Quality matters for udon noodles

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Australian wheats are tested in AEGIC’s Western Australian laboratory for the necessary udon noodle quality characteristics. PHOTO: AEGIC

The Australian Export Grains Innovation Centre’s grain quality specialist Dr Ken Quail gives an overview of the importance of wheat quality for Japanese udon noodles

Sota Tanaka works in the Tokyo business district as an accountant. In this megacity of 30 million people, his commute of two hours in each direction by train is not uncommon. Some of his colleagues have a three-hour commute, so he is lucky.

Sota leaves home at 6am and, after finishing work at 7pm, is typically home by about 9pm. With such a long day, he looks forward to his lunch and dinner breaks.

Sota loves his food and his enjoyment of every morsel is an important part of daily life. He is intimately familiar with traditional Japanese food and attuned to slight variations in colour, texture and taste.

Sota often eats udon noodles for lunch. He always goes to the same restaurant, where he knows the noodles will be just right. His noodles are served in soup with vegetables, prawns and seasoning. As he lifts the noodles with his chopsticks he eyes their bright, shiny and creamy white colour with satisfaction. He sucks the smooth, slippery noodles into his mouth and lightly bites down, experiencing their softness, which is quickly followed by a chewiness.

In this moment his teeth lightly bounce on the gentle elasticity of the noodle. This chewy and slightly sticky texture he refers to as ‘mochi mochi’ – similar to the experience of eating sticky rice.

Sota has enjoyed eating udon noodles all his life, but he knows little about the wheat used to make them. He would be amazed to discover that Japan buys virtually all of its wheat for the noodles from Australia, which is supplemented with a small Japanese domestic supply.

The imported wheat is supplied exclusively from Western Australia as a special blend of Australian Noodle Wheat (ANW) and Australian Premium White (APW). The preferred blend shipped to Japan is 60:40 ANW/APW. The ANW component accounts for the noodle colour and texture that Sota likes so much.

Wheat varieties are carefully selected to have the correct appearance characteristics, including brightness and a creamy white colour which is stable, so that if we make the noodles today they will be a similar colour tomorrow. The colour characteristics are largely controlled by genetics and wheat breeders use preferred types to make crosses, selecting lines with the best appearance attributes.

What really gives ANW the coveted ‘mochi mochi’ mouth feel are the starch characteristics. To be classified in the ANW class, a wheat line must have the right starch genetics. There are three gene locations on wheat chromosomes that influence starch properties. If all three starch synthesis genes are present at these locations, we get what is referred to as ‘normal’ starch properties, which accounts for most bread-making wheat globally.

If just one of these specific gene locations is missing the starch synthesis gene, then starch with the unique properties for udon noodles is produced. This ‘missing gene’ is referred to as a null allele and this wheat type is referred to as ‘null 4A’, where the 4A describes the chromosome location. When these noodles are cooked in water the starch swells more than starch from ‘normal’ wheat, producing the texture required for udon noodles. All ANW varieties are characterised as null 4A and were developed through traditional crossing and selection.

Wheat grown for noodles in Japan has the same starch genetics. The null alleles occur naturally and fortuitously; Australia included these genetics in early breeding material.

Sota Tanaka must appreciate that ANW is a brilliant and internationally unique combination of the right colour characteristics and null 4A starch genetics for noodle texture, and is produced by skilful farmers to meet the required grade specifications.

Sota considers udon an art and tradition to be enjoyed; what he may now learn is that there is also a science behind the ‘art’ of udon.

A similar noodle market exists in Korea, with the noodle blend comprising a slightly different ratio of ANW and APW. Together, Japan and Korea purchase about 1.6 million tonnes of the noodle wheat blend.

In collaboration with Japan, AEGIC runs a highly trained sensory noodle evaluation program to assess unreleased ANW varieties (for taste, appearance, mouth feel). This aids ANW classification and ensures we are meeting Japan’s requirements.

Separately, AEGIC is investigating Japan’s wheat quality requirements for ramen noodles, a totally different noodle style generally made from hard wheat varieties.

More information

Dr Ken Quail
08 6168 9900