disk-diffusion assay The MBC values for tea tree oil against E coli and S aureus were 8 77 and 6 08 mg/mL respectively

Date of Award	2019
Original language	English
Supervisor	Bing-Hung Chen (Supervisor)