FR2997268A1 - Extract of plant origin, useful as an additive for a food product that is a dairy product such as yoghurt, fermented milks and infant milk, comprises polyphenols that are randomly esterified on hydroxyl group with a fatty acid - Google Patents

Abstract

Extract of plant origin comprises more than 80%, preferably 90% of polyphenols that are randomly esterified on at least one hydroxyl group with a fatty acid. Independent claims are included for: (1) preparing the extract of plant origin comprising (i) mixing a powder of vegetable with potassium tert-butoxide in the presence of a solvent, and (ii) adding one or more chloride(s) of fatty acid(s), where a molar ratio of vegetable powder/fatty acid is 1/1-1/3, preferably 1/1.5-1/2; and (2) masking the bitterness of extract of plant origin comprising the steps as per above se. ACTIVITY : Cytostatic; Cardiovascular-Gen. MECHANISM OF ACTION : None given.

Description

FOOD ADDITIVE BASED ON ESTERIFIED POLYPHENOLS The invention relates to a food additive based on esterified polyphenols. Polyphenols are powerful antioxidants. They are naturally present in food, some fruits but also some leaves like tea. The tea leaves contain appreciable amounts. Polyphenols represent 36% of the dry matter of green teas. Among these are flavonoids present in green tea such as the following catechins: - epigallocatechin-3-gallate (EGCG) - epigallocatechin (EGC), - epicatechin-3-gallate (ECG), - epicatechin (EC). Regular consumption of tea may provide protection against several types of cancer and reduce the risk of cardiovascular disease or other types of diseases through the activity of these compounds. However, they are responsible for the bitterness of these products. It is therefore interesting to modify these polyphenols to mask the bitterness so that they can be incorporated into food products.

FR 0511354 discloses a process for the enzymatic esterification of catechins with a fatty acid or a functional fatty acid derivative. The enzyme used is Candida antarctica lipase. Esterification is carried out selectively on the secondary alcohol of catechins. Gallic acid is therefore removed from gallate catechins. EP 0 698 595 describes a process for the preparation of polyphenols stabilized by esterification, these products being intended for the pharmaceutical, cosmetic and food industry. The process comprises esterifying polyphenols with a long chain hydrocarbon fatty acid chloride in the presence of triethylamine and an organic base other than pyridine. EP 1 849 779 discloses a process for the chemical synthesis of catechin ester and an enzymatic process for the esterification of pure catechin. These methods make it possible to obtain pure catechin esters. They are not prepared from a plant extract.

The inventors have now surprisingly and unexpectedly shown that the random esterification of the hydroxyl groups of the catechins of a green tea extract with a saturated fatty acid makes it possible to mask the bitterness thereof. Therefore, a first subject of the invention relates to an extract of plant origin of which more than 80%, preferably 90%, particularly preferably 95%, polyphenols are randomly esterified on at least one hydroxyl group with a fatty acid. Advantageously, said polyphenols are esterified on one, two or three hydroxyl groups with a fatty acid. They are mono-, di- or tri-esters of polyphenols. Thus, the bitterness is masked while limiting the load in fatty acid. Said extract may be any plant extract known to those skilled in the art having a large amount of polyphenols, in particular bitter polyphenols. Among these, suitable extracts include olive leaf extracts comprising catechins and oleuropeins, pomelo extracts comprising naringin, vine or cocoa extracts comprising procyanidins. Advantageously, said extract is a tea extract, in particular green tea, since the tea naturally comprises a high concentration of polyphenols. According to this embodiment, said polyphenols are in large majority, preferably more than 90% represented by catechins. These include epicatechin, epicatechin gallate, epigallocatechin gallate, epigallocatechin, gallocatechin gallate. The catechins may be esterified to 3-O-decanoyl or to another hydroxyl group. The process of the invention makes it possible to esterify catechins carrying a 3-O-decanoyl gallate group on a hydroxyl group instead of transesterifying the fatty acid on the 3-O-decanoyl group. Thus, the extract according to the invention may comprise catechin gallate esters. Advantageously, said esterified polyphenols of the extract according to the invention are esterified with one or more fatty acids comprising 8 to 18 carbon atoms, preferentially 10 to 16. Advantageously, said polyphenols are esterified with one or more fatty acids chosen from palmitic acid, lauric acid or myristic acid.

Esterification polyphenols extract of the invention can hide its bitterness and thus use it as a food additive. Another object of the invention is therefore an extract of the invention as a food additive.

Another subject of the invention relates to a process for the preparation of an extract of vegetable origin of which more than 80%, preferably 90%, particularly preferably 95%, polyphenols are esterified randomly on at least one group hydroxyl with a fatty acid, comprising the following successive steps: mixing a vegetable powder with potassium tert-butoxide in the presence of a solvent, (ii) adding one or more acid chloride (s) ( s) fat, the vegetable powder / fatty acid molar ratio being between 1/1 and 1/3, preferably between 1 / 1.5 and 1/2. Preferably, the solvent used in step (i) is acetone.

The ratio by weight potassium tert-butoxide / vegetable powder is between 0.2 and 0.5, preferably it is 0.3. Preferentially, step (i) takes place between 30 and 45 ° C. for less than one hour, preferably for 30 minutes. Preferably, one or two fatty acid chlorides are used.

Preferentially, fatty acid chlorides of 8 to 18 carbon atoms, more preferably 10 to 16 carbon atoms, are used. Saturated fatty acids are preferred. Preferably, the fatty acid chloride (s) are first diluted in a solvent, preferably acetone.

Step (ii) lasts between 2h and 3h, preferably 3h. It is preferably carried out at 30 to 50 ° C, particularly preferably at 45 ° C. Step (ii) may advantageously be followed by a washing step (iii), preferably in distilled water. Step (iii) may advantageously be followed by a filtration step (iv), preferably on a 251.1m filter and, preferably, several times. Step (iv) may advantageously be followed by a step (v) of drying the product.

Optionally the product is crushed and sieved (Step (vi)). The method of the invention allows a random esterification on the various OH sites because a chemical catalyst is used and not an enzyme, so there is no regioselectivity. The number of ester bonds remains low: more than 2/3 of the catechin esters have only 1, 2 or 3 ester bonds per polyphenol. The starting material is preferably a green tea extract concentrated in polyphenols (> 90%), mainly the following four catechins: - epigallocatechin gallate (45.18%) - epicatechin gallate (24.74%) - epigallocatechin (18.74 %) - gallocatechin gallate (11.34%) OH Epigallocatechin Gallate (EGCG) Epicatechin Gallate (ECG) Another object of the invention relates to an extract capable of be obtained by the process according to the invention. Another subject of the invention relates to a food additive comprising an extract according to the invention.

Another object of the invention relates to a food product additive with a food additive according to the invention. Advantageously, this food product is chosen from the group consisting of dairy products, fermented dairy products, including yogurts, fermented milks, infant milks, vegetable juices, beverages and their mixtures including fruit juices and / or of vegetables, fruit compotes. Dairy products and fermented dairy products are preferred. By dairy product is meant according to the present invention, in addition to milk, products derived from milk, such as cream, ice cream, butter, cheese, yogurt; secondary products, such as whey, casein and various prepared foods containing milk or milk constituents as the main ingredient. Another object of the invention relates to a process for masking the bitterness of a plant extract comprising the random esterification of the polyphenols of said extract with one or more fatty acids. The following examples illustrate the invention without limiting its scope. Compounds Molar weight g / mol Lauroyl chloride 219 Myristyl chloride 247 Palmitoyl chloride 275 Green tea powder 426 EXAMPLE 1: Esterification of tea catechins with C16: 0 Ratio molar green tea powder / fatty acids = 2/3 21 5 g of green tea powder (> 95% polyphenols and> 75% catechins) are mixed with 150 ml of acetone and 8 g of potassium tert-butoxide at 45 ° C. for 30 minutes with medium stirring. 20.6 g of palmitoyl chloride, previously diluted in 50 ml of acetone, are then added. The whole is mixed and heated for 3 h at 45 ° C.

The reaction is stopped by adding to the reaction medium 500 ml of cold distilled water with gentle stirring for 1 h. After this washing, the medium is filtered on a 25 μm filter. The operation is repeated 3 times in order to remove the acetone, the tert-butoxide, the potassium chloride formed during the reaction and the water.

The product thus recovered is dried 24 hours under vacuum at a gentle temperature (30 ° C.) in order to remove water residues. A fine light brown powder is obtained without bitterness. Depending on the desired particle size, the product can be crushed and sieved.

EXAMPLE 2: Esterification of tea catechins with C16: 0 Ratio molar green tea powder / fatty acids = 1/1 21.5 g of green tea powder (> 95% polyphenols and> 75% catechins) are mixed with 150 ml of acetone and 8 g of potassium tert-butoxide at 45 ° C for 30 min with medium stirring.

13.75 g of palmitoyl chloride, previously diluted in 50 ml of acetone, are then added. The whole is mixed and heated for 3 h at 45 ° C. The reaction is stopped by adding to the reaction medium 500 ml of cold distilled water with gentle stirring for 1 h. Following this washing, the medium is filtered on a 25 μm filter. The operation is repeated 3 times to remove acetone, tert-butoxide, potassium chloride formed during the reaction and water. The product thus recovered is dried 24 hours under vacuum at a gentle temperature (30 ° C.) in order to remove water residues. A very light, light brown powder is obtained without bitterness.

Depending on the desired particle size, the product can be crushed and sieved. Number of ester bonds% Non-esterified catechins 3.1 Mono-ester 8.5 Di-ester 27.7 Tri-ester 30.8 Tetra-ester and more 29.930 Analysis carried out by exclusion HPLC with 4 columns PL-GEL 30 cm serial. Measurement by refractometry. Distribution of Free Forms and Esters for 100 g of Tea Palmitate: Free Fatty Acids: 17g / 100g Free Catechins: 3.1g / 100g Catechins Esters: 79.9g / 100g EXAMPLE 3: Esterification of Tea Catechins with C12 : 0 and C16: 0 Ratio tea / fatty acid = 2/3 with 50/50 mixture of fatty acids. 21.5 g of green tea powder (> 95% polyphenols and> 75% catechins) is mixed with 150 ml of acetone and 8 g of potassium tert-butoxide at 45 ° C. for 30 min with medium stirring. 8.1 g of lauroyl chloride and 10.3 g of palmitoyl chloride, previously diluted in 50 ml of acetone, are then added.

The whole is mixed and heated for 3 h at 45 ° C. The reaction is stopped by adding to the reaction medium 500 ml of cold distilled water with gentle stirring for 1 h. Following this washing, the medium is filtered on a 25um filter. The operation is repeated 3 times to remove acetone, tert-butoxide, potassium chloride formed during the reaction and water.

The product thus recovered is dried 24 hours under vacuum at a gentle temperature (30 ° C.) in order to remove water residues. A coarser powder is obtained, without bitterness. Depending on the desired particle size, the product can be crushed and sieved.

EXAMPLE 4: Esterification of tea catechins with C14: 0 Ratio molar green tea powder / fatty acids = 1/2 21.5 g of green tea powder (> 95% polyphenols and> 75% catechins) are mixed with 150 ml of acetone and 8 g of potassium tert-butoxide at 45 ° C for 30 min with medium stirring.

24.9 g of myristyl chloride, previously diluted in 50 ml of acetone, are then added.

The whole is mixed and heated for 3h at 45 ° C. The reaction is stopped by adding to the reaction medium 500 ml of cold distilled water with gentle stirring for 1 h. After this washing, the medium is filtered on a 251.1m filter. The operation is repeated 3 times to remove acetone, tert-butoxide, potassium chloride formed during the reaction and water. The product thus recovered is dried 24 hours under vacuum at a gentle temperature (30 ° C.) in order to remove water residues. A dark brown powder with coarse particles without bitterness is obtained. Depending on the desired particle size, the product can be crushed and sieved.

EXAMPLE 5: Tasting Panel Nine people participate in this panel. The products tested are as follows: Product 1: Green tea powder Product 2: Green tea powder esterified with palmitic acid obtained in Example 1 Test results Product 1: Bitterness noted 8/10 Product 2: Bitterness noted 1 / 10 Very convincing results of bitterness masking for 100% of the tasting panel.

Claims (14)

REVENDICATIONS1. Extract of plant origin of which more than 80%, preferably 90%, polyphenols are esterified randomly on at least one hydroxyl group with a fatty acid. 2. Extract according to claim 1, said esterified polyphenols representing a mixture of mono-, di- and tri-esters of polyphenols. 3. Extract according to claim 1 or 2, said esterified polyphenols comprising catechins esterified to 3-O-decanoyl and catechins esterified to another hydroxyl group. 4. Extract according to any one of claims 1 to 3, said polyphenols being esterified with one or more fatty acids comprising 8 to 18 carbon atoms. 5. Extract according to any one of claims 1 to 4, said polyphenols being esterified with one or more fatty acids selected from palmitic acid, lauric acid or myristic acid. 6. Use of an extract according to any one of claims 1 to 3 as a food additive. 7. A process for preparing an extract of plant origin of which more than 80%, preferably 90%, of the polyphenols are randomly esterified on at least one hydroxyl group with a fatty acid, comprising the following successive stages: ) mixing a vegetable powder with potassium tert-butoxide in the presence of a solvent, (ii) adding one or more fatty acid (s), the molar ratio of plant powder to fatty acid being between 1/1 and 1/3, preferably between 1 / 1.5 and 1/2. 8. The method of claim 7, the solvent of step (i) being acetone 9. The method of claim 7 or 8, the step (i) taking place between 30 and 45 ° C for less than one hour, preferably 30 min. 10. Extract obtainable by the method according to any one of claims 7 to 9. 11. Food additive comprising an extract according to any one of claims 1 to 6 and 10. Food product additive with a food additive according to claim 11. 13. Food product according to claim 12, characterized in that it is a dairy product, preferably a yoghurt. A method of masking the bitterness of a plant extract comprising the process of any of claims 7 to 9.