PHYSICOCHEMICAL PROPERTIES OF MORINGA OLEIFERA SEED OIL

Transcription

1 709 PHYSICOCHEMICAL PROPERTIES OF MORINGA OLEIFERA SEED OIL 1 G. Rekha, 2 Dr. A. Leema Rose 1 G. Rekha, Research Scholar, Department of chemistry, Holy cross College, Trichy. 2 Associate Professor, Department of chemistry, Holy cross College, Trichy. Abstract Moringa Oleifera seed oil was extracted using the solvent extraction method using n-hexane. The physicochemical properties of the oil were determined. The following parameters are Oil yield, Acid value, free fatty acid,saponification value, density, specific gravity, iodine, peroxide, refractive index, viscosity value. The seed oil of M. Oleifera showed good physicochemical properties and could be utilized successfully as a source of non-edible oil for human consumption and for industrial applications. Keywords: Moringa seed oil, Solvent extraction, n-hexane Introduction Moringa Oleifera, commonly referred to as "Moringa" (from Tamil: Muringa) is the most widelycultivated species of the genus Moringa, which is the only genus in the family Moringaceae. Moringa, which is the only genus in the family Moringaceae, is an exceptionally nutritious vegetable tree with a variety of potential uses. Every part of Moringa Oleiferasuch as the seed, root and stem are useful. The tree itself is rather slender, with drooping branches that grow to approximately 10m in height [1]. The tree ranging in height from 5 to 12m with an open, umbrella-shaped crown, straight trunk and corky, whitish bark, the tree produces a tuberous tap root. The evergreen or deciduous foliage (depending on climate) has leaflets 1 to 2 cm in diameter; the flowers are white or cream coloured. The fruits (pods) are initially light green, slim and tender, eventually becoming dark green, firm and up to 120cm long, depending on the variety. Fully mature, dried seeds are round or triangular, the kernel being surrounded by a lightly woodedshell with three papery wings [2]. In the tropics, it is used as forage for livestock; in many countries, Moringa is used as a micronutrient powder to treat diseases. The green pods, fresh and dried leaves are used as vegetable. The seeds contain up to 40% of oil by weight which is used for cooking, soap manufacture, cosmetic base and in lamps. All parts of the plant are used in a variety of traditional medicines. The press cake, obtained following oil extraction, is useful as a soil conditioner; the plants are grown as live fences and windbreaks. It is also used as fuel wood source after coppicing (cutting back the main stem to encourage side shoots); as an intercrop with other crops and the wood pulp may be used for paper-making. In the tropics, it is used as forage for livestock; in many countries, Moringa is used as a micronutrient powder to treat diseases. The green pods, fresh and dried leaves are used as vegetable [3,4]. Material and Methods Oil extraction The Soxhlet apparatus used for solvent extraction where 300ml of n- Hexane was poured into round bottom flask.10 grams of powdered Moringa seed was placed in the thimble and inserted in the centre of the extractor. The Soxhlet was heated at 60 o c. When the solvent was boiling, the vapour rises through the vertical tube into the condenser at the top. The liquid condensate drips into the filter paper thimble in the centre, which contains the oil to be extracted. The extract seeps through the pores of the thimble and fills the siphon tube, where it flows back down into the round bottom flask. This was allowed to continue for 30 minutes. It was then removed from the tube, dried in the oven, cooled in the desiccators and weighed again to determine the amount of oil extracted. The experiment was repeated by placing 5g of the Moringa seed into the thimble. The weight of oil extracted was

2 710 determined at 30 minutes interval. At the end of the extraction, the resulting mixture containing the oil was distilled off using simple distillation to recover solvent from the oil. The oil extracted was stored in a plastic container for further use. : W 1 W 2 M c = X 100 W 1 Determination of Physicochemical Properties The following physicochemical properties were determined; 1. Acid Value 1ml oil was weighed separately in 250ml conical flasks. 5ml of isopropyl alcohol was added into the conical flasks containing the oil samples with through stirring. 3 drops of phenolphthalein indicator was added and titrated against 0.1 N of KOH solution while shaking constantly until a faint pink persist for 30s.The end point was recorded and the acid value was calculated as; [5]. Titre value x 0.1KOH x 28.2 Acid value =. Weight of oil sample FFA = acid value Saponification Value 1ml of the oil sample was added into a conical flask containing 25ml of alcoholic NaOH solution. The flask was sealed and heated in the oven for 5mins at 105 o C. 1ml of phenolphthalein solution was added, the excess alkali was then titrated with 0.5M HCl when hot. A blank was carried out at the same time (without oil) [6]. Saponification value = Where, B - Blank titer value S - Sample titer value 3. Density (B S) x 0.5 x Weight of the sample The weight of an empty 100ml beaker was determined. A specific volume of biodiesel was added to the 100ml beaker and the weight of the oil and beaker determined. The density is calculated using the formula [7]. Density of oil sample = Weight of oil sample Volume of oil sample 4. Specific Gravity An empty washed and dried as beaker was weighed on the top load weighing balance. The weight of the beaker and weighed was recorded. Exactly 50cm 3 of the samples were recorded. The procedure was repeated with water of 50cm 3 of water was obtained. The specific gravity was calculated [8].

3 711 Specific gravity of oil sample = Weight of oil Weight of equal volume of water 5. Iodine Value 0.4g of the samples was weighed separately in 250ml conical flasks. 20ml of carbon tetra chloride was added to dissolve the oil samples. Then 25ml of Dam s reagent was added to the flasks using a safety pipette in fume chamber. Stoppers were inserted and the content of the flasks were vigorously swirled. The flasks were then placed in the dark for 2 hours 30mins. At the end of this period, 20ml of 10% aqueous potassium iodide and 125ml of water were added to each sample using a measuring cylinder. The contents were titrated with 0.1M sodium-thiosulphate solutions until the yellow color almost disappeared. Few drops of 1% starch indicator was added and the titration continued by adding thiosulphate drop wise until blue coloration disappeared after vigorous shaking. The same procedure was used for blank test and other samples. The iodine value is given by the expression [9]. C (V 1 V 2 ) Iodine value = M Where, C Concentration of sodium thiosulphate used V 1 Volume of sodium thiosulphate used for blank V 2 Volume of sodium thiosulphate used for determination M Mass of the sample 6. Peroxide Value Weigh the test portion into a 250ml Erlenmeyer flask with glass stopper. Add 30ml of acetic acid- chloroform solution. Swirl to dissolve the test portion. Add 0.5ml of saturated KI solution using a suitable volumetric pipet. Allow the solution to stand for exactly 1min, thoroughly shaking the solution at least three times during the 1 min. Immediately add 30 ml of DI water. Titrate with 0.1N Sodium thiosulphate, adding it gradually and with constant and vigorous agitation. Continue the titration until the yellow iodine colour has almost disappeared. Add about 0.5ml of starch indicator solution. Continue the titration with constant agitation, especially near the end point, to liberate all the iodine from the solvent layer. Add the thiosulphate solution drop wise until the blue colour just disappears [10]. (S B) x N thiosulphate (0.1N) Peroxide value =.. x 1000 Weight of oil sample (5 ml) Where, S Titration of sample, B- Titration of blank 7. Refractive Index Abhe refractometer (Refractive indices vary between to ) can be read from the instrument to the fourth decimal place accurately. The temperature of the refractometer should be controlled to within C and for this purpose it should be provided with a thermostically controlled water bath and to circular water through the instrument.

4 712 Calibration of the instrument The instrument is calibrated with a glass prism of known refractive index on optical contact naphthalene or using distilled water which has a refractive index of at 20 0 C. Clean the refractometer with alcohol and ether. A drop of oil or fat in case of a solid fat the temperature should be suitably adjusted by circulating hot water is placed on the prism. The prism is closed by the ground glass-half of the instrument. The dispersion screw is adjusted so that no colour line appears between the dark and illuminated halves. The dark line is adjusted exactly on the cross wires and the refractive index is read on the scale. Usually commercial instruments are constructed for with white light but are calibrated to give the refractive in terms of sodium light of wavelength 589.3nm at a temperature of C unless otherwise specified [11-15]. 8. VISCOSITY A clean, dried viscometer with a flow time above 200 seconds for the fluid to be tested was selected. The samples were filled through a sintered glass (fine mesh screen) to eliminate dust and other solid material in the liquid samples. The viscosity meter was charged with each of the samples by inverting the tube s thinner arm into the liquid samples and suction force was drawn up to the upper timing mark of the viscometer, after which the instrument was turned to its normal vertical position. The viscometer was placed into a holder and inserted to a content temperature bath set at 40 o c and allowed approximately 10mins for the sample to come to the bath temperature at 40 o c. the suction force was then applied to the timing the flow of the samples as it flow freely from the upper timing mark to the lower timing mark was recorded [16]. S. NO CHARACTERISITICS MORINGA OLEIFERA OIL 1 Percentage of oil Yield 45% 2 Acid value (mg KOH/g) Free fatty acid Value (mg KOH/g) Saponification Value (mg KOH/g) Density (gcm 2 ) Specific gravity (40 0 C) Iodine Value (gi 2 /100g of oil) Peroxide Value Refractive index at 40 0 C Viscosity at 40 0 C mm 2 /s 4.3 Result and Discussion The oil from Moringa Oleifera seed was extracted with n- hexane as solvent in the Soxhlet extractor. The extracted oil was pale yellow liquid at ambient temperature with characteristic unique odor. The oil yield of Moringa Oleifera was determined as 43%.

5 713 Acid value of oil is an important parameter which affects the transesterification of oils. Oils which have high acid value will produce soap during transesterification. The extracted oil was analyzed to determine its acid value; the acid value was found 4.91mg KOH/g. Free Fatty Acids (FFA) are produced by the hydrolysis of oils and fats. The level of FFA depends on time, temperature, moisture content because the oils and fats are exposed to various environments. The free fatty acid value measures the extent to which glycerides in the oil have been decomposed by lipase action. It increased significantly with increase in moisture content. The value obtained for Moringa Oleifera seed oil was 2.45%. Saponification is a chemical reaction that involves the production of a metal salt or soap. The long chain fatty acids found in fats have a low saponification value because they have a relatively fewer number of carboxylic functional groups per units mass of the fats as compared to short chain fatty acids. If more moles of base are required to saponify. N grams of fat then there are more moles of the fat and the chain lengths are relatively small. The value for the Moringa Oleifera seed oil was 164. The specific gravity of Biodiesel varies with its fatty acid composition. A denser biodiesel has higher energy content and will give better mileage and increased power. Vegetable oil will typically have a specific gravity from to about depending on its fatty acid composition and temperature. There are a no. of contaminates that can alter the specific gravity of biodiesel. One of those contaminates is methanol. Biodiesel will have a range of about 0.86 to The value obtained for Moringa Oleifera seed oil was 0.9 at 40 o C. Density is a fuel property which directly affects the engine performance characteristics. Many performance characteristics, such as cetane number and heating value, are related to the density. On the other hand, diesel fuel injection system measures the fuel by volume. So the changes in the fuel density will influence engine output power due to a different mass of fuel injected. The density and viscosity of the fuels affect the start of injection, the injection pressure, and the fuel spray characteristic, so that they influence the engine performance, combustion and exhaust emissions. Density for Moringa Oleifera biodiesel was 8.44gvm -3 respectively. The extracted Moringa Oleifera oil was analyzed to determine the iodine value. The iodine value was obtained as I 2 100g. The low iodine value of this oil makes it suitable for biodiesel production since high iodine value leads to the formation of deposits on engines and problem during storage of the fuel. The peroxide value of Moringa Oleifera is 3.50 within the standard value. Peroxide value is a measure of its oxygen content, which is used to monitor the rancidity through the evaluation of the quantity of peroxide generated in the product. The lower peroxide value of Moringa Oleifera seed oil means it will not easily go rancid which is related to its longer shelf life and stability; this is in conformity with that reported for Moringa Oleifera seed oil has a shelf life of up to 5 years. Refractometer was used in this determination. Few drops of the samples were transferred into the glass slide of the refractometer. Water at 40 o C was circulated round the glass slide to keep its temperature uniform. Though the eyepiece of the refractometer, the dark portion viewed was adjusted to be in line the intersection of the cross. At no parallax error, the pointer to the refractive index. This was repeated and the mean value was noted and recorded as the refractive index. The value of refractive index was 5.21 at 40 o C. The viscosity of Moringa Oleifera seed oil value is 4.3. Acknowledgment The authors acknowledge Ms. Dr. A. Leema Rosefor giving support to work carry out. PG and Research, Department of chemistry, Holy cross college, Trichy. Conclusion In this paper, a study on the physicochemical properties of Moringa Oleifera seed oil for their suitability in biodiesel production as raw materials to obtain biodiesel fuel of high quality and could be suitable alternative to fossil diesel. Reference [1] Corbett P. (2003), Moringa Oleifera seed; 18(8): [2] Quattro chi U. (2000), CRC world dictionary of plant names: Common names, scientific names, eponyms, synonyms and etymology, Volume 3. CRC Press, pp

6 714 [3] Folkard G, Sutherland J, Shaw R. Moringa Oleifera (2004), Water and Environmental Health at London and Lough borough. pp [4] National Research Council. Moringa Oleifera. Lost crops of Africa: Volume II: Vegetables. Lost crops of Africa. 2. National Academies Press. 2006, pp [5] L. Jian, A.H. Lee, C.W Binns, Tean and lycopene protect against prostate cancer. Asian pac. J. Nutr. 16 suppl [6] Sabahelkhier, K.M, Hussain, A. S. and K.E.A. Ishag. (2010), Effect of maturity stage on Protein fractionation, in vitro protein digestibility and anti-nutrition factors in pineapple (Ananascomosis) fruit grown in Southern Sudan. African Journal of Food Sciences 4(8): [7] Chopra R.N. and J. S. Kanwar, (1992), Analytical Agricultural Chemistry, fourth edition, Kalya Publishers new Delhi- Ludhiana, Pp.351 [8] Sabahelkhier, K.M, Hussain, A. S. and K.E.A. Ishag. (2010), Effect of maturity stage on Protein fractionation, in vitro protein digestibility and anti-nutrition factors in pineapple (Ananascomosis) fruit grown in Southern Sudan. African Journal of Food Sciences 4(8): [9] Raziq. S, Anwar, F., Mahmood, Z., Shahid, S.A., and R. Nadeem.(2012), Characterization of Oils from Different Varieties of Watermelon (Citrullus lanatus (Thunb.)Pakistan Journal of Agricultural Science, volume 63, No. 4 [10] Chopra R.N. and J. S. Kanwar.(1992), Analytical Agricultural Chemistry, fourth edition, Kalya Publishers new Delhi- Ludhiana. Pp.351 [11] Sabahelkhier, K.M, Hussain, A. S. and K.E.A. Ishag. (2010), Effect of maturity stage on Protein fractionation, in vitro protein digestibility and antinutrition factors in pineapple (Ananascomosis) fruit grown in Southern Sudan. African Journal of Food Sciences 4(8): [12] Anwar F, and M.I. Bhanger. (2003), Analytical Characterization of Moringa Oleifera Seed Oil Grown In Temperate Regions of Pakistan, Journal of Agriculture and Food Chemistry 51, [13] Chopra R.N. and J. S. Kanwar, (1992), Analytical Agricultural Chemistry, fourth edition, Kalya Publishers new Delhi- Ludhiana, Pp.351 [14] Sabahelkhier, K.M, Hussain, A. S. and K.E.A. Ishag. (2010), Effect of maturity stage on Protein fractionation, in vitro protein digestibility and anti-nutrition factors in pineapple (Ananascomosis) fruit grown in Southern Sudan. African Journal of Food Sciences 4(8): [15] Raziq. S, Anwar, F., Mahmood, Z., Shahid, S.A., and R. Nadeem.(2012), Characterization of Oils from Different Varieties of Watermelon (Citrullus lanatus (Thunb.)Pakistan Journal of Agricultural Science, volume 63, No. 4 [16] Chopra R.N. and J. S. Kanwar.(1992), Analytical Agricultural Chemistry, fourth edition, Kalya Publishers new Delhi- Ludhiana. Pp.351