Beyond the Ri’ichi: Part 5: Processing wheat - Satake PeriTec System
by Hiromi Saita, Senior Staff, International Management Office, Satake Corporation, Japan
What is wheat?
Different from rice, wheat is not cooked and eaten as grain in its natural form but turned into flour beforehand. The bran within rice is more rigid, so it has to be polished, making it more suitable for consumption as a grain, while wheat is better for consumption as flour because of its softer inner part, yet a tough outer skin. Wheat is edible as grain in some parts of the world, but it is common to use it in the form of flour.
Also, rice and wheat look completely different from their appearance in colour and shape, wheat has a groove (crease) in the grain. However, observations through electronic microscope show that their structures are very similar. Like peeling the skin from a fruit, the seed coat, as well as the glue powder layer, are peeled off during the milling process in the case of rice. Generally, in the case of wheat, the outer skin is separated while crushing the grains and the endosperm turned into powder which is used to make bread, noodles, confectioneries, etc. Another reason for using wheat in the form of flour is that it is easier to obtain gluten from it.
What is gluten?
Gluten is one of the protein components specific to wheat that is not present in other grains like rice or corn and is the main reason why wheat flour is widely used as food worldwide. Gluten is formed by two types of protein glutenin and gliadin, contained in wheat flour, in which quantity and balance determine the elasticity and stickiness of flour. Gluten increases proportionately with the amount of proteins in the wheat, so does the stickiness of flour made from it. The quality and quantity of this gluten are also the determinants of the swelling (rising) condition of the bread as well as the chewy sensation of Udon noodles, etc.
Classification of wheat
Excluding durum wheat (pasta's raw material), wheat is classified into three types based on the amount of protein contained in it:
- Hard wheat: Processed into strong flour, highly viscous and elastic, suitable for bread and Chinese noodles
- Semi-hard wheat: Processed into medium flour, with moderate elasticity and viscosity, suitable for dry noodles and boiled noodles
- Soft wheat: Processed into thin powder with low viscosity or elasticity, suitable for cakes and biscuits.
Japan relies on import for wheat consumption because Japanese climates and soil conditions make the stabilisation of the quality of products considerably difficult. In addition, the wheat harvesting season falls mostly during the rainy period in Japan and problems such as germination, mold, and fungus are more likely to occur.
However, imported wheat, traveling across the Pacific Ocean to Japan, require application of pesticides before shipment to prevent the multiplication of insects and, quite often, a small amount of these chemicals are left on the wheat skin, and then it can be mixed up with the wheat during the milling process which definitely affects the quality of the derived products such as bread, etc, hence the need of reduction of this type of contamination during the wheat processing stage.
Satake, flour milling and the PeriTec System
The relationship between Satake and wheat goes back to 1946. At that time, Satake developed and announced the vertical abrasion type debranning machine (D-type debranning machine) and the circulation abrasion type debranning machine (E-type debranning machine) to process wheat, imported as substitutes for insufficient rice production after the end of the war.
This debranning machine was awarded multiple times with gold and silver plaques at exhibitions held by the National Agricultural Equipment Development Conference. Afterwards, Satake was certified as an 'Important Plant' by the Ministry of Commerce and Industry for agricultural equipment production. Satake has long been researching and developing applications of rice milling technology for wheat, but the definitive entry into the flour milling business was in 1991, after the acquisition of the Robinson Milling Systems, a British mill manufacturer which had acquired Henry Simon (formerly the world's largest mill manufacturer) in 1988. Subsequently, it did not take long to fuse rice milling technology with flour milling technology to establish the new flour milling theory: the PeriTec System.
What is the PeriTec System?
Traditional flour milling methods use flour milling machines which gradually mill the wheat with roller mills while the outer skin (bran) is still attached to the grain. In contrast, the PeriTec system utilises a technique in which the outer skin of wheat is removed first, using a debranning machine in the same way as rice milling, and it is only then when the endosperm part is milled with roller mills. On the other hand, a small amount of water is added right before the wheat is milled to make it easier to remove the outer skin, a specific technique not used for rice.
Debranning machine structures
The debranning machine is divided into an abrasive section and a friction section. The first section is to remove the outer skin from the wheat while the second one is to clean the grain surface once the outer skin is removed.
Depending on the purpose, the propriety of debranning with the abrasive section and the cleaning with the friction section can be adjusted with the pressure and external counterweight the same way as it is performed for rice milling machine. Also, one unique feature of Satake's debranning machine is the adoption of a vertical milling chamber with a large capacity, designed intentionally to get a uniform skin removal when processing a large quantity of grain.
Features of PeriTec system wheat flour
Characteristics of the wheat flour obtained with PeriTec system are:
・ Reduced outer skin
・ Increased whiteness
・ Higher mineral content
Apart from the above, as the outer skin is removed prior to the milling process, it greatly contributes to the food safety by reducing the residual agricultural chemicals and the number of bacteria present. Also, baking bread using PeriTec flour gives it a rich flavour and soft texture. One British bakery introduced a bread made from PeriTec flour into the market, it became highly popular not only in the UK but all over Europe. In Italy, one of the major flour companies produces a superior quality of semolina with the PeriTec System. Domestic pasta factories in Italy uses the semolina to produce pasta, exporting them all over the world.