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Asian End-Product Testing
at the Grain Research Laboratory

  

 
 

 

Staff of the
Asian End-Products
Research Unit

 Staff of the Asian End-Products Research Unit left to right:
Donna Daniel,
Dr. Margaret Anderson,
Wendy Barker
Helena Facto and
Dr. Dave Hatcher

Canada exports approximately $2.4 billion dollars of grain to Asia each year. A significant percentage of such grain is incorporated into a diverse selection of Chinese steamed bread and dumplings. The Asian end-product section of the Grain Research Laboratory was established in 1991 to focus specifically on such products, and in particular on noodles. Some of the objectives of the section are:

  • To carry out research in order to best determine how Canadian wheat can be used to make such products.
  • Assist in the development of improved Canadian wheat cultivars for making "top quality" Asian end-products
  • To develop testing protocols to evaluate the suitability of Canadian wheat classes and newly developed wheat cultivars for making "top quality" Asian end-products.
  • To provide customers and marketers of Canadian grain with information on Asian end-quality resulting from new harvest surveys or in export cargoes.
  • To better respond to any quality concerns by customers of Canadian grain in utilization of Canadian wheat for Asian end-products.

The noodlemaking and breadmaking processes are quite different and require different testing protocols.

Comparison of noodlemaking and breadmaking processes

Comparison of noodlemaking and breadmaking processes

Noodle production requires far less water than bread using about 32-35% water absorption or approximately half that in a bread dough. The low amount of water does not allow the flour/water mixture to develop any of the inherent viscoelastic character associated with bread dough. A wide variety of ingredients dissolved in the water are commonly added to the flour during the mixing process. White salted noodles utilize anywhere from 1 to 5% NaCl (salt) in their production while Chinese alkaline noodles use 1 to 3% of an alkaline mixture of sodium and potassium carbonates (9:1) (Kansui). In some countries it is desirable to add a solution of caustic sodium hydroxide (NaOH). Alkali is added to develop a pleasant yellow color while firming the bite of the noodle.

In addition to ingredients, factors such as the size and shape of the noodles as well as the final treatment i.e. steaming and frying, steaming and drying, boiling or frying of raw noodles, etc. contribute to the vast myriad of noodle types.

Laboratory testing protocols tend to focus on the most common noodle types and employ conditions which are standardized in order to facilitate comparisons of different wheat flours. For example one typical procedure for evaluating noodles is illustrated below.

 
 

 
Figure 1 In the laboratory a small Hobart mixer is used to mix the liquid with the flour.
Figure 2 The flour is mixed by itself for 30 seconds prior to the solution being added. The solution is slowly introduced over another 30 seconds. Care must be taken not to introduce the liquid too quickly or you will get localized areas of dough developing while others remain too dry.
Figure 3 The flour and liquid are mixed for a total of 4.5 minutes to ensure even distribution of the water and to form a uniform crumb consistency. This particular picture highlights the bright yellow color which develops when an alkaline solution reacts with the normally clear flavanoid pigments to produce the desired intense yellow color.
Figure 4 The crumbs are introduced into the top of a small scale noodle machine, imported from Japan, and pressed between two temperature controlled, 28° C, moving rollers which have a 3.0 mm gap setting.
Figure 4b The Ohtake (Japan) noodle machine is used in the production of different types of noodles.
Figure 5 After the first pass the noodle sheet is folded and passed through the rollers for a second time.
Figure 6 A 25 cm piece is then cut from the sheet for use in the noodles. Knowing the size and weight of the noodle piece allows differences to be detected between flours using the exact same conditions.
Figure 7 The noodle sheet is passed through the roller 6 more times, reducing the gap and consequently noodle thickness with each passage.
Figure 8 After the final pass the noodle sheet length is recorded to determine how much it has stretched. This measurement gives us some idea of the quantity and quality of the viscoelastic proteins in the wheat flour. The noodles are then passed through grooved rollers which cut the noodle sheet into long strings all of equal size.
Figure 9 Some noodles are then dried in special temperature and humidity controlled driers to ensure that all noodles dry evenly and no tiny cracks or imperfections form on the noodle. Other noodles are immediately cooked. Cooking has a very large effect on the texture of the noodle. It is critical to optimally cook the noodle as overcooking dramatically changes its eating quality or "mouthfeel".
Figure 10 Figure 11Figure 12
We use objective testing equipment, called the Instron Universal Texture Machine (IUTM) to help us mimic the force measurements inside your mouth when eating a noodle (above left).

One blade, called a compression blade, 3.5 mm wide, is used to mimic molar teeth (above centre).

Another blade, only 1mm wide is used to measure the cutting force required by our front teeth (above right).
Figure 13 Noodle colour is extremely important to the consumer. Regardless of the noodle type they are particularly concerned with its appearance, especially brightness. We use a HunterLab colorimeter which can measure brightness, L*, independently from other color components. The machine also provides us with an indication of the redness, a*, and yellowness, b*. Each of these characteristics allow us to quantify changes in noodle color which could not be done by normal subjective measurement.
Figure 14 The enzyme polyphenol oxidase (PPO) is believed to be important in the formation of undesirable off colours in noodles. The section works closely with plant breeders to ensure varieties which are low in this enzyme and thus better suited for noodle production.
For more information contact dhatcher@grainscanada.gc.ca






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This page last updated: November 3, 1998

 
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