Food or edible material: processes – compositions – and products – Processes – Preparation of product which is dry in final form
Reexamination Certificate
2000-05-05
2002-12-24
Weier, Anthony J. (Department: 1761)
Food or edible material: processes, compositions, and products
Processes
Preparation of product which is dry in final form
C426S472000, C426S473000, C426S453000, C426S285000, C426S594000, C426S597000, C426S388000
Reexamination Certificate
active
06497911
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the preparation of a water soluble coffee or tea product from a non-rewetted particulate material obtained from an extract by drying.
BACKGROUND OF THE INVENTION
Different processes are known for drying of extracts of coffee or tea so as to obtain a particulate material. Spray drying and freeze drying are examples of such processes. Also combined spray drying and belt drying processes, e.g. processes of the type known under the trademark FILTERMAT® (Niro) may be selected out for mentioning.
Furthermore different processes for agglomeration of the obtained particulate material have been devised, such as different rewet-agglomeration processes, e.g. the process described in applicant's international patent application No. PCT/DK00/00009.
Thus it is known to spray dry a coffee extract in a spray drying plant so as to achieve a product, which is subsequently agglomerated e.g. by a rewet-agglomeration process as mentioned above.
Spray drying of a coffee extract in a combined spray and belt dryer of the FILTERMAT® type has been disclosed in U.S. Pat. No. 4,351,849. By this process a comparatively wet product is collected as a mat on a gas-permeable conveyor belt on which it is dried to final moisture content and cooled in sections immediately following the spray drying section before it is comminuted to agglomerates of desired size.
The appearance of the products obtained by the above two kinds of processes differ from each other and from that of a freeze dried product. The quality of the products obtained by each of the processes depends on the process details.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a process for the preparation of a coffee product having an appearance similar to that of freeze dried coffee and a quality, particularly a taste, being comparable to or better than that of freeze dried coffee, which process may be carried out in a process line being less expensive than a freeze drying line.
It is a further object to provide a process which can be carried out using a non-rewetted particulate material as starting material.
The above objects are achieved by the process according to the invention. However it should be noticed that the process according to the invention is not limited to the preparation of coffee products; it is also applicable to the preparation of tea products, including herbal teas and the like and mixtures of different teas. Furthermore, the expression coffee products should be understood so as to include both coffee and mixtures of coffee with coffee substitutes and the like.
For the sake of simplicity, the invention will be explained with particular reference to coffee.
Extensive experiments carried out by the inventors have shown that a certain combination of features is essential for achieving the above objects.
As starting material for the process according to the invention a non-rewetted particulate material obtained from an extract by drying is used. This particulate material should have a moisture content which is higher than the moisture content desired in the final product. Thus the starting material has not as yet been dried to final moisture content. Contrary to rewet-agglomeration processes where only a moistening of the surface layer of the particles is aimed at, the moisture content should be substantially uniform. The particles having a substantially uniform moisture content which is higher than the moisture content desired in the final product should be subjected to a heat treatment which is carried out essentially without affecting the moisture content of the particulate material. When they are subjected to the heat treatment, the particles should be present as a layer, and the heat treatment should be carried out at a combination of temperature and time being adequate for effecting fusion so as to convert the layer of particles into a compact cake-like structure. Finally the resulting cake-like structure should be disintegrated into granular material before the final drying is carried out. By this feature two advantages are obtained, one being that the final drying can be carried out more efficiently on a granular material than on a cake, and the other being that off-size particles may be separated and recirculated in the process without becoming subjected to more than one “final drying” and any consequential damage to the product quality. As furthermore a non-rewetted particulate material is used as starting material, it will be appreciated that a very lenient process is at issue.
From EP 0 373 697 B1 a process is known, wherein a granular beverage material is formed from a powdered extract of the beverage by sintering a powdered extract, which is already essentially dry, in an environment not being open to air, so as to form an agglomerate in which the particles of the starting material have been brought in a point-to-point contact so that they are bridged to one another without loosing their identity as a particle followed by granulation of the agglomerate. It is mentioned as essential that water vapour inherent in the powdered extract is retained during the sintering step. In line with the fact that the starting material is essentially dry, no subsequent drying of the obtained granulate is carried out. Thus, the condition of the material subjected to the sintering according to EP 0 373 697 B1 differs substantially from that of the material subjected to the heat treatment according to the invention, and the product obtained by the process according to EP 0 373 697 B1 has a much more loose structure than the product obtained by the process according to the invention, which has been confirmed by the present applicant by reproducing Example 1 of EP 0 373 697 B1.
Accordingly, the present invention provides a process for the preparation of a water soluble coffee or tea product from a non-rewetted particulate material obtained from an extract by drying, which comprises subjecting a layer of particulate material having a substantially uniform moisture content which is higher than the moisture content desired in the final product to a heat treatment, the heat treatment being carried out essentially without affecting the moisture content of the particulate material at a combination of temperature and time being adequate for effecting fusion so as to form a compact cake-like structure, disintegrating the cake-like structure into granular material after cooling as necessary, and subjecting the granular material to final drying, optionally after separation of off-size particles.
The particulate material having a substantially uniform moisture content which is higher than the moisture content desired in the final product may be obtained in a simple manner, viz. by interrupting the drying process before the moisture content desired in the final product has been reached. This procedure gives the additional advantage that the energy other-wise needed for final drying at this stage, is saved. Furthermore any loss of flavour during a final drying at this stage is avoided.
In a presently preferred embodiment, the particulate material is obtained from a combined spray drying and belt drying process, particularly a process of the type known under the trademark FILTERMAT®. It may also be obtained from other drying processes such as a spray drying process, e.g. using a spray dryer/fluid bed combination. However processes of the FILTERMAT® type are particularly suited for providing a starting material of adequate moisture content giving a very lenient drying due to the possibility of operating this process with a drying gas outlet temperature as low as 50-60° C.
The moisture content of the particulate material subjected to the heat treatment will typically be in the range from 4-12%, particularly in the range from 5-11% and preferably in the range from 6-10% by weight. Furthermore, the moisture content of the particulate material subjected to the heat treatment will typically be 1-10% and particularly 3-8% by weight (abs.) higher than the m
Hansen Ove Emil
Ilkjær Jørgen
Sørensen Jens Mourits
Sørensen Per Bo
Niro A/S
Sughrue & Mion, PLLC
Weier Anthony J.
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