Food or edible material: processes – compositions – and products – Processes – Separating volatile essence and combining the separated...
Reexamination Certificate
2002-08-16
2003-07-15
Weier, Anthony J. (Department: 1761)
Food or edible material: processes, compositions, and products
Processes
Separating volatile essence and combining the separated...
C426S594000
Reexamination Certificate
active
06592922
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a process for the recovery of aroma components from roasted and ground coffee. The recovered aroma components are useful for aromatising soluble coffee powders. The invention also relates to new aromatized soluble coffee powders.
BACKGROUND OF THE INVENTION
Aromas are an important part of many products since consumers associate certain aromas with certain products. If the product lacks the aroma associated with it, consumer perception of the product is adversely affected. This is particularly a problem in the field of soluble coffee powders, although it also exists in other fields. Soluble coffee powders, which are obtained from commercial processes involving extraction, concentration, and drying are usually substantially aroma-less. For this reason, it is conventional to recover coffee aromas which are given off during the processing of the soluble coffee powder and to reincorporate these aromas into concentrated coffee extract prior to drying into the soluble coffee powder.
The coffee aromas are recovered at several points during processing of the soluble coffee powder and most commonly during grinding of the roasted beans and by steam stripping of the coffee extract prior to concentration and drying of the soluble coffee solids.
The recovery of aroma from ground coffee is disclosed in U.S. Pat. No. 3,535,118. This patent discloses a process in which roast and ground coffee is placed in a column and maintained at about 40° C. The bed of coffee is then moistened by spraying water on it to assist in displacing aromas from the coffee particles. An inert gas, usually nitrogen, is heated to about 44° C. and introduced into the column from beneath the bed. As the inert gas passes up through the bed, it strips the aromas from the coffee particles. The inert gas is then fed to a condenser which is operated at a temperature of about 5° C. to condense water in the inert gas. The de-watered inert gas is ultimately fed to a cryogenic condenser to condense the aroma as a frost. The frost is then recovered.
Another process for recovering aroma from roast and ground coffee is described in international patent application WO 97/10721. In this process, the ground coffee is transported through an elongated mixing zone while being agitated. At the same time, an aqueous fluid is sprayed into the elongated mixing zone to moisten the ground coffee as the ground coffee is being transported and agitated. Aroma gases released by the moistened ground coffee in the elongated mixing zone are drawn off and are collected.
One of the problems perceived to arise with these processes is that they result in pre-wetting of the coffee grounds outside of the extraction cell or column. According to Sivetz, M and Desrosier N. W.; 1979
; Coffee Technology,
AVI Publishing Company, Inc., page 334, this practice is bad because it “causes staling of ground coffee in less than an hour, accompanied by a heavy, undesirable flavour and a loss in natural coffee volatiles.” Sivetz and Desrosier strongly advocate that first wetting of the coffee grounds should occur in the extraction cell or column. Consequently recovery of aroma from ground coffee by pre-wetting is not common practice, despite ground coffee being a good source of aroma.
Further, not all components of the aroma obtained in a cup of freshly brewed coffee are captured during pre-wetting. Consequently, unless further aroma is captured later during the process, some aroma components are lost; components which would, if incorporated into instant coffee powder, improve the aroma of a beverage prepared from the instant coffee powder. Further, many of the conventional recovery techniques damage or alter the aroma components.
Therefore there is still a need for a process for recovering aroma from ground coffee.
SUMMARY OF THE INVENTION
This invention provides a process for the recovery of aroma components from fresh coffee grounds, the process comprising:
wetting the coffee grounds,
heating the coffee grounds,
exposing the coffee grounds to decreased pressure for providing aroma containing gas, and
capturing the aroma containing gas.
The process provides the advantage that significantly larger amounts of aroma components may be obtained from the coffee grounds than with conventional processes. Further, since the aroma components are obtained from the coffee grounds prior to extraction, thermal degradation of the aroma is reduced to a minimum. Also, since these aroma components are removed from the coffee grounds, staling of the coffee grounds prior to extraction may be reduced. The aroma components may be readily incorporated to provide a soluble coffee product which has increased and improved aroma and flavour. Further, volatile compounds which arise during extraction and which are responsible for a processed aroma and taste, are not collected.
The process may further comprise repeatedly exposing the coffee grounds to decreased pressure followed by heating. The coffee grounds are subjected to this cycle from about 2 to about 10 times.
The process may further comprise heating the coffee grounds while they are exposed to the decreased pressure. For example, the coffee grounds may be maintained at a substantially constant temperature while they are exposed to decreased pressure.
This process allows about 40% to about 95% of volatile aroma components in the coffee grounds to be collected in the aroma containing gas. In the present context the volatile aroma is measured above roast and ground suspension by static headspace sampling and gas chromatography. The aroma recovery % is determined by comparing aroma concentration of roast and ground before and after the process of the invention.
Further, the process provides that the collected aroma containing gas will contain at least 700 parts per million of aroma carbon, based on fresh ground coffee.
The invention also provides a soluble coffee product containing the aroma components recovered as described above.
The invention further provides a new aromatised, spray-dried soluble coffee powder which when reconstituted in water to a solid content of 3.3% by weight of the reconstituted beverage comprises a concentration of aroma volatile of at least 50 ppm for the sum of aroma compounds having a retention index RI
DBWAX
<1130, and at least 4 ppm for the sum of aroma compounds having a retention index of 1130≦RI
DBWAX
≦1430.
The invention also provides a new aromatised, freeze-dried soluble coffee powder which when reconstituted in water to a solid content of 3.3% by weight of the reconstituted beverage comprises a concentration of aroma volatile of at least 100 ppm for the sum of compounds having a retention index RI
DBWAX
<1130, and at least 7 ppm for the sum of compounds having a retention index of 1130≦RI
DBWAX
≦1430.
In the present context the concentration of the aroma volatile is given in values measured by static headspace sampling and gas chromatography above reconstituted beverage. Instant coffees are reconstituted in water to a solid content of 3.3% by weight of the reconstituted beverage. Samples of 5 ml are measured at 60° C. as described above. Headspace sampling is obtained by pressurizing 22 ml vials at 10 Psi. Elution is performed on a polar capillary column coated with polyethyleneglycol phase, and coupled with an atomic emission detector. The detector response is calibrated with an external standard, 4-methylthiazole 50 ppm in water, analysed with similar conditions. Volatile aroma compounds are summed into zones according to their retention index: zone 1: RI
DBWAX
<1130, zone 2: 1130≦RI
DBWAX
≦1430.
It has been found that the present invention is very efficient to recover high volatile compounds from roast and ground coffee. It has further been found that the reconstituted beverage according to the invention has a significantly higher concentration of volatile compounds than a beverage reconstituted from commercial available instant coffee, namely for compounds having a retention index (RI) inferior to 1430 as defined on a Carbowax
Furrer Marc
Gretsch Catherine
Nestec S.A.
Weier Anthony J.
Winston & Strawn
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