In the processing chain that produces foods from wheat, the milling efficiency of wheat is the first quality criterion assessed by the industry. It represents an advantage that could be further enhanced, both in response to demands from the primary processing industry and to encourage grain exports. However, the assessment of milling efficiency, or the ability of a wheat to produce a high flour yield, remains very difficult because of the large number of factors on which it depends. For this reason, a research consortium involving INRA and eight partners covering all sectors of the cereal industry (from breeding to secondary processing) has been working since 2003 to study the physicochemical and structural bases of the milling efficiency of wheat and to develop new methods for its assessment.
Based on a prototype developed at INRA, a minimill was designed in collaboration with the company Chopin and Arvalis-Institut du Végétal. A specific mill diagram comprising two breaking steps on corrugated rolls and three semolina reduction steps on plain (smooth) rolls was able to achieve milling yields of about 75%. By making appropriate adjustments and automating the different steps, the minimill proved to be easy to use and enabled good productivity (about 10 milling trials/day). The results obtained displayed excellent repeatability, thus enabling the good discrimination of wheat samples. A comparison of the results with those obtained using a reference mill with four break rolls, four coarse reduction rolls and six fine reduction rolls showed that the minimill could predict the milling behaviour of different batches of wheat. Based on milling trials on more than a hundred batches of wheat of different genetic origins, from different locations and grown under different agri-environmental conditions, as well as during several harvest years, it was shown that the minimill could predict not only the total flour extraction but also the yields of different grinding and conversion flours and the degree of bran finishing. Finally, a supplementary study was performed to optimise control of the prototype, and particularly to adjust the level of damaged starch, so as to obtain flours with characteristics close to those achieved by industry. Under these conditions, the rheological properties of dough measured using an alveograph were comparable to those obtained by an industrial mill.
Figure 1. MILL DIAGRAM FOR THE MINIMILL
A patent covering the equipment and the method to assess milling efficiency has been filed in joint ownership with Chopin and Arvalis-Institut du Végétal. This new system should be on the market in 2011 (see the prototype in Figure 1). By enabling the assessment of both the milling efficiency and baking efficiency of wheat, this highly polyvalent minimill should respond to many of the needs expressed by partners in the cereals industry, from the breeding of varieties to the optimisation of mixtures of milled wheat.
Partners
This work was carried out in the context of the "Milling Efficiency" research consortium. Set up in 2003, this consortium now involves nine partners: Arvalis-Institut du Végétal, the National Association of French Millers (ANMF), the French Seeds Association for Straw Cereals and other Autogamous Species (AFSA), Buhler, Chopin Technologies, the National School for Milling and the Cereals Industry (ENSMIC), INRA, the Institute for Technological and Agri-Food Research in Cereals (IRTAC) and Kraft Biscuit Europe. The work carried out by this consortium aims to:
- Design equipment for the conduct of reference milling trials,
- Develop methods for the assessment of milling efficiency,
- Study the genetic and agronomic variability of milling efficiency.
Scientific contacts:
For further information:
- ABECASSIS J., BAR L’HELGOUACH C., DUBAT A., GREFFEUILLE V. AND LULLIEN-PELLERIN V. 2007. Predicting the milling efficiency of wheat grain.1st Latin American ICC Conference, Rosario, Argentina, 23-26 September.
- BAR L’HELGOUACH C., TOMMY-MARTIN V., CHAURAND M., ABECASSIS J. 2004. Prediction of the milling value of common wheat using an instrumentally controlled micromill. Poster, 12th ICC Cereal & Bread Congress "UCST 2004". 24-26 may, Harrogate, UK
In French
- ABECASSIS J., BAR-L’HELGOUACH C., CHAURAND M., DUBAT A., GEOFFROY S., PUJOL R. 2009. Procédé et appareil de fabrication simplifiée, d’une mouture de blés de référence. Brevet n° 0905572 déposé le 20/11/2009.
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