Product Drying
What is product drying?
The product drying process involves the removal of free moisture, hygroscopic moisture, or a combination of both. Free moisture is water held on the surface and hygroscopic moisture is water between molecules of a substance.
Free moisture occurs when actual liquid water is used to mix or wash the product prior to drying. Hygroscopic moisture will take up or dispel water in relation to the relative humidity of the which it is exposed. Any hygroscopic material when exposed to 100% RH humidity, it is full saturated.
Grape Drying
Grapes are dried to produce raisin or kishmish (as commonly known in India). There are four primary methods for producing raisins traditional natural drying, dehydration, continuous tray, and dried-on-the-vine methods. The most popular and commonly used one is the natural drying method.
Problems
The natural drying process depends upon the humidity & temperature level of the environment. As a result of humid conditions, drying cannot be achieved within the desired time period. High humidity also affects the quality of the output.
Our Solution
The drying rate can be increased if RH is maintained at 25% and the temperature at about 35ºC. TDS provides desiccant based Dehumidifiers on rent supported by our technical manpower to achieve the ideal conditions. This increases the drying rate and saves both time & money. Drying time can be reduced substantially. Reduction of drying time leads to profitability and enhances product quality.
Kattha Drying
Kattha is an extract derived from the hardwood of khair (Acacia catechu) by boiling. It is a clay-coloured crystalline substance used in the preparation of “pan,” a chewing material popular in Asia and East Africa. Katha is dried by the cold room drying process. The moisture levels are reduced from typically above 50% to about 12-15%. The temperature in the cold room is maintained at slightly above 0ºC, throughout the processing time. However, the process takes a long period of about 24 days.
Problems
Natural process drying depends upon the humidity & temperature level of the environment. As a result of which during humid conditions, drying cannot be achieved within the desired time period. High humidity also affects the quality of the output.
Our Solution
Spice Drying
Spices have been dried throughout history. Spices are hygroscopic in nature and tend to absorb moisture from the air so drying is required to extract the unwanted moisture.
Problems
As spices are highly hygroscopic in nature and tend to absorb moisture from the air, this absorbed moisture leads to a loss in flavour, aroma, colour, and freshness. Once spices are dried and powdered, it absorbs moisture from the surrounding air during packaging and storage and become sticky. This inhibits their free flow through the packaging machine. The damp powder also sticks to the wrapping paper slowing the process and creating hygiene problems. Moisture not only creates operational problems but also reduces the shelf life of the product. Also, inadequate drying leads to the growth of mould and fungus.
Our Solution
Technical Drying Services (TDS) provides product drying services with the help of desiccant based Dehumidifiers. Dehumidification of the air in the packaging and storage area keeps the area dry letting production and packaging equipment run effectively. Also, it helps in retaining the flavour, aroma and freshness of spices. Caking & lumping of products can be avoided.
The desiccant based dehumidifier removes moisture from the air by chemical attraction rather than condensation. Humid air is directed across a desiccant material that acts as a drying agent. The moisture is collected in the desiccant. The moist desiccant is dried using second hot air stream that heats the desiccant and releases the moisture. Then the desiccant is reused to provide more dry air. In a continuous process the air is dried by the desiccant, at the same time the moist desiccant is dried for reuse so that dry air is available at all times continuously.
Specific relative humidity level needs to be maintained for different spices:
| Spice | RH (%) | Temperature °C |
|---|---|---|
|
Cardamom |
30 - 35% |
28°C |
|
Dry Onion |
50 - 55% |
10 - 20°C |
|
Cinnamon |
40% |
15°C |
|
Chillies |
18 - 20% |
45 - 50°C |
Key Installations
Chilli Drying, ITC
Spice Drying, ITC
