Oil Extraction and GC-MS Analysis of the Seeds oil of three Nigerian Cucurbits

Abstract

Extraction and quantification of the yield (percentage) of the seed oil was performed on the seeds of three species of Cucurbitaceae family. Analyses of the oil properties as well as the GC-MS analysis of the seed oil were carried out using standard biochemical procedures. Oil extraction was carried out using n-hexane as the solvent of extraction. The percentage seed oil obtained was subjected to Physico-chemical analysis which revealed the percentage oil yield to be highest in the seeds of Cucumeropsis mannii with (53.88±2.23), followed by Lagenaria breviflora with (51.43±1.20) while seeds of Cucurbita pepo had (44.92±0.98). With significant difference P≤0.05 between the oil yield in the seeds of C. mannii, L. breviflora and that obtained in the seeds of C. pepo. Acid value (mg/KOH/g) was evaluated and revealed the highest in the seeds of L. breviflora with (41.78±1.26) C. mannii and C. pepo had (40.93±1.21) and (37.03±0.78) respectively. With significant difference only between the obtained value in L. breviflora and the duo of
C. mannii and C. pepo respectively. Saponification value was evaluated and results obtained indicated L. breviflora was the highest (41.78±1.26) while C. mannii had (40.93±1.21) while the least value of (36.52±0.97) was obtained in the seeds of C. pepo. Kinematic viscosity analysis also revealed the values as (0.75±0.06), (0.69±0.06) and (0.71±0.07) for C. pepo, C. mannii and L. breviflora respectively. There was no significant difference (P≤0.05) in the three specimens studied. For iodine value, (112.94±2.64) was recorded for C. pepo; (120.05±3.00) was for C. mannii while (104.06±1.78) was recorded for L. breviflora with significant difference (P≤0.05) among the three species. Analysis for specific gravity revealed that C. pepo had (0.9±0.09) while C. mannii had (0.92±0.09) and L. breviflora had (0.90±0.08). For Cetane number, (43.00±1.79) was obtained for C. pepo, while (41.00±1.50) was C. mannii while
(39.99±1.21) with no significant difference (P≤0.05) in the specific gravity and Cetane number among the three species studied. Results of Gas Chromatography Mass Spectrometry analysis of the seed oils have been presented on retention time, compounds names, chemical formulae, molecular weights as well as the respective peak area percent of each of the compounds identified. A total of four compounds have been identified as present in Cucurbita pepo with oleic acid and 9, 12-Octadecanoic acid and Squalene being the predominant. In Cucumeropsis mannii, five compounds have been identified with 1, 8, 11-Heptadecatriene, 10, 13-Octadecanoic acid methyl ester, Linoelaidic acid and Oleic acid being present. In Lagenaria breviflora, eight compounds have been found to be present. nHexadecanoic acid, Conjugated Linolaidic acid, 9,12-Octadecadienoic acid and 2-Hydroxy-1-(hydroxyl methyl) ethyl ester. Others were 9-Heptadectriene, Saturated Tetradec-13-en-11-yn-1-ol, Squalene as well as gamma-Tocopherol. Based on the obtained results on oil yields and the Physico-chemical analysis and the Gas Chromatography Mass Spectrometry (GC-MS) analysis of the seed oils, it can be said that the studied cucurbits have exhibited an excellent status in serving the quest for alternative biofuel that gives them unique characteristic for use as they could greatly help reduce overdependence on the fossil fuel. More so, the GC-MS analysis of the seed oils revealed a number of active compounds with wide applications that could be harnessed to better the lots of humanity