Food or edible material: processes – compositions – and products – Processes – Extraction utilizing liquid as extracting medium
Reexamination Certificate
2001-06-25
2003-01-14
Weier, Anthony J. (Department: 1761)
Food or edible material: processes, compositions, and products
Processes
Extraction utilizing liquid as extracting medium
C426S432000, C426S435000, C426S386000, C426S651000
Reexamination Certificate
active
06506433
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method for recovering aroma concentrate from a caffeine- or theobromine-comprising food base material, such as coffee or tea, and in particular cocoa, at least comprising the steps of:
introducing the food base material into an aqueous extractant and incubating the food base material at a suitable temperature and for a suitable period, substantial extraction of the aromas taking place to form an aqueous food extract,
pervaporating the food extract using a hydrophobic pervaporation membrane to form a food aroma permeate,
recovering the permeate to obtain the aroma concentrate.
BACKGROUND OF THE INVENTION
The term “aroma concentrate” in this context refers to an isolated mixture of aromatic substances as it exists in the base material, said mixture being present in a solvent, particularly water. Preferably, the recovered aroma concentrate substantially has an aroma profile which matches that of the base material, which is to say that the concentration ratio of the aromatic substances in the recovered aroma concentrate according to the invention substantially matches that of the aromatic substances in the base material. An aroma profile can be determined by methods known in the art, for example by means of dynamic headspace analysis (Dynamic Headspace; see T. P. Wampler, in Techniques for analysing food aroma, edited by P. Marsili, 1977, pp. 31-33, ISBN 0-8247-9788-4, and references therein). The invention therefore does not relate to the purification of a single chemical compound.
In the art, aroma concentrates obtained with the aid of steam distillation and liquid extraction are known. Reference is made in this context to U.S. Pat. No. 3,579,349 and to Food Tech Europe, December 1994/January 1995, pp. 48-54, respectively.
In the case of steam distillation, the high temperature results in thermal degradation of a considerable fraction of the aroma molecules, the product not having as full a taste as a result. In the case of liquid extraction, use is often made of organic solvents which must be removed completely from the extract obtained, which entails high costs and is problematic from an environmental point of view. Reference can be made in this context to DE-C-2 055 030.
U.S. Pat. No. 3,492,027 discloses a method for preparing a cocoa aroma by extracting cacao shells in boiling water. Such an extract, however, contains suspended particles, is brown in colour and contains purines, catechols and other water-soluble components such as proteins, carbohydrates and minerals, which considerably hamper further concentration of the desired aroma. In this context, purines mainly mean caffeine and theobromine. Catechols such as catechol, epicatechol and epigallocatechol are also known as antioxidants.
The pervaporation process is known per se in the art, see for an overview, e.g. Baudot and Marin, Food and Bioproducts Processing (1997) 75, pp 117-142. For separating azeotropic mixtures and for the dealcoholization of beverages, see for example DE-A-3 804236 and Karlsson and Tragardh, Trends in Food Science & Technology, 1996 (7), pp 78-83.
Also known per se in the art is the use of pervaporation to isolate individual aroma concentrates, i.e. to purify and separate individual chemical compounds (See e.g. DE-A 4 421 682).
Pervaporation is used especially to isolate aroma components from fruit juices, for example to obtain an aroma concentrate from apples. To this end, the juice is obtained from apples, and this juice is then subjected to pervaporation (see for example Borjesson et al., Journal of Membrane Science, Volume 119, 1996, pp. 229-239). The permeation conditions can be optimized by those skilled in the art in a simple manner, although in the case of fruit juices it did not prove possible to obtain an aroma concentrate having a satisfactory original aroma profile.
JP-A-05049840 describes a method for isolating a biologically active aroma concentrate from leaves of the medicinal plant Eucommia ulmoides. To this end, an aqueous extract of the leaves is subjected to permeation or pervaporation, the concentrate being recovered, however, on the primary side of the membrane, i.e. as the retentate. Pervaporation is thus used solely as a dehydration method; the aroma constituents do not pass through the pervaporation membrane.
A method of the above mentioned type for isolating seperate aroma components from in particular food juices is described in SE-C-500 579. In order to obtain desired concentration of aroma components, the hydrodynamics of the seed are altered. However, an aroma concentrate having an original aroma profile is not obtained.
The process of employing pervaporation to isolate an aroma concentrate having an aroma profile which substantially matches that of the base material in question (herein also referred to as “original aroma profile”) is not known, however.
Surprisingly it is found that in the case of caffeine- and theobromine-comprising food base materials, particularly in the case of cocoa-containing base materials, pervaporation at elevated temperatures (i.e. 30° C. or more) can be used without the original aroma profile being lost. It is precisely at lower pervaporation temperatures that important aromatic substances will be partially retained in the retentate, so that a full aroma having the original aroma profile cannot be obtained.
In this context it is noted that pervaporation in the art, i.e. the isolation of odorous substances and flavourings, i.e. aromatic compounds, in contrast is carried out at lower temperatures. Those skilled in the art will choose precisely the pervaporation technique as a separation technique for mixtures comprising temperature-sensitive components (such as fruit juices, for example) and will therefore employ low temperatures. If such components are not present in the mixture to be separated they will predominantly use other thermal techniques such as steam-stripping and vacuum distillation.
SUMMARY OF THE INVENTION
The present invention therefor provides an improved method for recovering aroma concentrate from a caffeine- or theobromine-comprising food base material, such as coffee or tea, and in particular cocoa, of the above-discusses type, and is characterised in that the temperature of the extract and the permeate, respectively, during the pervaporation is more than 30° C.
It was found that the use of pervaporation according to the invention affords excellent aroma concentrates, in particular cocoa aroma concentrates, without valuable aromatic substances being lost during the preparation, which is to say that it is possible, via the method according to the invention, to obtain an aroma concentrate having an aroma profile which substantially matches that of the base material from which the aroma concentrate has been obtained (see example). It is also possible, via the method according to the invention, to obtain an aroma concentrate which substantially comprises all the desired aromatic substances from the base material which can be perceived by human taste and smell, as a result of which a “full” and “complete” aroma concentrate is obtained.
In addition, temperatures above room temperature are advantageous, as the fats present in the feed are then dissolved and as such cause fewer problems with clogging and fouling of the membrane. It should be noted that the said fats substantially do not pervaporate through the permeation membrane; consequently, the permeate is substantially fat-free.
It is important to note that the present inventors have established that as a result of pervaporation substantially no purines and catechols are present in the permeate obtained, the aroma becoming less bitter and astringent as a result, which is highly advantageous for preparing, for example, a purine-free coffee aroma, tea aroma or cocoa aroma. An aroma is thus obtained which in terms of smell and taste largely matches the smell and taste, respectively, of the starting material. Thus a cocoa aroma obtained according to the method of the present invention has a taste which is qualitatively compara
Hoving Hendrik Derk
Kattenberg Hans Robert
Nijhuis Herman Henk
Starmans Dick Antonius Johannes
Willemsen Jeroen Harold Anton
ADM Cocoa B.V.
Browdy and Neimark , P.L.L.C.
Weier Anthony J.
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