Md. Delowar Hossain
Department of Applied Chemistry and Chemical Technology, Dhaka University, Dhaka-1000, Bangladesh
Bishwagith Kumer Paul
Department of Chemistry, Jagannath University, Dhaka-1100, Bangladesh
Sudhangshu Kumar Roy*
Chemical Research Division, BCSIR Laboratories, Dhaka-1205, Bangladesh
Gour Chandra Saha
Chemical Research Division, BCSIR Laboratories, Dhaka-1205, Bangladesh
Feroza Begum
Chemical Research Division, BCSIR Laboratories, Dhaka-1205, Bangladesh
Dilruba Huq
Department of Applied Chemistry and Chemical Technology, Dhaka University, Dhaka-1000, Bangladesh
Black Pepper, Fatty acid composition, Saturated fatty acids, Lauric acid, Gas Liquid Chromatography
Department of Applied Chemistry and Chemical Technology, Dhaka University, Dhaka-1000, Bangladesh
Resource Development and Management
Plant materials Black Pepper sample was collected from Dhaka New Market. The sample was cleaned to separate dirt, sun-dried and followed by the determination of the moisture content and then steam-distilled to make it free from essential oil and again sun-dried.
Extraction The essential oil free dried samples were powdered by a warring blender. Crushed Black Pepper seed-cake (100.0 g) was then subjected to extraction with n-hexen (b.p. 68°C) in Soxhlet apparatus for 72 hours to isolate the oil with three replications. In each experiment, the mass filtered and filtrate was vacuum distilled to remove solvent completely. The yield of oils were calculated and stored in a refrigerator for further analyses using AOAC methods.
Physico-chemical study of the oil The physico-chemical properties of extracted oil were determined with three replications using cited standard methods 10-13.
Nutritional analysis The meal left after oil extraction was sun-dried and it was used for determination of the percentages of moisture, ash, nitrogen, protein, carbohydrate and crude fiber according to the standard methods 10-14 with three replications. The gross food energy was estimated using the equation7, 15, 16: FE = (% CP×4) + (% Lipids ×9) + (%CHO×4).
Where: FE = Food energy (in gcal -1 ), CP=Crude protein and CHO=Carbohydrate
Identification and quantification of fatty acids The fatty acid contents were determined by GLC as their methyl esters. The fatty acid methyl esters (FAMEs) were prepared by complete esterification (checked by TLC) of oil using BF3-MeOH complex.
Standard FAMEs (E. Merck) were used for the identification and quantification of the peaks the results are given.
Instrument and separation conditions The FAMEs were analyzed by a PYE UNICUM PU: 4500U Gas Chromatograph (England) fitted with a flame ionization detector (FID) and an electronic integrator equipped with SE-54 quartz capillary column (30 m × 0.25 mm i .d. and 0.25µm film thickness). Carrier gas nitrogen (N2) at a flow rate of 3 mL/min. The separation was affected at 100°C - 220°C. The following temperature program carried out during GC analysis: initial oven temperature 100°C, increases at a rate of 4°C min1 to 220°C for 30 min. The oven, injection and detection temperatures were fixed at 100°, 220° and 230°C respectively. Splitting 80%, speed of the chromatogram was 0.5 mm/min. The fatty acids were identified by comparison of relative retention times and peak positions of the chromatogram with that for the standard fatty FAMEs. The amounts of fatty acids were calculated from the peak areas computed by LKB 2220 electronic recording integrator.
Dhaka Univ. J. Sci. 62(2): 65-68, 2014 (July)
Journal