Effect of different drying methods on the volatile components of selected herbs

DORCAS ODUNAYO OSHO

Master's thesis

Abstract:

This study was conducted to examine the effect of different drying methods on the volatile components of selected spices which include parsley, sage, basil, rosemary, ginger, and thyme. The volatiles were extracted with a Soxhlet extractor and subsequently analyzed using gas chromatography with mass detection. The result revealed that commercial parsley contained 76.48 % apiol while parsley dried at room temperature and 45 °C oven-drying contained 65.45 % and 93.64% apiol, respectively. A total of 23 volatile compounds were identified in rosemary. The analysis identified Eucalyptol as the most abundant volatile compound in commercial rosemary (47.73 %), air-dried rosemary (22.95 %) and oven-dried rosemary (19.28 %). A total of 27 volatile compounds were identified in sage. The analysis identified 2-Bornanone, Eucalyptol and Epimanool as abundant volatile compounds in sage. This study identifies a total of 32 volatile compounds in ginger. The analysis identified Curcumene, β-Bisabolene, and β-Sesquiphellandrene as abundant volatile compounds in commercial and air-dried ginger. The study found β-Elemene, epi-β-Caryophyllene, and alfa-Copaene as abundant volatile compounds in oven-dried ginger. This study identifies a total of 31 volatile compounds in basil. The result identified Eugenol, α-Bergamotene, and Linalool as abundant volatile compounds in commercial, air-dried, and oven-dried basil. A total of thirteen compounds were identified and Thymol, γ-Terpinene and m-Cymene were identified as the abundant compounds in thyme. Commercial thyme contained 71.01 % Thymol while thyme dried at room temperature and 45 °C oven-drying contained 58.70 % and 59.98 % Thymol respectively. The study concludes that oven-drying at 45 °C is ideal for drying ginger, basil and thyme as it increased the availability of some volatile compounds, while drying at room temperature is ideal for drying parsley as there are more volatile compounds in the essential oil.

Keywords

Spices, Essential oil, Volatile compounds, Drying, GC/MS

Language used: English

Date on which the thesis was submitted / produced: 21. 4. 2022

Thesis defence

• Supervisor: Ing. Klára Urbanová, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme:
Agri-food Systems and Rural Development