CHAPTER ONE

INTRODUCTION

1.1. BACKGROUND OF STUDY

Cereal grains have been and will continue to be a major source of food for

humans and animals throughout the world. Amongst all cereals the most

important is the maize grain. (Leonard et al 1963). Maize corn and products can

be used for various purposes; human food alternative medicine chemicals bio

fuels ornamentals fodder to mention but a few (Leonard Warren H. and John

H. Martin). Maize crop is intensively and extensively cultivated in all the geo-

political zones of Nigeria. Early maize is planted between late March and late

May while the late maize is planted between August and September. The

harvest time for the early maize is usually between late July and September.

During this period corns are harvested fresh and cannot be preserved by drying

owing to the unavailability of sunshine during the rainy season. It is usually

roasted or cooked fresh. This practice does not encourage maize farmers as they

would sell the maize corn at a give-away prices and this does not guarantee

returns on their investment. In addition to this dried maize grains will guarantee

food sufficiency during the scarce period. Notably corn of high moisture

content does not stored very well and is usually vulnerable to damage due to

deterioration molds and insects during the period of storage.

However open air-sun drying as practiced in most rural areas often yields poor

quality dried corn since the product is not protected against dust moisture

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wind rodents as well as other domestic animals while carrying out the drying.

As a result they are often contaminated with pathogens. Another common

practice in maize corn-on-cob drying is drying over a fire place. This has its

own problems as the maize grains are contaminated with smoke. Moreover the

temperature of drying is not properly controlled such that grains become dead

after drying. There are various research works that have been carried out on

grain drying (Zare et al 2006; Mellmann et al 2011; Adzimah and Seckley

2009). These works were silent on drying and dryer design for maize corn-on-

cobs.

There are four major drying techniques; open air sun drying fire wood /fuel

drying electrical drying and solar drying(Anyanwu et al 2006 Scanlin 1997

and Whitefield 2000). This research project will address these problems

associated with postharvest handling of maize corn-on-cobs in particular

drying by designing and fabricating electrically operated tray dryer that will be

simple but very robust in operation.

1.2 STATEMENT OF THE PROBLEM

Maize corns are usually stored when dried to certain percentage moisture

content. In Nigeria maize corn drying is done in dry season because of low

humidity of atmospheric air and adequate sunshine. However it is a common

place to see peasant maize farmers dry their maize corn-on-cobs over fire place

but this practice contaminates the dried maize corn with smoke and usually

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small quantity of maize corn-on-cob are dried. The reverse is the case during the

rainy season. Unfortunately bulk of the maize corn is harvested in the rainy

season and farmers can not dry the fresh maize corn rather they sell them at

very cheap prices to corn roasters and for other delicacies. To give value to

farmers and also to guarantee maize corn sufficiency during scarce period it

becomes necessary that a simple but robust corn-on-cob dryer should be

designed and fabricated to assist farmers have good returns on their investment

especially during post-harvest handling of maize corn during rainy season.

1.3 OBJECTIVES OF THE RESEARCH

The aims of this research include:

i. To develop a drying rate curve for maize corn-on-cob at constant drying

condition.

ii. To generate design data for tray dryer to be used to dry maize corn-on-

cob.

iii. To develop and draw working diagrams for the tray dryer.

iv. To fabricate a tray dryer.

v. To test run the tray dryer.

1.4 SIGNIFICANCE OF THE RESEARCH

Some of the benefits derivable from this research project include:

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i. It will encourage maize farmers by giving them good returns on

their labour and enhance maize corn production.

ii. It will provide Nigerian populace with a cleaner dried maize grains.

iii. It will attract foreign exchange for Nigeria as cleaner dried maize

can be export.

iv. It will ensure maize grain sufficiency during the scarce period.

1.5 SCOPE OF THE RESEARCH

This research will be restricted to the following areas;

i. Generation of design data for corn-on-cobs.

ii. Designing the corn-on-cob dryer.

iii. Fabrication of the dryer.

iv. Test run.