Bioresource Technology 64 (1998) 245-247 © 1998 Elsevier Science Ltd. All rights reserved Printed in Great Britain 096(}-8524/98 $19./)(} ELSEVIER
PII:S0960-8524(97)00163-6
Short Communication
the physico-chemical characteristics of the oils derived from the seeds.
Studies on Some Seeds and Seed Oils Abstract
The chemical compositions of seeds and the physicochemical characteristics of the oils extracted from them have been investigated for six varieties of mango (Mangifera indica) seeds and for five other tropical seeds. The oil contents of Mangifera indica seeds were in the range 12"2-25"8°/o, while those of the other seeds were as high as 54"7% in Bridelia ferruginea. Characterization of the oils of Mangifera indica varieties showed that they were non-drying, except for Petters-Ibadan which was semi-drying. Of the other tropical seeds, Monodora myristica gave a drying oil, Crysophilum abidum and Bridelia ferruginea gave semi-drying oils, while Canarium schweinfurthii and Khaya senegalensis gave non-drying oils. The chemical compositions of the seeds suggest they may be suitable as animal feeds. © 1998 Elsevier Science Ltd. All rights reserved
METHODS
The oils were extracted from the seeds with a soxhlet extractor using n-hexane, except for K. senegalens& which was extracted with petroleum ether (40-60°C). The oils were characterised by standard methods (Cocks & Van Rede, 1966; Basir, 1971) for oil and fat analysis. Proximate protein contents of the seeds were determined by the Kjeldahl digestion method (Cocks & Van Rede, 1966). RESULTS AND DISCUSSION
The physico-chemical characteristics of the oils from six varieties of M. indica and from other seeds are shown in Table 1. For M. indica, the oil from Petters-Ibadan is semi-drying, judging from its iodine value (IV) of 139-4 g/100 g. The oils of the other varieties are non-drying and can be classified as fats. From the peroxide values, the oils of M. indica would be stable to oxidative degradation, but the high acid values for some of the oils (PettersIbadan, Hindi-Sinnar and Alphonse) suggest some in vivo hydrolytic activities in the oil seeds. The IVs of the oils suggest that M. myristica is a drying oil; C. abidum and B. ferruginea are semidrying oils while C. schweinfurthii and K. senegalens& are non-drying oils. The latter two oils would be prone to peroxide formation, based on their peroxide values, but may be suitable for soap production judging from the high saponification values. The chemical compositions of the seeds of M. indica and other seeds are shown in Table 2. The oil contents of the seeds of M. indica are as high as 25"8% in Hindi-Sinnar and are comparable to the ones for some commercial vegetable oils, e.g. soyabean (11-25); cotton seed (18-28), rubber seed (21-25) (Ajiwe et al., 1994). The protein contents are low, not higher than 5.4%, but could be signifi-
Key words: Physico-chemical characteristics of seed oils, chemical composition of seeds.
INTRODUCTION
A number of tropical plants growing within the rain forest and the semi-arid zones of Nigeria bear fruits, some of which are edible, but with seeds which are largely discarded. Recent studies have shown that some of the seeds could find industrial application as animal feeds, based on their nutritional values, and as raw materials for paint formulation based on the amounts and nature of the oils contained in them (Eromosele & Eromosele, 1993; Eromosele et al., 1994; Offem & Dart, 1989; Ajiwe et al., 1994; Ukhun & Uwatse, 1988; Adesomoju, 1987; Nwadinigwe, 1987; Dosumu & Ochu, 1995). Recent studies (Nwadinigwe, 1987) showed that Mangifera indica, linn has oil, although in low yield. The studies, however, were not specific on the variety of M. indica, although several varieties of the fruit are known. The present communication is on studies of the chemical compositions of six varieties of M. indica seeds and five other tropical seeds and 245
Short communication
246
Table 1. Some physico-chemical characteristics of the oils from varieties of Mangifera indica and other seeds
Variety/species
Iodine value (g/100 g)
Peroxide value (mEg/kg)
Saponification value (mg KOH)
139.4 47.0 21.6 41.9 40.6 49.5 177-5 157-5 149-9 87-0 68.0
0.0 0-0 0-0 0.0 0.0 0"0 6.5 0"0 0.0 40.0 26.0
102.7 41.0 164-4 257-8 157.4 74.3 44.9 32.3 213.0 186.0
Acid value % FFA (mg KOH/g) (as oleic acid)
Class of oil
Mangifera indica Petters-Ibadan Hindi-Sinnar Petters Kazaure Alphonse Binta-Sugar Dabsha
Monodora myristica Crysophilum abidum Bridelia ferruginea Canarium schweinfurthii Khaya senegalensisa
20.4 21.6 55.7 5.6 4-6 2-2 16.3 26.9 23.4 0.3 -
10.2 10.8 27.8 2.8 2.3 1.1 8.1 13.5 11.7 0.2 -
Semi-drying Non-drying Non-drying Non-drying Non-drying Non-drying Drying Semi-drying Semi-drying Non-drying Non-drying
Extractant: n-hexane except for: aPet. ether (40-60°C).
Table 2. Chemical composition of varieties of Mangifera indica and other seeds
Variety/species
Oil content (%)
Protein (%)
Moisture (%)
Carbohydrate (%)
14.0 25.8 12.2 21-7 22.1 16.1 52"0 2.9 54-7 52-5
2-9 3.0 3.9 4-3 5-4 4.0 14.6 10.8 -
54.5 49.9 40.9 35.3 48.3 40.5 12-1 4.4 5"1 -
28.6 21.3 43-0 38.7 24.2 39.4 21"3 81.9 -
Mangifera indica Petters-Ibadan Hindi-Sinnar Petters Kazaure Alphonse Binta-Sugar Dabsha
Monodora myristica Crysophilum abidum Bridelia ferruginea Khaya senegalensis
cantly higher as a percentage of dry weight of the seeds in view of the high moisture contents. The oil contents of M. myristica, B. ferruginea and K. senegalensis are significant. In particular, M. myristica as a drying oil could serve as a viable alternative to linseed oil for paint formulation judging by an oil content much higher than linseed (35-40) (Ajiwe et al., 1994). The protein contents of M. myristica and C. abidum are a factor of 2 higher than the value for M. indica, but lower than the values for cotton seed (28"72 +0"1) (Eka & Isbell, 1994) and shelled rubber seed (Ukhun & Uwatse, 1988). The results of these studies show that the oils from the Petters-Ibadan variety of M. indica, and from M. myristica, C. abidum and B. ferruginea might find application for industrial finishes and paints. The oils of the other varieties of M. indica are fats and might be suitable as lubricants and a cosmetic base, for body cream and pomade, as previously suggested (Nwadinigwe, 1987). The seeds are potential sources of animal feeds, subject to standard toxicological tests.
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REFERENCES
Adesomoju, A. A. (1987). Fatty acid composition of the seed oil of Chlorophora excelsa. Bull Chem. Soc. Nig., 12, 69-71. Ajiwe, V. I. E., Umerie, S. C., Okeke, C. A. & Oburota, V. N. (1994). Extraction and utilization of cassava seed oil Bioresource Technol., 47, 85-86. Basir, O. (1971). Handbook of Practical Biochemistry, pp. 32-34. Ibadan University Press. Laboratory Handbook for Oil and Fat Analysts, pp. 30-37, 107-130. Academic Press. Dosumu, M. I. & Ochu, C. (1995). Physico-chemical properties and fatty acid composition of lipids extracted from some Nigerian fruits and seeds, Global J. Pure Appl. Sci., 1, l&2 45-49. Eka, O. U. & Isbell, B. (1994). Nutrient content of cotton seeds from three varieties of cotton grown in Nigeria. Nig. J. Sci., 18, 76-78. Eromosele, I. C. & Eromosele, C. O. (1993). Studies on the chemical composition and physico-chemical properties of seeds of some wild plants Plant Foods Hum. Nutr., 43, 251-258. Eromosele, I. C., Eromosele, C. O., Akintoye, A. O. & Komolage, T. O. (1994). Characterization of oils and chemical analyses of the seeds of wild plants Plant Foods Hum. Nutr., 46, 361-365.
Short communication Nwadinigwe, C. A. (1987). Chemical and toxicological studies on the seed oils of Mangifera indica, linn, and Persea americana, mill. Bull. Chem. Soc. Nig., 12, 73-75. Offem, J. O. & Dart, R. K. (1989). Analysis and potentials of the seed oil of Mimusops djave. Nig. J. Appl. Sci., 7, l&2 1-5. Ukhun, M. E. & Uwatse, G. M. (1988). Nutritional evaluation of selected Nigerian rubber seed products - - a chemical approach. Plant Foods Hum. Nutr., 38, 309-318.
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I. C. Eromosele*, C. O. Eromosele, P. Innazo & P. Njerim Department of Chemistry, Federal University of Technology, PM.B. 2076, Yola, Adamawa State, Nigeria (Received 29 May 1997; revised version received 21 October 1997; accepted 22 October 1997) *Author to whom correspondence should be addressed.