Determination of the Flavoring Components in Vitex doniana Fruit Following Hydrodistillation Extraction

Abstract

In traditional medicine and aromatherapy, use of essential oils and their flavor compounds have been known for the management of various human diseases. The flavor structures of black plum (Vitex doniana) sweet fruit are unavailable though widely eaten by natives. Therefore, this research is aimed at using spectroscopic techniques to identify the chemical structure of the specific flavor in the syrup responsible for its unique aroma and taste. Hydrodistillation (HD) in a Clevenger-type apparatus and GC-MS (HD-GC-MS) were used to extract the essential oil and analyse the volatile compounds (VOCs) respectively from Vitex doniana sweet fruit. 24 different volatile compounds (VOCs) were identified and grouped into eight classes of organic compounds comprising of 6 terpenes, 5 carboxylic acids, 3 ethers, 2 alcohols, 2 ketones, 2 lactones, 2 aldehydes and 2 esters. It is noteworthy that GC-MS following hydrodistillation offers invaluable information about the aroma components of the fruit, because fingerprints of volatile compounds profiles using novel extraction methods are currently highly valued due to its importance to sensory properties of foodstuffs. Therefore, characterization of the aroma compounds as markers in putrefied and fresh fruits and their products are of great importance as a quality control parameter. The sugars were then identified using a combination of 1D 1H NMR and GC-MS. Characterization of the specific sugars in black plum fruit was done using GC-MS spectroscopic techniques via derivatization. This method converts the sugars in the sample to the respective trimethylsilyl-derivatives of the sugars, which are thermally stable, volatile and amenable for GC-MS analysis. The sugars identified are Alpha.-D-Glucopyranose, Glucopyranose, D-Glucose, d-(+)-Xylose, 2-Deoxy-pentose, Glucofuranoside, beta.-D-Galactopyranoside, D-Fructose, alpha.-DL-Arabinofuranoside, alpha.-DL-Lyxofuranoside, Ribitol, 2-Keto-d-gluconic acid, D-Xylofuranose and alpha.-D-Galactopyranose as obtained from their raw area percentage based on the total ion current. In conclusion, derivatization along with the coupling of GC with MS allows invaluable information about the composition and structure of sugars.