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Int'l Conf. on Chemical & Advanced Computational (ICCEACT’2014) Nov. 24-25, 2014 Pretoria (South Africa)

Tobacco Seed Oil as an Economically Viable Alternative for the

Haleden Chiririwa, Aavian Hapanyengwi, and Edison Muzenda

 policies intended to reduce the incidence of -related Abstract—Virginia, Burley and Oriental tobacco are the most disease adversely affect thousands of tobacco farmers, common varieties farmed in . In Zimbabwe there is no manufacturers, and other businesses that produce, distribute, documented use or commercial use of tobacco seed products. Three and sell tobacco products [2]. Loss of tobacco income and jobs tobacco seed varieties namely Virginia, Burley and Oriental were will have noticeable long-term effect on the Zimbabwean assessed for their oil content using soxhlet extraction. The three tobacco seeds varieties yielded glyceride oil of 34.17% to economy as a whole and there will be difficult transitions for 36.55%.The glyceride oil was then analysed with thin layer many farmers, workers, businesses, and communities. Since chromatography. The FTIR spectrum showed that the oil contained the economic life-line of millions of people world-over carboxylic acid, alcohol, alkyl, vinyl functional groups. Fatty acid depends on tobacco, the crop needs to be sustained by taking methyl content was as follows palmitic [8.83 % - 9.26%], stearic advantage of its potential for alternative uses. To convert this [0.57 % - 0.94%], oleic [9.97 % - 11.69 %], linoleic [64.38 % -68.49 threat into an opportunity and to sustain the crop, it is %],linolenic [0.51 % - 0.71 %], and the physical properties were as follows density [925.63kgm-3] and viscosity of 94.30.The oil had imperative to intensify the research efforts towards iodine and saponification values of 133.71 and 189.48 respectively. channelling tobacco into non-conventional and economically In addition, the seed cake was also rich in protein. viable alternative uses. The ever-increasing population of both the developing and Keywords—Glyceride oil, iodine value, saponification value, developed nations of the world and the consequent increase in tobacco seed oil their diesel consumption and the non-renewability of diesel source (petroleum), as well as the adverse environmental I. INTRODUCTION effects of diesel burning are some of the factors that has made IMBABWE is one of the world‘s leading competitive alternatives to petroleum diesel very attractive [3]. The air Z producers of high quality tobacco. The tobacco industry occasioned by diesel use has been identified to be plays a vital role in the Zimbabwean economy, it generates one of the reasons for climatic changes that result in frequent about 30 % of the country‘s foreign exchange earnings and heavy rains, hurricanes and floods that threaten lives and employment. Approximately four million people directly or properties [4]. Biodiesel life cycle analysis showed 78 % indirectly depend on the tobacco crop. The reduction in CO2 (greenhouse gas) emissions relative to petro through WHO has set up a Framework Convention on diesel. The unpredictable price fluctuations of crude oil in the (FCTC) whose main objective is to protect international market have also been a major source of concern present and future generations from the devastating health, in total dependence on . Reports by Rudolf Diesel in social, environmental and economic consequences of tobacco the early1900’s showed that oils could be used as consumption and exposure to by providing a diesel fuel [5, 6, 7]. Some other was carried out on the framework for tobacco control measures to be implemented by use of vegetable oils in diesel engines in the 1930's and 1940' the Parties at the national, regional and international levels in [8, 9, 10, 11, 12, 13]. order to reduce continually and substantially the prevalence of In this paper oil from Virginia, Burley and Oriental tobacco tobacco use and exposure to tobacco smoke [1]. seeds has been extracted using soxhlet extraction. Isolation However, the worldwide anti-tobacco campaign due to the and separation of the chemical constituents of the TSO by perceived health hazards associated with the traditional form Thin Layer Chromatography (TLC) was performed and the of tobacco consumption is posing a serious challenge to TSO was fully characterised by Fourier Transform Infrared tobacco production, commerce and industry. Public health Spectroscopy (FT-IR) before quantification of the chemical composition of TSO using Gas Chromatography (GC). Haleden Chiririwa is a Lecturer in the Department of Applied Chemistry, National of Science & , P.O Box AC939 Ascot II. EXPERIMENTAL Bulawayo, Zimbabwe (phone: +263-9- 2828442 ext 2445; fax: +263-9- 286803; e-: [email protected]. Tobacco seed [1 g] was weighed in a metallic dish and was Aavian Hapanyengwi was with the Department of Applied Chemistry, dried in an oven for an hour. The seed was then left to cool National University of Science & Technology, P.O Box AC939 Ascot Bulawayo, Zimbabwe e-mail: [email protected] down in a desiccator. The changes in mass were noted and Edison Muzenda is a Full Professor in the Department of Chemical recorded. Seed was crushed in a pestle and dish and Engineering Technology at the University of Johannesburg, Doornfontein, were left to dry on air, the dried seed was then weighed and South Africa e-mail: [email protected]

http://dx.doi.org/10.15242/IIE.E1114017 36

Int'l Conf. on Chemical Engineering & Advanced Computational Technologies (ICCEACT’2014) Nov. 24-25, 2014 Pretoria (South Africa) placed in a cellulose thimble and glass was placed on top volumetric flask and made up to the mark with N- hexane. to prevent sample loss during extraction. Boiling chips were This was called solution C2 and had a concentration of 1x10-8 placed in round bottom flask and the total weight was noted as g/ml. This solution was ready for injection on GC. tare weight of the container. Hexane [100 ml] was then added The standard was weighed (0.1 g) and placed in 100 ml into the round bottomed flask, and the thimble into the volumetric flask and made up to the mark with N- hexane, extractor. The soxhlet extractor was used and leaching was standard had a composite concentration of 1x10-4 g/ml. 1 ml of done at the boiling point of hexane for eight hours. The oil the solution was pipetted to another 100ml volumetric flask was separated from the solvent by vacuum distillation on a and this was made up to the mark with N- hexane. This was rotory evaporator until all the solvent has been recovered. The called mixed solution B1 and had concentration of 1x10-6 oil was left to air dry and the weight of oil, boiling chips and g/ml. 1 ml was pipetted into another 100 ml volumetric flask flask was noted the changes in weight were recorded as the and made up to the mark with N- hexane. This was ready for yield of oil. injection into the GC. A. Fourier Transform Infrared Spectroscopy F. Determination of Density The Fourier Transform Infrared Spectroscopy was operated A 5ml volumetric flask of known mass was filled with oil at room temperature of 25 °C. Methylene chloride was used to and was closed with a glass capillary tube. The mass of the oil clean the plates and the plates were thoroughly dried prior to was noted, and this was repeated with other varieties and their use. duplicates. B. Gas Chromatography /Flame Ionisation Detector G. Determination of Iodine Value (GC-FID) 0.5g of oil was transferred into a flask and 10 ml of hexane A flame ionization detector (FID was used for the were added and the solution was warmed till the oil dissolved. identification of some selected compounds in the tobacco seed 25ml of Wij’s solution were added into same flask and mixed oil. vigorously. The flask was allowed to stand in a dark place for C. Thin Layer Chromatography (TLC) half an hour.10ml of KI solution was added and the solution was titrated against 0.1N Na S O until appearance of a yellow TLC plates coated with silica gel were used. The sample 2 2 3 colour. Starch indicator was added and the solution titrated was applied carefully on the baseline using a dropper. In with 0.1N Na S O until the blue colour disappeared marking between each application, the oil was allowed to dry before a 2 2 3 the end point. The above procedure was repeated with other further application was made. The sample was eluted using the samples and their duplicates [15]. appropriate solvent (mobile phase). After separation the solvent front was marked using a pencil and the plates were H. Determination of Saponification Value allowed to dry and viewed under UV light. The distances Approximately 2g of each variety of oils where transferred travelled by spots and by the solvent front were measured and into separate flasks, 25ml of methanolic KOH solution was Rf values calculated. added to each sample and a blank sample and the flasks where D. Preparation of Fatty Acid Methyl Esters heated under reflux in a steam bath for an hour. The samples were cooled and phenolphthalein indicator was added and the Each of the three varieties of Tobacco seed oil [200 mg] sample where titrated with 0.5N H SO until the pink colour was accurately weighed into a separate glass stoppered 2 4 disappeared. centrifuge vial and 2ml of n- hexane was added, followed by 0.1 ml of 2 N methanolic potassium hydroxide. The vial was III. RESULTS AND DISCUSSION sealed and centrifuged for 30 seconds, and the products were left to settle and the upper layer was discarded and the The FTIR spectra for the TSO are shown in Figure 1 below remainder was diluted with hexane making a concentration of and all the associated corresponding peaks shown in Table 1. fatty acid methyl esters of approximately 0.5 %. The fatty acid methyl esters were then analysed on the GC/FID. E. Determination of Fatty Acid Methyl Esters By GC FID The methyl esters were identified by comparison with retention times with those of standard methyl esters. The oil solution was prepared by weighing 0.024 g of fatty acid methyl esters into a 100ml volumetric flask and made up to the mark with N- hexane and the solution was sonicated. This solution was 1x10-4 g/ml concentration and it was labeled solution C. 1ml of solution C was pipetted into another 100 ml volumetric flask and made up to the mark with N- hexane. This was labeled solution C1 and had a concentration of 1x10- Fig. 1 FTIR Spectra for tobacco seed oil 6 g/ml.1 ml of solution C1 was placed into another 100ml

http://dx.doi.org/10.15242/IIE.E1114017 37

Int'l Conf. on Chemical Engineering & Advanced Computational Technologies (ICCEACT’2014) Nov. 24-25, 2014 Pretoria (South Africa)

TABLE I As shown in Figure 2 above, Virginia tobacco has the FTIR WAVELENGTHS AND THEIR CORRESPONDING FUNCTIONAL GROUPS highest average oil content, followed by Burley tobacco, while Wavelength Type of vibration Functional cm-1 group oriental tobacco has the least oil content even though it is 3001.39 stretch C-H considered as the most valuable in terms of the leaf quality. However the oil contents have little significant differences as 2919.58 stretch O-H shown by the F calc values which were less than the F crit , 2851.88 stretch O-H meaning that the hypothesis that there are no significant 2361.04 unknown unknown differences in the oil yields of the three varieties is true.

1740.43 stretch C=O

1461.16 stretch C=C virginia burley oriental

1156.50 stretch -C-H 36.5

719.26 bending =C-H 36

35.5 It is observed from the Table 1 that - C-H were the most

abundant in tobacco seed oil and they all possess bending type 35 of vibrations appearing at low peak wave number 719.26 cm-

1. Other saturated functional groups detected are C-O at yeild% 34.5 1156.50 cm-1, C-H at 3001.39 cm-1 and O-H at 2919.58- 2851.88 cm-1, all of which have stretch mode of vibration at 34 much higher peak except O-H that have both stretch vibration and hydrogen bonding, the hydrogen bonding indicate the 33.5 presence of undesirable water molecules. The C=O bond wave length is 1740.43 cm-1 which is in the range for ketones, 33 aldehydes and carboxylic acids. 0.025 0.05 0.1 Generally all of the three tobacco seed varieties have been ratio found to be rich in glyceride oil, ranging from 34.17 % - 36.55 % and it were slightly lower than the values reported for the Bulgarian species [14]. The high yield was due to grinding the seed prior to extraction. Grinding the seeds increased the Fig. 3 Effect of seed to solvent ratio on oil yield surface area for interaction with the solvent, and also destroyed the seed coat and the cells barriers, enabling the In all the extractions the volume of the solvent was kept solvent to have an intimate contact with every part of the seed. constant, at 100 ml, whilst the mass of seeds varied from 2.5 g, 5.0 g and 10 g, hence varying the seed to solvent ratio. The 35.1 yield of oil decreased with increase in seed to solvent ratio, as shown in Figure 3 above. Large volumes of solvent are 35 required for the yield to be considerably higher. For Burley and Oriental tobacco the yield is proportional to the seed to 34.9 solvent ratio as evidenced by the linear graphs. Tobacco seed oil varieties are classified under semi drying oils because they have high iodine values ranging from 130 - 34.8 138.Tobacco seed oil can find uses in surface coating where %ge drying properties are essential for example in , resins 34.7 and . Thin Layer Chromatography shows that TSO contains oleic acid. Since the oil had not yet been trans esterified, the oleic 34.6 acid is probably a free fatty acid. Stearic and Palmitic acid could not be visualised on the plate using UV light, Iodine 34.5 vapour and Sulphuric acid. This might be due to the fact that virginia burley oriental Stearic and Palmitic acid standards where in solid form and variety they dissolved in warm polar solvents. On spotting the TLC the standards recrystallized and could not be dissolved by the

Fig. 2 Average oil yields of each variety mobile phase solvent. The oils are rich in linoleic acid [64.38 % - 68.48 %] so most of the applications will be due to the linoleic acid

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Int'l Conf. on Chemical Engineering & Advanced Computational Technologies (ICCEACT’2014) Nov. 24-25, 2014 Pretoria (South Africa) content. Linolenic acid content is very low and favourable [7] Diesel, R. Die Entstehung des Dieselmotors. Verlag von Julius since linolenic acid is unstable and can be oxidised into Springer, Berlin, 1913, p. 115. http://dx.doi.org/10.1007/978-3-642-64948-6 undesirable compounds which affect the quality of the oil. [8] Tatti, E. and Sirtori, A. Use of peanut oil in injection, high- Linoleic acid can be used in making quick-drying oils, which compression, high-speed automobile motors. Energia termica, 5, 59-64 are useful in oil paints and varnishes. These applications (1937). Chem. Abstr., 32, 2318 (1938). [9] Gautier, M. Use of vegetable oils in diesel engines. Rev. combustibles exploit the reaction of the linoleic acid with oxygen in air, liquids, 11, 19-24 (1933). Chem. Abstr., 27, 4372 (1933). which leads to crosslinking and formation of a stable film. [10] Gautier, M. Vegetable oils and the diesel engines. Rev. combustibles Reduction of linoleic acid yields linoleyl alcohol. Linoleic liquids, 11, 129-136 (1935). Chem. Abstr., 29, 4611 (1935). [11] Cheng, F.-W. produces fuels from vegetable oils. Chem. Metall. acid is a surfactant with a critical micelle concentration of 1.5 Eng., 52, 99 (1945). −4 x 10 M at pH 7.5. Linoleic acid has become increasingly [12] Chowhury, D.H., Mukerji, S.N., Aggarwal, J.S. and Verman, L.C. popular in the beauty products industry because of its Indian vegetable fuel oils for diesel engines. Gas Oil Power, 37, 80-85 (1942). Chem. Abstr., 36, 5330 (1942). beneficial properties on the skin. Research points to linoleic [13] Amrute, P.V. Ground- oil for diesel engines. Australasian Engr., 60- acid's anti-inflammatory, acne reductive, and moisture 61 (1947). retentive properties when applied topically on the skin. [14] Zlatanov. M, M. A. a. G. A., 2007. Lipid Composition of Tobacco Seeds, Bulgarian Journal of Agricultural Science, Volume 13, pp. 539-544. IV. CONCLUSION [15] Seatons, 2014. Croda International PLC. [Online] Available at: http://www.seatons-uk.co.uk Our locally grown tobacco varieties are rich in glyceride oil. The three tobacco seeds varieties yielded glyceride oil of 34.17 % - 36.55 % by mass. The FTIR spectrum showed that the oil contained carboxylic acid, alcohol, alkyl and vinyl functional groups. Fatty acid methyl content was as palmitic [8.83 % - 9.26 %], stearic [0.57 % - 0.94 %], oleic [9.97 % - 11.69 %], linoleic [64.38 % -68.49 %],linolenic [0.51 % - 0.71 %], and the physical properties such as density [925.63 kgm-3] and viscosity of 94.30. The oil had an iodine and saponification values of 133.71 and 189.48 respectively. In addition, the seed cake was also rich in protein. These properties are essential when considering the applications of the oil which range from the fuel industry to pharmaceuticals. The by- products such as seed cake can be used as stock feeds in . The research can also be diversified using cheaper and non-toxic methods such as oil press machines for extractions, designing of reactors for large scale extraction and purification of the oil and also the economics part, where there is need to conduct cost benefit analysis and identifying the markets. Commercialisation of tobacco seed products has a lot of potential and can contribute immensely to the Zimbabwean economy.

ACKNOWLEDGEMENTS Grateful acknowledgement is made to the Tobacco Research Board (TRB) and SIRDC where most of the experimental work was carried out.

REFERENCES [1] Article 3, A/FCTC/INB6/5, Draft WHO framework convention on tobacco control, Sixth session, Agenda Item 4, March 2003. [2] H. Frederick Gale, Jean C. Buzby. Imports from China and Safety Issues, USDA Economic Bulletin, No. 52, July 2009. [3] Shah.I, S. S. M. G., 2004. Biodisiel Preparation by lipase - catalysed transesterification of jatropha oil. Energy and fuels, 18(1), pp. 154-159. [4] Bamgboye.A .I, A. H., 2008. Prediction of cetane number biodiesel fuel from the fatty acid methyl ester composition. International Agrophysics, Volume 22, pp. 21-29. [5] Diesel, R. The Diesel oil-engine. Engineering, 93,395-406 (1912), Chem. Abstr., 6, 1984. [6] Diesel, R. The Diesel oil-engine and its industrial importance particularly for Great Britain. Proc. Inst. Mech. Eng., pp. 179-280 (1912). Chem. Abstr., 7, 1605 (1913).

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