Original Articles
Imoisi Chinyere and Iyasele Uc
Abstract
The fresh fruits of black plum (Vitex doniana) were collected from several randomly selected trees in a farm site in Uromi metropolis, Esan North-East Local Government Area of Edo state and then processed into an extract in form of syrup. The sugars were identified using a combination of 1D 1H NMR and GC-MS. For the NMR analysis, 5 mg of the sample was dissolved in deuterated DMSO (DMSO-d6), a common solvent for NMR analysis. Then the sample, was analysed with 1D 1H NMR at 500 MHz to obtain the spectrum showing the chemical shifts, peak multiplicity and coupling constants of the prospective sweeteners (sugars) in the sample. While characterization of the specific sugars in black plum fruit syrup 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 volatile and amenable for GC-MS analysis. The sugars identified in Vitex doniana fruit syrup are fourteen and are presented based on the percentage of each sugar constituents and contribution to the sweetness profile of the syrup as obtained from their raw area percentage based on the total ion current. The sugars identified are Alpha.-D-Glucopyranose (16.11%), Glucopyranose (11.19%), D-Glucose (11.15%), d-(+)-Xylose (8.95%), 2-Deoxy-pentose (8.92%), Glucofuranoside (6.84%), beta.-D-Galactopyranoside (6.37%), D-Fructose (6.16%), alpha.-DL-Arabinofuranoside (6.14%), alpha.-DL-Lyxofuranoside (4.85%), Ribitol (4.58%), 2-Keto-d-gluconic acid (3.62%), D-Xylofuranose (3.05%). While the least contributor is the alpha-D-Galactopyranose (2.07%).