ORGANIC COMPOUNDS

TECHNICAL FIELD

Disclosed are compounds that allow to mask or block undesirable off-notes in consumables and the method of blocking off-notes employing said compounds in consumables.

SUMMARY Provided are the following:

(1) An off-note blocking compound of Formula (I)

wherein n is 0 or 1 (thereby forming cyclopentane or cyclohexane); wherein the ring residue together with the dashed lines is selected from a cyclopentane residue (for n=0), a cyclohexane residue (for n=1), or a bicyclo[2.2.2]octane residue (with the dashed lines forming single bonds); wherein for the cyclopentane and cyclohexane ring residues, R1 comprise a C3 to

C10 alkane or arylalkane residue; wherein for the bicyclo[2.2.2]octane residue, R1 comprises a C2 to C10 alkane or arylalkane residue; wherein said R1 alkane or arylalkane residues are optionally selected from propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, isopentyl, hexyl, isohexyl, 2-methyl- hexyl, heptyl, isoheptyl, 2-methyl-heptyl, octyl, isooctyl, 2-methyl-octyl, nonyl, isononyl, 2-methyl-nonyl, decyl, isodecyl, 2-methyl-decyl, phenyl, tolyl and benzyl; wherein the number of carbon atoms in the residues of R1 and R2 together maximally is 12; and wherein the optional ring substituents R2, R2', R2" and R2'" are each independently selected from H and methyl, or alternatively, instead of two of the

methyl substituents, one cyclopropyl residue formed of two of the methyl residues R2-R2'" and a ring atom is present, or alternatively, instead of one of the methyl residues R2-R2'", a cyclopropyl residue formed of one of the methyl residues R2- R2'" and two ring carbon atoms may be present.

(2) The off-note blocking compound as described herein selected from one or more of c/s-4-propylcyclohexanecarboxylic acid, cis-4-tert-butylcyclohexanecarboxylic acid, cis-4-propylbicyclo[2.2.2]octane-1-carboxylic acid, cis-4-sec- butylcyclohexanecarboxylic acid, cis-4-(4-methylpentyl)cyclohexanecarboxylic acid, cis-4-benzylcyclohexanecarboxylic acid, and cis-4-phenylcyclohexanecarboxylic acid.

(3) A flavor composition comprising an off-note providing consumable ingredient and one or more off-note blocking compounds of Formula (I).

(4) A consumable comprising a) at least one ingredient in a concentration sufficient to provide an off- note, b) one or more compounds off-note blocking compounds of Formula (I).

(5) A consumable as herein described wherein the off-note providing ingredient comprising one of sweeteners, artificial sweeteners, beverages, chewing gums, nutraceuticals, and pharmaceuticals.

(6) A consumable of as herein described wherein the off-note providing ingredient comprises one or more artificial sweetener selected from aspartame, acesulfame K, saccharin, sucralose, and sodium cyclamate.

(7) A consumable as herein described wherein the off-note providing ingredient comprises one or more sweeteners selected from stevioside, swingle extract, glyccerhizin, perillartine, naringin dihydrochalcone, neohesperidine dihydrochalcone, mogroside V, rubusoside, rubus extract, and rebaudioside A

(8) A consumable as herein described wherein the off-note providing ingredient comprises a consumable selected from the group consisting of cocoa, coffee, caffeine, theobromine, diketopiperazines, vitamins, amino acids, vitamin B, casein, soy protein, ibuprofen, salicylic acid, glucoronolactone, acetaminophen, dextromethorphan, naringin, taurin, macrolide (including bioxin and erythomycin),

paracetamol, acetylsalicylic acid, cimetidine, ranitidine, amoxicillin, acetominophen, cephalosporines, quassia, propylene glycol, triacetin, salts of potassium, salts of zinc, loperamide, limonin, flavonoides, isoflavones (including genistein and diadzein), polyphenol (including catechin and epicatechin), mint oil, D-menthol, hydrolysed vegetable protein, bitter peptides, preservatives (including benzoic acid, potassium sorbate, polysorbate 80, sodium and potassium lactate, sodium benzoate), citric acid, quinine, urea (contained in chewing gums), essential oils (inclluding thyme, sage, basil, mint), Maillard reaction products (including cyclic amines made from pyrrolidine/glucose, alanine/xylose, proline/sucrose or alanine/xylose, for example diketopiperazines), beer, hops, humulone, trans-isohumulone, lupulone, and hulupone.

(9) A method of blocking off-notes in consumables comprising admixing with the consumable (a) at least one off-note providing ingredient in a concentration sufficient to provide an off-note, and (b) one or more off-note blocking compounds of Formula (D-

(10) A method as herein described wherein the off-note providing ingredient comprises selected one of sweeteners, artificial sweeteners, beverages, chewing gums, nutraceuticals, and pharmaceuticals.

(11 ) A method as herein described wherein the off-note providing ingredient comprises one or more artificial sweetener selected from aspartame, acesulfame K, saccharin, sucralose, and sodium cyclamate.

(12) A method of as herein described wherein the off-note providing ingredient comprises one or more sweetener selected from stevioside, swingle extract, glyccerhizin, perillartine, naringin dihydrochalcone, neohesperidine dihydrochalcone, mogroside V, rubusoside, rubus extract, and rebaudioside A.

(13) A method as herein described wherein the off-note providing ingredient comprises a consumable selected from the group consisting of cocoa, coffee, caffeine, theobromine, diketopiperazines, vitamins, amino acids, vitamin B, casein, soy protein, ibuprofen, salicylic acid, glucoronolactone, acetaminophen, dextromethorphan, naringin, taurin, macrolide (including bioxin and erythomycin), paracetamol, acetolsalicilic acid, cimetidine, ranitidine, amoxicillin, acetominophen, cephalosporines, quassia, propylene glycol, triacetin, salts of potassium, salts of zinc, loperamide, limonin, flavonoides, isoflavones (including genistein and diadzein), polyphenol (including catechin and epicatechin), mint oil, D-menthol, hydrolysed vegetable protein, bitter peptides, preservatives (including benzoic acid, potassium sorbate, polysorbate 80, sodium and potassium lactate, sodium benzoate), citric acid, quinine, urea (contained in chewing gums), essential oils (inclluding thyme, sage, basil, mint), Maillard reaction products (including cyclic amines made from pyrrolidine/glucose, alanine/xylose, proline/sucrose or alanine/xylose, for example diketopiperazines), beer, hops, humulone, trans-isohumulone, lupulone, and hulupone.

DETAILED DESCRIPTION

The off-note blocking compound of Formula (I) provided herein include, without limitation, the following off-note blocking compounds: c/s-4- propylcyclohexanecarboxylic acid, c/s-4-tert-butylcyclohexanecarboxylic acid, c/s-4- propylbicyclo[2.2.2]octane-1 -carboxylic acid, c/s-4-sec-butylcyclohexanecarboxylic acid, c/s-4-(4-methylpentyl)cyclohexanecarboxylic acid, c/s-4- benzylcyclohexanecarboxylic acid, and c/s-4-phenylcyclohexanecarboxylic acid.

Their chemical structures are indicated below.

c/s-4-propylcyclohexanecarboxylic acid, c/s-4-tert-butylcyclohexanecarboxylic acid, c/s-4-propylbicyclo[2.2.2]octane-1-carboxylic acid, c/s-4-sec- butylcyclohexanecarboxylic acid, c/s-4-(4-methylpentyl)cyclohexanecarboxylic acid, c/s-4-benzylcyclohexanecarboxylic acid, and c/s-4-phenylcyclohexanecarboxylic acid are either available commercially or can be synthesized as will be apparent to the skilled person.

c/s-4-propylcyclohexanecarboxylic acid, cis-4-tert-butylcyclohexanecarboxylic acid and cis-4-sec-butylcyclohexanecarboxylic acid can be synthesized by hydrogenation of corresponding benzoic acid as will be apparent to the skilled person, c/s-4-tert- butylcyclohexanecarboxylic acid also is commercially available from TCI America,

Portland, Oregon, USA. c/s-4-propylbicyclo[2.2.2]octane-1-carboxylic acid is commercially available from AsInEx, Moscow, Russia. c/s-4-(4-methylpentyl)cyclohexanecarboxylic acid is commercially available from

Sigma-Aldrich, St. Louis, Mo, USA. c/s-4-benzylcyclohexanecarboxylic acid can be synthesized by reducing cis-4- benzoylcyclohexane-1-carboxylic acid, and this starting material is available from Rieke Metals, Inc, Lincoln, NE, USA. c/s-4-phenylcyclohexanecarboxylic acid commercially available from ChemBridge,

San Diego, CA, USA.

All compounds of Formula (I) are either available commercially or can be synthesized easily by methods well known in the art, in particular hydrogenation, or as indicated herein.

A taste receptor screen and concentration-response analysis was performed and from results inhibitory concentration (IC) IC ₅₀ values can be calculated by nonlinear regression using the function f(x) = (a-d)/(1 +(x/C) ^πh )+ d; with a = minimum signal, d = maximum signal, nh = hill coefficient, C = IC ₅₀ and x = concentration of antagonist. IC ₅₀ is the molar concentration of an antagonist which produces 50% of the maximum possible inhibitory response for that antagonist. A more potent antagonist will have a lower IC ₅₀ value.

Most of the off-note blocking compounds disclosed herein, and in particular the compounds listed below, have an IC ₅₀ in the range of about 0.1 to about 20 micromolar when tested with the TAS2R44 bitter taste receptor: c/s-4- propylcyclohexanecarboxylic acid, c/s-4-tert-butylcyclohexanecarboxylic acid, c/s-4- propylbicyclo[2.2.2]octane-1-carboxylic acid, c/s-4-sec-butylcyclohexanecarboxylic acid, c/s-4-(4-methylpentyl)cyclohexanecarboxylic acid, c/s-4- benzylcyclohexanecarboxylic acid, and c/s-4-phenylcyclohexanecarboxylic acid

For most food applications, a low IC ₅₀ [micro molar] of about 0.05 to about 10 is desirable, however, IC ₅₀ of about 10 to about 25 are still good and above about 25 may also still acceptable depending on the application.

Various food ingredients (including ingredients naturally contained in food or additives admixed to food including flavor ingredients) provide undesirable taste notes, so-called off-notes. Particularly undesirable off-notes are the bitter off-notes, metallic off-notes, lingering, licorice-type and astringent off-notes. The term off-note refers to an unpleasant after taste that develops over time after consumption of consumables.

Other particular examples are the bitter and/or metallic and/or astringent and/or "artificial" off-notes and/or a cloyingly sweet off-note (as opposed to the "cleaner" taste of sugar) that are associated with a number of artificial sweeteners including aspartame, acesulfame K, saccharin, sucralose, and sodium cyclamate. Sometimes these off-notes of artificial sweeteners are described collectively as bitter off-notes.

Further examples of off-note providing ingredients are naturally occurring sweeteners including stevioside, swingle extract, glyccerhizin, perillartine, naringin dihydrochalcone, neohesperidine dihydrochalcone, mogroside V, rubusoside, rubus extract, and rebaudioside A

Still further examples of off-note providing ingredients include cocoa, coffee, caffeine, theobromine, diketopiperazines, vitamins, amino acids, vitamin B, casein, soy protein, ibuprofen, salicylic acid, glucoronolactone, acetaminophen, dextromethorphan, naringin, taurin, macrolide (including bioxin and erythomycin), paracetamol, acetolsalicilic acid, cimetidine, ranitidine, amoxicillin, acetominophen, cephalosporines, quassia, propylene glycol, triacetin, salts of potassium, salts of zinc, loperamide, limonin, flavonoides, isoflavones (including genistein and diadzein), polyphenol (including catechin and epicatechin), mint oil, D-menthol, hydrolysed vegetable protein, bitter peptides, preservatives (including benzoic acid, potassium sorbate, polysorbate 80, sodium and potassium lactate, sodium benzoate), citric acid, quinine, urea (contained in chewing gums), essential oils (inclluding thyme, sage, basil, mint), Maillard reaction products (including cyclic amines made from pyrrolidine/glucose, alanine/xylose, proline/sucrose or alanine/xylose, for example diketopiperazines), beer, hops, humulone, trans-isohumulone, lupulone, hulupone.

The addition of off-note blockers will block or mask the off-notes and make them less apparent or unnoticeable. Artificial sweeteners will thereby lose their bitter/metallic taste and/or their cloyingly sweet lingering sweetness and instead taste more like actual sugar (sucrose).

Aspartame is the name for aspartyl-phenylalanine-1 -methyl ester, a dipeptide. It is known under various trademark names including Equal®, and Canderel®. In the European Union, it is also known under the E number (additive code) E951.

Acesulfame potassium (AceK) is the potassium salt of 6-methyl-1 ,2,3- oxathiazine- 4(3H)-one 2,2-dioxide, an N-sulfonylamide. It is also known as Acesulfame K or AceK, or under various trademark names including Sunett® and Sweet One®. In the European Union it is also known under the E number (additive code) E950.

Saccharin is the Na salt of 1 ,2-Benzisothiazol-3(2H)-one, 1 ,1 -dioxide, an N- sulfonamide. It is also known under various trademark names including Sweet'n low®.

Sucralose is the name for 6-dichloro-1 ,6-dideoxy-β-D-fructo-furanosyl 4-chloro-4- deoxy-α-D-galactopyranoside, which is a chlorodeoxysugar. It is also known by the trade name Splenda®. In the European Union, it is also known under the E number (additive code) E955. Sucralose has an off-note (also designated "aftertaste") that is a lingering liquorice-like off-note sometimes also described as bitter.

The off-note blockers can be added to consumables to block the undesirable off- notes of ingredients present in said consumables or added to such consumables.

Flavor compositions for addition to consumables can be formed that provide the off- note blockers and an off-note providing ingredient for addition to consumables, and optionally food grade excipients. Alternatively, the off note blockers can be directly added to consumables.

In particular, the off-note blockers can be added to flavor compositions or directly to consumables to block the undesirable off-notes of off-note providing ingredients including natural and artificial sweeteners added to such consumables.

Consumables include all food products, food additives, nutraceuticals, pharmaceuticals and any product placed in the mouth inluding chewing gum, oral care products, and oral hygiene products including but not limited to, cereal products, rice products, tapioca products, sago products, baker's products, biscuit products, pastry products, bread products, confectionery products, desert products, gums, chewing gums, mouthwash, dental floss, flavored or flavor-coated straws, flavor or flavor-coated food/beverage containers, chocolates, ices, honey products, treacle products, yeast products, baking-powder, salt and spice products, savory products, mustard products, vinegar products, sauces (condiments), tobacco products, cigars, cigarettes, processed foods, cooked fruits and vegetable products, meat and meat products, jellies, jams, fruit sauces, egg products, milk and dairy products, yoghurts, cheese products, butter and butter substitute products, milk substitute products, soy products, edible oils and fat products, medicaments, beverages, carbonated beverages, alcoholic drinks, beers, soft drinks, mineral and aerated waters and other non-alcoholic drinks, fruit drinks, fruit juices, coffee, artificial coffee, tea, cocoa, including forms requiring reconstitution, food extracts, plant extracts, meat extracts, condiments, nutraceuticals, gelatins, pharmaceutical and non-pharmaceutical gums,

tablets, lozenges, drops, emulsions, elixirs, syrups and other preparations for making beverages, and combinations thereof.

For example, in consumables containing salts of potassium, the off-note blocker may be added to suppress the bitterness and the metallic off-note associated with salts of potassium.

In coffee and cocoa products, the off-note blocker may be added to suppress the bitterness associated with caffeine, theobromine, and/or diketopiperazines present in said products.

In cheese products, in particular in enzyme-modified cheese products, the off-note blocker may be added to suppress the bitterness associated with bitter peptides present in said cheese products.

In soy products, the off-note blocker may be added to suppress the bitterness and beany off-notes associated with peptides, isoflavones such as genistein and diadzein present in said products.

In HVP (hydrolysed vegetable protein) products, the off-note blocker may be added to suppress the bitterness associated with bitter peptides present in said products.

In functional ingredients used in fortified foods, the off-note blocker may be added to suppress the bitterness associated with vitamins and amino acids present in said products.

In pharmaceuticals, the off-note blocker may be added to suppress the bitterness associated with actives or bitter additives present in said products.

In consumables containing solvents, the off-note blocker may be added to suppress the bitterness associated with propylene glycol, triacetin, or ethanol present in said products.

In citrus products, the off-note blocker may be added to suppress the bitterness associated with naringin present in said products.

In neutraceuticals and herb medicines, the off-note blocker may be added to suppress the bitterness associated with actives or additives present in said products.

In consumables containing polyphenols such as catechin and epicatechin, the off- note blocker may be added to suppress the bitterness associated with these ingredients.

In consumables containing preservatives such as potassium sorbate, polysorbate 80, sodium and potassium lactate, sodium benzoate, the off-note blocker may be added to suppress the bitterness associated with said preservatives.

In consumables containing zinc and other mineral supplements, the off-note blocker may be added to suppress the bitterness and metallic off-notes associated with said these mineral supplements.

In consumables containing mint oil or menthol (e.g. D-menthol) and citric acid of above 7%, the off-note blocker may be added to suppress the bitterness associated with this combination of ingredients.

In consumables containing quinine, the off-note blocker may be added to suppress the bitterness associated with quinine.

In consumables containing artificial sweeteners (e.g. aspartame, saccharin, acesulfame K, sucralose, cyclamate), for example beverages, a off-note blocker may be added to suppress the bitterness associated with artificial sweeteners.

In chewing gums, particular dental-type chewing gums, the off-note blocker may be added to suppress the bitterness associated with urea contained in chewing gums.

In consumables containing essential oils (e.g. thyme, sage, basil, mint), the off-note blocker may be added to suppress the bitterness associated with these essential oils.

In consumables containing vegetables or herbs or their extracts, the off-note blocker may be added to suppress the bitterness associated with these ingredients.

In consumables containing Maillard reaction products (i.e. cyclic amines made from proline/sucrose or alanine/xylose, e.g. diketopiperazines), the off-note blocker may be added to suppress the bitterness associated with Maillard reaction products.

In beer and consumables containing beer or hops, the off-note blocker may be added to suppress the bitterness associated with hops.

EXAMPLES

The following examples are set forth to describe the off-note blocking compounds in further detail and to illustrate the methods of employing the off-note blocking compounds to block or otherwise mask off-notes in consumables. The examples are illustrative and should not be construed as limiting the compounds, consumables or methods in any manner.

Example 1 Sensorial evaluation in various consumables

Off-note blockers as herein described are tested by panels of 6 to 10 bitter sensitive panelists.

Panelists are asked to describe the differences in off-notes and bitter notes between the product with 0.001% (wt/wt) off-note blocker unless otherwise stated and a control without off-note blocker.

A) Aspartame/Acesulfame-K containing Diet Energy Drink

The diet energy drink contained taurin, acesulfame K, aspartame, sucralose, glucuronolacton, caffeine, B-group vitamins (Niacin, pantothenic acid, B6, B12), aroma, sucrose, glucose, colours

The sample containing the off-note blocker is found to be less bitter compared to the control.

B) Sucrose/glucose-sweetened energy drink

The diet energy drink contains taurin, glucuronolacton, caffeine, B-group vitamins (Niacin, pantothenic acid, B6, B12), aroma, sucrose, glucose, colours.

The sample containing the off-note blocker is found to have less off-notes, to be less bitter, and less astringent compared to the control.

C) Iced low-sugar coffee

The sample containing the off-note blocker is found to be less bitter, and less astringent compared to the control.

D) Commercial Vanilla Flavored Nutritional Drink

Vanilla flavored nutritional drink containing calcium caseinate, soy protein isolate, sodium caseinate, vitamins and minerals.

The sample containing the off-note blocker is found to be less chalky, to have reduced protein/vitamin induced off-notes notes, and to be less astringent compared to control.

E) Saccharin sweetened cola soft drink

The sample containing the off-note blocker is found to be less bitter and to have a reduced after taste compared to the control.

F) Loperamide containing mint-flavored pharmaceutical syrup

The syrup contained 1 mg loperamide HCI per 7.5 ml serving. The off-note blocker is used in a concentration of 0.004% (wt/wt).

The sample containing the off-note blocker is found to be less bitter with especially the lingering bitter after taste reduced.

G) Daytime cough syrup

The daytime cough syrup contains 325 mg acetaminophen, 10 mg dextromethorphan HBr, 5 mg phenylephrine HCI per 15 ml serving.

The sample containing the off-note blocker is found to be less bitter.

H) Dark chocolate

The sample containing the off-note blocker is found to be less bitter.

I) Baking Chocolate (100% Cocoa, Unsweetened)

The off-note blocker is used in a concentration of 0.002% (wt/wt).

The sample containing the off-note blocker is found to be less metallic, less bitter, especially the alkaloid/caffeine-like bitterness is reduced while the upfront, warm, woody bitterness was retained.

J) Overcooked coffee

Coffee is brewed and cooked on a burner for 3 hours. The off-note blocker is used in a concentration of 0.0005% (wt/wt).

The sample containing the off-note blocker is found to be less bitter.

K) Aspartame/Acesulfame-K sweetened plain nonfat yogurt

The yogurt contained 0.0193% (wt/wt) and acesulfame-K 0.0083% (wt/wt). The off-note blocker is used in a concentration of 0.00175 % (wt/wt).

The sample containing the off-note blocker is found to have less off-notes compared to control.

L) Aspartame/Acesulfame-K sweetened cola soft drink

The off-note blocker is used in a concentration of 0.0063% (wt/wt).

The sample containing the off-note blocker is found to have less off-notes than the control.

M) Sucralose sweetened cola soft drink

The off-note blocker is used in a concentration of 0.0035% (wt/wt).

The sample containing the off-note blocker is found to have less off-notes and be less bitter than the control.

Example 2

TAS2R44 bitter taste receptor assay for IC 50 determination

1) Generation of human TAS2R44 expression vector The full length gene of human TAS2R44 was amplified by polymerase chain reaction (PCR) using gene-specific primers that span the entire coding region as described in WO 2004/029087.

The TAS2R44 cDNA was subcloned into an expression cassette based on either of the following plasmids/expression vectors: pcDNA3.1Zeo (Invitrogen). These vectors contain within their multiple cloning sites the nucleotide sequence coding for the first

45 amino acids of the rat somatostatin receptor subtype 3 (RSS tag) to facilitate cell surface targeting of the transgene (SEQ ID #4) and the nucleotide sequence coding for the herpes simplex virus (HSV) glycoprotein D epitope (HSV epitope in aminoterminal to carboxyterminal direction, HSV tag). (SEQ ID #3) for facilitating immunocytochemical detection.

The TAS2R44 construct contains RSS tag, TAS2R44, and the HSV tag which are fused in frame to allow translation into the receptor protein and the resulting receptor cDNA.

This transfected expression vector is called pcDNA3.1Zeo-TAS2R44 (SEQ ID # 1) and allows for expression of the TAS2R44 protein (SEQ ID #2).

2) Generation of a cell line stably expressing Gα16-gustducin44 and TAS2R44 A cell line that stably expresses the human bitter taste receptor (TAS2R44) was generated by transfecting pcDNA3.1Zeo-TAS2R44 into HEK293T/Gα16-gustducin 44 cells (both formed as described in under 1) above). The host cell line HEK-293T is commercially available from the American Tissue Culture Collection (catalog #CRL- 1573).

Transfection was performed as follows:

On day 0, the HEK293T Gα16-gustducin44 cells were seeded in a 6-well plate at a density of 900,000 cells per well and grown over night in selective growth medium (DMEM with 10% (v/v) heat-inactivated fetal bovine serum, 2 mM L-glutamine, 100 units/ml penicillin, 100 μg/ml streptomycin, 200 μg/ml G418 and 200 μg/ml zeocin).

On day 1 , the medium was exchanged with 2 ml of antibiotic-free and serum-free growth medium. 10 μl Lipofectamine 2000 was dissolved in 250 μl DMEM and incubated for 5 minutes at room temperature. In parallel, 4 μg TAS2R44 vector DNA were dissolved in 250 μl DMEM. These two resulting solutions are mixed and incubated for 20 minutes at room temperature before they are added to the cells into the cell culture medium. After 4 hours, the medium is replaced with antibiotic-free, serum-containing growth medium.

The cells were incubated in humidified atmosphere (37 ⁰ C, 5% CO ₂ ).

After 24 hours, the cells were re-plated in selective growth medium and were further incubated in a humidified atmosphere (37 ⁰ C, 5% CO ₂ ).

After 2 to 4 weeks of culture (replacing medium as necessary), zeocin-resistant colonies were selected and expanded.

The selected clone was tested successfully for functional expression of TAS2R44.

3) Fluo-4 Calcium Assay

Fluo-4_AM (Invitrogen) is a fluorescent indicator of intracellular calcium dynamics (change in concentration) and allows monitoring changes in the calcium concentration, particularly an increase in response to receptor activation occurring after agonist exposure.

At day 0, the HEK293T cell line stably expressing Gα16-gustducin44 and TAS2R44 formed as described under 2) was seeded in antibiotic-free growth medium (standard DMEM with 10% (v/v) heat-inactivated fetal bovine serum, 2 mM L-glutamine standard DMEM with 10% (v/v) heat-inactivated fetal bovine serum, 2 mM L- glutamine, 100 units/ml penicillin, and 100 μg/ml streptomycin) into black wall/clear bottom 96-well plates, coated with poly(ethylenimine) (0.005% v/v) at a concentration of 15,000 cells per well and incubated for 48 hours in humidified atmosphere (37 ⁰ C, 5% CO ₂ ).

At the time of the assay, the growth medium was discarded and the cells were further incubated in a humidified atmosphere (37 ⁰ C, 5% CO ₂ ) for 1 hour with 50 μl of loading buffer consisting of 1.5 μM Fluo-4 AM and 2.5 μM probenicid (Sigma-Aldrich) in DMEM.

Afterwards, the 96-well plate was washed 5 times with 200 μl of assay buffer (130 mM NaCI, 5 mM KCI, 10 mM HEPES, 2 mM CaCI ₂ , and 5 mM dextrose, pH 7.4) per well, using an automated plate washer (BioTek). The plate was further incubated for 30 minutes at room temperature in the dark to allow for complete de-esterification of the Fluo-4. Afterwards the plate was washed 5 times with 200 μl of assay buffer per well, and reconstituted with 180 μl of assay buffer per well.

For assay reading, the plate was placed in a Fluorometric Imaging Plate Reader (FLIPR) (FLIPR-TETRA™, Molecular Devices), and receptor activation was initiated by addition of 20 μl of a tenfold concentrated agonist stock solution (to give the desired agonist end concentration when added to the 180 microliter assay buffer volume), which was prepared in assay buffer.

Fluorescence was continuously monitored for 20 seconds to give a signal baseline (averaged to give F ₀ ) prior to agonist addition and for 120 seconds after agonist addition. The change in signal divided by F ₀ gives δF/F ₀ indicated in the table, with δF being the maximum signal occurring within the 120 seconds minus the minimum signal (occurring within the 120 seconds after agonist addition.

All data was collected from at least two independent experiments each carried out in triplicate.

A concentration-response analysis was performed and IC ₅₀ values were calculated by nonlinear regression using the function f(x) = (a-d)/(1 +(x/C) ^nh )+ d; with a = minimum signal, d = maximum signal, nh = hill coefficient, C = IC ₅₀ ., and x= antagonist concentration. IC ₅₀ is the molar concentration of an antagonist which produces 50% of the maximum possible effective/inhibitory response for that antagonist. A more potent antagonist will have a lower IC ₅₀ value.

The obtained calcium signals were corrected for the response of cells expressing only the G Protein α subunit (Gα16-gustducin44) and normalized to the fluorescence of cells prior to the stimulus using δF/F0 (Fmax-Fmin/F0).

Example 3

Determination of IC50 of off-note blockers

The following off-note blockers were tested: c/s-4-propylcyclohexanecarboxylic acid, cis-4-tert-butylcyclohexanecarboxylic acid.

The method was performed as described in example 2, using saccharin as agonist.

The cells are exposed to a constant concentration of saccharin (0.5 mM) and to a set of different concentrations of the off-note blocker. A fluo-4 calcium assay was performed as described above in example 2 and gave an IC ₅₀ [micro molar] within the range of 0.05 to 25.

This means that the off-note blockers inhibited the response of the TAS2R44 bitter taste receptor and will be useful to block bitter taste.

Example 4 Determination of IC50 for off-note blockers

The method was performed as described in example 3, exchanging saccharin for Acesulfame K (0.8 mM) as agonist. An IC ₅₀ within the same range was determined. This means that the off-note blockers inhibited the response of the TAS2R44 bitter taste receptor and will be useful to block bitter taste.

While the compounds, consumable and methods have been described above in connection with illustrative embodiments, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments for performing the same function without deviating therefrom. Further, all embodiments disclosed are not necessarily in the alternative, as various embodiments of the invention may be combined to provide the desired characteristics. Variations can be made by one having ordinary skill in the art without departing from the spirit and scope of the invention. Therefore, the compounds, consumables and methods should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the attached claims.