Beyond the Ri’ichi: Part 6: Flour milling – Added value for the health-conscious market
by Yutaka Kawamoto, Deputy Head of Asia Business Division, Yoshihiro Tokui, Head of Supporting Grain Processing Group, Technical Division, Satake Corporation, Japan
What is good flour?
Common wheat flour is obtained by milling the wheat grain and then extracting the endosperm out from it. The wheat flour obtained is never eaten as it is but added with water and kneaded to form gluten in making a dough. It will be then processed into food for consumption such as bread and noodles. Based on this processing of wheat grain, and from the appearance of the finished product, a good quality flour is attributed to the flour with the least bran mixed with it.
These factors, such as degree of whiteness and the ash content, are used as a primary method to evaluate the quality of wheat flour. The degree of whiteness is the quantification of the flour colouring due to the mixture of brown bran in the flour. As for the ash content, it indicates the amount of bran mixed in the flour by measuring the residual matter after combusting and incinerating the flour. This is because only the bran, along with its minerals, will remain after incineration, whereas the endosperm is totally combusted.
In recent years, a rise in health consciousness has led to a demand for more functional food, and nutritional content is cited as one of those functionalities. As the body cannot synthesise minerals, it is necessary to intake them from foods. However, the minerals naturally found in the wheat grains are not contained much in the flour but will be retained mostly in the bran and the residual powder after the milling process. Although the whole grain wheat flour contains fibres and minerals, the small quantity of minerals in the ordinary flour is a widely known fact.
General features of PeriTec flour have been already mentioned in the previous article in this series. Here, characteristics specific to this flour will be detailed more in-depth. The PeriTec flour is made from wheat whose skin has been peeled off from the grain before the milling process in the same way as rice milling. The wheat grain's skin is formed with multiple layers, and the layer which contains the most minerals is the layer called Aleurone. This Aleurone layer lies between the skin and the endosperm and has a hue very similar to that of the endosperm.
To obtain flour with more nutritional content with the conventional milling method, where the milling is done with the Aleurone layer still attached to the bran, a large amount of bran is collected with the powder and its hue becomes poorer. But with the PeriTec system, the milling is only done after peeling off the bran up to the Aleurone layer, meaning as there will be no bran layer protecting this Aleurone layer, it will be milled altogether with the endosperm and will be collected with the flour afterward.
PeriTec flour made this way contains more Aleurone layers, but its hue does not differ from the flour made with the traditional milling method since most of the skin is peeled beforehand. However, as it contains many more minerals, it has higher nutritional content and a good hue at the same time, which is its specific feature compared to the usual flour. In other words, PeriTec flour is such that it can be situated between the whole grain wheat flour and the usual flour.
Besides, impurities (viable bacteria, residual agricultural chemicals, etc) adhering to the outer skin are peeled off and will not be brought into the milling process. Although these cannot be reduced to zero contamination, the total number of these impurities is reduced greatly.
Nowadays, facing the rise in demand of whole wheat grain flour due to more health-conscious eating habits, a product with fewer impurities can be produced just by gently peeling off the outer skin of the grain from which an improvement of the shelf-life of the final product can also be expected. PeriTec flour, therefore, gives rise to the production of more hygienic food products.
Through this method, PeriTec flour is containing abundant levels of minerals from wheat grain such as Niacin, γ-aminobutyric acid, inositol, etc. It has more functionalities than usual flour. It should be also mentioned that the yield increases by about 4 percent since a part of the outer skin layer, the Aleurone layer, is retained with the endosperm to be milled together with it.
Application of PeriTec flour
Bread made with PeriTec flour has a good texture and is not dried out as it does not contain any bran, but it has a higher nutritional content than bread made from conventional flour. Furthermore, the PeriTec System is also used in the milling of durum wheat for semolina, although it is different from other wheat grain, and it contributes very much to the improvement of the quality of the product.
The durum wheat, unlike the usual wheat, is harvested in a condition called coarse grain. When milling durum wheat into semolina with the PeriTec System, there is only one small outer skin protecting the endosperm as they were separated beforehand. Good quality semolina can be produced as early as from the stage of breaking the whole wheat grain.
During tests at our company, the extraction rate of semolina up to three breaks has increased by 10 percent. Also, if the Aleurone layer with high nutritional value is separated from the coarse grain semolina, the ash content in semolina made with the PeriTec system is lower, even though a higher yield of products with the same nutritional value can be achieved.
GABA rice flour
Flour milling at Satake does not only consist of wheat flour milling. The demand for more functional food due to heightened health consciousness is also the same as in the rice market, leading to the development of GABA rice rich in GABA (γ-aminobutyric acid). GABA, mainly known as an inhibitor of neural transmission, is an agent acting to lower the blood pressure. GABA rice has a GABA content of 5-to-10 times higher than of those in untreated white rice.
GABA rice was primarily developed to be cooked and served at the dining table, but apart from that, a technology that turns broken rice and immature brown rice into GABA rice flour was created. Ten years ago in Japan, a technology to make bread and noodles using rice flour instead of wheat flour was developed to increase rice consumption. Since then, it has become possible to make bread from rice flour mixed with gluten from wheat flour. More recently, the technique has evolved into producing gluten-free bread without using gluten from wheat flour.
When making bread using GABA rice flour added with gluten, compared to the flour without any GABA supplement, bread made with usual rice flour was 1.4mg/100g d.b. against 6.9mg/100g d.b. for bread using GABA rice flour. This confirmed that levels five times higher for GABA were contained in the bread made with GABA rice flour.
Furthermore, making a gluten-free bread with rice flour without mixing gluten with it will also increase the GABA value contained within the bread. When making products with rice flour, taking into account that GABA is water-soluble and dissolves at temperatures above 150℃, using GABA rice flour with a higher GABA content can affect positively the quality of the finished products.
When baking bread made from rice flour, the crust part (or outer part) is heated at high temperatures, however, the inner temperature does not rise so highly, such that GABA remains inside the baked bread. GABA rice flour is not only a substitute to wheat flour as a gluten-free powdered ingredient but also contributes many more useful functionalities.
The rise of awareness regarding health and quality of life improvements through food consumption, health and wellbeing trends and daily diets are the future consumers' needs and are expected to expand worldwide. Satake is thriving to develop health-conscious products and provide consumers with products that are healthy, safe and secure. We firmly believe that our flour, with intentionally added functionalities, is helpful to our secondary flour processors and helping them, in turn, to develop health-conscious foods to consumers.