PHYSICOCHEMICAL PROPERTIES AND FATTY ACID COMPOSITION OF AFRICAN STAR APPLE SEED OIL
Oil extracted from African star apple by continuous extraction process using soxhlet apparatus was subjected to physico chemical and fatty acid profile analysis. Results obtained show that the acid value, lodine value, peroxide value, saponification value, free fatty acid, refractive index, melting point, smoke point, flash point, fire point, and specific gravity are 30.67mg/g, 20.67mg/g, 5.00mg/g, 48.00mg/g, 0.87%, 0.96, 1.47, 19.00OC, 1.03, 122.00OC, 156.00OC, and 180.00OC respectively. All these values confirm that African star apple oil is suitable for human consumption as well as for industrial uses which compared favourably with the value obtained in palm oil, groundnut oil as well as cotton seed oil (Adewusi, 1997). In term of fatty acid profile African star apple oil contains high percentage of unsaturated fatty acids 85% oleic acid 7% and 6% of linoleic and linolenic respectively while saturated fatty acid such as arachidoic, lauric were recorded with maximum value of 17% recorded for arachidoic and lauric. Therefore African star apple oil can be described as oil that has more unsaturated fatty acids than saturated fatty acids which made it suitable for human consumption as it prevent low density lipoprotein which is a precursor of cholesterol that results into heart attack and hypertension.
TABLE OF CONTENTS
Title page i
Table of content vi
2.0 LITERATURE REVIEW
2.1 AFRICAN STAR APPLE (CHRYSOPHYLLUM ALBIDUM)
2.1.1 CLIMATIC RANGE OF THE PLANTED AFRICAN STAR APPLE
2.2 CULTIVATION, HARVESTING AND YIELD
2.3 HARVEST PERIOD
2.4 SPOILAGE OF THE AFRICAN STAR APPLE
DISEASES ASSOCIATED WITH AFRICAN STAR APPLE
STORAGE METHOD OF THE AFRICAN STAR APPLE
2.5 NUTRIENT COMPOSITION
2.6 ECONOMIC IMPORTANT OF AFRICAN STAR APPLE
2.7 OIL EXTRACTION
2.8 USES OF OIL FROM PLANTS
2.9 FATTY ACID
TYPES OF FATTY ACIDS
LENGTH OF FREE FATTY ACID CHAINS
UNSATURATED FATTY ACIDS
EXAMPLES OF UNSATURATED FATTY ACIDS
ESSENTIAL FATTY ACIDS
EXAMPLES OF SATURATED FATTY ACIDS
FREE FATTY ACIDS
FATTY ACIDS IN DIETARY FATS
REACTION OF FATTY ACIDS
HYDROGENATION AND HARDENING
AUTO OXIDATION AND RANCITY
CIRCULATION OF FATTY ACIDS
DIGESTION AND INTAKE
3.0 MATERIALS AND METHODS
3.21 EXTRACTION OF OIL
3.22 PHYSICO CHEMICAL ANALYSIS OF OIL
3.22.1 SPECIFIC GRAVITY DETERMINATION
3.22.2 REFRACTIVE INDEX
3.22.3 MOISTURE CONTENT
3.22.4 ACID VALUE
3.22.5 FREE FATTY ACID
3.22.6 SAPONIFICATION VALUE
3.22.7 PEROXIDE VALUE
3.22.8 IODINE VALUE
3.22.10 DETERMINATION OF SMOKE POINT
3.22.11 DETERMINATION OF FLASH POINT
3.22.12 DETERMINATION OF FIRE POINT
3.23 FATTY ACID PROFILE ANAYSIS
3.23.1 DETERMINATION OF Nacl (salt)
3.23.2 VOLUMETRIC ANALYSIS DATA
4.0 RESULTS AND DISCUSSION
4.1 PHYSICO CHEMICAL PROPERTIES OF AFRICAN STAR APPLE OIL
4.2 RESULT OF ANALYSIS OIL ON FATTY ACID PROFILE
5.0 CONCLUSION AND RECOMMENDATION
The African star apple (Agbalumo in Yoruba) is a native of many parts of tropical African. The tree grows as a wild plant and belongs to the family Sapotaceae (hutchinson and Daiziel, 1963). It is an evergreen tree that can grow up to 40 meters high and about 2 meters in girth. It has a straight and long fluted bole with small buttress at the base. The bark is thin and light brown and when incised exudes a gummy latex. The African star apple in Nigeria has a very wide geographical spread but its ideal habitat is lowland tropical rain forest. The fruits usually appear in July, ripen between December and March. The fruit contain three to five shiny seeds, which are not eaten.
The fruit has been shown to have tremendous economic value by Okafor (1975) and Inoh et al. (1977) who reported that jams comparable to raspberry jams and jellies could be made from it, Its high pectin content (Inoh et al., 1977) is also suggestive of its vast medicinal benefits, which include plasma cholesterol level reduction, rate of sugar uptake as well as its detoxifying action and effectiveness in diarrhea therapy (Hulme, 1970).
However, up till now only the juice component of the fruit is consumed to a large extent, while a few people relish the gummy. tasty pulp as well. The fruit, as is the situation with most tropical fruits, is seasonal and highly perishable. These factors militate against its large scale production. Nwadinigwe (1982), however, reported effective cold storage preservation of the fruit up to a period of l2months with 2, 4 dichlorophenoxy-acetic acid. Adoption of this approach could serve as impetus for massive cultivation and large scale processing of the fruits. As a prelude to processing of the fruits, some important physical properties need to be determined. Therefore, the essence of this study was to determine the proximate composition and mineral contents of the different parts of the fruit namely the peel, pulp or (fibre) and the juice as well as the physical properties, such as the weight of the fruit, weight of the peel, juice and pulp. the characteristic surface area and the bulk density.
Trees and shrubs with medicinal and nutritional potentials abound in Nigeria (Burkill, 1985). Several of these plants have fruits which have been identified to be nutritionally important (lhekoronye and Ngoddy, 1985).
In recent times, the desire to conserve resources spent on importation of oil for domestic and industrial use gave renewed impetus in the search for novel sources to complement the traditional ones. Attention has therefore, been focused on under-utililsed local seeds for possible development and use. There are several of these under-exploited plant seeds in Nigeria.
Chrysophyllum albidum Linn (African Star apple) belongs to the family sapotaceae. It is found in many ecozones of Africa, Nigeria inclusive (Bada, 1997). Its leaves are used in ethnomedicine (Adewusi, 1997). The fruit pulp is rich in iron and vitamin C and is good source of raw material for some industries (Asenjo, 1946: Conrad, 1999; Adisa, 2000).
While the pulp is eaten, the seeds are usually thrown away.
Dacyodes edulis G.doh (African pear) is a Burseracea and has many medicinal and nutritional uses (Burkill, 1985). The fruit pulp is eaten and the seeds usually thrown away (Ajayi and Oderinde, 2002). Obasi and Okolie (1993) studied the potential of the seeds for food supplement.
Landolphia owariensis P.Beauv (Vine rubber) belongs to the family apocynacea. It has many medicinal and nutritional uses (Gill, 1992; Ebi and Ofoelue, 1997; Owoyele et al., 2001). The fruit pulp which is contained in a pod is eaten and the seeds usually thrown away. Napoleana imperidis is of the family Lecythidacea. Its leaves have many medicinal uses. (Obute, 2005) the pulp is eaten and the seeds, thrown away.
Eleals guineansis (Palm tree) is commercially very relevant. The nutritional uses, the palm kernel all (PKO) is particularly useful. Therefore, except for E.guineensis seed, the potential of the other four plant seeds are presently under-exploite4 (the present study was therefore undertaken to explore their potential as possible sources of oil for domestic (and industrial uses, relative to the established potentials ‘-of palm kernel oil (PKO) from E.guineensis seed.
Consequently this project works is designed to achieve the following aim and objectives.
1. To extract oil from African star apple seeds.
2. To evaluate the physico-chemical properties and fatty acids compositions of the oil extracted from African star apple seeds..