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European Journal of Applied Sciences – Vol. 12, No. 3

Publication Date: June 25, 2024

DOI:10.14738/aivp.123.16948

Tangka, J. K., Bongmo, J. M., & Etengeneng, A. E. (2024). Investigations on Specific Phytochemical Characteristics of Seed Oil and

Defatted Seeds of Four Oil-Producing Plants Found in Cameroon. European Journal of Applied Sciences, Vol - 12(3). 215-232.

Services for Science and Education – United Kingdom

Investigations on Specific Phytochemical Characteristics of Seed

Oil and Defatted Seeds of Four Oil-Producing Plants Found in

Cameroon

Julius Kewir Tangka

Renewable Energy laboratory, FASA, University of Dschang Cameroon

Jaff Marilyn Bongmo

Renewable Energy laboratory, FASA, University of Dschang Cameroon

Agbor Esther Etengeneng

Department of Biochemistry, Faculty of Science, University of Dschang, Cameroon

ABSTRACT

A study was conducted to find and create new possible sources of seed oils that

might be extracted locally and utilised in Cameroon to produce biodiesel, while

also valuing the defatted seeds as alternate sources of nutrients for consumption

by humans and animals. Pretreatment procedures included washing and drying

the seeds of Ricinodendron heudelotii (njangsa), Cucurbita maxima (pumpkin),

Citrullus lanatus (watermelon), and the pulp of Raphia hookeri (raphia). A

hydraulic press operating at 200 bars was then used to extract the oil from each

sample. A proximate analysis was performed on both the defatted and intact

seeds. While the proximate composition of the defatted cakes was examined, the

extracted oils' potential for use as biodiesel was examined. The four samples' oil

quality parameters were determined to be as follows: acid value (3.6 to 5.8

mgKOH/g), iodine value (19.0 to 39.0 gI2/100g), saponification value (56.1 to

280.6 mgKOH/g), and oil extracted (11.40% to 37.40%). All samples' crude

protein, crude ash, and crude carbohydrate contents increased after defatting,

whereas their crude lipid and crude fibre contents decreased. The highest protein

content was found in defatted pumpkin seeds (41.11% DM), whilst the lowest

protein content was found in defatted raffia palm pulp (7.35% DM). The findings

of the oil parameter analysis indicated that all four oils have the potential to be

employed as low-cost alternatives as feedstock for the production of biodiesel. The

defatted seeds' results demonstrated that, with the exception of lipids, defatting

concentrates macronutrients.

Keywords: Oil seeds, Ricinodendron heudelotii, Cucurbita maxima, Citrullus lanatus,

Raphia hookeri, defatted cakes, oil, free fatty acid, proximate composition.

INTRODUCTION

Agriculture uses a lot of energy, as does related primary industry such as the manufacturing

of equipment, fertilisers, animal feed concentrates, agrochemicals, water, and agro-processing

(Jochen et al., 2012). Agriculture is becoming more energy-intensive in order to meet the

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European Journal of Applied Sciences (EJAS) Vol. 12, Issue 3, June-2024

rising global food demand; in certain circumstances, energy costs can account for as much as

20–50% of the overall cost of inputs used in agricultural production.

The Food and Agriculture Organisation (2011) estimated that in order to feed the world's

population—which is expected to exceed nine billion people by the year 2050—food

production would need to rise globally by seventy percent. Improving agricultural methods is

essential to alleviating poverty now and providing for the needs of future generations. Energy

inputs are needed at every link in the agro-food production chain to increase agricultural

output, which calls for advancements in post-harvest and storage facilities, distribution, retail,

and agro-processing. Fossil fuel energy use raises the concentration of carbon dioxide, which

causes global warming. This energy is predicted to run out soon (Thangaraja et al., 2022). The

yearly distribution of over 14 million tonnes of carbon dioxide emissions results from the use

of petroleum-based goods in diesel engines (Liu and Tao, 2022). One potential substitute for

fossil fuels in meeting the world's energy needs is biodiesel.

In addition to a climate goal to cut emissions by 32% by 2035, Cameroon has constructed its

Nationally Determined Contributions with the goal of actualizing the lofty objectives outlined

in its Vision 2035 (KAS and S2 Services, 2018). The majority of this reduction will come from

land-use-based measures, since in the base year of 2010, land-use contributed more than 60%

of Cameroon's 40 MtCO2eq emissions. Therefore, Cameroon is in a prime position to take

advantage of its enormous bioenergy potential to drive the realisation of its strategic goals

under Vision 2035 and fulfil its global climate commitments under the Paris Agreement. This

is because the country has a climate that is conducive to the growth of a variety of biofuel

feedstock, likewise adequately fertile land.

While biodiesel can be produced using both edible and non-edible oils, edible oils are now

utilised extensively for this purpose (Demirbas et al., 2016). Edible oils derived from palm,

soybean, sunflower, rapeseed, rice bran, mustard, coconut, and crops (wheat, sugarcane, and

corn) are among the edible oils utilised in biodiesel production. Vegetable oils are preferred

because of their high viscosity indices, which are roughly twice as high as those of mineral

oils, and their comparatively low viscosity-temperature fluctuation (Honary, 2004).

Furthermore, their high flash points indicate low volatilities (Emmanuel et al., 2009, Honary,

2004). Most importantly, they are biodegradable, non-toxic, and renewable, all of which are

favourable to the environment (Howell, 2007). On the other hand, the levels of free fatty acids

in vegetable oils can vary widely.

Several studies have found that using edible oil as a feedstock raises the cost of producing

biodiesel (Aghbashlo et al., 2021, Mardhiah et al., 2017), which restricts the product's

commercialization. Additionally, edible oil has a negative impact on the supply of food

(Martindale and Trewavas, 2008; Nguyen et al., 2017; Tuntiwiwattanapun et al., 2017) and

negatively affects the balance of demand between fuel and food (Aderibigbe, 2020). Given the

enormous disparity between the availability and demand of edible oils in developing nations,

the use of edible oil to make biodiesel has been deemed "not feasible" in Africa and other

developing continents. For instance, Cameroon, the biggest producer of palm oil in Central

Africa, produced over 450,000 tonnes in 2020, yet it still needs to import over 60,000 tonnes

annually to meet its local needs (CIFOR, 2022). Nevertheless, no research has looked into the

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Tangka, J. K., Bongmo, J. M., & Etengeneng, A. E. (2024). Investigations on Specific Phytochemical Characteristics of Seed Oil and Defatted Seeds of

Four Oil-Producing Plants Found in Cameroon. European Journal of Applied Sciences, Vol - 12(3). 215-232.

URL: http://dx.doi.org/10.14738/aivp.123.16948

possibility of using marginalised and non-edible seed oils for the production of biodiesel while

also using their defatted seeds for animal and human nutrition.

Studies on the overall nutritional quality of defatted seeds are scarce, despite the growing

body of research on edible oil seeds. Knowledge of the qualities of seed oils and the defatted

seed nutrient composition with regard to the conventional extraction procedure must be

created in order to valorize defatted flours and comprehend the properties of their oils that

may be utilised for the manufacture of biodiesel.

Therefore, the long-term objective of the research is to discover and create new, viable

sources of seed oils that can be extracted locally and utilised in Cameroon to produce

biodiesel, while also repurposing the defatted seeds as alternate sources of nutrients for

animal and human consumption. The investigation specifically sought to extract and

characterise oil from the pulp of Raphia hookeri (raphia), Cucurbita maxima (pumpkin),

Citrullus lanatus (watermelon), and the seeds of Ricinodendron heudelotii (njangsa). The

study samples' defatted seeds were further examined for their approximate composition

before being consumed.

The study's findings would give industrial practitioners in the transportation, energy, and

agriculture sectors access to scientific data. Additionally, it will give information to food

industry practitioners in order to find new sources of nutrients for feeding both humans and

animals.

MATERIALS AND METHODS

Seed Collection and Preparation

Citrullus lanatus seeds were purchased from the Foumban market, while Ricinodendron

heudelotii and peeled Cucurbita maxima seeds were purchased from Dschang market. Fresh

matured (yellow colored) Raphia hookeri fruits were purchased from a local farmer in

Dschang, West Cameroon.

The Raphia hookeri fruits were tied in a plastic bag (to accelerate fermentation, eliminate the

hydro cyanide acid and ease peeling) for three days. The fermented fruits were then boiled

with sufficient water for 20 minutes (to eliminate micro-organisms, further reduce the anti- nutrients and ease peeling). The boiled raffia fruits were then peeled. The mesocarp /pulp

(edible part) was then removed and sun-dried for three days. The other samples were air- dried, and further dehydrated in an automatic electric drier at an average temperature of 45 ±

5°C for 12 to 36 hours.

Seed Processing

The collected seeds were examined for freshness, washed with clean water and sun dried for

12 h. Approximately two kilograms (2 kg) of each sample was taken from the dried seeds and

was dried to constant mass in an oven at 110 °C in order to determine the initial moisture

content. One kg of each of the dried seed samples was pressed using a manual hydraulic

cylinder press to separate the oils from the cakes.

Fig. 1 shows the different samples used for this research.