Bekele Eshetu
Essential Oils Research Center, P. O. Box 5747, Addis Abeba, Ethiopia, Tel: 00251 1 611311, Fax: 00251 1 611764

Seminararbeit im Rahmen der Vorlesung Ölpflanzen - Züchtung, Anbau, Verwertung im Wintersemester 1999/2000, Wien, 2. Februar 2000

Abstract
1. Introduction
2. Background
3. Methodology
4. Results and Discussion
References

Abstract
Nicotiana tabacum L. (tobacco) of the family Solanaceae or the night shade family has small seeds that can give an oil and a subsequent by-product, meal. Tobacco seed is a by-product of tobacco leaves production in Ethiopia and in other countries. About 30% of the seed is oil. The remaining parts are protein, crude fibre, carbohydrate and inorganic material. Trilinolein and palmitodilinolein are the main triglycerides in the seed oil which account for about 90% of the composition of the oil. The major individual fatty acids are linoleic acid in the range of 66-76%, oleic acid 17-27%, palmitic acid 7-10% and stearic acid 3.1%. Drying index and iodine values of the seed oil are in the range of 55-75 & 135-147 respectively. Hence, the seed oil is classified as a linoleic oil, which is in the semi-drying oil category. Vegetable oils are common raw materials in the coating industry, especially for alkyd resins. In this areas of applications the oil from the seed of Nicotiana tabacum can find some uses. The chemical characterisation of Nicotiana tabacum seed oil has been found important to look at alternative products of the crop, find new uses for the crop and also for preserving seed purity. From the quality point of view, tobacco seed oil is comparable to other oils.

1. Introduction

The species Nicotiana tabacum deserves its name from Joan Nicot, a Portuguese who introduced the tobacco plant in to France. The specific name being derived from the pipe in which the herb is smoked.

The plant is a handsome unbranched annual growing to a height of 3 to 6 ft with large oval leaves. It bears pink flowers and its fruit is a capsule with numerous very small seeds.

The seeds of the tobacco plant are surprisingly small but with large number per plant. They are more or less ovate in shape, about 0.75mm long, 0.53mm broad and 0.47mm thick. They are long-lived, stored in dry conditions at ordinary temperature, resistant to rather high humidity, except at high temperature.

The average 1000 seed weight is in the range of 0.08 - 0.09gm.

The protective coat of the mature seed has a prominent epidermis and below this epidermis are parenchyma cells. The outer walls are composed of cellulose. The endosperm contains thin walled cells rich in aleurone and oil.

Fig. 1: Tobacco Seeds

2. Background

The tobacco plant is grown in Ethiopia and in other parts of the world for long times. In Ethiopia it is grown in Awassa and Wollayta plantation areas in the Southern part of the country. The leaf of the plant is used in the production of cigarettes in the tobacco processing industries.

The annual production of tobacco seeds as by-product from Awassa and Wollayta Plantation areas is about 150-200 tones of oriental type (Hailu and Eguale, 1992 ).

Oil content of tobacco seed has been found to range from 33.6-39.4 (EL-Hamid et al., 1982 ).

The proportions of individual fatty acids in Nicotiana tabacum seed oil are linoleic acid 70.6%, oleic acid 17.1%, palmitic acid 7.9%, stearic acid 3.1% and others (Gofur et al., 1993).

The limited number of available oil seed crops, with concurrent limited variability in fatty acid composition, has spurred industrial interest to look other oils from oil seeds, which are optimized for specific applications. These kinds of crops can contain a higher percentage of a desirable fatty acid.

In industries different kinds of resins (binders) can be used in the production of paints depending on the end use after application, for instance, alkyd resin for air-drying glossy finishes. Alkyd resin is an oil- or fatty acid modified polycondensation product of polyols and polycaroboxylic acids. This resin being brittle, to avoid and improve its performance, oil is added to the resin. For air-drying finishes oils from linseed & soybean are used.

In architectural coating systems alkyd resins play an important role because of their benefits such as the economical balance, an uncomplicated application and an outstanding appearance of the films.

Nutritional value of the tobacco seed oil is also better than groundnut and cotton seed oils and comparable to safflower oil. Refined tobacco seed oil is used as an edible oil in some European countries (Talaqani et al., 1986).

Among the different types and cultivars of tobacco studied, chewing tobacco cv. A 145 gives the highest yields, seed yield 1171 kg/ha and oil yield 432.9 kg/ha (Patel et al., 1998). From the quality point of view, the seed oil is comparable to other oils, for instance, the crude oil is as good as groundnut and cottonseed oils.

The chemical characterisation of Nicotiana tabacum seeds has been found important to look at alternative products of the crop i.e. oil and meal and find some uses of these products. The study is also useful for preserving seed purity.

Table 1: Fatty Acid Composition of Oils Obtained from Tobacco Seeds Compared with  those of Other Oil-bearing Seeds

Oil Seed	C16:0	C16:1	C17:0	C18:0	C18:1?9	C18:1?11	C18:2	C18:3	C20:0	C22:0
Kentucky 104	9.5	0.1	0.1	2.8	10.6	0.6	74.9	1.1	0.2	0.1
Bright Italia	9.2	0.1	0.1	2.5	9.5	0.8	76.1	1.4	0.2	0.1
Bright V	8.9	0.1	0.1	2.6	11.1	0.7	75.1	1.1	0.2	0.1
Grape Seed	7.7	0.2	-	3.8	14.0	0.6	73.1	0.4	0.2	-
Safflower	7.5	-	-	2.8	12.0	0.8	76.1	-	-	-

Source: Frega et al., 1991

Table 3: Composition of Tobacco Seed Compared to Other Oil-bearing Seeds (% dry wt)

Oil Seed	Moisture	Raw Protein	Lipids	Unsaponifiable Oil Fraction	Fibre	Ash	Nitrogen-Free Extract
Kentucky 104	5.1	25.0	48.0	1.2	19.9	3.2	2.7
Bright Italia	5.1	25.3	47.8	1.5	21.2	3.6	0.6
Bright V	3.3	25.9	47.2	1.5	21.0	3.2	1.2
Sunflower	5-6	20-30	30-50	0.8-1	11-22	3-6	8-20
Rapeseed	-	-	-	-	15.1	-	-

Source: Frega et al., 1991

3. Methodology

Soxhlet extraction apparatus is used for extraction work using hexane as a solvent. The seeds are dried for 15-19 hrs at 60-70 degrees, crushed to a fine powder & taken to the extraction apparatus and extracted. Gas chromatography is used for the determination of the fatty acid composition.

Literature survey has been conducted to start the study of the unexploited oil and meal potential of tobacco seed.

4. Results and Discussion

The seed of the tobacco plants taken from Ethiopia and also from other countries has been found potentially rich in oil, 33 - 40%. From the fatty acid composition, it can be observed that the tobacco seed would be classified as a linoleic oil (tables 1 & 2). The high degree of unsaturation of the seed oil could render the oil to be susceptible to autoxidation and polymerization, resulting in cross-linked and tough films upon exposure to air. Hence the oil could find some uses in industrial applications (paint industries). It will either alone or blended with linseed oil, will be used in the syntheses of modified alkyd resin for air-drying glossy paints.

The high percentage of unsaturated acids, which has been found comparable to grape seed oil (table 1), also suggests potential food use of tobacco seed oil. But the oil will find this use after refining.

The percentage composition of meals obtained from tobacco seeds (table 3) shows fat, raw protein and ash content similar to those meals obtained from other common oil bearing seeds. Also the high fibber content makes these meals similar to those obtained from other crops with little dimension seeds. The tobacco seed cake after extraction of oil is rich in nitrogen (around 6%) and could serve as an animal feed supplement.

References

Akehurst, B.C, 1981, Tobacco, 2^nd ed., Longman Inc., New York.
EL-Hamid, M.F.A., EL-Naggar, H.A., EL-Sakr, A.S. Abdel-Hamid, M.F., 1982, Chemical Studies on Tobacco Seed Oils from some Varieties Cultivated in Egypt, Research Bulletin, Fac. Agric., Aiin Shams Univ. No. 1737.
Frega, N., Bocci, F.,Conte, L.S., Testa, F., 1991, Chemical Composition of Tobacco Seeds (Nicotiana tabacum L.), JAOCS, 68: 29-33.
Gofur, M.A., Rahman, M.S., Ahmed, G.M., Hossain, A, Haque, M.E., 1993, Studies on the Characterisation and Glyceride Composition of Tobacco (Nicotiana tabacum L.) Seed Oil, Bangladesh J. Sci. Ind. Res. 28: 25-31.
Hailu A., Eguale, S., 1992, Extraction of Oil from the Seed of Nicotiana tabacum L., Dil Paints Factory, Unpublished Research Paper, Ethiopia.
Nyle'N, P., Sundeland, E., 1965, A Text Book of the Chemistry and Technology of Paints, Varnishes, and Laquers, Interscience Publishes, Inc., New York.
OCCA (ed.), 1972, Paint and Technology Manuals, Part three Convertible Coatings, 2^nd ed., Great Britain.
Patel, J.A., Patel, B.K., Chakraborty, M.K., 1998, Production Potential and Quality Aspects of Tobacco Seed Oil, Tobacco Research 24: 44-49.
Talaqani, T.E., Shafik, J., Mustafa, F.K., 1986, Fatty Acids Composition of the Seed Oil of Certain Tobacco Varieties Cultivated in Northern Iraq, Indian J. Agric. Chem. 19: 147-154.