WO2012072631A1 - Process for producing flavours - Google Patents

Abstract

Disclosed is a process for the preparation of flavor compositions with unique aroma profiles obtained by carrying out a reaction of 3,4,5-trihydroxypentan-2-one with a sulphur source.

Description

PROCESS FOR PRODUCING FLAVOURS

This disclosure refers to a process for the preparation of fla or compositions and consumable products with unique flavor profiles obtained by carrying out a reaction of 3,4,5-trihydroxypentan-2-one with a sulphur source.

There is an ongoing demand in industry for compositions having unique flavoring properties and which are suitable for use in a variety of products. Various flavoring agents are known which are intended lo produce lite flavor with intense sulphury, roasty, eggy characteristics. In general these compounds give only an approximated imitation of the natural flavor of roasted meat.

Generally known flavoring agents possessing a meaty, sulphury roasted flavors are mainly those that contain a sulphur atom, such as, for example, 2-methyl-3-furanthiol, 2-methyl-4,5-dihydrofuran-3-thiol, thiolactic acid, 2-methylthiophen-3-ol, and 2- methyltetrahydro-thiophen-3(2H)-one. Further compounds which have been reported to possess meaty olfactory characteristics are, for example, methy!thiopropanal, 5-methyl- 4-mercaptotetrahydrofuran-3-one, bls(2-methyl-3-furyl)disulphlde, and 1-[(2-methyl-3- furyl)thio]ethanethiol.

It has now been found that flavour compositions comprising a high amount of sulphur- containing compounds possessing unique flavor profiles can be obtained by carrying out a heat-induced reaction of 3,4,5-trihydroxypentan-2-one with a sulphur source in a liquid phase. The flavor compositions obtained by this process were found to have remarkable flavor characteristics and are particularly useful for imparting pleasant flavor notes to foodstuffs and beverages.

Thus there is provided in a first aspect, a process for preparing a flavoring composition comprising

a) admixing 3,4,5-trihydroxypentan-2-one with a liquid selected from the group consisting of water, oil, alcohol {e.g. methanol or ethanol), and mixtures thereof, and a compound containing sulphur;

b) adjusting the pH to 2-10, e.g. in a range of about 3 to about 8;

c) heating the admixture to a treatment temperature to 50° C or higher, e.g. in a range from about 50 - about 180°C, such as about 80 - 140°C. The flavoring composition thus prepared may then optionally be cooled down to room temperature and then either be used as crude product or optionally further processed, e.g. by phase separation, or extraction, e.g. using solvents commonly used in the flavor industry, e.g. 1 ,2,3-triacetoxypropane (more generally known as triacetin) ortriethyl citrate. In a final step the products may be spray dried or encapsulated using techniques known to the skilled person.

Suitable oils are of any kind which are acceptable in the food industry, such as vegetable oils, e.g. sunflower oil, corn oil, soybean oil, palm oil, a medium chain triglyceride ( CT oil) oil, or mixtures thereof.

3,4,5-Trihydroxypentan-2-one, which exists naturally in an equilibrium with its cyclic form, comprises two chiral centers and as such may exist as two diastereomers (la known as 1-deoxy-D-xylulose (DXX); lb known as 1 -deoxy-D-ribulose) as depicted below, each of which may exist as enantiomer pairs.

la !b

deoxyxylulose deoxyribulose

It is an aspect of certain embodiments to use 3,4,5-trihydroxypentan-2-one as isomeric mixture, as racemic mixture (3S/4R and 3R/4S) or, in a further aspect, to use 1-deoxy- D-xylulose (DXX; la) in its optically pure form.

DXX is commercially available (Carbosynth Limited, or Echelon Biosciences Inc.). It can be produced chemically following the general procedure as described, e.g. by Meyer O., J.F.Hoeffler, C.Grosdemange-Billiard, and . Rohmer (Tetrahedron 2004 60:12153- 12162). Optionally DXX may be produced according to the following procedure, as depicted in Scheme 1 below, by treating the aldehyde 1 with the ylide 2 in

dichloromethane providing the olefin intermediate 3 as described by Giner et al.

(Tetrahedron Lett., 1998, pp. 2479-2482). Dihydroxylation of 3 using catalytic osmium tetroxide and W-methylmorpholine-A/-oxide (NMO) in a 50:50 mixture of t-butanol and water provides the racemic diol 4. Finally, hydrogenoiysis of the benzyl protecting group provides the desired racemic deoxyxylulose (DXX) as a mixture of its linear (5) and cyclic (6) forms. Scheme 1 : Racemic Synthesis of deoxyxylulose

deoxyxylulose (DXX)

Optically pure DXX can be obtained by treatment of intermediate 3 with catalytic osmium tetroxide, 4-methylmorpholine-A -oxide NMO and AD-mix β (e.g. offered by

Sigma-Aldrich), followed by hydrogenoiysis leading to 1-deoxy-D-xylulose with an ee of 98%, as depicted in Scheme 2. Instead of using methanol as solvent, as reported by Giner et al., one may use ethyl acetate, thus eliminating the problem of solvolysis of 6. In addition, high pressure (60 psi = 4.137 bar) of hydrogen along with Pearlman's catalyst (Pd(OH)₂) led to a more efficient hydrogenoiysis relative to the reported Pd/C. Scheme 2: Asymmetric route to 1 -deoxy-D-xylulose

P

DXX from a microbial or botanical source may also be used. Non-phosphorylated DXX has been found, for example, in the broth of a Streptomyces species (Rohmer, M. 2007. Pure Applied Chemistry. 79(4):739-751 ). It has also been made enzymatically with the enzyme 1-deoxyxyluIose synthase. Both the phosphorylated and non-phosphorylated form may be produced depending upon the starting material (if the glyceraldehyde is phosphorylated) (Brammer and Meyers. 2009. Organic Letters. 11 (20):4748-4751 ).

By a "compound containing sulphur" is meant both, organic or inorganic chemical compounds. The sulphur containing compounds may be selected from the group consisting of amino acids, such as cysteine, cystine, methionine, glutathione, salts thereof (e.g. cysteine hydrochloride), and mixtures thereof; and other sulphur containing source, for example, ammonium sulphide, thiamine hydrochloride, or hydrogen sulphide. Instead of using a single amino acid, autolysed yeast extracts, hydrolysed vegetable proteins, or hydrolyzed dairy proteins such as enzyme modified cheeses could be used as sulphur containing source. Yeast extracts are commonly available from DSM Food Specialties, Bio-springer and Kerry Bio-science.

The molar ratio between 3,4,5-trihydroxypentan-2-one and the sulphur containing compounds may be between about 3:1 to about 1 :10, the ratio being calculated on the estimated sulphur content present. However, even much higher amounts of sulphur containing compounds may be added, in particular when hydrogen sulphide is used, which might get partly lost due to the handling and volatility of the material. In a further aspect one may add organic solvents such as triacetin (1 ,2,3- triacetoxypropane) ortriethylcitrate to the mixture before adjusting the pH. One may also add carbohydrates, in particular monosaccharides and oligosaccharides (e.g. di- and tri-saccharides) or mixtures thereof. The carbohydrates may be added in its pure form or in form of fruit juices or other food sources containing them.

The pH range of the mixture may be adjusted with acid or base solutions, e.g. sodium hydroxide solution, sodium bicarbonate, sodium citrate, or sodium phosphate, to about 2 - 10, optionally pH 3 - 8. Controlling the pH during the reaction may maintain conditions to favour certain desired aroma chemicals.

Particularly treatment temperatures are about 100 - 140° C (e.g. up to 130° C) and the reaction mixture may be maintained at these temperatures for about 30 minutes to 48 hours, optionally 1 to 16 hours. However even higher temperatures might be suitable, in particular when a continuous reactor is used for the process instead of a batch reactor. The appropriate time and temperature conditions may easily be evaluated by a person skilled in the art.

In another aspect of certain embodiments, one may further add sulphur free amino acids, such as proline, alanine, phenylalanine, glutamic acid, lysine, leucine, ornithine and arginine, and salts thereof, or mixtures thereof. Addition of non-sulphur containing amino acids may lead to products with distinctly different flavor profiles.

The flavoring composition obtainable through the process as hereinabove described may be used alone or in combination with a base material. As used herein, the "base material" includes all known flavor ingredients that will modify, enhance or create flavor to a food product or beverage to be flavored.

In addition to additional flavor ingredients the flavor composition may contain other ingredients useful as excipients such as carriers, diluents or bulking agents orthe like, the purpose of which is to aid in the processing of a flavor composition or a product containing same, or otherwise impart a desirable property on the composition or product. Examples of such ingredients may include carbohydrates and carbohydrate polymers, e.g. polysaccharides, cyclodextrines, starches, starch hydrolysates, modified starches, modified celluloses, gums such as gum arabic, ghatti gum, traganth, karaya, carrageenan, guar, locust bean, alginates, pectin, inulin, or anthan.

The flavor composition obtained through the process as hereinabove described may be used to impart a meat-like aroma to consumable products by incorporation of said composition into the consumable product.

In a further aspect there is provided an aroma product comprising flavor compositions, obtainable through the process comprising

a) admixing 3,4,5-trihydroxypentan-2-one with a liquid selected from the group consisting of water, oil, and alcohol (e.g. methanol o ethanol), and mixtures thereof, and a compound containing sulphur;

b) adjusting the pH to 2-10, e.g. in a range of about 3 to about 8;

c) heating the admixture to a treatment temperature of 50° C or higher, e.g. in a range from about 50 - about 180°C, such as about 80 - 140°C;

d) optionally cooling down to room temperature.

The required concentration of the flavor composition obtained through the process described above may vary over a wide range, depending on the desired taste and aroma effects, but as a general guide, they are employed in concentrations of from 1 to 2000 ppm by weight of foodstuff in consumable form. Good results are obtained by using from 5 to 1000 ppm, e.g. about 10 - about 200 ppm in the final product. However, these values are given only by way of example, since the experienced flavorist may also achieve effects with tower or higher concentrations.

Instead of adding flavor compositions obtained through the process as herein above described to a product, one may add the admixture of 3,4,5-trihydroxypentan-2-one and the sulphur containing compound in form of an emulsion or suspension to a

consumable product first and the heating step (c) may take place when the consumable product is heated and thus generating the flavoring composition during the normal cooking process of the consumable product.

Thus there is provided in a further aspect a process for preparing a flavouring composition comprising a) admixing 3,4,5-trihydroxypentan-2-one with a liquid selected from the group consisting of water, oil, alcohol (e.g. methanol or ethanol), and mixtures thereof, and a compound containing sulphur;

b) admixing the mixture of step a) to a consumable product; and

c) heating the admixture to a treatment temperature of 50° C or higher, e.g. in a range from about 50 - about 180°C, such as about 80 - 140°C.

The thus obtained consumable product may then either be consumed in its heated form or cooled down either to room temperature or might get frozen.

The flavor composition obtained through the process as hereinabove described may be used to impart unique aroma to consumable products. By "consumable product" is meant any product, whether natural or manufactured, intended for oral intake, either for ingestion, or for oral use only followed by spitting out. In general, this includes any foodstuff, beverage, confectionery, medicinal or cosmetic oral care composition, pharmaceutical and the like.

Typical non-limiting examples of consumable products include:

Animal protein from any desired animal source, for example, beef, pork, poultry, lamb, kangaroo, shell fish, crustaceans, fish, and combinations thereof;

Vegetable protein from any vegetable source, for example, lupin protein, wheat protein, soy protein, and combinations thereof;

Fruit-derived products, for example, those derived from tomatoes, apples, avocado, pears, peaches, cherries, apricots, plums, grapes, oranges, grapefruit, lemons, limes, cranberries, raspberries, blueberries, watermelon, cantelope, muskmelon, honeydew melon, strawberries, banana, and combinations thereof;

Vegetable-derived products, for example, those derived from peas, carrots, corn, potatoes, beans, cabbage, tomatoes, celery, broccoli, cauliflower, and leeks nuts and nut products, processed foods, vegetable products, and food compositions thereof; Cereals and cereal-derived products, for example, farinaceous matter including grains such as, rice, com, milo, sorghum, barley, and wheat, and the like, and products derived therefrom; tapioca products, sago products, and food compositions thereof; pasta (for example, ground pasta), breading, and food compositions, dough derived from any of a variety of dough sources, include wheat dough, corn dough, potato dough, soybean dough, rice dough, and combinations thereof, baker's products, biscuit products, pastry products, bread products, baking-powder, and food compositions thereof;

Confectionery and dessert products, for example, hard and soft candies, chocolate, ice creams, chewing gums, jellies and jams;

Milk and dairy products, for example, yoghurts, cheese products, butter and butter substitute products, milk and milk substitute products, milk powders, soy products, edible oils and fat products, and food compositions thereof;

Beverages, for example, carbonated and non-carbonated beverages, alcoholic drinks such as beers, wines and spirits, non-alcoholic drinks such as soft drinks and sodas, including forms requiring reconstitution including, without limitation, beverage powder, milk-based beverage powder, sugar-free beverage powder, beverage syrup, beverage concentrate, coffee and tea, and food extracts;

Medicinal products, whether for ingestion or oral use only, for example,

pharmaceuticals and nutraceuticals, syrups, pastes, aerosols, emulsions, tablets and lozenges, and gums;

Oral care compositions, for example, mouthwashes, toothpastes and tooth gels, malodor counteractants and breath fresheners in solid, liquid and aerosol form;

Food additives and ingredients, for example, yeast products, salt and spice products, snackfoods, savoury products, mustard products, vinegar products, seasonings, plant extracts, meat extracts, condiments, and gelatins;

Prepared food products, including such products preserved by being, for example, dried, powdered, baked, refrigerated, frozen, fermented, pasteurized, sterilized, brined, for example, sauces (condiments), gravies, soups, prepared meat and vegetable products, pizzas, pre-cooked and oven-ready meals and microwave meals.

In one particular embodiment the consumable products wherein flavor compositions obtained through the process as herein above described may find use are minced meat, bouillon, chicken fillets, chicken nuggets, nutty flavors, chocolate, milk product, such as cheese, yogurt and the like.

In a further embodiment the flavor composition may be added to coffee products, such as instant coffee and ready to drink coffee.

The compositions and methods are now further described with reference to the following non-limiting examples. These examples are for the purpose of illustration only and it is understood that variations and modifications can be made by one skilled in the art without departing from the scope of the claims. It should be understood that the embodiments described are not only in the alternative, but can be combined.

Example 1. Reaction of 1-deoxy-D-xylulose with cysteine

In a 300-ml teaclor vessel, cysteine hydrochloride salt (9.7 mMol) was dissolved in deionized water (65 ml). The solution was adjusted to pH 6-7 with either sodium hydroxide (10% in de-ionized water) or sodium bicarbonate (10% in deionized water).

1-deoxy-D-xyluiose (9.7 mMol) and 5 ml of medium chain triglyceride oil were added.

The vessel was closed and heated at 100°C for 3 hours. After cooling to room temperature, the mixture was centrifuged at 3,600 RPM for 20-25 minutes. The layers were separated and the oily top layer contained the meaty aroma.

Example 2. Reaction of 1-deoxy-D-xylulose with hydrogen sulphide

In a 300-ml reactor vessel, 1-deoxy-D-xylulose (7.5 mmol) was added to methanol- anhydrous (100 ml). While the reactor was cooled in a bath of dry ice and isopropyl alcohol, hydrogen sulphide (0.6 mol) was bubbled in the reaction mixture. The vessel was closed and heated at 110^DC for 24 hours. After cooling to room temperature, the vessel valve was opened to vent the excess of hydrogen sulphide. De-ionized water (75 ml) was added and the cloudy resulting mixture was extracted with hexane. The layers were separated. The bottom methanolic aqueous layer was extracted with TBE. The analyses of both layers revealed the formation of the following sulphur containing compounds, among other: 2-methylfuran-3-thiol; 2,5-dimethyIfuran-3-thiol; 2-methyl-5- (methylthio)furan.

Example 3. Reaction of 1-deoxy-D-xylulose with ammonium sulphide

In a 25 ml microwave vial, DXX was added to deionized water at a final concentration of 90 mM, admixed with 340 mM ammonium sulphide. The reaction was carried out in an Emrys Optimizer (Biotage AB, Sweden) at a pH of 8.0 at 140°C for 30 minutes. The vessel were removed from the device and allowed to cool overnight at room

temperature. Aroma descriptors of the reacted product when tasted at 20 ppm in water include: chicken fat, roasted chargrilled, burnt coffee, and onion fried. Example 4: Comparison of DXX with other carbohydrates

Following the general procedure described in Example 3, cysteine was admixed with a carbohydrate in a mol ratio of approximately 2:1. The pH of the reaction mixture was adjusted to pH 3.1 prior to heating at 140°C for 30 minutes in a pressure reactor. The volatiles of the mixture were analyzed by GC- S, the results are listed in Table 1 below.

Table 1 : Sulphur containing mixtures

Compound A = 2-methyl-3~furanthiol

Compound B = 2-methyl-4,5-dihydrofuran-3-thiol

Compound C = 2-methyltetrahydrothiophen-3(2H)-one The mixture obtained by reacting DXX (Reaction E) with cysteine produced at least approximately four times the sulphur containing volatile compounds as compared to the other carbohydrates (Comparison Reaction A - D).

Example 5: Sensory evaluation

A group of 6 trained panelists evaluated an aqueous solution comprising 50 ppm of a composition obtained starting from a mixture comprising Cysteine and of Xylose (Reaction A), Ribose (Reaction B), Rhamnose (Reaction C), Glucose (Reaction D) and DXX (Reaction E) respectively (acid :sugar in a mol ratio of approximately 2:1 ). The pH of the reaction mixture was adjusted to pH 3.1 prior to heating at 40"C for 30 minutes in a pressure reactor. Aroma Product Taste description

Xylose (Reaction A) Roasted, popcorn, woody, beef

Ribose (Reaction B) meaty, livery, dark roast, charcoal

Rhamnose (Reaction C) weak, seared steak, metallic

Glucose (Reaction D) weak, slightly bitter

DXX (Reaction E) meaty, livery, eggy, nice crusty, chicken, dark meat

As can be seen from the table above the reaction product obtained from DXX compared to the reaction product obtained by using reducing sugars such as Xylose, Ribose, Rhamnose or Glucose is much more desirable.

Example 6: Chicken Bouillon

Control Test

Maltodextrin 352 g 351.25 g

Sodium chloride 320 g 320 g

Sugar 150 g 150 g

Yeast Extract powder 85 g 85 g

Chicken Broth powder, IDF 75 g 75 g

Onion Powder 20 g 20 g

Celery powder 8 g 8 g

Example 5 Reaction E (liquid) o g 0.75 g

The bouillon comprising a flavor com position obtained by the process of the present process has more chicken flavor with more roasted chicken-like background with more fullness and lingering chicken flavor.

Example 7: Beef soup

To Swanson^® beef broth (Sample 7A) 0.025 weight % of material generated in according to Example 3 above (Sample 7B).

Both samples were heated to 50°F (65.5°C) and evaluated by a group of 9 trained panelists, which have been asked to describe the aroma of each sample. They described Sample 7B to be stronger, more onion-like, roasted, more meat flavor, and a stronger overall flavor impression, more beef aroma. Example 8: Ground Beef Patties

Sample 8A Sample 8B

% by weight % by weight

Ground beef 99.5 99.4

(85% lean meat/15 % fat)

NaCI 0.5 0.5

Reaction product of Example 3 0.1

The ingredients were mixed until well blended. From the mixture 3 oz (about 85 gram) patties were formed and cooked on flat top griddle at about 190°C until an internal temperature of about 68°C. The patties were allowed to cool down slightly and then cut into pieces for evaluation. Sample 8B was preferred and described to be more salty, more rounded meaty, beefy, grilled, seared, and savory compared to Sample 8a.

Claims

Claims

1. A process com rising

a) admixing 3,4,5-trihydroxypentan-2-one with a liquid selected from the group consisting of water, oil, alcohol, and mixtures thereof, and a compound containing sulphur;

b) adjusting the pH to 2-10; and

c) heating the admixture to a treatment temperature of 50°C or higher.

2. A process according to claim 1 wherein the admixture is heated for at least 30

minutes.

3. A process according to claim 1 wherein the admixture is heated for up to 48 hours.

4. A process according to claim 1 admixing (3S,4R)-3,4,5-trihydroxypentan-2-one

(=DXX) with the compound containing sulphur.

5. A process according to claim 1 wherein 3,4,5-trihydroxypentan-2-one is obtained from a microbial source.

6. A process according to any of the proceeding claims wherein the compound

containing sulphur is selected from the group consisting of amino acids and salts thereof, ammonium sulphide, thiamine hydrochloride, and hydrogen sulphide, autolysed yeast extracts, hydrolyzed vegetable proteins, and hydrolyzed dairy proteins, and mixtures thereof.

7. A process according to claim 1 further admixing to the mixture of step a) compound comprising nitrogen.

8. A process according to claim 7 wherein the nitrogen compound is selected from the group consisting of cysteine, cystine, methionine, glutathione, proline, leucine, ornithine, arginine, salts thereof, and mixtures thereof.

9. A process according to claim 1 wherein the admixture resulting from step b) is added to a consumable product and the heating step c) takes place during the cooking process of the consumable product.

10. A product comprising a flavor composition obtainable through the process as defined in any one of the proceeding claims.

11. A product according to claim 10 wherein the product is a foodstuff.

12. A product according to claim 11 wherein the foodstuff comprises 1 to 2000 ppm of the flavor composition based on the weight of the foodstuff in consumable form.

13. A product according to claim 11 wherein the foodstuff is selected from the list

consisting of meat products, coffee products, and milk products.

14. A method of imparting a meat-like aroma comprising adding a flavor com position obtained through the process as defined in claim 1 to foodstuff or beverages.