DE2425592A1 - METHOD OF MAKING AN IMPROVED INSTANT COFFEE - Google Patents

Description

DR. ING. A. VAN DERWERTH DR. FRAN Z LE DE RE R

21 HAMBURG 90 8 MUNICH 80

WILSTORFER STR 33 TEL. I040I 77 08 61 LUCITE-GRAHN-STR. 33 · TEL. t089> 47 29

Munich, May 14, 1974 Q361

UNILEVER N.V.

Burgemeester s'Jacobplein 1, Rotterdam, Netherlands

Process for making an improved instant coffee

The invention relates to a method for the modification of coffee products.

There are a number of factors which go against the greatest possible Talking about consumption of coffee. One of these factors is that coffee beverages are considered too bitter or in taste too dark in color or found to give adverse reactions in some individuals. It is believed that acids such as chlorogenic acids found in coffee are the cause adverse reactions in a certain proportion of the coffee drinking population. It is believed, that chlorogenic acids from coffee acid, which is esterified with quinic acid, exist. The occurrence of at least three possible isomers is known. One way of working for the removal of chlorogenic acids from coffee, which is known to the applicant,

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involves treating whole coffee beans with steam and tannase followed by acetone extraction. These The operation is described in US Pat. No. 2,089,116.

The object of the invention is an improved method for improving the coffee quality.

It has now been found that the treatment of aqueous coffee with a peroxidase enzyme in the presence of a peroxide, z. B. hydrogen peroxide, causes a significant improvement in the quality of coffee. Such treatment enables the production of a coffee beverage with one or more of the following advantages: The beverage has a pleasant, mild aroma reminiscent of mocha coffee, it has a reduced content of chlorogenic acids and it has a darker color compared to a coffee beverage made without a treatment according to the invention.

Examples of Peroxidaseenzymsy stones, which in the invention Methods that can be used are described in the literature, but in general any peroxidase can be used be used. For examples of peroxidases, see "Encyclopedia of Biochemistry, Williams and Lansford, Reinhold Publishing Company, pp. 634 and 635, wherein peroxidases and reactions which they catalyze, are described. A preferred peroxidase for use in the present invention is that from horseradish isolated product. This enzyme is available in commercial quantities, e.g. from Worthington Biochemical Corporation, and it is found in Worthington Manual, "Worthington Enzymes" (1972) pp. 43-45, published by Worthington Biochemical Corporation, Freehold, New Jersey 07728, USA. Such an enzyme can also be obtained from P. L. Biochemicals, Milwaukee, Wisconsin and Boehringer-Mannheim, New York, N.Y., USA.

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It has been found that amounts of enzyme which range from 10 to 200 Enzyme units per gram of coffee solids to be treated rich, show particularly good results. Of course, in the method according to the invention, the Coffee solids normally completely dissolved in the aqueous system. Enzyme amounts below this range can be used, but they provide minimal response. At pH 5 there will be at least 50 units of enzyme per gram of coffee solids preferably used. At a pH of 6 to 7, acceptable results will be obtained reached levels as low as 10 enzyme units per gram of solids. Amounts above this range will be, though they could be wasteful in terms of the enzyme and are therefore not required. Preferably there is enough enzyme to complete the reaction ensure the peroxide present in the system; Excess peroxide contributes to an inferior flavor in the End product and should therefore be avoided. On the other hand, excess, unreacted enzyme does not represent any The problem is that the coffee extract inactivates the enzyme in a short period of time.

The enzyme activity of a certain composition can be determined by means of a peroxidase analysis. the specific test method used in the composition used in the method according to the invention is a modification of the "Wörthington Enzyme Manual", P. 43 and 44 method described above. A full description of this study is in Example 1 below given.

The peroxidase can be introduced into the reaction mixture in any suitable manner, many of which are disclosed in US Pat quite general way of working, with enzymes known to it

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however, it has been found that it is preferably incorporated on a solid support such as glass or a polymer surface. By this technique, the fixed enzyme preparations can be recovered for reuse and provide a means for completely removing the enzyme from materials which have been treated therewith. In addition, the insolubilized enzymes are conveniently supplied in particulate form which can advantageously be packed in columns for use in continuous processes. Techniques for effecting fixation of enzymes on an insoluble matrix are described in U.S. Patents 3,519,538, 3,536,587, and 3,556 94-5. Further explanations of these techniques can be found in: Silmen et al., Annual Review of Biochemistry, J5 £ (1966), pp. 873-908 and in the article "Colloquium on Insolubilized Enzymes", Biochemical Journal (1968), 107 «1P- 5P · In general, enzyme insolubilization processes require fixation of the enzyme on an insoluble matrix by covalent bonding, by absorption, or by entrapment.

The peroxide used in the process according to the invention is preferably hydrogen peroxide, and it has been found to be advantageous to supply hydrogen peroxide as a 35% (w / w) aqueous solution during the reaction. Hydrogen peroxide is preferably used in an amount of about 0.5 to about 2.5 mmol H ₂ ⁰ ? ^{per s of} coffee solids applied in the extract. The amount of peroxide preferably used is calculated so that it is completely consumed in the reaction so that no residual HpO ^ remains in the extract at the end of the treatment. It has been found that residual HpOp has a tendency to produce an undesirable off-taste in the product.

Other examples of peroxides which are advantageous in the process of the invention include peracetic acid and per-

carbonate.

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Although the exact mechanism by which the inventive Procedure is not known, it is believed that the enzyme peroxidase is a reaction between hydrogen peroxide and certain coffee solids including chlorogenic acids and likely caffeic acid. the Coffee solids that participate in the reaction are hydrogen donors. The reaction causes oxidation the coffee solids, thereby drawing hydrogen ions therefrom and transferring them to the hydrogen peroxide with the formation of water.

Attempts have been made by the applicant to carry out this reaction using only hydrogen peroxide, under using only peroxidase and using enzymes other than peroxidase. In all however, in three cases unfavorable results were obtained.

The pH range over which the process according to the invention is preferably carried out is from about 4.5 to about 9 · Particularly preferred results are achieved within a pH range of 5 to 7. At a pH above about 9 provides the oxidation taking place a completely different product that is less desirable. When the pH drops below 5, the enzyme becomes less active, and the reaction takes a much longer period of time to produce the same result. Products with undesirable, bitter flavors are formed at a pH of 4 or lower.

The temperature at which the reaction according to the invention can be carried out is the temperature at which Peroxidase is active. It was found that in those examined Enzymes a fairly wide range from about 5 ° C to about 60 ° C is possible. Temperatures above about 60 ° C cause the enzymes to be inactivated with the result

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that products are made with bad flavor.

The aqueous coffee which is treated according to the method according to the invention is preferably a product which is produced by Hot water extraction from roast and ground coffee beans has been obtained.

The extract can have been obtained in any desired manner; numerous working methods are known for this purpose. at In a further preferred embodiment, the method is applied to an instant coffee powder (coffee extract powder) carried out that in water and to form an aqueous Solution has been resolved. In addition, an extract from caffeine-free coffee according to the invention Procedures are treated with advantage. Here, the color and the aroma can be improved. The coffee solids preferably form from 5% by weight to 30% by weight of the of the invention treated, aqueous coffees.

The invention is explained in more detail by means of the following examples.

example 1

The peroxidase activity of the enzyme preparations used in the following examples was determined by a spectrophotometric method which is a modification of the procedure described in the Worthington Enzyme Manual, pp. 43 and 44, published 1972 by Worthington Biochemical Corporation, Freehold, NJ, USA. The substrate solution was freshly prepared daily by diluting 1 ml of 0.3% (w / w) hydrogen peroxide solution to 100 ml with 0.01M citrate-phosphate buffer of pH * 5 »0. A dye solution of 1 % o-dianisidine in methanol was also freshly prepared every day and stored in the dark. For each study, 0.05 ml of the dye solution was added to 6.0 ml of the substrate solution, and

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after mixing, 2.9 ml of the combined substrate dye solution was placed in a 1 cm reaction cell of a recording spectrophotometer. The remainder of this solution was used as a blank in the control 1 cm cell. The reaction was completed by ml of suitably diluted peroxidase enzyme, dissolved in 0.01M citrate-phosphate buffer was added to the reaction cell 0.1, and it was the rate of change in absorbance (A) at 460 nm in the reaction mixture at 25 ⁰ C while recorded over a period of 2 minutes. The values: enzyme units / mg enzyme are given by the following equation:

, - ,. , .. / Λ 4-60 / min

Precision / mg =

One unit of the peroxidase activity is defined according to this method as the amount of enzyme which 1 uHol peroxide per Decomposed for min at 25 ° C.

The peroxidase enzymes used in the following examples were purified horseradish peroxidase preparations, referenced by Boehringer Mannheim Corporation, New York, N.Y. or P. L Biochemicals, Inc. Milwaukee, Wisconsin.

b2 Determination of chlorogenic acids in solutions of coffee solids

The chlorogenic acids in coffee samples were determined by a gas chromatographic method after the preparation of trimethylsilyl derivatives of chlorogenic acids.

Example 2

Soluble coffee solids, which are in the form of an instant coffee powder by Tenco, Linden, N.J. received and 2.6% Chlorogenic acids were used with a peroxidase enzyme preparation treated in the following way:

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25.0 grams of the instant coffee solids were dissolved in 4-75 grams of water to form a 5% solids solution. The temperature of the solution was adjusted to 25 ⁰ C. 5 * 6 ml of a 35% (w / w) HgOg solution _and 5000 units of peroxidase (determined according to the procedure of Example 1) were added. The peroxidase used had 500 units of enzyme activity / mg enzyme, which means said that 10 mg of enzyme or 200 units of peroxidase / g of coffee solids were added The solution was stirred at 25 ° C. for 60 min, during which time the pH remained almost constant at pH * = 5.0 Product was analyzed for chlorogenic acid content and diluted with hot water to a 1% solution for testing.

The procedure used to prepare Product A was repeated except that the amount of hydrogen peroxide solution was changed to 2.0 ml and 1.0 ml for products labeled B and C, respectively. The conditions used in the preparation of the product B were further repeated with the exception that the coffee extract was treated at a solids concentration of 10%, in which case the product D was obtained. The amount of enzyme used in the production of product B was reduced by a factor of A to produce product E and by a factor of 16 to produce product F. The product G contained

the
no enzyme / used in the manufacture of product E.

Conditions were used to produce the products H to L in the temperature range from 10 ^° C to 85 ^° C.

The results of the tests described above are summarized in the following Table I, and they show that a peroxide value of 2.0 ml gives optimal results, see Table I, Part 1, while the treatment with equally good results at 5% and 10 % Solids are carried out

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can, see Table I, Part 2. The use of peroxidase enzyme in an amount of 50 to 200 units / g coffee solids resulted in the desired reduction in chlorogenic acids, see Table I ₁ Part 3 · A temperature change between 10 ⁰ C and 55 ° ^C j see Table I, Part 4-, gave acceptable products, while at elevated temperatures of 70 ^° C. and 85 ^° C. the amount of chlorogenic acids removed was very much less and the taste of the product became unfavorable.

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Table I.

Peroxidase treatment of 25 g samples of instant coffee solids in aqueous solution

for an hour

Per- Hand- Amount of applied Concentrate- Destroyed taste Dükt treatment-reversed enzyme 35% (w / w) ion of chlorogen

tempera- (units / g HpO _p (ml) treat- able acids (%)

door ( ⁰ C) -Coffee Festival- ^ tem plague

fabrics) fabric (%)

Part 1: Changing the amount of peroxide

O CO OO

AWAY

25 25

25th

200 200

200

5.6 2.0

1.0

bad, burned

good, mild, mocha-like

good, mild, mocha-like

Part 2: Changing the concentration of pesticides

B D

200 200

2.0 2.0

95 good, mild, ro mocha-like ■ Ρ- ro 95 good, mild, cn mocha-like cn co ro

Table I (continued)

Part J: Change in the amount of enzyme

B. 25th E. 25th ί ¹ 25th G 25th

H 10 E. 25th I. 40 J 55 K 70 L. 85

200
50
12th
0

Part 4: change in temperature

50
50
50
50
50
50

2.0 2.0 2.0 2.0 2.0 2.0

5 95 good, mild, mocha-like 5 80 good, mild, mocha-like 5 <10 no changes tion 5 0 no changes tion

5 70 good, mild, 2
mocha-like, ^ 25592 5 80 good, mild,
mocha-like νπ 85 good, mild,
mocha-like 5 75 good, mild,
mocha-like 5 55 low, weaker
Mocha character 5 410 bad, burned
bitter

Example 3

45.4 kg of a 5% (wt./wt.) Instant coffee solids solution at 25 ⁰ C was treated with 182 ml of 55% (Gew./Gew)H ₂ 0 ₂ solution. 910 mg of horseradish peroxidase with a specific activity of 500 enzyme units per mg (equivalent of about 200 units of peroxidase enzyme per gram of coffee solids) dispersed in 500 ml of the coffee solution was added and the solution was stirred at 25 ° C for one hour. The treated solution was concentrated to about 40% solids and spray dried to form an instant coffee powder. The analysis showed that 95% of the chlorogenic acids had been destroyed. Furthermore, the product was darker in color than a sample of the starting coffee solids before the treatment and had a noticeably more pleasant, less bitter taste. The taste of the peroxidase-treated instant coffee product with the reduced chlorogenic acid content was classified as "mocha-like" and it was preferred by an arbitral tribunal to the taste of the untreated instant coffee.

Example 4

An extract was prepared by boiling 150 grams of ground roast coffee beans (Maxwell House Regular Grind, General Foods, White Plains, NY) in 1500 ml of water for 5 minutes and filtering the slurry through filter paper. 100 ml of the extract, which contained 2.44% solids, with 0.21 ml of 35% (wt./wt.) H ₃ O _2, and 244 units Peroxidaeeaktivität at 40 ⁰ C for 30 minutes was treated. The treated extract was diluted 1: 1 with hot water and tested for its taste. The product was rated as having a good, rich, aokka-like flavor. Analysis of the product showed that the untreated coffee extract contained about 6% chlorogenic acids on a coffee solids basis, and that with peroxidase

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"treated coffee product only about 15% of the original Amount of chlorogenic acids contained.

Example 5

Roasted, ground coffee beans (White Coffee Co., Long Island City, NY) were extracted in a commercial drip coffee machine to produce a beverage extract having about 1% solids concentration. 2 1 of this extract was mixed with 1.6 ml of 35% (wt./wt.) And treated H2O2 peroxidase enzyme (100 units / g coffee solids) "at 40 ⁰ C for 30 minutes. The coffee thus formed. Product was examined for taste and graded, which was found to have a dark color and a mild, pleasant aroma faintly reminiscent of cocoa aroma The amount of chlorogenic acid in the product was determined to be about 5 % of that in the extract before peroxidase treatment Reduced value, this was 3 »5% of the original content, based on coffee solids.

Example 6

Soluble coffee solids were dissolved in water to make a 5 % solids solution by adding 25.0 grams of instant coffee powder (solids) to 475 grams of water. The pH of the coffee solids solution was adjusted from its natural pH of about 5 * 0 by adding the required amounts of 6N hydrochloric acid or 45% (w / w) potassium hydroxide to the pH of the particular reaction mixture to a pH of 4.5 * 6> 7 *, 8, 9 and 10 before adding the hydrogen peroxide and the peroxidase to the reaction mixture. In all cases, 50 units of peroxidase activity / g of coffee solids and 2.0 ml of 35% (w / w) hydrogen peroxide solution were added to each reaction mixture to induce the enzyme treatment, which was carried out at 25 ° C for 1 hour.

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At the end of the reaction period, the pH of the treated extracts was adjusted to about pH = 5 ₅ O by adding the required amounts of 45% (w / w) potassium hydroxide solution or 6 N hydrochloric acid.

The pH-adjusted extracts were frozen and freeze-dried to make instant dried coffee powder to manufacture. The powders were analyzed for their chlorogenic acid content, and they were used as coffee beverages 1.0% solids concentration graded on their taste. The results of these tests are shown in Table II below. These results show that only about 65% of the chlorogenic acids due to the peroxidase treatment pH »4 had been destroyed and that the good, mild, mocha-like aroma did not develop in this sample.

However, 80 % or more of the chlorogenic acids were destroyed when the peroxidase reaction was carried out at pH values varying from about pH = 5.0 to pH * 10.0. Furthermore, the good, mild, mocha-like aroma also developed when the peroxidase reaction was carried out at pH values between about pH = 5 and pH = 8, while at pH> 9 and higher an undesirable off-flavor developed during the peroxidase treatment.

For comparison, a second product at pH »10 was used in the same Treated like the first product except that peroxidase was omitted. The results of this Experiments are given as product H in Table II. No chlorogenic acids were destroyed and the flavor was unpleasant.

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Table II

Peroxidase treatment on instant coffee solids at different pH values of the reaction mixture

Product pH-Vert of the percent

Reaction destroyed mixture of chlorogen

. acids

Taste of the product

A. 4th 7th 65 B. 5 80 C. 6th 95 D. 7th > 95 E. 8th > 95 F. 9 > 95 G 10 > 95 H
(no
Peroxy
that) 10 0 example

bad, bitter
mild, mocha-like mild, mocha-like mild, mocha-like mild, mocha-like

mild, mocha-like, slightly burning secondary aroma

bitter, unpleasantly bitter, not drinkable

Soluble coffee solids were dissolved in water to make 5%, 10%, 20%, 30%, and 40% solids solutions by adding 25.0 grams of instant coffee solids to either 475, 225, 100, 58 »3, or 37.5 6 water were added. In all cases, 200 units of peroxidase / g coffee solids and 2.0 ml Wasserßtoffperoxidlösung were a 35% (wt./wt.) Was added to each reaction mixture to the enzyme treatment to bring about, which was carried out for 1 hour at 25 ⁰ C. At the end of the reaction period, all of the reaction mixtures were diluted to 5% coffee solids by the addition of water and they were then frozen and freeze-dried to produce instant dry coffee powder. The powders were based on their content

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Chlorogenic acids analyzed, and they were rated for their taste as coffee beverages at 1% solids concentrations. The results of these tests are shown in Table III. These results show that only about 30% of the chlorogenic acids were destroyed by the peroxidase treatment at 40% solids concentration, and that the aroma was bitter and only slightly mild and mocha-like. It appears that high levels of coffee solids have an inhibitory effect on the activity of the enzyme.

However, 75% or more chlorogenic acids have been destroyed, and the good, mild, mocha-like flavor developed in any case, if the peroxidase was carried out at solids concentrations varying from 5 ° / ° to 30% "

TabelLe.III

Peroxidase treatment on instant coffee solids at different solids concentrations in the reaction mixture

Product destroyed the taste of chlorine

concentration of genetic acids (%) product

A. VXl B. 10 C. 20th D. 30th E. 40

95 good, mild,
mocha-like 95 good, mild,
mocha-like 95 good, mild,
mocha-like 75 good, mild,
mocha-like 30th bitter., only
weak mocha
similar

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Claims (3)

Claims 1. Process for the enzymatic treatment of coffee, characterized in that aqueous coffee is treated with peroxidase in the presence of a "peroxide". 2. The method according to claim 1, characterized in that the treatment is carried out on an aqueous coffee with a solids concentration of 5 % to 30%. 3. The method according to claim 1 or 2, characterized in that the treatment is carried out at a pH of 4.5 to 8 will. 409851/0322