ARCHIVED - Harvest Science - Issue 2 The grain science and technology newsletter

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Photo essay: Durum variety registration

Plots of durum grown in co-operative trials.

Before a new durum line is registered as a variety for commercial production, it is grown for 3 years in multiple locations across the prairies as part of co-operative trials. The durum lines are evaluated against check varieties for agronomy, disease and end-use quality. Breeders are the driving force in developing new varieties with the desirable traits that producers and customers are looking for.

Photo by Jim Downey, SeCan Association.

Technician pours composite durum sample onto a scale for weighing.
The Grain Research Laboratory is responsible for the end-use quality testing of all durum lines being considered for registration. Composite samples are prepared, graded and milled to assess milling performance and to provide semolina for further evaluation.
Allis Chalmers laboratory purifier
Durum wheat lines are milled using the Allis-Chalmers laboratory mill along with a laboratory purifier to generate semolina. Each line is milled at least twice at the same controlled conditions to a constant extraction rate for fair comparison in semolina quality.
Semolina
Milling performance of durum lines is assessed based on semolina yield, total milling yield, and semolina ash content and speck count. The resulting semolina is further evaluated for protein content, pigment concentration, yellowness, pigment loss potential, wet gluten content and gluten strength.
Lab technician operating an asymmetric centrifugal mixer.
Evaluation of pasta is the ultimate test of durum wheat quality. Semolina and water are first mixed in an asymmetric centrifugal mixer to prepare dough.
Lab technician handling semolina dough.
The semolina dough crumbs are fine, uniform, and evenly hydrated after mixing, consistent with commercial requirements.
Lab technican cutting spaghetti strands produced from a micro-extruder.

Spaghetti is processed from semolina dough crumbs using a customized micro-extruder and a four-hole, Teflon-coated spaghetti die. The system is sealed with a vacuum during extrusion.

Temperature is precisely controlled along the extruder barrel. The system also allows for monitoring extrusion pressure.

Lab technician positioning spaghetti in a pilot pasta drier.
Spaghetti is dried in a pilot pasta drier at the Canadian International Grains Institute using a drying cycle commonly used in commercial production.
Lab technician holding dried spaghetti strands.
Before evaluation for colour and texture, dried spaghetti strands are visually inspected to make sure they are free of quality defects due to processing. This is to ensure that any observed difference in quality is solely attributed to the variety.
Colormeter, spaghetti strands on white cardboard.
Spaghetti strands are cut and mounted on white cardboard. Colour is determined using a colorimeter. Pasta with a high bright yellow colour is desired.
Lab equipment for cooking spaghetti.
Spaghetti samples made from different lines are cooked in the same set of conditions. Consistent sample preparation is critical to texture measurement.
Texture analyzer, close up of cutting blade.
The firmness of cooked spaghetti is determined by using a texture analyzer with a cutting blade which simulates the sensory biting process.
Durum field

Once quality testing is completed for a new durum line, the results are sent for review to the Quality Evaluation Team of the Prairie Recommending Committee for Wheat, Rye and Triticale. In order to be registered for commercial production, a new durum line needs to meet the quality model set for the Canada Western Amber Durum wheat class and perform as well or better than the check varieties in the durum co-operative trials.

Photo by Cigi (Canadian International Grains Institute).

Plate of spaghetti

The comprehensive evaluation of quality in variety registration assures high and consistent quality of end products made from Canadian durum wheat. It is the cornerstone for keeping satisfied customers and happy consumers of Canadian durum wheat around the world.

 

Photo by Edward ONeil.