Study on Extraction and Determination of Chemical Composition of Pomelo (Citrus Grandis L.) Oil in Tien Giang Province, Vietnam Tan Phat Dao1,2,3, Thi Cam Quyen Ngo1,2, Thien Hien Tran1,2, Thi Kim Ngan Tran1,2, Long Giang Bach Center of Excellence for Biochemistry and Natural Products, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam Graduate University of Science and Technology, Ho Chi Minh City, Vietnam *Corresponding author: Abstract Hydro-distillation extraction method was used to extract essential oil from pomelo (Citrus Grandis L.) peels in Vietnam, the method is applicable from laboratory scale to pilot scale, production scale The effects of extraction variables including size of material, temperature, extraction time, and water-to-material ratio on the yield of essential oil were investigated In addition, to assess the quality of pomelo essential oil, the chemical composition has also been presented in detail The optimized conditions was as follows: material size of grind, temperature of 120 oC, ratio of mL/g, and extraction time of 105 From this parameter, subsequent extraction process related to pomelo oil would a significantly reduce extraction time and improve the quality The chemical composition of the pomelo oil was then determined by GC-MS, and components were identified In particular, Limonene had the highest content (96.122%) in pomelo essential oil extracted by hydro-distillation extraction This method can be considered as a green method of extraction method as it is less energy intensive process and offers high performance This method is the conventional method but it has great potential for industrial applications and the optimization of pomelo oil extraction conditions is essential Keywords: Pomelo peels (Citrus Grandis L.), hydro-distillation, GC-MS analysis Introduction Essential oils are the smallest droplets, concentrated of the herbs, sometimes it is only aromatic molecules formed through the regulatory function in plants It is a mixture of organic substances mixed together, has a characteristic odor, is widely applied in manufacturing and life, especially in the cosmetics, food and pharmaceutical industry [1-13] Pomelo (Citrus Grandis L.) belongs to genus Citrus, a flowering plant in the Rutaceae family [14] Pomelo fruit is one of the most popular citrus fruits and is the largest of citrus fruits Currently, pomelo essential oil has been widely applied in many different fields such as cosmetics, perfumes, detergents, aromas and preservatives of food products Pomelo essential oil also has many healing effects and they aid in the distribution of drugs and disinfectants [15] Pomelo essential oil is also used for its bactericidal, antioxidant and anti-cancer properties [16] The chemical composition of Pomelo essential oil from different countries is also a subject of extensive research In this study, hydro-distillation technique was used to extract pomelo essential oils Hydrodistillation does not require a lot of complex equipment, but is capable of almost completely distilling essential oils in raw materials In addition, the method allows the separation of the constituents contained in essential oils into separate parts of higher purity based on differences in volatile properties The volatiles released from the pomelo peel were analyzed by gas chromatography-mass Spectrometry (GC-MS) Limonene is generally at 85 to 96% in pomelo essential oil, while myrcene, sabinene, α-pinene and α-terpinene have been reported at less than 2.5% [17, 18] Other compounds such as: nootkatone, octanal, octyl acetate, citronellyl acetate, citral and carvone have been found at trace levels in essential oil (