thin king

Good morning to all,

The Processing of Sugar

Is refined sugar refined as it appears;
Is it as pure as it is claimed ?

Here is how it is done.

When the sugar canes arrived from the fields they are stored in a yard, allowing the mill to process them at a constant throughput. Cane growers are paid for the tonnage of sucrose that is extracted by the mill rather than the canes delivered.

There are four stages in the processing of sugar from the canes to the refined white sugar. These are Juice Extraction, Boiler House Recovery, Refining and Drying and Conditioning.

1. The cane is first cut up into a pulp with cane knives, resulting in a fluffy mass. The pulp is then diffused by washing the sugar out of it when they pass through a slow moving bed of water. Milling is the next step where the sugar is squeezed from the pulp by large grooved rollers. The juice is then screened to remove the pulp, the fibre.

This Juice Extraction process extracts the sucrose from the cane, leaving the fibre to be used as fuel for the mill itself.

2. The sucrose j uice is heated under pressure to above boiling point and then allowed to flash, or exposed to atmosphere, to rid the juice of air bubbles which may retard clarification. In the clarification process the remaining suspended solids are combined into a tricalcuim phosphate precipitate by adding lime. The precipitate is then removed by filtration, resulting in a clear juice, from which the sugar will be made.

The juice is then boiled in multiple effect evaporators to make the solution super-saturated with sugar, leaving a concentrate . A hot solution dissolves more sugar, and when carefully cooled, sugar crystals start to form. The crystallisation results is a warm, dark brown solution. The light brown sugar crystals are then separated by the batch centrifugal filters and retained in a perforated basket. The liquid removed is called molasses.

The remaining moisture is then removed by using either Rotary Louvre Dryers, rotating drums which pick sugar up in louvres and dropping it through a stream of air, or Fluidised Bed Dryers where heated air is passed through nozzles into the sugar, fluidising it. The sugar produced at this stage is about 99% pure sucrose called brown sugar .
This Boiler House Recovery boils the juice to leave behind the brown sugar crystals.

3. The brown colour is due to impurities. This sugar is further refined to bring it to the state for the table.

In refining, the crystals are returned to a solution and then clarified. The clarification process employs one or more of the four following methods. In the first method, lime and carbon dioxide are added to trap the colour in a calcium carbonate precipitate which is then removed by filtration. A second way is to add lime and sulphur dioxide to absorb the colour in a calcium sulphate precipitate. The sulphur dioxide also has a bleaching effect. The precipitate is then removed by filtration. A third way is to add lime and phosphoric acid, to trap the colour in a calcium phosphate precipitate which is then removed by floatation after the melt has been aerated. The colour in sugar tends to be negatively charged, and it can be removed by ion exchange with chloride ions. Finally, the sugar is recrystallised and dried.

In Refining the colour is removed and the sugar is then recrystallised.

4. This sugar is then dried and packaged for delivery to the consumers.

Man cannot do without sugar
Because sugar is sweet
And darlings are sweethearts
And man needs darlings

Have a nice day
Ronald

Note: The simple terms of the additives used in refining the sugar are process chemicals.
Whether these are harmful and completely removed the consumers do not know.
Some of these process chemicals are as follows:

Acid based Evaporator Cleaning Additive (powder)
Acid based Pan Cleaning Additive
Alcohol Defoamer - Organic Based
Caustic based Evaporator Cleaning Additive
Corrosion Inhibitor for HCl
Crystallizing /Vacuum Pan Aid
Crystallizing /Vacuum Pan Aid
Crystallizing /Vacuum Pan Aid
Dextran Control Bio-Surfactant
Evaporator Scale Inhibitor
Evaporator Scale Inhibitor
Juice Clarification Flocculant
Juice Clarification Flocculant
Juice Clarification Flocculant
Juice Defoamer - Organic Based
Mill Sanitation Biocide - DTC
Mill Sanitation Biocide - QUAT
Syrup Clarification Flocculant
Syrup Clarification Flocculant
Syrup Clarification Flocculant
Syrup Decolorizing Agent (polymer)
Syrup Decolorizing Agent (polymer)
Syrup Decolorizing Agent (polymer)
Syrup Decolorizing Agent (polymer)
Syrup Defoamer - Silicone Based
Syrup Defoamer - Silicone Based