Food or edible material: processes – compositions – and products – Measuring – testing – or controlling by inanimate means
Reexamination Certificate
1999-05-14
2003-04-15
Hendricks, Keith (Department: 1761)
Food or edible material: processes, compositions, and products
Measuring, testing, or controlling by inanimate means
C426S496000
Reexamination Certificate
active
06548091
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods for assessing the quality of cereals.
BACKGROUND OF THE INVENTION
It is known that different qualities of wheat are required for different applications. Bread-baking, for example, requires wheat which ensures that the dough rises a great deal and that a large bread volume is obtained. On the other hand, biscuits are preferably baked from wheat which provides doughs which are not as fluffy. Pasta-making, in turn, requires wheat which provides a dough which can be extruded, while wheat which is to be used as forage should have high forage functionality, i.e. result in large growth in the animals which are being fed.
In order to optimize the use of wheat and to produce finished products which are the best possible, it is thus important for users to be able to buy wheat of the right quality. This presupposes that the quality is known. However, the fact is that different types of wheat can be of different qualities, but the same types of wheat can also be of different qualities because of, for example, different growing conditions, different weather conditions and different fertilizing. Consequently, the quality must be assessed experimentally.
In Swedish grain depots, the quality of a shipment of wheat is normally assessed by a sample being taken from the shipment and its falling number, its water content and its protein content being assessed. Payment is then based on these values. However, this method is not completely reliable, since it does not always measure the quality of the wheat. For example, it is possible to increase the protein content by increased fertilization without improving the quality in terms of baking volume or forage functionality. Consequently, the quality assessment described above is often combined with test baking. However, test baking takes such a long time that the result cannot be used at depots for sorting shipments of grain by quality.
Accordingly, there is a need for a new method for assessing cereal quality.
A known apparatus, which is used in studies of the quality of wheat, is the mixograph, which is available from TMCO, 501 Jay Street, Lincoln, Nebr., USA. The use of the mixograph is described in the AACC Standard 54-40A.
In short, the mixograph comprises a bowl, in the bottom of which three pins are fixedly placed and in the lid of which four pins are movably arranged. The mixing bowl is mounted on a vertical shaft so that it can rotate around it. An arm is fitted to the bowl. In the one end of the arm a spring is attached, which extends perpendicular to the arm and which is fixedly anchored in the base of the mixograph. A pen is attached to the other end of the arm.
The mixograph is used as follows. A sample of wheat of which the quality is to be assessed is milled into flour and is poured into the bowl of the mixograph. Water is added. The flour and the water are mixed to form a dough by the movably arranged pins being caused to rotate around the fixed pins. Subsequently, the mixing of the dough continues for a predetermined period of time. In connection with the mixing, stress arises in the dough. The stress causes a torque on the mixing bowl. The torque is registered on a sheet of paper which scrolls forward at a constant speed under the pen. The curve obtained is called a mixogram and is used as an aid for assessing the quality of the wheat. Normally, the mixogram is studied visually, in which case mixograms of different samples are compared. It is also known to correlate individual parameters which are determined from the mixogram with measures of quality, such as baking volume or dough quality. The parameters mentioned in the AACC Standard are:
Peak time, i.e. the time it takes for the torque to reach the maximum level;
The area under the curve from the beginning of the mixing to a specified point in time;
Middle peak height, i.e. the maximum height in the middle of the curve; and
The angle between the ascending and the descending parts of the curve at the maximum torque.
So far, the mixograph has only been used in laboratories, and not in depots. In order to permit its use in depots, it must be possible to carry out the quality assessment in a short period of time. This is not the case at present, since the mixograph only produces curves which then have to be evaluated. Furthermore, a high correlation is required with the cereal quality which is to be assessed. A minimum level of 80-85% has been mentioned.
Other well-known apparatus for testing the quality of doughs are the farinograph, the extensograph and the alveograph, which are described in, for instance, an article by P. W. Heaps et al. “The rheological testing of wheat glutens and doughs”, p. 1095-1096 in Chemistry and Industry, Aug. 10, 1968. These apparatus are likewise unsuitable for quality assessment at depots or other commercial applications where it is a requirement that the quality assessment can be carried out simply and in a short period of time.
In the article “Relaxometrie—ein neuer Weg zur Qualitatskontrolle von Lebensmitteln” in Lebensmittel-industrie 29 (1982), the inventor of the present invention suggests that the viscous and elastic properties of semi-solid substances can be studied by means of stress relaxation. More specifically, a sample of the semi-solid substance is sheared between a cone and a plate, and a relaxing curve for the semi-solid substance is registered. The relaxing curve can be used for quality control of gluten in wheat. This known equipment is only used in laboratory tests and thus is not suitable for commercial use.
Naturally, the problems described above with respect to quality assessment of wheat also exist in the quality assessment of other cereals.
SUMMARY OF THE INVENTION
One object of the invention is thus to provide a new method, which can be used for assessing the quality of cereals.
Another object of the invention is to provide such a method and such an apparatus which can be used for quick and easy quality assessment of cereals.
A further object of the invention is to provide such a method and such an apparatus which can be used for quality assessment of cereals with a high degree of prediction.
Yet another object of the invention is to provide such a method and such an apparatus which are suitable for use in grain depots.
The above-mentioned objects are achieved by methods and apparatus which have the features stated in the appended claims.
The invention thus combines the known mixograph technique with the insight that valuable information about the quality of a cereal type can be obtained by studying how the stress in a dough, which contains the cereal in question, relaxes subsequent to the dough having been subjected to deformation. Mixing is a simple and known technique for achieving a dough and deforming the same. However, unlike in the known mixograph technique, the deformation is interrupted and the quality assessment is based on the stress in the dough when it relaxes. As a result, a very high degree of prediction can be achieved. Tests show that relaxing parameters correlate very well with the quality of cereals. For example, with three relaxing parameters a correlation of more than 88% with baking volume for wheat has been achieved.
Moreover, the fact that the deformation is effected by means of mixing and the mixing and the relaxing are effected in one and the same container, permits the quick and simple handling which is suitable for use in, for example, grain depots.
As was indicated in the introduction, the quality of a cereal type can be represented by, for example, a measure of the baking volume, a measure of the extrudability, or a measure of the forage functionality. It can also be represented by of a measure of some other quality characteristic, which correlates with one or more relaxing parameters.
The invention has been tested with very good results as regards wheat. It is presumed that it can be applied to other types of bread cereals, such as barley, rye, and oats, with equally good results. It is also presumed that the invention can be used for
Birch & Stewart Kolasch & Birch, LLP
Hendricks Keith
Skanska Lanimännen Ek För
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