Material that been used to absorb water from wet food to produced dried food.

Function- to make sure that the food can used in long time.

drying agents are materials, the water extract. The water can be chemically bound, e.g. with sulfuric acid or phosphorus pentaoxide, or the drying process can take place via adsorption, e.g. with calcium chloride or Bentonit.

here are various ways of removing water and other impurities from a solution. This can become a major task once the used reagents are also sensitive towards water e.g. Grignard reagents or enolates.

One differentiates between static and dynamic drying process. During the static drying process the drying agent is added to the material which can be dried and again removed, with the dynamic drying process flows through the gaseous or liquid substance the drying agent which can be dried.

If water is one of the products, it also has a detrimental effect on the yield and/or reaction rate. In those cases, drying agents like activated alumina¹, calcium hydride (CaH2), sodium metal (in combination with benzophenone which forms a dark blue ketyl radical), lithium aluminum hydride (LiAlH4) or phosphorous pentoxide (P4O10) are used to chemically destroy the water

The drying agents commonly used in the organic laboratories are calcium chloride (CaCl2), sodium sulfate (Na2SO4) Calcium sulfate (CaSO4, as Drierite (R)) and magnesium sulfate (MgSO4), all in their anhydrous form.Listed below are the drying agents that are commonly used.Organic liquids are considered to be wet if they contain water. Realize that the organic liquid will still be a liquid after it is dried.

Activated alumina ¹ is a very porous form of aluminum oxide of high surface area which adsorbs liquids and gases without any change in form. Activated alumina will not soften or disintegrate when immersed in liquids. Activated alumina may be regenerated to its original adsorption efficiency by heating to a temperature between (177-316°C).

Reconditioning of mineral oils like transformer or insulating oils. Removal of oil vapor mist from compressed air. Drying of organic liquids to a moisture level of 10 ppm or below. Drying of various liquids such as Benzene, Carbon, Tetrachloride, Chlorobenzene, Ethyl Acetate, Transformer oil, Vegetable oils etc.

There are 3 types of drying methods:•Air drying either wind or blowers; it is used for solid and semisolid foods.•Spray and vacuum drying are used for liquids.•Freeze drying the food is first frozen and then dehydrated, is used for a variety of foods, including coffee, meat, vegetables, and fruits. The advantage of this method is that the product retains its original volume and shape and re-hydrates easily.

• Most of the disease-causing organism only can multiply and survive in wet and moist state.

• Drying is the natural technique to prevent spoilage.• Indeed, the act of simply leaving foods out in the sun and wind to

dry out the moisture.• For example, the traditional way to preserving rice is allow it to

dry naturally in the field or drying racks in bam for two weeks. After a period of time, the native rice is threshed and dried again on straw mat under sunlight for three days.

• Modern drying technique now apply for controlled environment such as fan and heater. This method avoid uncertainties from arise when the crops leaved in the field in traditional way.

• Controlled temperature air drying is especially popular for the preservation of grains such as maize, barley, and bulgur.

In hot air dryers, the heat required for the drying process is

supplied by hot air which cycles through the dryer and

contacts the product. For an example making dried fruit.

Freeze-drying is used to preserve food and make it very lightweight.

The process has been popularized in the forms of freeze-dried ice cream, an example of astronaut food.

It is also popular and convenient for hikers because the reduced weight allows them to carry more food and reconstitute it with available water

Instant coffee is sometimes freeze-dried, despite the high costs of the freeze-driers used. The coffee is often dried by vaporization in a hot air flow, or by projection on hot metallic plates.

Freeze-dried fruit is used in some breakfast cereal. Culinary herbs are also freeze-dried, although air-dried herbs are far more common and less expensive. However, the freeze-drying process is used more commonly in the pharmaceutical industry.

Spray drying is a method of producing a dry powder from a liquid by rapidly drying with a hot gas.

This is the preferred method of drying of many thermally-sensitive materials such as foods and pharmaceuticals.

Air is the heated drying media; however, if the liquid is a flammable solvent such as ethanol or the product is oxygen-sensitive then nitrogen is used.

The designed fruit dryer machine