Extraction of local ginger essential oil using microwave assisted extraction (MAE) and steam distillation

• Main Authors: Broncano, Mary Lene C., Manongdo, Jasmin Karina T., Oliveros, Lilly-Ann R.
• Format: text
• Language: English
• Published: Animo Repository 2007
• Subjects: Essences and essential oils; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/7300
• Institution: De La Salle University

Ginger oil was extracted from the air-dried rhizomes of Zingiber officinale by steam distillation and microwave assisted extraction (MAE). Conditions for MAE were varied and the setting with ethanol as solvent, 1 minute extraction time at 60°C, 20 g sample per 70 ml solvent, gave the highest yield of 2.185%. For steam distillation where 200 g sample was distilled for 4 hours at room temperature, the yield was only 0.180%. Physicochemical tests of the steam distilled oil gave the following values: refractive index (25°), 1.48 specific gravity (25°), 0.86 acid and ester numbers were 3.83 and 8.67 respectively. For the MAE, refractive index was undetermined due to the color, acid number was 0.012, ester number was 0.028 and the specific gravity (25°) was 0.762. The GC-MS analyses of the extracts were also determined and steam distilled oil were found to contain the following compounds: zingiberene, sesquiphellandrene, farnesene, phellandrene, nerolidol, geranial, curcumene and linalool. Of the major components mentioned by Yonei et al (1995) and Macleod et al (1987) only neral and camphene were undetected. Geranial was responsible for the lemony odor and phellandrene was the major volatile component of local steam distilled oil. On the other hand, the MAE extract contained both the volatile and the non-volatile components of ginger. Zingiberene was the major volatile compound and gingerol was the main non-volatile component. The MAE extract which was viscous and dark brown in color is the oleoresin. Thus, MAE alone was not able to recover the essential oil therefore further extraction procedure must be performed to separate the essential oil from the oleoresin.