NZ621830B2 - Process for the production of a liquid coffee concentrate - Google Patents
Process for the production of a liquid coffee concentrate Download PDFInfo
- Publication number
- NZ621830B2 NZ621830B2 NZ621830A NZ62183012A NZ621830B2 NZ 621830 B2 NZ621830 B2 NZ 621830B2 NZ 621830 A NZ621830 A NZ 621830A NZ 62183012 A NZ62183012 A NZ 62183012A NZ 621830 B2 NZ621830 B2 NZ 621830B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- extract
- process according
- coffee
- coffee extract
- heat treatment
- Prior art date
Links
- 235000016213 coffee Nutrition 0.000 title claims abstract description 258
- 235000013353 coffee beverage Nutrition 0.000 title claims abstract description 258
- 238000000034 method Methods 0.000 title claims abstract description 74
- 239000012141 concentrate Substances 0.000 title claims abstract description 73
- 239000007788 liquid Substances 0.000 title claims abstract description 73
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 9
- 239000000284 extract Substances 0.000 claims abstract description 226
- 125000003118 aryl group Chemical group 0.000 claims abstract description 113
- 238000000605 extraction Methods 0.000 claims abstract description 58
- 235000019749 Dry matter Nutrition 0.000 claims abstract description 54
- 238000010438 heat treatment Methods 0.000 claims abstract description 48
- 239000007787 solid Substances 0.000 claims abstract description 41
- AAWZDTNXLSGCEK-ZHQZDSKASA-N Quinic acid Natural products O[C@H]1CC(O)(C(O)=O)C[C@H](O)C1O AAWZDTNXLSGCEK-ZHQZDSKASA-N 0.000 claims abstract description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 20
- AAWZDTNXLSGCEK-WYWMIBKRSA-N Quinic acid Chemical compound O[C@@H]1C[C@](O)(C(O)=O)C[C@@H](O)[C@H]1O AAWZDTNXLSGCEK-WYWMIBKRSA-N 0.000 claims abstract description 15
- 238000011084 recovery Methods 0.000 claims abstract description 12
- -1 Quinic acid lactone Chemical class 0.000 claims abstract description 9
- JPESOGFYFXAURP-UHFFFAOYSA-N 3-(furan-2-yl)-2-phenylprop-2-enal Chemical compound C=1C=CC=CC=1C(C=O)=CC1=CC=CO1 JPESOGFYFXAURP-UHFFFAOYSA-N 0.000 claims abstract description 8
- 238000005194 fractionation Methods 0.000 claims abstract description 6
- 239000002253 acid Substances 0.000 claims description 20
- 239000012467 final product Substances 0.000 claims description 14
- 230000000630 rising Effects 0.000 claims description 14
- 238000005349 anion exchange Methods 0.000 claims description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 4
- 229910052700 potassium Inorganic materials 0.000 claims description 4
- 239000011591 potassium Substances 0.000 claims description 4
- KEAYESYHFKHZAL-UHFFFAOYSA-N sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 claims description 4
- 239000011734 sodium Substances 0.000 claims description 4
- 229910052708 sodium Inorganic materials 0.000 claims description 4
- 102000037197 Anion exchangers Human genes 0.000 claims 2
- 108091006437 Anion exchangers Proteins 0.000 claims 2
- 150000002500 ions Chemical class 0.000 abstract 1
- 240000007154 Coffea arabica Species 0.000 description 209
- 235000008504 concentrate Nutrition 0.000 description 55
- 239000000047 product Substances 0.000 description 30
- 239000003513 alkali Substances 0.000 description 15
- 239000000796 flavoring agent Substances 0.000 description 14
- 238000007792 addition Methods 0.000 description 13
- 150000001875 compounds Chemical class 0.000 description 12
- 235000019634 flavors Nutrition 0.000 description 12
- 238000003860 storage Methods 0.000 description 12
- 238000001816 cooling Methods 0.000 description 8
- 239000004793 Polystyrene Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 229920002223 polystyrene Polymers 0.000 description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M potassium hydroxide Inorganic materials [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- WEVYAHXRMPXWCK-UHFFFAOYSA-N acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 6
- 239000012224 working solution Substances 0.000 description 6
- 150000001450 anions Chemical class 0.000 description 5
- 230000001809 detectable Effects 0.000 description 5
- 239000000945 filler Substances 0.000 description 5
- 238000006460 hydrolysis reaction Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 244000020998 Acacia farnesiana Species 0.000 description 4
- 235000019568 aromas Nutrition 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- QSJXEFYPDANLFS-UHFFFAOYSA-N diacetyl Chemical compound CC(=O)C(C)=O QSJXEFYPDANLFS-UHFFFAOYSA-N 0.000 description 4
- VLKZOEOYAKHREP-UHFFFAOYSA-N hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 4
- 239000003456 ion exchange resin Substances 0.000 description 4
- 229920003303 ion-exchange polymer Polymers 0.000 description 4
- 230000020477 pH reduction Effects 0.000 description 4
- 238000011064 split stream procedure Methods 0.000 description 4
- 150000003512 tertiary amines Chemical group 0.000 description 4
- 230000002378 acidificating Effects 0.000 description 3
- 238000004164 analytical calibration Methods 0.000 description 3
- 238000011088 calibration curve Methods 0.000 description 3
- 239000012482 calibration solution Substances 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 238000010979 pH adjustment Methods 0.000 description 3
- 229920000058 polyacrylate Polymers 0.000 description 3
- 229920000768 polyamine Chemical group 0.000 description 3
- RSZPVOABCKCPKY-UHFFFAOYSA-N 2-ethyl-6-methoxyphenol Chemical compound CCC1=CC=CC(OC)=C1O RSZPVOABCKCPKY-UHFFFAOYSA-N 0.000 description 2
- 235000007460 Coffea arabica Nutrition 0.000 description 2
- YPJUNDFVDDCYIH-UHFFFAOYSA-N Heptafluorobutyric acid Chemical compound OC(=O)C(F)(F)C(F)(F)C(F)(F)F YPJUNDFVDDCYIH-UHFFFAOYSA-N 0.000 description 2
- 241000533293 Sesbania emerus Species 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 125000003277 amino group Chemical group 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000003957 anion exchange resin Substances 0.000 description 2
- 239000008373 coffee flavor Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000007865 diluting Methods 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 238000002290 gas chromatography-mass spectrometry Methods 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 239000008079 hexane Substances 0.000 description 2
- 235000014666 liquid concentrate Nutrition 0.000 description 2
- 230000000813 microbial Effects 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 238000009928 pasteurization Methods 0.000 description 2
- 238000011002 quantification Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 238000002470 solid-phase micro-extraction Methods 0.000 description 2
- AAWZDTNXLSGCEK-LNVDRNJUSA-N (3R,5R)-1,3,4,5-tetrahydroxycyclohexane-1-carboxylic acid Chemical compound O[C@@H]1CC(O)(C(O)=O)C[C@@H](O)C1O AAWZDTNXLSGCEK-LNVDRNJUSA-N 0.000 description 1
- JPESOGFYFXAURP-XFXZXTDPSA-N 3-(2-Furanyl)-2-phenyl-2-propenal Chemical compound C=1C=CC=CC=1C(/C=O)=C\C1=CC=CO1 JPESOGFYFXAURP-XFXZXTDPSA-N 0.000 description 1
- 235000003276 Apios tuberosa Nutrition 0.000 description 1
- UHNPTKKPZHPRIX-UHFFFAOYSA-N C(C)C1=CC(=C(C=C1)O)OC.C(C)C1=C(C(=CC=C1)OC)O Chemical compound C(C)C1=CC(=C(C=C1)O)OC.C(C)C1=C(C(=CC=C1)OC)O UHNPTKKPZHPRIX-UHFFFAOYSA-N 0.000 description 1
- YOLHAWVKRARCGR-UHFFFAOYSA-N C1(=CC=CC=C1)C(C=O)=CC=1OC=CC1.C1(=CC=CC=C1)C(C=O)=CC=1OC=CC1 Chemical compound C1(=CC=CC=C1)C(C=O)=CC=1OC=CC1.C1(=CC=CC=C1)C(C=O)=CC=1OC=CC1 YOLHAWVKRARCGR-UHFFFAOYSA-N 0.000 description 1
- 244000016593 Coffea robusta Species 0.000 description 1
- 235000002187 Coffea robusta Nutrition 0.000 description 1
- LHGVFZTZFXWLCP-UHFFFAOYSA-N Guaiacol Chemical class COC1=CC=CC=C1O LHGVFZTZFXWLCP-UHFFFAOYSA-N 0.000 description 1
- 240000005158 Phaseolus vulgaris Species 0.000 description 1
- 235000010627 Phaseolus vulgaris Nutrition 0.000 description 1
- 102000014961 Protein Precursors Human genes 0.000 description 1
- 108010078762 Protein Precursors Proteins 0.000 description 1
- 244000170226 Voandzeia subterranea Species 0.000 description 1
- 235000013030 Voandzeia subterranea Nutrition 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 238000010909 chemical acidification Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000000658 coextraction Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 235000007924 ground bean Nutrition 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- AMIMRNSIRUDHCM-UHFFFAOYSA-N isopropylaldehyde Chemical compound CC(C)C=O AMIMRNSIRUDHCM-UHFFFAOYSA-N 0.000 description 1
- 150000002596 lactones Chemical class 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000003472 neutralizing Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000005373 pervaporation Methods 0.000 description 1
- 230000037039 plant physiology Effects 0.000 description 1
- OZAIFHULBGXAKX-UHFFFAOYSA-N precursor Substances N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 125000002924 primary amino group Chemical class [H]N([H])* 0.000 description 1
- NBBJYMSMWIIQGU-UHFFFAOYSA-N propionic aldehyde Chemical compound CCC=O NBBJYMSMWIIQGU-UHFFFAOYSA-N 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 150000003216 pyrazines Chemical class 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 230000001953 sensory Effects 0.000 description 1
- 230000035943 smell Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000001256 steam distillation Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000004704 ultra performance liquid chromatography Methods 0.000 description 1
- 239000003039 volatile agent Substances 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/02—Treating green coffee; Preparations produced thereby
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/24—Extraction of coffee; Coffee extracts; Making instant coffee
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/24—Extraction of coffee; Coffee extracts; Making instant coffee
- A23F5/243—Liquid, semi-liquid or non-dried semi-solid coffee extract preparations; Coffee gels; Liquid coffee in solid capsules
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/24—Extraction of coffee; Coffee extracts; Making instant coffee
- A23F5/26—Extraction of water-soluble constituents
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/24—Extraction of coffee; Coffee extracts; Making instant coffee
- A23F5/28—Drying or concentrating coffee extract
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/24—Extraction of coffee; Coffee extracts; Making instant coffee
- A23F5/28—Drying or concentrating coffee extract
- A23F5/285—Drying or concentrating coffee extract by evaporation, e.g. drying in thin layers, foam drying
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/46—Coffee flavour; Coffee oil; Flavouring of coffee or coffee extract
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/46—Coffee flavour; Coffee oil; Flavouring of coffee or coffee extract
- A23F5/48—Isolation or recuperation of coffee flavour or coffee oil
- A23F5/50—Isolation or recuperation of coffee flavour or coffee oil from coffee extract
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/46—Coffee flavour; Coffee oil; Flavouring of coffee or coffee extract
- A23F5/48—Isolation or recuperation of coffee flavour or coffee oil
- A23F5/50—Isolation or recuperation of coffee flavour or coffee oil from coffee extract
- A23F5/505—Isolation or recuperation of coffee flavour or coffee oil from coffee extract by distillation, e.g. stripping the extract; Recovering volatile gases, e.g. during concentration
Abstract
Disclosed herein is a process for the production of a liquid coffee concentrate with a pH of 4.8 to 6 comprising a) subjecting roasted, ground coffee to one or more extraction steps with water resulting in a coffee extract, b) separating the coffee extract, either by fractionation during the extraction step(s) in a) or by aroma recovery after step a) resulting in a high aromatic coffee extract and a low aromatic coffee extract, c) subjecting at least 50% of the low aromatic coffee extract to a heat treatment of at least 120 °C at a holding time for at most 30 minutes, d) concentrating at least the treated low aromatic coffee extract, e) combining at least the concentrated low aromatic coffee extract with the high aromatic coffee extract, thereby obtaining a liquid coffee concentrate. Also disclosed is a liquid coffee concentrate with a pH of 4.8 to 6 comprising 2 mg/kg dry matter solids or more of 2-phenyl-3-(2-furyl)-2-propenal and a liquid coffee concentrate with a pH between 5 and 5.2 and a QA/QaL (Quinic acid/Quinic acid lactone) mol/mol ratio between 10 and 100. ion step(s) in a) or by aroma recovery after step a) resulting in a high aromatic coffee extract and a low aromatic coffee extract, c) subjecting at least 50% of the low aromatic coffee extract to a heat treatment of at least 120 °C at a holding time for at most 30 minutes, d) concentrating at least the treated low aromatic coffee extract, e) combining at least the concentrated low aromatic coffee extract with the high aromatic coffee extract, thereby obtaining a liquid coffee concentrate. Also disclosed is a liquid coffee concentrate with a pH of 4.8 to 6 comprising 2 mg/kg dry matter solids or more of 2-phenyl-3-(2-furyl)-2-propenal and a liquid coffee concentrate with a pH between 5 and 5.2 and a QA/QaL (Quinic acid/Quinic acid lactone) mol/mol ratio between 10 and 100.
Description
Title: PROCESS FOR THE PRODUCTION OF A LIQUID COFFEE
CONCENTRATE
F F F Fi i i ie e e el l l ld d d d o o o of f f f t t t th h h he e e e i i i in n n nv v v ve e e en n n nt t t ti i i io o o on n n n
The invention relates to a process for the production of a liquid coffee
concentrate that has an improved storage stability at ambient temperature.
B B B Ba a a ac c c ck k k kg g g gr r r ro o o ou u u un n n nd d d d o o o of f f f t t t th h h he e e e i i i in n n nv v v ve e e en n n nt t t ti i i io o o on n n n
Liquid coffee, and liquid coffee concentrates, are increasingly in demand
for commercial and/or industrial purposes. The production and sales of liquid
coffee, e.g. liquid coffee concentrates for use in coffee dispensing machines,
makes it desirable to provide liquid coffee that has a sufficient shelf-life. Up to
now, such liquid coffee products are mostly available in a frozen form, and
sometimes refrigerated. Non-refrigerated storage would decrease supply chain
costs. However, any products sold for non-refrigerated storage still have an
undesirably short shelf-life.
Generally speaking, a liquid coffee (such as a concentrate or an extract)
is unstable over time and becomes increasingly acidic at room temperature. As
is known by the skilled man, the pH drop might be due to microbial action and
to chemical reaction, such as a slow hydrolysis reaction of some compounds
such as esters and lactones, oxidation of carbonyl group containing compounds
or even the Maillard reaction occurring among polysaccharices and proteins. A
pH of 4.8 is commonly considered in literature as the lower limit for taste
acceptability. Below that pH level the coffee extract becomes undrinkable.
To overcome microbial acidification the liquid coffee is often treated by
UHT (Ultra High Temperature). Particularly suitable UHT treatment is at
120ºC for a couple of seconds.
A reference addressing the chemical acidification is US 2010/0316784.
Therein a treatment is proposed comprising adding an edible alkali source to a
liquid coffee concentrate. This serves to artificially increase pH. Before or after
the addition of alkali, a heat treatment is conducted so as to artificially drive
acid-generation reactions in the coffee concentrate to completion. More
particularly, the heat treatment is conducted between 140 and 146 ºC at a
holding time of at most 3 minutes. This method fails, however, to produce
products of sufficient shelf-life and quality.
Another drawback of the aforementioned process is the addition of
alkali. In many jurisdictions, such an addition is considered undesired and/or
the resulting product is no longer entitled to be called a “coffee”, like under the
EC food regulations. It would be desirable to develop a process for making
liquid coffee whereby the addition of ingredients other than those obtained
from a coffee extract itself is unnecessary, and yet provide a storage stable
liquid coffee concentrate of good flavor qualities.
Another reference addressing the stabilization of liquid coffee by
treatment with alkali is EP 861 596. Herein a coffee extract is treated with an
alkali, which is present in an amount effective to convert acid precursors
present in the coffee extract to their respective acid salts, and thereafter
neutralizing the treated coffee extract with an acid, in an amount sufficient to
neutralize any excess alkali from the first step. Apart from the aforementioned
drawback of using alkali, this method also adds acid, which increases the
amount of foreign components present in the liquid coffee. Moreover, the
method is essentially based on introducing ionic substances (salts) which are
prone to adversely affect taste.
Yet another reference addressing shelf life of liquid coffees is EP 1 374
690. Herein a coffee extract is subjected, essentially immediately after
preparation, to correction of acidity by the addition of a base or an anion resin.
The resulting extract is subjected to pasteurisation. The pasteurisation is
discussed with reference to holding times and temperatures that do not affect
the organoleptic properties of the coffee extract. A typical temperature range is
100ºC-140ºC at a holding time of at most 1 minute. This method fails also to
produce products of sufficient shelf-life and quality.
The object of the present invention is to provide a process with which an
improvement of the quality of the coffee concentrate is obtained in storage
stability as well as in flavor; and/or to at least provide the public with a useful
choice.
In this specification where reference has been made to patent
specifications, other external documents, or other sources of information, this
is generally for the purpose of providing a context for discussing the features of
the invention. Unless specifically stated otherwise, reference to such external
documents is not to be construed as an admission that such documents, or
such sources of information, in any jurisdiction, are prior art, or form part of
the common general knowledge in the art.
S S S Su u u um m m mm m m ma a a ar r r ry y y y o o o of f f f t t t th h h he e e e i i i in n n nv v v ve e e en n n nt t t ti i i io o o on n n n
In order to better address one or more of the foregoing desires, the
invention, in one aspect, presents a process for the production of a liquid coffee
concentrate with a pH of 4.8 to 6 comprising the steps of
a) subjecting roasted, ground coffee to one or more extraction steps with
water resulting in a coffee extract,
b) separating the coffee extract, either by fractionation during the
extraction step(s) in a) or by aroma recovery after step a) resulting in a high
aromatic coffee extract and a low aromatic coffee extract,
c) subjecting at least 50% of the low aromatic coffee extract to a heat
treatment of at least 120 °C at a holding time for at most 30 minutes,
d) concentrating at least the treated low aromatic coffee extract,
e) combining at least the concentrated low aromatic coffee extract with
the high aromatic coffee extract,
thereby obtaining a liquid coffee concentrate.
The invention, in another aspect, presents a process for the production
of a liquid coffee concentrate with a pH of 4.8 to 6 comprising the steps of
a) subjecting roasted, ground coffee to one or more extraction steps with
water resulting in a coffee extract,
b) separating the coffee extract by fractionation during the extraction
step(s) in a) in a high aromatic coffee extract and a low aromatic coffee extract
comprising a second primary extract and a secondary extract,
c) subjecting at least part of the second primary extract to a heat
treatment of at least 120 °C at a holding time for at most 30 minutes which
part to be treated comprises at least 25 v/v% of the low aromatic coffee extract,
d) concentrating at least the treated low aromatic coffee extract,
e) combining at least the concentrated low aromatic coffee extract with
the high aromatic coffee extract,
thereby obtaining a liquid coffee concentrate.
In another aspect, the invention provides a liquid coffee concentrate
with a pH of 4.8 to 6 obtainable by the above-mentioned processes.
In another aspect, the invention provides a liquid coffee concentrate
with a pH of 4.8 to 6 comprising 2 mg/kg dry matter solids or more of 2-phenyl-
3-(2-furyl)propenal.
In another aspect, the invention provides a liquid coffee concentrate
with a pH between 5 and 5.2 and a QA/QaL (Quinic acid/Quinic acid lactone)
mol/mol ratio between 10 and 100, preferably between 30 and 100.
In the description in this specification reference may be made to subject
matter which is not within the scope of the appended claims. That subject
matter should be readily identifiable by a person skilled in the art and may
assist in putting into practice the invention as defined in the appended claims.
The term “comprising” as used in this specification and claims means
“consisting at least in part of”. When interpreting statements in this
specification and claims which include the term “comprising”, other features
besides the features prefaced by this term in each statement can also be
present. Related terms such as “comprise” and “comprises” are to be
interpreted in similar manner.
D D D De e e et t t ta a a ai i i il l l le e e ed d d d d d d de e e es s s sc c c cr r r ri i i ip p p pt t t ti i i io o o on n n n o o o of f f f t t t th h h he e e e i i i in n n nv v v ve e e en n n nt t t ti i i io o o on n n n
In a broad sense, the invention is based on the judicious insight to
conduct a relatively strong heat treatment at a certain holding time on a coffee
extract wherefrom aroma components have been recovered prior to
concentration. Further, the invention provides, preferably, a judicious
combination of such a heat treatment step and a pH-rising treatment. More
preferably, the pH rising step does not involve the addition of alkali. Most
preferably, the process results in a hydrolysation of at least 150 mmoles
acid/kg dry matter solids content in the final product. This is the difference
between the amount of mmoles/kg dry matter solids content in the low
aromatic coffee extract to be treated before and after the heat treatment
multiplied by the wt/wt ratio dry matter solids content of the low aromatic
coffee extract in the final product.
The coffee chosen for the extraction in step a) can be any type of roasted
coffee. The provision of roasted coffee is well-known to the skilled person. E.g.,
the starting material can be a customary coffee bean raw material for
industrial extraction processes, which coffee origins are roasted in the
customary manner. As a rule, to that end, a mixture of different types of coffee
origins is used. The roasted coffee beans are ground, while generally, for the
degree of grinding a compromise is sought between obtaining the largest
possible surface and obtaining a lowest possible pressure drop across the
extraction cell. As a rule, the ground beans have an average size of 2.0
millimeters.
In order to better preserve coffee aromas, the process of the present
invention is conducted on a low aromatic coffee extract. This is obtained by
a) subjecting roasted, ground coffee to one or more extraction steps with
water resulting in a coffee extract, and
b) separating the coffee extract, either by fractionation during the
extraction step(s) in a) or by aroma recovery after step a) resulting in a high
aromatic coffee extract and a low aromatic coffee extract,
Examples of aroma recovery after step a) include steam stripping, supercritical
CO extraction, and pervaporation. In another embodiment, the coffee extract
is fractionated during the extraction step a). The specific coffee aroma, present
in the high aromatic coffee extract resulting therefrom, has a more natural
coffee character compared to coffee aroma recovered by means of steam
stripping from the complete extract after step a). A high aromatic coffee
extract and a low aromatic coffee extract are obtained. As known to a skilled
man, a high aromatic coffee extract distinguishes itself from a low aromatic
coffee extract by having a comparably high amount of volatile flavor
compounds compared to semi volatile flavor compounds. Such compounds are
known for example from Clarke R.J. and Vitzthum O.G., Coffee Recent
Developments, 2001 (ISBN 005553-7), p. 71, table 3.3. From this table it
is clear that on the one hand propanal, methyl propanal, and 2,3 butanedione
are measurable volatile flavor compounds. Pyrazine compounds and guaiacol
compounds on the other hand are semi volatile flavor compounds. Taking e.g.
2,3-butanedione as an example of a volatile coffee flavor compound and ethyl
guaiacol (4-ethyl 2-methoxyphenol) as an example of a semi volatile coffee
flavor compound, when these compounds are in a wt/wt ratio of 2,3-
butanedione / ethyl guaiacol >30 in a particular coffee extract, that extract can
be described as a high aromatic coffee extract. Consequently, a low aromatic
coffee extract has a wt/wt ratio of 2,3-butanedione / ethyl guaiacol < 30.
The high aromatic coffee extract is stored.
The low aromatic coffee extract is an undiluted or unconcentrated
extract. Whilst, preferably, the treatment is conducted on an extract as is, it
will be understood that a small change of the extract, by insubstantial dilution
or insubstantial concentration, will not deviate from the gist of the invention.
This is markedly different from the method disclosed in US 2010/0316784,
where it is expressly required that the extract is concentrated prior to the heat
treatment. An extract will generally have a dry matter solids content of 15% by
weight or less, preferably of from 2 to 10% by weight. A concentrate is
distinguished from an extract by having undergone a substantial water
removing step such as water evaporation. Whilst a concentrate will generally
have a dry matter solids content of 6 wt.% to 80 wt.%, it will usually be at
least 10 wt.% higher in dry matter solids than the preceding extract, and
regularly has a dry matter solids content of above 10 wt.%, particularly above
15 wt.%.
At least 50 v/v%, more preferably 75 v/v%, most preferably all (100%) of
the low aromatic coffee extract is subjected to a heat treatment of at least 120
°C at a holding time for at most 30 minutes, preferably at a temperature of at
least 135ºC at a holding time of at most 15 minutes, more preferably at least
150ºC at a holding time of at most 10 minutes. In general, the higher the
temperature the shorter the holding time. In particular, below 150 ºC the
holding time has to be at least 10 minutes. In this respect, the above-
mentioned publications teach away from the present invention as the
temperatures and holding times disclosed are below 150 ºC and shorter than 3
minutes. Preferably, the heat treatment is conducted from 120 °C to 200 °C at
a holding time of 30 minutes to 10 seconds. More preferably, the heat
treatment is conducted from 135 °C to 180 °C at a holding time of 15 minutes
to 1 minute. Most preferably, the heat treatment is conducted from 150 °C to
180 °C at a holding time of 10 minutes to 1 minute. As a particular example
the heat treatment can be conducted at about 150°C with a holding time of
about 5 minutes.
Heating times may include heating from ambient temperature to the
holding temperature during 1-8 minutes, preferably 3-5 minutes.
Cooling times may include cooling to ambient temperature during 1-8
minutes, preferably 3-5 minutes.
In a preferred embodiment, the process comprises a pH rising step (de-
acidification or pH adjustment step) after step b). This pH rising step may be
conducted before or after the concentration step d). Preferably, the pH rising
step is conducted before the concentration step whereby the low aromatic
extract is subjected to a pH rising step, i.e. the low aromatic extract is
subjected to the pH rising step before or after the heat treatment step c).
With the pH-rising step the pH is raised to a less acidic (more alkaline)
pH, preferably having a value of from 5-10.
This raise is relative to the starting pH. I.e., if the starting pH is 4, the
pH rise could be to a value that is still acidic, e.g. 5. However, preferably the
starting pH of the coffee stream is 4.5 to 6.5, more preferably of from 4.9 to 5.7.
After the treatment steps the pH will again be at normal level such as between
4.8 and 6.
In a preferred embodiment of the process of the invention, the pH rise of
the low aromatic extract is conducted prior to the heat treatment. In this
embodiment it is further preferred that the pH is raised to a value of 6 to 8. In
another preferred embodiment, the pH rise is conducted after the heat
treatment. In this embodiment it is further preferred that the pH is raised to a
value of 5 to 7.
The pH-rising step can be conducted by adding edible alkali. Sources of
edible alkali are known, and have also been described in the aforementioned
US 2010/0316784.
More preferably, however, the pH-rising step is conducted without
adding alkali. By avoiding the addition of foreign substances, it is secured that
the product after treatment remains considered to be “coffee” in accordance
with the applicable food legislation in many jurisdictions. For, in such
jurisdictions the addition of substances other than those obtained from the
extraction will result in a product that is not allowed to be indicated as a
coffee. It will be understood that such a product may receive a different
perception by consumers. An underlying technical problem thus is the
provision of a process that sufficiently treats the coffee so as to result in a
product of sufficient storage stability and aroma quality, yet without the
addition of foreign substances such as edible alkali.
This is secured in a preferred embodiment of the invention, wherein in
the pH rising step use is made of an ion exchange resin and/or an adsorber.
The adsorber may be carbon based, polyacrylate based or polystyrene based.
Examples of commercial adsorbers include Purolite® MN 200, Purolite® MN
202, and Lewatit® AF5. Examples of the ion exchange resins include strong or
weak basic anion exchange resins. Preferably, the ion exchange resin is a weak
basic anion exchange resin. The resin is based on polyacrylate or polystyrene,
preferably polyacrylate. The functional groups are e.g. amine functional
groups, such as primary, tertiary, and quaternary amine groups as well as
polyamine groups, preferably tertiary amine groups. In the following table
examples of commercial ion exchange resins are listed.
% % % % o o o of f f f
g g g ge e e el l l l////m m m ma a a ac c c cr r r ro o o o- - - - q q q qu u u ua a a at t t te e e er r r rn n n na a a ar r r ry y y y t t t to o o ot t t ta a a al l l l c c c ca a a ap p p pa a a ac c c ci i i it t t ty y y y
N N N Na a a am m m me e e e M M M Ma a a at t t tr r r ri i i ix x x x f f f fu u u un n n nc c c ct t t ti i i io o o on n n na a a al l l l g g g gr r r ro o o ou u u up p p p
p p p po o o or r r ro o o ou u u us s s s a a a am m m mi i i in n n ne e e es s s s ( ( ( (e e e eq q q q////L L L L) ) ) )
( ( ( (S S S SB B B BA A A A) ) ) )
Rohm & Haas IRA 67
polyacrylic gel tertiary amine 24% 1,6
Lewatit® XA 945
Lewatit® MP 62 polystyrene macroporous tertiary amine 3% 1,7
Purolite® A 172 polystyrene gel tertiary amine 2% 1,2
Lewatit® A 365 polyacrylic gel poly amine
Lewatit® VP OC 1075 polyacrylic gel poly amine 14% 2,9 (3,4)
Lewatit® VP OC 1065 polystyrene macroporous primary amine 2,2
Lewatit® MonoPlus M quaternary
polystyrene gel 100% 1,2
500 amine, Type I
quaternary
Lewatit® M 600 polystyrene gel 100% 1,1
amine, Type II
In the lower temperature ranges, viz. from 120ºC to below 150ºC, the
pH-rise is preferably effected prior to the heat treatment. Without wishing to
be bound by theory, the present inventors believe that the pH-rise is capable of
catalyzing acid-releasing reactions. The effect thereof is more pronounced in
the lower regions of the heat treatment conditions.
Preferably, the heat treatment is an extreme heat treatment in the
sense that it is conducted in the higher temperature ranges of 150ºC or above.
Here the process is more robust in the sense that the order as well as the
strength of the pH rising step is less critical. This has significant advantages
not only creating a greater freedom of processing (viz. the order of the
treatment steps), but also requiring a lesser degree of de-acidification.
In connection with the addition of foreign substances such as edible
alkali, it is particularly preferred in this embodiment to choose the
aforementioned conditions of extreme heat treatment. Thus, the addition of
alkali can be minimized.
In the last steps the low aromatic coffee extract is concentrated.
Preferred concentrates comprise 6 wt.% to 80 wt.% coffee solids, preferably 10
wt.% to 65 wt.%, more preferably 15 wt.% to 50 wt.%. Methods of concentration
such as evaporating water are well-known to the skilled person.
In the event that part (i.e. at least 50%) of the low aromatic coffee
extract has been treated, the untreated low aromatic coffee extract may be
combined with the treated low aromatic coffee extract, i.e. before
concentration, or with the treated concentrated low aromatic coffee extract, i.e.
after concentration.
Generally, after concentration the concentrated treated low aromatic
extract is mixed with the high aromatic extract. This can be done in the factory
before optionally further treatment steps and packaging or just before dosing
by the consumer. In the latter case, two separate packages are provided to the
consumer to be introduced in the coffee preparing machine.
In the factory, after temporary, preferably cooled, storage, preferably at
a temperature below 25°C, more preferably below 10°C, most preferably
below 0°C, the high aromatic coffee extract may directly, without further
processing, be added to the concentrated low aromatic coffee extract. It is
preferred that the high aromatic coffee extract is stored as briefly as possible
and cooled, preferably at an atmosphere of an inert gas such as nitrogen for
adding to the concentrated low aromatic coffee extract; owing to these steps
loss of aroma and aroma degradation reactions are limited as much as
possible.
Accordingly, the present process provides for a liquid coffee concentrate
with a pH of 4.8 to 6 that can be stored at ambient temperature (generally
indicating a temperature of 5ºC to 25ºC, and preferably without the need for
refrigerating equipment) at an acceptable shelf-life without acidification to
occur, and capable of being kept without substantial off-flavors to arise.
In a preferred embodiment, the extraction in step a) is preferably done
as a split extraction. Processes of split extraction are known. A reference in
this respect is . More particularly, the process involves
primary and secondary extraction.
In a preferred embodiment of split extraction, the invention is put to use
in the following method for preparing a coffee concentrate. In the method,
roasted, ground coffee is subjected to a primary extraction with water, whereby
a first primary extract (i.e. the high aromatic coffee extract) is obtained with a
draw-off factor of at most 2.5, preferably at most 2.0, more preferably at most
1.5 and most preferably at most 1.0. Thereafter, optionally, a second primary
extract is obtained.
The primarily extracted, roasted, ground coffee is then fed to a
secondary extraction section in which, with water having a feed temperature
between 120 and 210°C, a secondary extract is obtained (the low aromatic
coffee extract). At least 50 v/v%, more preferably 75 v/v%, most preferably all
(100%) of the secondary extract is then subjected to the process steps of the
present invention. Optionally, the second primary extract may be added to the
secondary extract (the low aromatic coffee extract) before or after the
treatment step(s) of the present invention, preferably the second primary
extract is added before the treatment to the secondary extract.
The term "draw-off factor" is understood to mean the ratio of the mass of
the extract and the mass of the dry roasted and ground coffee in the primary
extraction cell. In practice, this draw-off factor is determined by a compromise
between, on the one side, a sufficient degree of coffee aroma recovery in the
first primary extract, and, on the other side, a lowest possible volume of the
first primary extract. The draw-off factor for that matter depends on the used
coarseness or degree of grinding of the roasted coffee, the extraction cell and,
in particular, the number of percolators placed in series, the used water-coffee
ratio, the cycle time, the feed water temperature and the desired concentration
of the end product and the like.
In a further preferred embodiment of split extraction, also a second
primary extract is recovered from the primary extraction cell. To that end,
after draw-off and storage of the first primary extract, further extraction takes
place in the primary extraction cell.
The recovery of both a first and second primary extract is particularly
attractive when a high water-coffee ratio is applied. Preferably, the water-
coffee ratio is between 5.0 and 15. More preferably, the water-coffee ratio is
lower than 10, and most preferably, the water-coffee ratio is between 6.5 and
8.5.
When a second primary extract is recovered, preferably, the first fraction
of the secondary extract is indeed used as primary feed water in the first
extraction cell. For this embodiment, the teachings of EP-A-0 352 842 are
included herein by reference.
The second primary extract can be subjected to aroma recovery. The
recovered aromas are added to the high aromatic extract. The second primary
extract after the aroma recovery may be added to the secondary extract (the
low aromatic coffee extract) before or after the treatment step(s) of the present
invention, preferably the second primary extract is added before the treatment
to the secondary extract. After concentration the concentrated low aromatic
coffee extract and the high aromatic coffee extract (comprising the recovered
aromas) are combined.
In this embodiment of the invention, the primary extraction is carried out
with water at a feed water temperature which is lower than that which is used
in the secondary extraction. Preferably, the temperature at which the primary
extraction is carried out is between 70 and 120°C.
The primary extraction can be carried out as an exhaustive extraction.
"Exhaustive extraction" is understood to mean that extraction takes place
until the extract hardly, if at all, differs from the water introduced into the
extraction cell. In practice however, it will be beneficial to the efficiency of the
entire process, in particular because of the subsequent concentration steps,
when extraction is not exhaustive.
"Water" for that matter is understood to include customary aqueous
solutions that can also be used in the known industrial extraction processes.
The primary and secondary extractions can be carried out in customary
extraction cells. In a preferred embodiment, both the primary and the
secondary extraction are carried out in a percolator or in percolators placed in
series. In particular, the secondary extraction is advantageously carried out in
at least 2, and preferably at least 4 series-connected percolators. As a rule, the
number of percolators used in the primary extraction section is at least 0.5
which means that during 50% of the cycle time a percolator is connected in the
primary extraction section. Preferably, at least 1 or 2 percolators are connected
in the primary extraction section.
In a preferred embodiment of the process according to the invention, the
low aromatic coffee extract is at least part but preferably the total of a
secondary extract. In one further preferred embodiment hereof, the treated low
aromatic coffee extract is combined with a second primary extract prior to the
concentration step. In another preferred embodiment hereof, the low aromatic
coffee extract is a mixture of at least part but preferably the total secondary
extract and the second primary extract.
It has also been found that the second primary extract can be subjected
to the treatment of the present invention. In that respect, both the second
primary extract and the secondary extract are considered the low aromatic
coffee extract of which at least part of the second primary extract is treated
which part to be treated comprises at least 25 v/v%, more preferably at least
v/v%, most preferably at least 50 v/v% of the low aromatic coffee extract.
After the treatment, the treated part of the second primary extract is added to
the non-treated part of the second primary extract and the secondary extract
and concentrated. Preferably, all of the second primary extract is treated.
Preferred is also the use of customary liquid or dried filler components. A
filler component is sometimes used to neutralize the marked flavour character
of the first primary extract to some extent. The filler is preferably a high yield
coffee product. It may be added to the low aromatic coffee extract before
concentration, more preferably before the temperature treatment.
The invention also pertains to a liquid coffee concentrate with a pH of 4.8
to 6 obtainable by a process according to the invention. The liquid coffee
concentrate comprises 6 wt.% to 80 wt.% coffee solids, preferably 10 wt.% to 65
wt.%, more preferably 15 wt.% to 50 wt.%. This coffee concentrate is
distinguished from coffee concentrates not according to the invention, on
account of its better storage stability at ambient temperature, as can be
identified with reference to the reduced, or preferably absent, pH lowering,
and to reduced, and preferably absent occurrence of off-flavors. Preferably, the
liquid coffee concentrate has a storage stability of more than 6 months, more
preferably more than 12 months, most preferably more than 18 months.
A product treated by the process according to the present invention
distinguishes itself by comprising at least 2 mg/kg dry matter of 2-phenyl(2-
furyl)propenal.
Accordingly, the present invention also relates to a liquid coffee
concentrate with a pH of 4.8 to 6 comprising at least 2 mg/kg dry matter solids
of 2-phenyl(2-furyl)propenal, preferably between 4 mg/kg dry matter
solids and 80 mg/kg dry matter solids, more preferably between 4 mg/kg dry
matter solids and 40 mg/kg dry matter solids.
Alternatively, a product treated by the process according to the present
invention distinguishes itself by having a QA/QaL mol/mol ratio between 10
and 100 at a pH between 5 and 5.2. More particularly, during the shelf life the
liquid coffee concentrate will enter a pH window between 5 and 5.2. In that pH
window it should have a QA/QaL mol/mol ratio between 10 and 100.
Accordingly, the present invention also relates to a liquid coffee
concentrate with a pH between 5 and 5.2 and a QA/QaL mol/mol ratio between
and 100, preferably between 30 and 100, most preferably 60 to 100. In a
preferred embodiment, this liquid coffee concentrate will have a potassium
content of 55 g or less per kg dry matter, preferably 20-55 g/kg and/or a sodium
content of 4 g or less per kg dry matter, preferably 0.1-4 g/kg.
The abbreviation QA stands for Quinic acid, i.e. 1,3,4,5-
tetrahydroxycyclohexanecarboxylic acid. The abbreviation QaL stands for
Quinic acid lactone, i.e. 1,3,4-trihydroxyoxabicyclo[3.2.1]octanone.
Various embodiments of the invention are further explained with
reference to the Examples and Schemes 1 and 2, which provide process
schemes for implementing the treatment steps of the invention in processes for
making coffee concentrates. These schemes serve illustrative purposes, and do
not limit the invention.
In Figure 5, a preferred embodiment of the invention is illustrated.
Roasted coffee is subjected to split extraction, with split tapping (rendering
first and second primary and secondary extractions). The second primary
extract is combined with the second secondary extract, and this stream is
subjected, before concentration, to pH adjustment (by anion exchange), and
extreme heat treatment (at the above-identified temperatures). The
concentrated extract is combined with the first primary extract resulting in a
liquid coffee concentrate of the present invention.
Figure 6 illustrates a further preferred embodiment. Therein, either the
second secondary extract or the 2 primary extract or both and mixtures
thereof are subjected to the pH adjustment by anion exchange and heat
treatment, before being combined with the first primary extract. The 2
primary extract may be subjected to aroma recovery, so that after
concentration the concentrated coffee extract is mixed with 1 primary extract
as well as the aroma recovery product. Optionally, a filler component can be
added either before or after concentration.
Analytical method for QA and QaL
Quinic acid lactone (QaL), was obtained from Syncom, Groningen, the
Netherlands. A working solution of approximately 0,5 mg per ml was obtained
by diluting QaL in acetonitrile. This working solution was further diluted in
0,1% acetic acid in acetonitrile to obtain calibration solutions of 15 ng/ml up to
15000 ng/ml.
Concentrated coffee products were diluted with water to 0,28% dry matter.
50 µl of the diluted coffee product is further diluted with 950 µl 0,1% acetic
acid in acetonitrile.
Quantification was performed with a Triple Quad MS, TSQ Quantum Ultra;
Thermo Scientific Mass spectrometer coupled to a Accela UPLC from Thermo
Scientific.
Concentrations were calculated from the calibration curve.
Quinic acid (QA), was obtained from Aldrich. A working solution of
approximately 1 mg per ml was obtained by dissolving the compound in water.
This working solution was further diluted in 0,4 mM heptafluorobutyric acid to
obtain calibration solutions of 10 µg/ml up to 40 µg/ml.
Concentrated coffee products were diluted with 0,4 mM heptafluorobutyric
acid to 0,1% dry matter (w/w) dry coffee solids.
Quantification was performed with a Dionex ICS 5000 DC suppressed
conductivity chromatograph.
Concentrations were calculated from the calibration curve.
Analytic method for 2-phenyl(2-furyl)propenal
2-phenyl(2-furyl)propenal, was obtained from Chemos GmbH, Werner-
von-Siemens-Straβe, D-93128 Regenstauf, Germany (purity 97%). A working
solution of 1 mg per ml was obtained by diluting the compound in hexane. This
working solution was further diluted to obtain calibration solutions of 0, 0.6, 1,
3, 6, 10 and 50 µg 2-phenyl(2-furyl)propenal per ml hexane.
Liquid coffee concentrates were diluted with water to 2.5% dry matter
Volatiles in the coffee headspace were analysed by solid phase micro-extraction
(SPME) coupled to gas chromatography/mass spectrometry (GC/MS),
essentially as described in Tikunov et al., 2005, Plant Physiology 139, 1125 –
1137, was calculated from the linear calibration curve of the authentic
standard in the coffee matrix.
EXAMPLE 1
Extraction (split stream)
From a single batch of ground coffee, a coffee extract is obtained by split
stream extraction as described in .
1 primary extract (stream A in scheme 1), which is high in flavor, the high
aromatic coffee extract, is left untreated or concentrated and will be added to
the concentrated low aromatic coffee extract (stream H) prior to UHT
treatment and packaging. All of the secondary extract is mixed with 2
primary extract (stream C). The resulting mixture (Stream G) is composed of
72,7% w/w secondary extract (stream E) and 27,3% w/w 2 primary extract
(stream C).
Adding filler
An unconcentrated high yield extract (stream F) is made from a second batch
of coffee. This high yield extract is directly added to the low aromatic coffee
extract. This results in a mixture of dry matter solids content of approximately
Processing
The pH of the low aromatic coffee extract is adjusted by passing the extract
over an anion column (Lewatit® XA 945) to pH 8.
The low aromatic coffee extract is heated from ambient conditions to 150ºC in
5 minutes, and kept at that temperature for 5 consecutive minutes, followed by
a cooling step of 3 minutes.
The heat treated low aromatic coffee extract is concentrated to a dry matter
solids content of 28% by evaporation.
During these process steps > 150 mMoles acid /kg dry matter solids content is
released by hydrolysis
The concentrated low aromatic coffee extract is mixed with the high aromatic
coffee extract (1 primary extract) (stream A).
Final product
The resulting pH of the liquid coffee concentrate is 6,2
No detectable off flavor is detected in the liquid coffee concentrate.
During a shelf life of 8 weeks the liquid coffee concentrate is not perceived as
acidified by a team of sensory experts.
By comparison, products manufactured according to the process described in
US 2010/0316784 do show acidification during this shelf life period.
EXAMPLE 2
A single batch of Arabica coffee is subjected to the extraction as described in
Example 1. The primary extract, i.e. the high aromatic coffee extract,
comprises 16 wt.% of the total coffee dry matter and has a BD/EG wt/wt ratio
of 100. The low aromatic coffee extract comprises 84 wt.% of the total coffee
dry matter. The pH of the low aromatic coffee extract obtained therefrom with
a dry matter solids content of approximately 6% is adjusted by passing the
extract over an anion column (Lewatit® XA 945) to pH 6. The amount of acids
was assessed by titration up to pH 8. The low aromatic coffee extract having
287 mmoles acid/kg dry matter is heated from ambient conditions to 160ºC in
approximately 3,5 minutes, and kept at that temperature for 10 consecutive
minutes, followed by a cooling step of approximately 2 minutes. The treated
low aromatic coffee extract has 818 mmoles acid/kg dry matter. The heat
treated low aromatic coffee extract is concentrated. This process results in a
hydrolysation of at least 446 mmol acid/kg dry matter solids content in the
final product ((818-287)*0.84).
The concentrated low aromatic coffee extract is mixed with the high aromatic
coffee extract (1 primairy extract) (stream A). The resulting pH of the liquid
coffee concentrate is 5,34. The liquid concentrate has a dry matter solids
content of 28%.
No detectable off flavor is detected in the liquid coffee concentrate.
The pH was followed in time as shown in Figure 1(▲). During 28 weeks shelf
life the product does not drop in pH below 5. When assessed by expert tasters,
no unpleasant acidity can be detected in the product.
The liquid coffee concentrate comprises an amount of 7,5 mg/kg dry matter
solids 2-phenyl(2-furyl)propenal.
The amount of potassium is 53 g/kg dry matter and the amount of sodium is 2
g/kg dry matter. After 8 weeks storage the pH of the concentrate is 5.1 and the
QA/QaL mol/mol ratio is 90.
For comparison, a liquid coffee concentrate is prepared in the same manner as
described above except that the heat treatment is omitted. The resulting liquid
coffee concentrate has a pH of 5.2. Within 4 weeks, this product drops below
pH 5 (see Figure 1 (▪)). When assessed by expert tasters the product is
unpleasantly sour.
EXAMPLE 3
Example 2 was repeated whereby the low aromatic coffee extract was
subjected to various temperature and time treatments. The experiments are
provided in Figure 2. On the y axis is given the temperature in degrees Celsius
at which coffee extracts were treated, the x axis gives the duration of the heat-
treatment in minutes. The numbers in Figure 2 indicate the amount of mMoles
acid /kg dry matter solids content in the final product which is released by
hydrolysis.
▪ indicates a coffee extract which yielded more than 150 mMoles acid /kg dry
matter solids content in the final product released by hydrolysis and thus are
obtained with a process according to the invention
● indicates a coffee extract which yielded less than 150 mMole acid /kg dry
matter solids content in the final product released by hydrolysis. Accordingly,
these are comparative examples.
EXAMPLE 4
A single batch of Arabica coffee is subjected to extraction whereby aromas
were fractionated from a highly aromatic coffee by means of steam distillation
as described in EP-A-0 352 842. This results in a steam destilate, i.e. the high
aromatic coffee extract (stream D) and a low aromatic coffee extract
comprising stream D’ and stream E in scheme 2.
The pH of the low aromatic coffee extract with a dry matter solids content of
approximately 5% is adjusted by passing the extract over an anion column
(Lewatit® XA 945) to pH 6. The low aromatic coffee extract is heated from
ambient conditions to 180ºC in 6 minutes, and kept at that temperature for 1,5
consecutive minutes, followed by a cooling step of 3 minutes.
The heat treated low aromatic coffee extract is concentrated. This process
results in a hydrolysation of 395 mMoles acid /kg dry matter solids content in
the final product.
The concentrated low aromatic coffee extract is mixed with the high aromatic
coffee extract (stream D).
The resulting pH of the liquid coffee concentrate is 5,35. The liquid concentrate
has a dry matter solids content of 28%.
No detectable off flavor is detected in the liquid coffee concentrate.
The pH was followed in time as shown in Figure 3 (▲). During 7 weeks shelf
life the product does not drop in pH below 5. When assessed by expert tasters,
no unpleasant acidity can be detected in the product.
The liquid coffee concentrate comprises an amount of 6 mg/kg dry matter
coffee solids 2-phenyl(2-furyl)propenal. The amount of potassium is
50g/kg dry matter and the amount of sodium is 3 g/kg dry matter.
For comparison, a liquid coffee concentrate is prepared in the same manner as
described above except that the heat treatment is omitted. The resulting liquid
coffee concentrate has a pH of 5.2. Within 6 weeks, this product drops below
pH 5 (see Figure 3 (
▪))When assessed by expert tasters the product is
unpleasantly sour.
EXAMPLE 5
Extraction (split stream)
From a single batch of ground coffee, a coffee extract is obtained by split
stream extraction as described in .
1 primary extract (stream A in scheme 2), the high aromatic coffee extract, is
left untreated. All of secondary extract (stream E) (about 55 v/v%) is left
untreated as well.
Processing
All of the 2 primary extract (stream C) (about 45/v%) is treated by adjusting
the pH to 6 by passing the extract over an anion column (Lewatit® XA 945).
The 2 primary extract is heated from ambient conditions to 180ºC in 6
minutes, and kept at that temperature for 2,5 consecutive minutes, followed by
a cooling step of 2,5 minutes.
This process results in a hydrolysation of at least 176 mMoles acid /kg dry
matter solids content in the final product
The heat treated 2 primary extract is mixed with the untreated secondary
extract and concentrated.
The concentrated low aromatic coffee extract is mixed with the high aromatic
coffee extract (1 primairy extract) (stream A).
The resulting pH of the liquid coffee concentrate is 5,27 and has a dry matter
solids content of 28%.
No detectable off flavor is detected in the liquid coffee concentrate during
storage.
EXAMPLE 6
A single batch of Arabic coffee is subjected to the extraction as described in
Example 2.. The pH of the low aromatic coffee extract obtained therefrom with
a dry matter solids content of approximately 6% is adjusted by addition of
KOH to pH 6. The low aromatic coffee extract is heated from ambient
conditions to 150ºC in approximately 3,5 minutes and kept at that
temperature for 10 consecutive minutes, followed by a cooling step of
approximately 2,5 minutes. The heat treated low aromatic coffee extract is
concentrated. The concentrated low aromatic coffee extract is mixed with the
high aromatic coffee extract (1 primairy extract) (stream A).
The resulting pH of the liquid coffee concentrate is 5,4 and a dry matter solids
content of 28%. This process results in a hydrolysation of at least 220 mMoles
acid /kg dry matter solids content in the final product. No detectable off smell
is detected in the liquid coffee concentrate but a metallic off taste was present
due to the presence of KOH.
The pH was followed in time as shown in Figure 4 (▲). During 28 weeks shelf
life the product does not drop in pH below 5. When assessed by expert tasters,
no unpleasant acidity can be detected in the product.
For comparison, a liquid coffee concentrate is prepared in the same manner as
described above except that the heat treatment is omitted. The resulting liquid
coffee concentrate has a pH of 5.2. Within 4 weeks, this product drops below
pH 5 (see Figure 4 (▪)). When assessed by expert tasters the product is
unpleasantly sour.
COMPARATIVE EXAMPLE 7
A liquid coffee concentrate having approximate 30 % w/w dry solids was
obtained by extraction a mixture of 50 % Arabica and 50 % Robusta coffee
beans and processed according to the steps described in US 2010/0316784.
The pH of the liquid coffee extract was adjusted to 5,7 by addition of edible
alkali, i.e. potassium hydroxide.
The resulting coffee concentrate was processed at 145 C with a holding time of
90 seconds followed by rapid cooling to ambient condition.
The pH of the final product was approximately 5,2.
Only 100 mmoles acid/kg dry matter content in the final product were
released. The pH dropped below 5,0 within 8 weeks.
When assessed by experts the product had a sour off taste.
Claims (42)
1. A process for the production of a liquid coffee concentrate with a pH of 4.8 to 6 comprising the steps of 5 a) subjecting roasted, ground coffee to one or more extraction steps with water resulting in a coffee extract, b) separating the coffee extract, either by fractionation during the extraction step(s) in a) or by aroma recovery after step a) resulting in a high aromatic coffee extract and a low aromatic coffee extract, 10 c) subjecting at least 50% of the low aromatic coffee extract to a heat treatment of at least 120 °C at a holding time for at most 30 minutes, d) concentrating at least the treated low aromatic coffee extract, e) combining at least the concentrated low aromatic coffee extract with the high aromatic coffee extract, 15 thereby obtaining a liquid coffee concentrate.
2. A process according to claim 1 comprising additionally a pH rising step after step b).
3. A process according to claim 2 wherein at least 50% of the low aromatic extract is subjected to a pH rising step. 20
4. A process according to claim 3 wherein at least 50% of the low aromatic extract is subjected to the pH rising step before or after the heat treatment step c) but before the concentrating step d).
5. A process according to any one of the preceding claims, wherein the heat treatment is conducted at a temperature of at least 135ºC at a holding 25 time of at most 15 minutes.
6. A process according to any one of the preceding claims, wherein the heat treatment is conducted at a temperature of at least 150ºC at a holding time of at most 10 minutes.
7. A process according to any one of claims 1 to 4, wherein the heat treatment is conducted from 120 °C to 200 ° at a holding time of 30 minutes to 10 seconds.
8. A process according to claim 7, wherein the heat treatment is 5 conducted from 135 °C to 180 °C at a holding time of 15 minutes to 1 minute.
9. A process according to claim 8, wherein the heat treatment is conducted at about 150°C with a holding time of about 5 minutes.
10. A process according to any one of claims 2 to 9 wherein the pH is raised to a value of 5 to 10. 10
11. A process according to any one of claims 4 to 10, wherein the pH is raised prior to the heat treatment.
12. A process according to claim 11 wherein the pH is raised to a value of 6 to 8.
13. A process according to any one of claims 4 to 10, wherein the pH 15 is raised after the heat treatment.
14. A process according to claim 13 wherein the pH is raised to a value of 5 to 7.
15. A process according to any one of claims 2 to 14, wherein the pH raise is conducted with an anion exchanger. 20
16. A process according to any one of claims 2 to 15, wherein the pH raise is conducted with an anion exchange column.
17. A process according to any one of the preceding claims wherein the process results in a hydrolysation of at least 150 mmoles acid/kg dry matter solids content in the final product. 25
18. A process for the production of a liquid coffee concentrate with a pH of 4.8 to 6 comprising the steps of a) subjecting roasted, ground coffee to one or more extraction steps with water resulting in a coffee extract, b) separating the coffee extract by fractionation during the extraction step(s) in a) in a high aromatic coffee extract and a low aromatic coffee extract comprising a second primary extract and a secondary extract, c) subjecting at least part of the second primary extract to a heat 5 treatment of at least 120 °C at a holding time for at most 30 minutes which part to be treated comprises at least 25 v/v% of the low aromatic coffee extract, d) concentrating at least the treated low aromatic coffee extract, e) combining at least the concentrated low aromatic coffee extract with the high aromatic coffee extract, 10 thereby obtaining a liquid coffee concentrate.
19. A process according to claim 18 comprising additionally a pH rising step after step b).
20. A process according to claim 19 wherein at least part of the second primary extract is subjected to a pH rising step. 15
21. A process according to claim 20 wherein at least part of the second primary extract is subjected to the pH rising step before or after the heat treatment step c) but before the concentrating step d).
22. A process according to any one of claims 18-21, wherein the heat treatment is conducted at a temperature of at least 135ºC at a holding time of 20 at most 15 minutes.
23. A process according to any one of claims 18-22, wherein the heat treatment is conducted at a temperature of at least 150ºC at a holding time of at most 10 minutes.
24. A process according to any one of claims 18 to 21, wherein the 25 heat treatment is conducted from 120 °C to 200 ° at a holding time of 30 minutes to 10 seconds.
25. A process according to claim 24, wherein the heat treatment is conducted from 135 °C to 180 °C at a holding time of 15 minutes to 1 minute.
26. A process according to claim 25, wherein the heat treatment is 30 conducted at about 150°C with a holding time of about 5 minutes.
27. A process according to any one of claims 19 to 26, wherein the pH is raised to a value of 5 to 10.
28. A process according to any one of claims 21 to 27, wherein the pH is raised prior to the heat treatment. 5
29. A process according to claim 28 wherein the pH is raised to a value of 6 to 8.
30. A process according to any one of claims 21 to 27, wherein the pH is raised after the heat treatment.
31. A process according to claim 30 wherein the pH is raised to a 10 value of 5 to 7.
32. A process according to any one of claims 19 to 31, wherein the pH raise is conducted with an anion exchanger.
33. A process according to any one of claims 19 to 32, wherein the pH raise is conducted with an anion exchange column. 15
34. A process according to any one of claims 18 to 33 wherein the process results in a hydrolysation of at least 150 mmoles acid/kg dry matter solids content in the final product.
35. A liquid coffee concentrate with a pH of 4.8 to 6 comprising 2 mg/kg dry matter solids or more of 2-phenyl(2-furyl)propenal. 20
36. A liquid coffee concentrate with a pH between 5 and 5.2 and a QA/QaL (Quinic acid/Quinic acid lactone) mol/mol ratio between 10 and 100.
37. A liquid coffee concentrate according to claim 36, wherein the QA/QaL (Quinic acid/Quinic acid lactone) mol/mol ratio is between 30 and 100.
38. A liquid coffee concentrate according to claim 36 or 37 comprising 25 a potassium content of 55 g or less per kg dry matter and/or a sodium content of 4 g or less per kg dry matter.
39. A process according to any one of claims 1 to 17 substantially as herein described with reference to any example thereof and with or without reference to the accompanying figures.
40. A process according to any one of claims 18 to 34 substantially as herein described with reference to any example thereof and with or without reference to the accompanying figures.
41. A liquid coffee concentrate according to claim 35 substantially as 5 herein described with reference to any example thereof and with or without reference to the accompanying figures.
42. A liquid coffee concentrate according to any one of claims 36 to 38 substantially as herein described with reference to any example thereof and with or without reference to the accompanying figures.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP11176077.3 | 2011-08-01 | ||
EP11176077 | 2011-08-01 | ||
PCT/NL2012/050543 WO2013019112A1 (en) | 2011-08-01 | 2012-08-01 | Process for the production of a liquid coffee concentrate |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ621830A NZ621830A (en) | 2016-02-26 |
NZ621830B2 true NZ621830B2 (en) | 2016-05-27 |
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