Innovations for the mill lab
April 01, 2005
by World Grain Staff
by David Cliffe
Over the past decade, much effort has been made in the flour mill laboratory to improve reliability of results and provide more useful information to the miller. Accreditation of laboratories to a quality standard body and working with standardized methods has achieved improvements, and proficiency schemes help maintain a high level of performance.
However, much of the equipment used in the lab has remained basically the same for many years. Techniques developed up to 60 years ago are still in use, often with new technology added, but essentially the same methodology.
Today’s mill lab is under pressure from many directions: faster analysis to keep up with process demands, more information for product quality and product development to meet the increasing demand for new products in the baking and food processing markets. At the same time the difficult economic situation in recent years has meant consolidation in the cereals industry and pressure on profits. Companies need to reduce overheads and with automation of the process, the laboratory stands out as a main source of labor costs.
Technological development in the laboratory is therefore becoming a priority. Millers and bakers no longer want to rely on older methods of testing, which may be slow, labor intensive and often not applicable to modern processing and products.
Recently there has been a significant increase in new instruments and techniques from suppliers of traditional instruments for flour and baking quality. These can help address the demands of the mill lab and provide an opportunity for technologists and researchers to develop new standards and methods for the future.
The Brabender Farinograph has been the workhorse of the industry for many years, providing measurements of water absorption and rheological properties. This system has served the industry well and the newer models have incorporated computer control with variable speed. The measuring mixers provide 300g or 50g tests but bowl design has not changed significantly over the years.
This standard method does not relate directly to modern industry processes. The major requirement is to understand work input. Research carried out during the 1990s identified that different mixing speeds coupled with tight control of dough temperature would provide the baker with more useful information. Whilst this has not been taken up by the industry, instrument manufacturers have made major moves to provide the miller with more capability. This has resulted in a huge increase in interest by millers in alternatives to the existing Farinograph Method.
Newport Scientific has introduced the doughLAB, based on the well-known Sigma blade geometry used in the Farinograph.
Measurements of water absorption, development time, stability and degree of softening are all available with additional features for those wanting to develop new methods: variable speed, work input, precise temperature control, together with practical innovations, like integrated and automated water addition and onboard computing.
As with the newest Farinograph, the Farinograph E, variable speed facilitates testing of difficult doughs such as the
very strong wheat flours in Australia, North America and Japan that do not develop using standard low energy American Association of Cereal Chemists International (AACC) and international Association for Cereal Science and Technology (ICC) Farinograph methods. It offers exciting possibilities for research, bakery and product development, not only for traditional bread products but for novel formulations, wholemeals and doughs for Asian products such as steamed bread and noodles. Most importantly, it will mimic commercial dough mixing in the bakery.
High energy input mixing is effective for testing wholemeal and non-traditional doughs, including novel formulations with nutriceutical benefit, such as with soy flour, or low carbohydrate formulations to meet the latest market trends and product development requirements.
Tripette & Renaud Chopin has been supplying dough rheology equipment such as the Alveograph and Consistograph for many years and these have been written into many trading specifications, but today’s modern processes require more relevant information. Chopin acknowledged this need and developed a new instrument, the Mixolab, which was introduced at the AACC annual meeting last year.
The mixer has a very different design and geometry with a dough capacity ranging from 40 – 100g.
It provides the user with the ability to develop dough rapidly and then follow its progress through different mixing and heating phases: protein development is followed by the degradation of the protein matrix. This in turn leads to starch gelatinization properties and finally enzyme activity, as the tem
perature is increased to 95C then back down to cooler temperatures. Initial work shows a very interesting possibility for predicting rheological properties on ground wheat.
The Mixolab is computer controlled with automated water dispensing and easy to clean bowl.
NIR is old hat. It’s been around in the mill lab since the 1970s. But while the packaging may remain the same the content has changed dramatically. Modern NIR instruments have utilized new technology and developments from online technology that runs continuously.
Filter instruments are still the most cost effective choice for standard tests such as protein and moisture in grain and milled flour.
Scanning systems have promised so much more and we are beginning to see some of this potential. Laboratory instruments are being equipped with an increasing number of "calibrations" that promise the user a black box solu
tion. This is not so easy to achieve however. Even though statistical information looks good, often correlations
in the normal working range are not so reliable. In addition, the often dusty, vibrating environment found in a flour mill does not suit older monochromator systems.
One scanning instrument that could meet the requirement of both laboratory and on-line transferability is the Diode
Array 7200 from Perten Instruments. It has no moving parts and needs no sample preparation — a major source of error with most instruments.
Based on the most up to date technology, this system is set to revolutionize the use of NIR for the next generation of instruments.
Many different methods to determine starch damage have been developed over the years but they have all suffered from the same problems: rests are too long, tests require a skilled operator and poor repeatability.
Out of necessity some of these methods have been adopted by AACC, ICC and other reference bodies but the overriding desire for an automated, rapid and reliable alternative has always been near the top of all cereal chemist’s wish list.
Tripette & Renaud Chopin has been working with the industry for over 12 years to provide millers with this facility and recently the latest instrument, the SDmatic has achieved this. Not only is it fast and accurate, Chopin’s innovation has made it so simple to use that it is likely to become an everyday tool in most mills. It is based on the principle of damaged starch absorbing iodine at a faster rate than undamaged starch. The method requires only simple sample preparation and results are available in only five minutes. Starch damage measurement does not have to be the laborious batch process; immediate control of production is now a possibility.
RAPID GRAIN MOISTURE MEASUREMENT
Moisture has been the greatest source of dispute for as long as anyone can
remember. The Aquamatic from Perten Instruments results from developments at USDA. Using high frequency penetration of the grains, it allows a full assessment of total moisture, not influenced by surface moisture or dryer outer surfaces. Problems like the rebound effect where drier outer layers can give false readings are no longer an issue.
There is only one calibration which covers all products without the need for calibration updates. Test results have shown improved performance, with standard deviations down to about 0.2 rather than existing methods at 0.3 or more.
FINAL PRODUCT TESTING
Millers have always used test baking as the ultimate quality check and despite many attempts to predict quality in other ways, this has remained the most common method for both quality control and product development. It is vulnerable to the subjective nature of the analysis, the experts who score bread samples. They may be reliable in many ways but the modern industry wants numbers, historical data, objective and comparative data.
Texture Analysers have been standardized to provide a lot of data but this is only part of the story. Now the final piece in the jigsaw is available.
Millers, bakers, ingredient manufactures, equipment manufactures and researchers around the world are now adopting a common language, the C-Cell language. This system, developed at Campden & Chorleywood Food Research Association in the U.K., uses advanced imaging techniques to provide rapid, objective analysis of crumb structures.
Objective data from C-Cell is reproducible and detailed enough to provide the final analysis of cell structure and physical features. The database created contains 48 measurements as well as up to six processed images for each sample.
A set of C-Cell data can be easily exchanged and archived between supplier and customer to provide harmony rather than disputes.
The milling and baking industry seems to be split when it comes to
adopting these new techniques. There are some forward thinking organizations that are prepared to work with the instruments, develop new, more relevant methods and who can see cost savings and improved performance in the future. There are however many in the industry who appear happy with the status quo. Not out of apathy but because they are too busy coping with the day to day, they have no time to innovate and look at new ideas. In this case it is up to industry bodies, research organizations and maybe specialized groups to evaluate and work with the new tools. There is a great danger of missing an opportunity and handing the competitive edge to others. WG
David Cliffe is the managing director of Calibre Control International Ltd., Warrington, U.K. He may be contacted for further information at email@example.com . To purchase copies of the publication, "Wheat and Flour Testing Methods…A Guide to Understanding Wheat and Flour Quality" (mentioned page 70) contact Tammy Elliot at firstname.lastname@example.org .