De-awning process

De-awner is used for pre-treatment of various grain types; the purpose of the de-awning operation means is to remove the awns from barley kernels, loose husks from wheat, and to clip oat kernels.

The de-awning process is usually carried out immediately after the crop has been harvested, the grain is fed with an air/screen cleaner in order to remove the loosened awns.

In a modern rice mill, de-awning is an important process before husking operation to eliminate awns of the paddy grains for easy conveying in the elevators, chutes, and hopper orifices.

Because of the awns, it cannot be processed mechanically as the seeds club with each other and makes the processing difficult by restricting the flow of material during processing.

The clipper/de-awner can be used where heavy de-awning is required but also for products where only a light de-awning is needed.

For de-awning of barley, breaking up clusters of beet seed and for surface polishing of grains and vegetable seeds, thereby improving appearance and increasing bushel weight.
De-awning process

Cereal processing: Dehulling of oats

The grain is then sorted by size into small grains, medium sized and large size grains. Three basic mechanical methods for dehulling oats include the impact dehuller, the compressed air dehuller, and the wringer dehuller.

Traditional oats mills used stones set at well-defined distances to split the hulls and enable them to be detached from the groats. Although this procedure is still used in some smaller mills, the larger mils that are needed to produce the quantities of oat products required today use impact hullers.

The impact dehuller feeds grain into a spinning rotor. The impact of the grain with a wall as they are expelled from the rotor releases the groats from the hulls. The hulls are then removed by aspiration. The compressed-air dehuller.

The groats is then subject to a polishing which removes the dust and hull which has not been properly dislodged.

The oat hull is mainly fiber; hemicellulose, cellulose and lignin. There are low levels of protein, fat, starch and water-soluble carbohydrates.

Hulls are by products of oat milling, and from this furfural is prepared which, with its derivatives, is used in making nylon, in oil refining and in some other industrial processes.
Cereal processing: Dehulling of oats

Processing of barley malt

Barley was one of the first grains used for human consumption. Its use for brewing has been dated back to at least 3000 BC. Barley is an excellent source of soluble and insoluble dietary fiber and other bioactive constituents, such as vitamin E (including tocotrienols), B complex vitamins, minerals, and phenolic compounds.

Malt is the key ingredients in beer that provides the starch and enzymes necessary to produce the fermentable sugars which yeast then turn into alcohol. Malt also provides the color and flavor compounds which contributes the final character of beer.

Malting is the precursor to brewing in priming the grain. It is the biological process that turns barley into malt. It removes internal cell wall barriers, stimulates the production of diastatic enzymes (responsible for converting starch into malt extract), promotes flavor and color development.

A basic rule is that, for malt to be made, the barley must be capable of germination, so maltsters source barley with a minimum germination of 98%. There are five stages in the process of converting barley into malt:
■ barley grading and cleaning
■ steeping (24 hours)
■ germination (96 hours)
■ kilning (24 hours)
■ malt cleaning and grading

The processing cycle is completed in approximately nine days.

Malting serves the purpose of converting insoluble starch to soluble starch, simplifying proteins, generating nutrients for yeast and the development of enzymes. In other words, malting is the process of modifying (force germinating) the grain in order to make the sugars trapped inside the kernel available for mashing.
Processing of barley malt

Oats cleaning process

As with numerous agricultural products, harvesting oats will lead to co-mingling of the oats with other components found in the field and transportation process, and these foreign materials need to be removed to make oats suitable for human consumption.

Cleaning removes the unwanted materials – such as corn, soybeans, foreign material, weed seeds, wheat, or barley – from the milling quality oats.

The oats are brought at harvest into the mill by the growers. The miller only accepts oats that will yield flakes of satisfactory quality, and will attempt to maximise profits by estimating the potential yield and looking at the price of the oats and any possible added value obtainable. The oats then cleaned and dried so that they may be safely stored until they are needed. When the oats enter the mill, they pass under a magnetic separator to remove foreign metal objects, a very common practice in many food-processing operations.

The they are cleaned, taking off straws, stones and weed seeds and are then sent through a stream of air to remove any dust or light grains that would be unsuitable for milling.

This is followed by a dry stoner that removes high-density but similar-sized particles such as rocks and other grains, such as maize.

Even high quality oat grain will require cleaning to ensure that only sound oats are processed. The oats must appear wholesome and clean, must be free from extraneous material, with large and light coloured oats that give a high yield being preferred.

Oats cleaning process 

Extrusion expanded cereal

Extrusion is a process in which foods are rapidly cooked under heat and pressure generated as the product progresses through an extruder barrel.

It is typically used in grain and soy-based products with applications in pet foods, expanded breakfast cereals, expanded or puffed snacks, textured vegetables proteins, meat analogs and pasta.

Extrusion cookers are used extensively in the ready-to-eat (RTE) cereal industry to cook doughs that are cold formed into various shapes and then gun or tower puffed. These products are what is called indirect expanded RTE breakfast cereal. In some instances, these types of cereals are referred to as half products because the cereal is only halfway through the extrusion process.

Cereals that have high amounts of lipids are more difficult to expand due to dough slippage within the extruder barrel. This type of cereal usually requires high moisture and high temperature before significant puffing will occur.

 Snack foods and cereals that expanded on exiting the extruder are called direct expansion. These are typically made from cereals grains such as corn, wheat, rice, and oats. Direct expanded snack products are typically produced in a high-shear cooking extruder at temperature greater than 100°C. In the extruder, pressure is high enough to keep the water in liquid form.

Ingredients for snack products are mixed and blended prior to being fed into the extruder. For some products the cereal grain is premoistened prior to being introduced by some feeding device into the extruder. The cooking process in extrusion generally enhances digestibility of the starches and proteins and can be effective in removing anti-nutrients.
Extrusion expanded cereal

Malting process

Malting is the limited germination of cereal grains or occasionally, the seeds of pulses (peas and beans), under controlled conditions. The starting and stopping of botanical growth is expertly timed by the maltster to achieve a minimum malting loss and maximum malt modification.

Sometime malt is used ‘green’ (undried), but it is usually used after drying in the sum or in a current of warm water. The three main steps of the malting process are steeping, germination and kilning. Final stage of malting process is kilning, enzyme activities decline as malt color and malt flavor develop.

This converts the endosperm of the grain into simple sugars which later be partially converted by fermentation into alcohol.

In the industrialized regions of the world, malt made from barley is by far the most important, but malts are, or have been, made from wheat, rye, oats, triticale, maize, sorghum, various millets and even rice.
Malting process

Wheat processing: Milling

The single term ‘milling’ applied in the context of cereals, covers a wide range of processes. Wheat is milled in a continuous process to remove the bran and germ and reduce the wheat kernel to flour to be used in various baked and nonbaked goods.

A small portion of production is geared towards the production of whole-wheat flours employing a simplified process flow sheet, but most demand and effort is directed towards the production of white flour. The conventional milling process of wheat first involves washing to remove foreign substance such as dirt or rocks.

Milling is a process by which kernel components are separated physically or chemically. Once the endosperm is separated it subsequently is ground multiple times in reduction rolls to become finer and finer for flour.

As the bran and germ are removed, the refined flour contains streams that contain less vitamins and minerals. If flours streams of the endosperm are blended during the milling process various flours are created. Other products of the process, e.g. vital gluten, can supplement other edible products.

Millfeeds, the material remaining after all the usable flour is extracted is used by the feed industry either directly or as a feed supplement.

Wheat milling practices might cause significant differences in flour quality, which are due to flour particle size, extraction rate, and the level of starch damage.

In general, 100 pounds of wheat will produce 72 pounds of flour. The remaining 28 pounds is classified as millfeed.
Wheat processing: Milling

Corn flour processing

Modern corn mills can produce a variety of grits, meals and flours. Corn milled for flour (corn meal) is cleaned, as is wheat the moistened to a water content of 21%. The germ is removed mechanically.

The endosperm is then dried to moisture content of 15% passed through crushing rolls, and sifted to remove the bran.

With the use of sieves, milled corn is separated into grits (largest-sized particles) and meals and flours (smallest sized particles). They are fried at 65 °C and cooled before packing. The flattened germs are used to produce corn oil.

Among many other industries, maize starch has its feet firmly placed in the high growth Indian food industry. Maize starch or corn starch or corn flour is avidly used in processed food industry majority in products like bakery, beverages and confectionery.
Corn flour processing

Wheat cleaning and milling

Before the wheat reaches the milling stage, first it has undergo several preliminary operations that ensure the correct of the main process. The first of these is wheat cleaning.

Wheat is passed through a series of machines that apply the principles of particle size and density separation.

Foreign materials such as metal, sticks, stones, straw, seeds and other grain are removed in steps by a magnetic separator, vibrating screens, a destoner, a disc separator and a scourer.

Sieves remove contaminants larger than wheat kernels as well as finer contaminants such as sand. In addition, air is used to remove plant material that is lighter than the grain.

After cleaning, the wheat is tempered prior to be milled. In this stage, the moisture content of the grain is increased by adding water and by allowing the grain to sit for a period of time.

Wheat is milled to remove the bran and germ and reduce the wheat kernel to flour to be used in various baked and nonbaked goods.

In general, 100 pounds of wheat will produce 72 pounds of flour. The aimed of white flour milling is to extract a maximum amount do endosperm from the wheat berry in as pure a form as possible.

The wheat is passed through a series of machines to break open the wheat kernels and reducing of the endosperm by grinding to obtain the final product – plain flour.

Additives of less than 1 weight % are added to the flour by a mixing process.

Family four for retail sale is packed in 5, 10, or 25 pound bags. Bakery flour may be packed in 50 or 100 pound bags or shipped in bulk trucks or railcars.

Wheat cleaning and milling

Oats Milling Process

The single term ‘milling’ applied in the context of cereal, covers a wide range of processes. In general they are methods of transforming whole grains into forms suitable for consumption or for consumption into consumable products.

Oats are taken into the mill at harvest time from a select registered panel of local growers. The oats are then dried and safely stored until needed. When the oats enter the milling process, there are five distinct stages to this process:
1. Cleaning, drying and grading.
2. Dehulling and cleaning.
3. Groats to pinhead
4. Pinhead to oatlets.
5. Packaging and distribution.

1. The oats are brought at harvest into the mill by the growers. They are then cleaned and dried so that they may be safely stored until they are needed. When the oats enter the milling process, they are cleaned, taking off straws, stones and weed seeds and are then sent through a stream of air to remove any dust or light grains that would be unsuitable for milling.

Even high quality oat grain will require cleaning t ensure that only sound oats are processed.

2. The grain is then sorted by size into small grains, medium sized and large size grains. The Oats are then fed into the oat sheller, which cracks the husk off the grain without damaging the kernel.

Traditional oats mills used stones set at well defined distances to split the hulls and enable them to be detached from the groats. Although this procedure is still used in some smaller mils, the larger mils that are needed to produce the quantities of oat products required today use impact hullers.

The mixture of kernel and hull is fed into a stream of air which blows off dust and hull. It is then subject to a polishing which removes the dust and hull which has not been properly dislodged.

Hulls are by products of oat milling, and from these furfural is prepared which, with its derivatives, is used in making nylon, in oil refining and in some other industrial processes.

3. The groats are then cut by feeding them into a cylinder with a large number of holes, the kernel fall through these holes and are cut to produce what is called Pinhead oatmeal.

This is the oatmeal which can be used to make traditional porridge.

4. The pinheads are steam cooked at over 100 degrees Celsius before being rolled into oat flakes.

The majority of wholegrain oats that is destined for human consumption is either processed to oat flakes by roller mill or to cut grains by cutting the groats into 3-4 pieces by steel cutter.

The flakes are then dried, cooled and stored in containers for packaging.

5. The product is then automatically weighed, dropped in its packet, the packet is then pressed down, folded and sealed.

The packets are then packed into cartons ready for distribution.

Oats flakes can be used as such for baking processes, as they will disintegrate readily once mixed with water.

The flavor of oatmeal is largely determined by the preliminary killing of the grain, and its texture as a cooked food by the degree to which it is milled.

Oats are kilning with the objects of assisting milling operations, producing a desirable flavor and avoiding the occurrence of a type of rancidity commonly found in stored oatmeal.
Oats Milling Process