Thesis Abstract

Thesis Overview

<p> </p><p><b>INTRODUCTION</b></p><p>Drying is probably the oldest and the most important method of<br>food preservation practiced by humans. This process improves the food<br>stability, since it reduces considerably the water and microbiological activity<br>of the material and minimizes physical and chemical changes during its storage.</p><p>Musa paradisiacal (unripe<br>plantain) is an important staple food in Central and West Africa, which along<br>with bananas provides 60 million people with 25% of their calories. According<br>to FAO, (2004), over 2.11 million metric tons of plantain is produced in<br>Nigeria annually. Plantain for local consumption, plays a role in food and<br>income security and has the potential to contribute to national food security<br>and reduce rural poverty.</p><p>Unripe<br>plantain has rich iron nutrient content (Aremu, et al., 1990). However, they<br>are highly perishable and subject to fast deteriorations, as their moisture<br>contents and high metabolic activity persist after harvest (Demirel, et al.,<br>2003).</p><p>Moreso, about 35-60%<br>post-harvest losses had been reported and attributed to lack of storage facilities<br>and inappropriate technologies for food processing. Air drying alone or<br>together with sun drying is largely used for preserving unripe plantain.<br>Besides helping preservation, drying adds value to plantain.</p><p><a target="_blank" rel="nofollow"><b>1.2<br>PROBLEM STATEMENT</b></a></p><p>Drying consists of a critical step<br>by reducing the water activity of the products being dried. Hot air drying of<br>agricultural products is one of the most popular preservation methods because<br>of its simplicity and low cost. Thin layer drying is a common method and widely<br>used for fruits and vegetables to prolong their shelf life.</p><p>However, drying of any food<br>substance is an energy intensive operation with grave industrial consequences,<br>and must be performed with optimal energy utilization.</p><p>This project work seeks to<br>ascertain the best thin layer model and the temperature and slice thickness<br>that optimizes time.</p><h2>1.3.<br>OBJECTIVE OF STUDY</h2><p>The objectives of this work are to;</p><p>Ascertain the type of thin-layer model that best fits the<br>moisture ratio/time data during the drying of unripe plantain.</p><p>To<br>determine the temperature and slice thickness that optimizes time (i.e. gives<br>the shortest drying time).</p><p><b>1.4<br>JUSTIFICATION</b></p><p>Production<br>of plantain is seasonal while consumption is all year round and therefore there<br>is the need to cut down on post-harvest losses by processing them into forms<br>with reduced moisture content.</p><p>This<br>agricultural product has high moisture content at harvest and therefore cannot<br>be preserved for more than some few days under ambient conditions of 20oC – 25oC (Chua, et al., 2001). This<br>post-harvest loss results in seasonal unavailability and limitations on the use<br>by urban populations. Plantain has however been having an increasing surplus<br>production since 2001 (Dankye, et al.,<br>2007). It is estimated that in 2015, there will be a surplus of about<br>852,000 Mt. This means that these surpluses have to be exported, processed or<br>go to waste.</p><p>A<br>reduction in moisture content potentially increases shelf life and hence<br>prevents excessive post-harvest loss and that drying is an alternative to<br>developing nations, where there is deterioration due to poor storage, weather<br>conditions and processing facilities</p><h2>1.5<br>SCOPE OF STUDY</h2><p>The<br>scope of this project work includes the following:</p><p>Using<br>the ten selected thin layer models to investigate the one that best fits the<br>data generated from drying of unripe plantain at specified temperatures, slice<br>thicknesses, and drying time.</p><p>Using<br>regression analysis to obtain the slice thickness and temperature for the<br>optimum (minimum) drying time.</p> <br><p></p>