Research into hot air drying

1. Background of the Study
The drying process with hot air-drying systems has been widely performed by food
industry players due to its numerous advantages such as less costly and applicable for
almost all food products. Among these advantages, there are several shortcomings
related to the quality of the product from drying; therefore, the pre-treatment before
drying is absolutely considered necessary. One of them is the treatment of blanching
and osmotic dehydration. Blanching becomes one of the processes of applying heat
with a temperature (mild heat treatment) on food with water or steaming media.

2. Problem Statement
Pretreatment on the Potato to remove
moisture so as to prevent it from spoilage.

3. Aim and Objectives
The aim of this research work is to investigate the drying
kinetics of osmotically pretreated Potato slices.
The Specific Objectives are:
• To determine the model that best describes the drying
behavior of the pretreated Potato slices.
• To determine the kinetic parameters of the drying process.
• To determine the effect of the osmotic treatment on drying
of pretreated Potato slices.

4. Significance of the Study
The study is to investigate the effect of osmotic pretreatment
on the drying kinetics of Potato slices. Knowledge of drying
behaviour is required for the development of any process for
the commercial drying of Potato for improving the shelf life.

5. Scope And Limitations of the Study
The work will cover the pretreatment of
Potato slices in salt solution under controlled
conditions. The pretreated slices will be oven
dried and their drying behaviour investigated.

6. Materials
• Potatoes (Solanum tuberosum) were purchased from local market in Uyo
Metropolis, sodium Chloride (NaCl).
Apparatus
• The apparatus to be use in this work are:
• Conical flasks (250, 500ml), Measuring Cylinders (100ml, 200ml), plastic
funnels, Retort stand and G-Clamp, 1 Burette (50ml), 1 Pipette (25ml),
Crucibles, Timer, Knife.
Equipment
• Electronic Weighting scale (0-600g), Domestic Microwave Oven.

7. Methods
Collection of the Material
• The sweet Potato tubers will be peeled and sliced to obtain a uniform size of 2cm diameter
and 1cm thickness.
Osmotic Dehydration Pretreatment
• The potato will be divided into the pretreated sample and the untreated sample. The treated
sample will be weighed first before treatment using an osmotic solution NaCl. The Potato
slices to be treated will then be soaked in the osmotic solution of different concentration of
10%, 15%, 20% and 25% (Clifford et al 2014). After soaking in the osmotic solution, the
Potato slices will then be removed and put in a desiccator to prevent further absorption of
water before it is being weighed.

8. Oven Drying Process
• The Potato from osmotic dehydration will be weighed and
put into an Oven at 40oC, 50 oC, 60oC, 70 oC. to determine
the drying behaviour of the Potato slices, the drying data
will be tested on selected model to ascertain the best model.

9. Drying Kinetics
• Drying kinetics is the representation of the drying rates versus the drying time or
the moisture content. It is a graphical representation of the evolution of the
moisture content. The models will be tested on each data to determine their
fitness. The model with the best fit will then be selected as the model describing
the drying process. Drying rate and other parameters will then be determined
from the selected models. The effect of treatments in the osmotic solution on the
drying behaviour will then be examined