S. K. Roya
Chemical Research Division, Bangladesh Council of Scientific and Industrial Research,Dhanmondi, Dhaka-1205, Bangladesh.
S. M. M. Karim
Department of Chemistry, Jagannath University, Dhaka
A.K.M.Z. Rahman
Chemical Research Division, Bangladesh Council of Scientific and Industrial Research,Dhanmondi, Dhaka-1205, Bangladesh.
S. Aziz
Chemical Research Division, Bangladesh Council of Scientific and Industrial Research,Dhanmondi, Dhaka-1205, Bangladesh.
S. M. M. Hassan
Chemical Research Division, Bangladesh Council of Scientific and Industrial Research,Dhanmondi, Dhaka-1205, Bangladesh.
Gossypium herbaceum, Fresh cotton seed oil, Fatty acid composition, Palmitic acid, Oleic acid
Nilphamari, the district in Rajshahi
Postharvest and Agro-processing
Plant materials:Different varieties of cottons are seen in Bangladesh. They are Shimul, Carpus, Akhondo etc. In this context Carpash (Gossypium herbaceum) seeds have been collected from Nilphamari, the district in Rajshahi, Bangladesh for the study of fatty acid composition and proximate analysis.
Extraction: The cottons along with seeds were cleaned to separate from dirt and grounded to obtain powder so that maximum particle exposure was got for extraction of oil. About 100 g of powder were extracted with ANALAR petroleum ether (b.p 40oC -60oC) in a soxhlet apparatus for 72h. The extract was first filtered and then vacuum distilled to remove solvent completely. The color of the extracted oil was chocolate maroon. Then the extracted oil was filtered through ANALAR activated charcoal. Finally, light golden color of the oil was obtained. The yield of oil was calculated and stored in a refrigerator for further analysis (Anonymous,1984).
Physicochemical study of the oil: The physicochemical properties of the extracted oil were investigated with three replication as per cited standard methods (Anonymous, 1984; Anonymous, 2004; Kirk and Sarwer,1991) e.g. solubility, specific gravity, fatty oil(%), acid value, Iodine value, saponification value. Identification and quantification of fatty acids: The fatty acid contents (qualitative and quantitative) were determined by GLC of methyl esters. The fatty acid methyl esters (FAMEs) were prepared by complete esterification of oil using BF3- MeOH complex (Anonymous, 1984; Metacalfe et al., 1966: Bannon et.al., 1982.). Standard FAMEs (E.Merck) were used for the identification and quantification of the peaks. For methylation, the lipid was first saponified with alcoholic sodium hydroxide, then cooled and diluted with water. After evaporation of alcohol, the acidified aqueous mixture was extracted with ether. Ether was then removed from ethereal solution to obtain fatty acid mixture. The fatty acid mixture was esterified with BF3- MeOH complex. After esterification, the reaction mixture was dissolved in diethyl ether in a separating funnel and was washed with dilute sodium carbonate solution until the effervescence was ceased. It was then washed with water, dried over anhydrous sodium sulphate and finally ether was removed to get methyl ester mixture (Anonymous, 1984; Metacalfe et al., 1966: Bannon et al., 1982.).
Instrument and separation conditions: The FAMEs were analyzed on a trace GC ULTRA, thermo electron Corporation, Gas Chromatograph fitted with a flame ionization detector and an electronic integrator. An SE-54 quartz capillary column (30mx0.25mm i.d. and 0.25 μm film thicknesses) packed with 10% diethylene glycol succinate on 100-200 mesh solid support was used. Nitrogen gas used as a carrier gas at a flow rate of 1.5 mL/ min. The separation was affected at 100oC- 220oC. The following temperature program was chosen in GC analysis; initial temperature 150oC, increasing at 7oC/min to 260oC for 30 min. The oven, injection and detection temperature were fixed at 150o, 180o, 220oC respectively. The fatty acid were identified by comparison of relative retention times and peak positions of the chromatogram with those of the standard FAMEs. The amounts of fatty acid were calculated from the peak areas computed by LKB 2220 electronic recording integrator.
Bangladesh J. Sci. Ind. Res. 47(3), 303-308, 2012
Journal