1.1 Background of study
Solid waste is a discarded solid fraction produced from domestic, commercial, industrial, agricultural, institutional, mining activities and public services. The waste is a term that means useless, unwanted or discarded material(Gaur, 2009) and one of these agricultural wastes is ackee seed. Anything that is not of further use in a process is known as waste for that process which can be useful for other process and can be termed as raw material for that process. When this waste is in a comparatively solid form it is known as the solid waste. Whatever may be the form of waste, it deteriorates the environment if it is disposed in an offensive manner.
Ackee seed was imported to Jamaica from West Africa in the late 1700s by Captain William Bligh of “Mutiny on the Bounty” lore, who is thought to have carried the seed from tropical West Africa (possibly Guinea) to the Caribbean Islands, and specifically to Jamaica in 1793 and is often grown as an ornamental tree. It is widespread in the equatorial region and found in West Sudan domain. Although the ripe fruits are edible, the unripe fruits and the walnut-like seeds are toxic due to their hypoglycin A and B content. Also, other hypoglycemic compounds and cyclopropanoid amino acids, are found in the seed (Adepoju, Abdul-Hammed, Esan, Bello, & Olajide, 2013).
Ackee fruit, scientifically known as Blighia sapida (BP), a member of Sapindaceae family that will be considered in this study is an evergreen dense crown tree of about 25 m which produces fruit 2 times a year, between January and March, and June and August. The fruit is a three-valved, more or less pear-shaped capsule that is round and bright red. At maturity the valve opens by reflex to expose 1-3 shiny black seeds with a yellow or white edible known as aril round the base. This whitish fruit is edible and the black seeds are thrown away which constitute environmental pollution (Tijani, Ndamitso, Aliyu, & Olakunle, 2013). The annual production of these fruits continues to increase and as such large quantity of waste is generated. Nigeria like any other developing country is facing the problem of solid waste disposal. It is on this basis that the present studies will ensure the development of more efficient ways to convert this readily available, affordable, underutilised agricultural waste into useful products with improved commercial value. BP seeds also serve as a viable low cost agricultural waste to remove potentially toxic elements from aqueous solution (Tijani et al., 2013).
There are also health benefits associated with the ackee fruit and several parts of the tree. Analysis of the arils has indicated the fruit to be a good source of nutriments. Although ackees (Blighia sapida) are eaten in several countries, its consumption has been integrally linked with Jamaica for centuries. A popular dish, ackee dish, is enjoyed by all age groups and socio-economic classes in Jamaica. Ingestion of immature ackee fruit results in Jamaica Vomiting Sickness (JVS), attributed to consumption of high levels of the non proteinogenic amino acid, hypoglycin A, found in the edible portion of the ackee (Goldson et al., 2014). Several additional health benefits have been reported based on local applications. In the Gold Coast, a mixture of pulverized bark and ground hot peppers is rubbed on the body as a stimulant; in Cuba, a blend of ripe arils with sugar and cinnamon is given as an antipyretic and as a treatment for dysentery. In the Ivory Coast, the bark is mixed with pungent spices in an ointment and applied to relieve pain; crushed new foliage is applied to the forehead to relieve severe headache. In some parts of Africa, the fruit is used to produce soap and in Cuba, an extract of the flower is used a perfume (Top Tropicals, 2007). Additionally, due to the pharmacologic ability of hypoglycin A to reduce blood sugar to extremely low levels, pharmacologic research has been geared toward exploring the hypoglycemic properties of hypoglycin A for the treatment of diabetes (Bowen, Camille, & Minott, 2012).
Extraction method using soxhlet extraction apparatus in extracting oil from ackee seed will be carried out, commonly used extraction solvent, petroleum ether will be used to extract the oil. There are three major steps in solvent extraction i.e., oil seed preparation, oil seed extraction and recovery of the extraction solvent. Physical and chemical properties of ackee seed oil (ASO) will be also characterised.
The quality characteristics of oil obtained by soxhlet extraction are primarily dependent on moisture content, ash content, saponification value, crude oil, peroxide value. Extraction of ackee oil from seeds will be optimized using organic solvent ether based on the amount of the oil to be extracted and this will be carried out.
In this study, the effect of conditioning on the yield of ackee seed oil will be investigated and this will be carried out by varying the process parameters temperature, time, solvent-solid ratio and agitation speed according to the experimental design. Although much work has been done on ackee seed oil extraction, optimisation has not been carried out extensively.
Design Expert (version 7.0. 0) software will be used to obtain optimized conditions for either maximizing or minimizing the process parameters as the case may be. Response surface methodology (RSM) will be used to develop mathematical expression correlating the variables using average experimental values under the design expert software (version 7.0.0) using central composite design (CCD) will be employed for the experimental design. Analysis of variance (ANOVA) will be performed to determine the significant differences between the independent variables.
Therefore, the present study aims at optimising the oil extracted from ackee seed which poses environmental challenges in its mode of disposal and use it for soap making.
1.2 Problem statement
Ackee seeds contribute to high volume of solid waste in agriculture, and because the disposals of these seeds are basically done by burning, thrown on dumped site as household waste, it contribute to other environmental nuisance associated with solid waste and the method of disposal poses danger to the environment. Furthermore the toxicity of the ackee seeds has been found to be associated with its content of hypoglycin B which has made it to be poisonous and of little value since the oil is not consumable. The focus of this work which is to extract oil from ackee seed and utilize the extracted oil for other valuable product will serve as an effective means of disposing of the seed and also converting waste to wealth.
1.3 Aim and Objectives
The aim of this work is to extract oil from ackee seed and use it for soap making processes.
Specific objectives of this study are:
- To extract oil from ackee seed (ASO).
- To characterize extracted oil from ackee seed.
- To optimize process conditions for the maximum recovery of oil from ackee
- To produce soap using ackee seed oil in place of palm kernel oil.
- To characterize the produced soap from ackee seed oil and compare its characteristic to those of selected commercial bar soap
1.4 Scope of study
This study is limited to optimization of oil extraction from ackee seed and eventual utilization of the oil for soap making by experimental study limited to laboratory work. The material to be used will be limited to ackee seed that will be sourced from Ado-Ekiti in Ekiti State. Extraction of oil from ackee seed will be carried out and extracted oil will be characterised. Optimisation of some selected process parameters will be done using central composite design under response surface method of Design Expert (7.0.0).
Ackee seeds have little or no commercial and nutritional significance in the West African sub-region. Blighia sapida fruit is cultivated for the arils which are used as meat substitute in soups while the seed is discarded and underutilized due to its anti-nutritional contents. The use of the seed is limited due to dearth of information on the properties but the seed had the potentials to be used in non-food industries. Ackee seeds is a good source of biochemical and nutritional compounds but the limitation to the full utilization of ackee seeds is the high concentrations of anti-nutritional factors (oxalate, phytate and tannin) and low alkaloid content which render it useless for human and animal nutrition(Aguemon, Digbeu, Mankambou, Dué, & Kouamé, 2018). This study therefore justifies that Blighia sapida seeds might serve as a viable low cost agricultural source for seed oil production.