1.0Comparative Calculation of the Percentage Moisture in Flour Using the Hot Air Oven

1.0Comparative Calculation of the Percentage Moisture in Flour Using the Hot Air Oven and the Infra-Red Moisture Analyser Methods

1.1Introduction

Flour is derived from wheat after this has been subjected to a process known as milling.Accurate determination of the moisture content of flour is considered to be a very important process that is instrumental in thedetermination of its shelf life. The lower the level of moisture in flour, the better its storage stability will be. The deterioration of baking quality is also less at lower moisture content.This may be attributed to the retarded respiration and activity of microorganisms.

Moisture is an important factor in controlling grain infestation. Insects that live on stored grains and their products, depend upon the moisture supply. Generally, a moisture content of 9% or lower is considered restrictive to infestation. Moisture is also of great importance for the safe storage of cereals and their products regarding microorganisms, particularly certain species of fungi. At lower moisture fungi will not grow but at about 14% or slightly above, fungal growth takes place.

Higher lipolytic and proteolytic activities are related to higher moisture content, which further lead to loss in nutrients (protein and fat) and production of more free fatty acids resulting in inferior characteristics.

Adequate food packaging is consequently very important because of the protection that this affords the enclosed product from contamination by macro and micro-organisms, prevention from loss or gain of moisture, shielding the product from oxygen and facilitation of handling.

With respect to moisture, the establishment of methods which reliably quantify the resident humidity are important in establishing the quality and shelf life of flour samples destined for human consumption.

2.0Methodology

2.1The Hot Air Oven Method

Switch the oven on and set it to 131OC
Label the supplied petri-dishes and their corresponding covers
Place the uncovered petri dishes and their corresponding lids into the previously heated oven facing upwards
After 10 mins have elapsed, remove the petri dishes and their lids from the oven, and place them into a dessicator until they reach room temperature
Weigh the covered petri dishes and record their weight
Weigh 10g ± 0.05g of flour for each supplied petri dish
Place this amount into each petri dish
Cover each petri dish
Weigh and record the weightof each covered petri dish
Remove the cover once again
Place the uncovered petri dishes together with their cover into the oven for 1 hour
After an hour elapses, cover the petri-dishes with their corresponding lid while theseare still in the oven
Remove them from the oven and place them in the dessicator until they reach room temperature
Weigh and record the weight of the covered petri dishes.
Calculate the moisture content of each sample.

2.2The Infra-Red Moisture Analyzer Balance

Place the provided aluminium tray in the Infra-Red Moisture Analyzer Balance
Weigh 5g ± 0.1g of flour
Place this in the aluminium tray while this is still in the Infra-Red Moisture Analyzer Balance.
Record the exact weight of the flour.
Close the Infra-Red Moisture Analyzer
Observe the weight of the flour in the Infra-Red Moisture Analyzer Balance until this becomes constant.
Record this new value.
Repeat this process for a second sample.
Calculate the moisture content of each sample.

3.0Data Manipulation

For each method present your result in tabulated format
Calculate the percentage humidity in the provided sample according to each method
Compare the results obtained from both methodologies should be carried out using appropriate statistical tools.
Comment on your results critically