CA1151940A

CA1151940A - Soluble coffee product

Info

Publication number: CA1151940A
Application number: CA000373160A
Authority: CA
Inventors: William J. Einstman
Original assignee: General Foods Corp
Current assignee: General Foods Corp
Priority date: 1980-04-10
Filing date: 1981-03-17
Publication date: 1983-08-16
Also published as: SE8102293L; JPS56151455A; GB2074007A; DE3112896A1; GB2074007B; FR2480089B1; FR2480089A1; KR830004792A

Abstract

ABSTRACT A dry soluble coffee product having added thereto aromatized particles or granules of a micro-porous structured soluble coffee product having a small nominal pore radius and one or more fractions of a microporous structured soluble coffee product having a larger nominal pore radius and/or a conven-tional soluble coffee powder. The soluble coffee product has improved initial jar, i.e. headspace aroma quality/ intensity.

Description

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DESCRIPTION
SOLUBLE COFFEE PRODUCT

Technical Field The present invention relates to soluble coffee.
More particularly, it relates to a soluble coffee product having added thereto particles or granules which have a unique microporosity capable of sorbing and retaining volatile aromatic compounds and releasing these volatile aromatic compounds in a controlled manner.

Background Art Many commercial soluble coffee products are enhanced with volatile aromatic compounds by combining the soluble coffee product with pure coffee oil or aroma-enriched coffee oil so as to provide the soluble coffee product with an aromatic quality more like that of roasted and ground coffee. However, aromatizing a soluble coffee product with coffee oil presents plant processing problems in recovery of the oil from the roasted coffee beans, storage of the oil and handling of the presscake remaining after recovery of the oil from the beans.

Generally, headspace aromatization of sol~b:Le coffee products without the use of coffee oil as an aroma source or aroma carrier has not met with marked commercial success. It is known that con-05 ventionally produced soluble coffee solids lack thecapacity or property of sorbing, retaining and releasing volatile aromatic compounds such as are contained in, or added to, coffee oil.
In applicant's Canadian Patent Applications 336,192 and 339,558 , porous soluble coffee particles having the capacity to sorb large quantities of volatile aromatics, to retain the aromatics for extended periods of time, and sub-sequently, to release the aromatics under repeated in-use conditions such as may be encountered in opening and closing a container in which the particles are packaged are described and claimed. The aromatized soluble coffee particles may be added in small amounts and mix.ed with unaromatized soluble coffe~e solids to provide a soluble coffee product with a desirable coffee aroma such as the aroma of freshly roasted and ground coffee.
The porous soluble coffee particles are characterized as having an average diameter of less than 200 microns and a microporous structure wherein the most frequently occurring radius of the pores is 150 A
or less and the pore volume per gram of dry soluble coffee solids is from 3 to 30 microliters per gram.
These microporous structured soluble coffee particles are generally prepared by instantaneously freezing an aqueous extract or solution of coffee solids as by spraying the extract or solution into a cryogenic fluid and subsequently freeze-drying the frozen particles, spheres or granules.
While the methods and products described and claimed in the hereinbefore mentioned patent applications 05 represent significant advances in the art of soluble coffee and soluble coffee aromatization, it has been found that the initial headspace, (i.e., jar aroma quality and/or intensity) and the in-use aroma quality and/or intensity may bot be optimum if only a microporous structured soluble coffee product whose pore diameter is within a very narrow range is utilized as the aroma substrate. Thus, a microporous structured soluble coffee product having a nominal small pore radius (e.g., 30 A) provides a more controlled aroma release to give the desired in-use aroma stability, while a microporous structured soluble coffee product of a larger pore radius (e.g., 55-60 A) provides a more de~irable initial aroma quality and intensity.
However, the in-use aroma stability of the 55-60 A
product is judged to be not as good as that of the 30 A product. Accordingly, there would be advantages to a soluble coffee product having both the best possible initial jar aroma quality/intensity and the best possible in-use aroma quality/intensity.
Disclo~ure of the Invention It has now been discovered that an improved soluble coffee product may be obtained by combining (either before or after the aromatization step) a small nominal pore radius microporous structured soluble coffee product (e.g., 30 A) with one or more fractions consisting either of a larger nominal pore radius microporous structured soluble coffee product material (e.g., 55-60 A or up to 150 A) or a coffee material such as freeze-dried soluble coffee ~19'~

or spray-dried soluble coffee, which may optionally be finely ground prior to aromatization and adding or mixing the mixture of aromatized materials with an unaromatized soluble coffee product. The mixture 05 of these different pore diameter/ particle size aromatized coffee materials is found to give a soluble coffee product having better initial jar aroma quality/ intensity than any single aromatized microporous structured soluble coffee and better in-use aroma stability than any commercial soluble coffee product not having an oil based aroma component.

Best Mode for Carrying Out the Invention Although it is not intended that the present invention be restricted by any particular theoretical explanation, the invention overcomes the problem of either insufficient initial jar aroma quality/intensity or in-use aroma quality/intensity that is inherent in using a single microporous structured soluble coffee pore diameter material by furnishing initial, as well as prolonged, gradual and sustained release of volatile aromatic compounds from the soluble coffee product by control of the partial pressure of ~he compounds.
The invention thus offers an attractive method for controlled release of volatile aromatic compounds from soluble coffee products and offers additional advantages for headspace aromatization of such products.
These structures are found to have microporosity that exhibits the ability to "fix" various aromas.

The volatile aromatic compounds associated with coffee, whether natural or synthetic, to be sorbed on the microporous structured products may be derived from many sources well-known to those skilled in the art. Depending on the method of contact to be employed, the compounds may be present as a component of a gas, a liquid condensate or a condensed frost.
The method of contacting the microporous particles with the volatile aromatic compounds for the purpose of sorbing aroma within the particles can also be many and varied. The use of high pressure and/or low particle temperatures may be employed in order to maximize the quantity of aroma sorbed or to shorten the period of time required to achieve a desired level or arom-atization.
The microporous structured soluble coffee products have the capacity of sorbing volatile aromatic compounds. Depending on how the aromatized soluble coffee solids are utilized, the aromatized particles may be blended with soluble coffee at a level of 1 to 20 parts, by weight. Then the blend may be com-bined with agglomerated spray-dried soluble coffee or freeze-dried soluble coffeeat 0.1 to 1% by weight.
The microporous particles contemplated for use in this invention will have a nominal pore radius of less than 150 R [5m2/g surface area], preferably between 55 and 60 R, and most preferably between 30 and 40 R [40 m2/g]. The pore structure of the microporous particles can be determined from analysis of the adsorption desorption isotherms of carbon dioxide or nitrogen gas on these particles at -78C or -196C, respectively~ using procedures recognized by those skilled in the field of surface chemistry.
05 Alternatively, the pore volume surface area and pore volume distribution may be obtained from analytical equipment which provide fully automated calculations.
A suitable unit of such equipment is the Digisorb*
2500 manufactured by Micromeritics Instrument Corpora-tion.
ExamP:iLe An aqueous coffee extract having a soluble solids content of 33% by weight was prepared by reconstituting spray-dried decaffeinated coffee solids. This extract was sprayed into an open vessel containing liquid nitrogen whereupon the particles of extract immediately froze and were dispersed. The extract was sprayed by means of a two-fluid, glass atomizing nozzle (a chromatographic nozzle obtained from SGA Scientific, Inc.) using air as the pressurizing fluid. The liquid nitrogen and particle mixture was poured into freeze drier trays and the liquid nitrogen was allowed to boil-off leaving behind a flat bed of frozen particles about 1/16 to 1/8 inches in thickness. The trays were placed in a freeze drier and subject to a vacuum of 100 microns of Hg. and a plate temperature of from -40 to +40C for a period of 16 hours. The vacuum on the freeze drier was broken with dry carbon dioxide and the dry particles having a moisture content of below about 1.5% were removed from the freeze drier and kept out of contact of moisture.
The dry particles were found to have a microporous * Trade Mark ~ 4 structure containing pores having a no~inal radius of 30 A and a surface area of 40 m2/g.
The dry particles were subsequently chilled in dry ice under a dry atmosphere and then aromatized under pressure with coffee grinder gas frost, having 05 a moisture content between 10 and 15% by weight, at a weight ratio of eight parts frost per particle.
The chilled aromatized particles, having a moisture content of below ~% by weight, were blended with unagglomerated spray-dried soluble coffee at a level of one part aromatized particles to 20 parts of unagglomerated soluble. The blend was then packaged in a 4 ounce (114 grams) glass jar with unplated, agglomerated spray-dried soluble coffee solids at a level of 0.5% by weight of spray-dried solids. The jar was then stored at 21C for a period of eight weeks. Upon initial opening and during in-use cycling, the intensity, quality and other character-istics of the jar aroma were judged by an expert panel. These results are summarized in the table hereinafter.

Example 2 The procedure of Example 1 is repeated in all essential respects except that the method of freeze-drying is varied so as to obtain a microporous structured soluble coffee product having a different pore radius and surface area.
A 33% aqueous coffee solution is formed by dissolving soluble spray-dried decaffeinated coffee solids in water. This extract is placed in an insulated tank where it is maintained at 16 to 21C.

Liquid nitrogen is introduced to an insulated refrigerant tank where it is maintained at its normal boiling point of -196C.
A metal freezing plate fabricated from stainless 05 steel is immersed in the liquid refrigerant tank until it is chilled thoroughly, approximately 30 seconds. The plate is then lifted and lowered into the coffee solution contained in the coffee solution tank. While immersed in the liquid extract for 1 to

2 seconds, a film o coffee freezes on the surface of the plate. The time of immersion determines the quantity of solution that will adhere to the plate.
Generally the thickness is from 0.25 to 2 mm. Here, it is 1.2 mm. The plate is then moved up and out of the coffee solution and back into the liquid refri-gerant. During this operation, a small amount of extract that is unfrozen (on the surface of the layer adhering to the plate) is quickly frozen by reimmersion into the refrigerant. At the same time (immersed in refrigerant) unequal contractions of the frozen layer take place, which tend to crack the product loose from plate, where it is collected in a basket maintained within the liquid refrigerant tank. Some auxiliary agitation or scraping may be required to loosen all product.
The frozen product is removed from the basket, ground, and placed in chilled freeze-drier trays. The trays are placed in a freeze-drier and subjected to a vacuum of <100 microns of Hg. and a plate temperature of -40C to ~40C for a period of 16 hours. The vacuum on the freeze-drier is broken with dry carbon dioxide and the dry particles having a moisture content of below about 1.5% are removed from the freeze-drier and kept out of contact of 19~0 moisture. The dry particles were found to have a microporous structure with pores having a nominal radius of 50 A and a surface area of 7 m /g. The particles are aromatized, blended and packaged as in 05 Example 1. Storage and evaluation are also as in Example 1 and the results also appear in the table hereinafter.

Example 3 In this Example, a pre-blend of 5~% of the particles of Example 1 and 50% of the particles of Example 2 is prepared. The pre-blend is then aromatized and blended with unagglomerated spray-dried soluble coffee as in Example 1 and the blend is packaged in a jar as in Example 1. Storage and evaluation are also as in Example 1 and the results also appear in the table hereinafter.

In this Example, a pre-blend of 50% of the particles of Example 1 and 50% of unaromatized freeze-dried (33% solids extract) decaffeinated coffee havin~ a surface area of 0.4 m2/g is prepared.
The pre-blend is then aromatized and blended with unagglomerated spray-dried soluble coffee as in Example 1 and the blend is packaged in a jar as in Example 1. Storage and evaluation are also as in Example 1 and the results also appear in the table hereinafter.

ExamPle 5 In this Example, a pre-blend of 50% of the aromatized particles of Example 1 and 50% of un-aromatized spray-dried (33% solids extract) de-caffeinated coffee having a surface area of 0.3 m /g o is prepared. The pre-blend is then aromatized and blended with unag-glomerated sp~ay-dried soluble coffe as in Example 1 and the blend is packaged in a jar as in Example 1. Storage and evaluation are also as in Example 1 and the results also appear in the tahle hereinafter.
TABLE
Round Table Expert Panel Results (Jars Aged 8 Weeks at 21C) Grinder Quality Diff-- Gas Frost/ Intensity erence From Closed Surface Substrate Standard Jar Substrate Area m2/g (Wt.Ratio) (Scale:10-6) Comment Example 140.0 8/1 5.7 7.8 Buttery Sweet R&G
Example 27.0 8/1 5.3 7.8 Sulfury Sweet Low R&G
Example 3 50$ Ex. 140.0 8/1 6.0 8.7 Sulfury 50% Ex. 27.0 Buttery Low R&G
Example 4 50% Ex. 140.1 8/1 6.5 8.4 Sulfury 50% Freeze- 0.4 R&G
dried Buttery decaffeinated soluble Example 5 50% Ex. 140.0 8/1 6.0 8.1 Sulfury 50* Spray-0.3 Pungent Dried Aldehydic decaffeinated soluble 19~0 From the results it may be seen that a combination of aromatized substrates, at least one of which has a surface area of 40 m2/g (30 A nominal pore radius), when added to a soluble coffee product provides greater 05 perceived aroma intensity. Moreover, an initial quality difference versus Example 1 or 2 alone is noted when such a combination is employed and this is indicated by improved quality being retained even a~ter eight week storage of the sample jars.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A dry soluble coffee product having added thereto aromatized particles or granules of (A) a microporous structured soluble coffee product having a nominal pore radius of about 30 A to 40 .ANG. and at least one further fraction selected from (B) a microporous structured soluble coffee product having a nominal pore radius in the range of from about 50 to 150.ANG., and (C) a soluble coffee powder selected from freeze-dried and spray-dried coffee powder and combinations thereof, to provide initial and extended aroma quality/intensity.

2. A dry soluble coffee product having added thereto aromatized particles or granules of (A) a microporous structured soluble-coffee product hav-ing a nominal pore radius of about 30 .ANG., and (B) aromatized particles or granules of a microporous structural soluble coffee product having a nominal pore radius in the range of about 50 to 150 .ANG., to provide initial and extended aroma quality/intensity.

3. A dry soluble coffee product having added thereto aromatized particles or granules of a microporous structured sol-uble coffee product having a nominal pore radius of about 30 .ANG., and aromatized particles or granules of soluble coffee powder selected from freeze-dried and spray-dried coffee powder and combinations thereof, to provide initial and extended aroma quality/intensity.

4. The dry soluble coffee product of claims 1, 2 or 3, wherein the aromatized particles or granules contain up to 5%
by weight of volatile aromatic compounds.

5. The dry soluble coffee product of claim 2 wherein the aromatized particles of (A) have a nominal pore radius of 30 .ANG.
and the aromatized particles of (B) have a nominal pore radius of 50 .ANG..

6. The dry soluble coffee product of claim 1 wherein the aromatized particles of (A) have a nominal pore radius of 30 .ANG., and the aromatized particles of (C) have a surface area of 0.3 to 0.4 m2/g.

7. The dry soluble coffee product of claim 3 wherein the aromatized particles of soluble coffee powder have a surface area of 0.3 to 0.4 m2/g.

8. The dry soluble coffee product of claim 7 wherein the aromatized particles of soluble coffee powder have a surface area of 0.3 m2/g.

9. The dry soluble coffee powder of claim 2, wherein the weight ratio of (A) to (B) is 1 to 1 and the amount by weight of (A) and (B) in the dry soluble coffee product is up to 2%.