Abstract

Our main objective in this work is to conceive and realize a specified drier for ERU. But after the prices of major export crops in Cameroon—cocoa and coffee—plummeted in the 1980s and 1990s, and subsequent food price spikes, farmer’s lost their ability to buy food.

Cameroon’s rural population turned to the forests for its food and income, and poor farmers began harvesting and selling ERU on mass. Originally consumed by Cameroon’s forest-dwelling Bayangi people, ERU is now one of Cameroon’s most widely consumed vegetables.

Hundreds of tons of ERU are exported every week to Nigeria—where it is known as okazi—and overseas for consumption by Central and West Africans living abroad. We therefore designed and dimensioned an active and hybrid solar drier in which the various conditions were found to be the best for drying eru.

After the dimensioning was done,  the drier was realized with the aim of drying the product in such a way that the product obtained will preserve its colour or not,  its flavour as well as its nutrients and taste. The results obtained of the drier have finally been analysed according to sensory bases to pull it from the optimal findings.

After having established our drier, to ascertain her efficiency, good numbers of tests were done in chapter four, it ensues some besides of these tests that the dried products are very good quality but also after have interpreted the data to recover the drier at the time of the solar drying, we had satisfactory results, confirm this fact the efficiency of our drier.

Our main problem is how to preserve this product by conserving the chemical and physical properties during times of excess and exportation, so we propose this drier. In our work, we dimension the dryer to dry 65g of wet eru at a temperature of 40^oc. after 40minutes of drying; we obtained eru of weight 35g.

CHAPTER ONE

GENERAL INTRODUCTION

In the majority of African countries, agriculture represents the biggest part of the economy. 80-90% of the working population is employed in agriculture [1]. Despite these large numbers, national food production still does not meet the needs of the population. The lack of appropriate preservation and storage systems cause considerable losses, thus reducing the food supply significantly.

The dent in food production caused by crop-failures as well as significant seasonal fluctuations in availability can be ironed out by food conservation, e.g., by drying, canning, freezing, dehydration etc. Among these, Sun drying of crops is the most widespread method of food preservation in a lot of African countries due to solar radiance being very high for most of the year [2]. 

There are some drawbacks relating to the traditional method of drying, i.e., spreading the crop in thin layers on mats, trays or paved grounds and exposing the product to the sun and wind. These include poorer quality of food caused by contamination by dust, insect attack, enzymatic reactions and infection by micro-organisms.

Also, this system is labour and time-intensive, as crops have to be covered at night and during bad weather, and the crops continually have to be protected from attack by domestic animals. Non-uniform and insufficient drying also leads to the deterioration of the crop during storage.

Serious drying problems occur especially in humid tropical regions where some crops have to be dried during the rainy season. In order to ensure continuous food supply to the growing population and to enable the farmers to produce high-quality marketable products, efficient and at the same time affordable drying methods are necessary.

Drying using solar radiation that is, drying under direct sunlight is one of the oldest techniques used by mankind to preserve agriculture-based food and non-food products. This form of energy is free,  renewable and abundant in many parts of the world, especially in tropical countries.

However, in order to maximize its advantages and optimize the efficiency of drying using solar radiation, appropriate technology needs to be applied.

Such technology is known as solar drying and becoming a popular option to replace mechanical thermal dryers owing to the high cost of fossil fuels which is growing in demand but dwindling in supply. For sustainability and climate change concerns, it is important to use renewable sources of energy as much as possible.

Drying in early times was done primarily with the sun, but nowadays many types of sophisticated equipment and methods of drying foodstuff are being developed. The most important thing however is to select or construct the right type of drier for the drying of a specific product.

This study is aimed at putting at the disposal of farmers a solar drier that will permit them to dry and preserve all their eru,  without deterioration of the colour, flavour, texture, constituent and taste after dehydration.

This project will also go a long way to raise the awareness of the population about one of their nutritional plants for those who do not know it while putting more strength to the benefits and uses of the plant in our day to day life.

As future teachers the piece of work we are about to  realize,  deals with heat transfer,  food preservation and solar energy and hence is a practical instrument that can aid in the teaching of these notions to students.

The preservation of chemical and physical properties of the product during the drying is the main problems of study. We can therefore pretend that Eru will be drying at 50^otemperatureduring the period of 30 minutes and the weight will be taken.

This stapes is helping us to plot the diagram. The analysing data should help us to solve the problems drying period and the estimation of a previous situation which is exportation and conservation of our product during the excess will be solved.

We are going to see in chapter one the general introduction, in chapter two we have literature review, chapter three we have dimensioning and realization of the system, chapter four will the result and discussion and chapter five is conclusion and perspective. The study of this drier will be done within the southwest region.

This implies that the working conditions of the drier will be that of Bayangii village and the targeted beneficiary will also be the population of this area. One of the main activities of this population is agriculture. The warm nature of this part of the country has made it favourable for the growth of many plants especially the eru.

This project as a whole will include a literature review on drying and solar drier as well as some information about eru. This is done with the aim of valorising the plant and the final product obtained after drying. We will therefore limit our work on the “conception and realisation of eru dryer”