IE61919B1 - "Process for the preparation of a powdered extract of valerian roots" - Google Patents

Abstract

Ground valerian roots are extracted at least once with water, the aqueous extract is concentrated until a dry matter content of between 10 and 20% is obtained, alcohol or acetone is added to the concentrate in order to precipitate the gelatinous substances responsible for the cloudy appearance of the drink reconstituted from the powder, a carbohydrate is added to the centrifuged water/alcohol or water/acetone mixture and the preparation is dried to obtain an instantaneous powder.

Description

This invention relates to a process for the preparation of a deodorized powder-form extract of valerian roots.

It is known that the aqueous extract of valerian root has the property of improving sleep in human beings (Pharmacology Biochemistry & Behavior, Vol. 17, pages 65 to 71). These mixtures are taken as infusions and the unpleasant taste and unpleasant odour of these beverages are well known. On the other hand, valerian powder as known at present, when dissolved in water, leads to certain deposits and to a cloudy beverage. Accordingly, the object of the present invention is to provide a process for the preparation of a powder-form extract of valerian roots in which the valerian is deodorized and the substances responsible for the cloudiness of the reconstituted valerian beverage are eliminated.

The invention relates to a process for the preparation of a powder-form extract of valerian roots in which the ground valerian roots are extracted at least once with water, the aqueous extract is concentrated to a dry matter content of 10 to 20%, alcohol or acetone is added to the concentrate to precipitate the gelatinous substances responsible for the cloudy appearance of the beverage reconstituted from the powder, a carbohydrate is added to the centrifuged water-alcohol or water-acetone mixture and the resulting mixture is dried to obtain an instant powder.

Valerian is a perennial herbaceous plant of the genus Valeriana which is found in the temperate regions of North America, Europe and Asia. Among the 170 known species, common valerian (Valeriana officinalis L.) is the most widely used for medicinal purposes. However, the process according to the invention is applicable to all species of valerian. Valerian roots are the subterranean part of the valerian plant.

The extraction with water is carried out over a period of 2 to 5 hours at a temperature in the range from 65 to 75’C. The temperature of the water is critical because an excessively high temperature would tend to degrade certain components of the root while an excessively low temperature would not give satisfactory extraction. Three successive extractions with water are preferably carried out. This extraction leads to degradation of the valepotriates while preserving the valerenic acids of the valerian roots.

The aqueous extract is then concentrated to eliminate the unpleasant odours which are volatile and which are produced by degradation products. This concentration step is carried out at a temperature in the range from 30 to 60°C under a pressure of the order of 2.104 Pa. After about one hour when the odour-producing substances have been removed, the pressure is reduced to approximately 2.103 Pa to complete the elimination of water to a dry matter content of approximately 13 to'17%. The concentration step is followed by the treatment with alcohol or acetone. The alcohol used is ethanol. Mixing is carried out in such a way that an alcohol or acetone concentration of 48 to 52% is obtained. The mixture is left standing for 8 to 20 hours at ambient temperature so that the insoluble gelatinous compounds precipitate. The precipitate is separated by centrifugation and the remainder of the aqueous extract is mixed with a maltodextrin before drying.

The function of the maltodextrin is to act as a support for the drying process. In addition, it enables a final powder to be obtained which is not too hygroscopic and which has a long shelf life.

Drying is then carried out either in vacuo or by spray drying to obtain an instant valerian powder which has retained its sedative character.

If the beverage is reconstituted in water, it is free from deposits and cloudiness, has a neutral taste and no odour. The absence of cloudiness has been demonstrated by nephelometric measures. The valerian powder reconstituted in water gives a maximum optical density peak at approximately 650 nm. In addition, there is no valepotriate in the powder.

In the process according to the invention, the alcohol or acetone enables the compounds responsible for cloudiness to be separated. Another function of the treatment with alcohol is to guarantee an almost sterile process in which the risks of bacterial contamination are minimized.

An extraction yield of 20 to 30% is obtained.

The process according to the invention is carried out in batches or by percolation.

The invention is illustrated by the following Examples.

Example 1 A 2000 litre capacity percolator is filled with 250 kg finely ground valerian roots and 1500 kg water preheated to 70°C. A sieve at the bottom of the percolator retains the particles and a heating jacket keeps the temperature at 70°C during the 4 hours of the first extraction. The extract is continuously recycled from the bottom of the percolator by means of a pump.

The first extract is pumped from the percolator to a reservoir from which it is immediately delivered to a vacuum evaporator having a heating jacket in which water at 48°C circulates. The volatile substances are eliminated in > this evaporator by application of a vacuum of 10A Pa for one hour and, when a dry matter content of 14% has been reached, a vacuum of 2.103 Pa is applied. 94% Alcohol (ethanol) is then added to the concentrated extract so that an ethanol content of 50% is obtained. The mixture is left standing for the precipitate to settle.

A second extraction lasting three hours is carried out in the same percolator with 1000 kg fresh water. A third extraction is carried out in the same percolator for two hours. The second and third extracts are treated in the same way as the first.

At the end of the three extractions, the reservoir contains the total extract containing 50% alcohol. Complete precipitation of the insoluble solids takes one night (12 hours) . A centrifuge is used to separate the clear liquid extract from the solids precipitated. The dry matter content of the centrifuged extract is determined to calculate the quantity of maltodextrin to be added to obtain a dilution of 1:1 by weight.

The calculated quantity of maltodextrin is introduced into a vacuum dryer and the clear, concentrated alcoholic extract is added thereto. The alcohol is removed at 50"C under a reduced pressure progressively reaching 103 Pa.

The final drying step is carried out in the same dryer or, when the extract has acquired the consistency of a syrup, it is dried by spray drying.

A final yield of valerian powder of 23 to 25% is obtained, i.e. approximately 62 kg valerian powder is obtained from 250 kg valerian roots.

Example 2 Example 1 is repeated using acetone instead of ethanol.

The extraction yield obtained is equivalent to that obtained with alcohol.

The difference lies in the fact that the use of the process is more economical.

Claims (10)

1. A process for the preparation of a deodorized powderform extract of valerian roots, characterized in that the ground valerian roots are extracted at least once with water, the aqueous extract is concentrated to a dry matter content of 10 to 20%, alcohol or acetone is added to the concentrate to precipitate the gelatinous substances responsible for the cloudy appearance of the beverage reconstituted from the powder, a carbohydrate is added to the centrifuged water-alcohol or water-acetone mixture and the resulting mixture is dried to obtain an instant powder.

2. A process as claimed in claim 1, characterized in that each extraction with water is carried out for 2 to 5 hours at a temperature of 65 to 75 e C.

3. A process as claimed in claim 2, characterized in that three extractions with water are carried out.

4. A process as claimed in any of claims 1 to 3, characterized in that the aqueous extract is concentrated at a temperature in the range from 30 to 60°C under a pressure of from 2.10 4 Pa to 2.10 3 Pa.

5. A process as claimed in any of claims 1 to 4, characterized in that ethanol or acetone is added to the concentrate so that an alcohol or acetone content of 48 to 52% is obtained and the mixture is left standing for 8 to 20 hours at ambient temperature.

6. A process as claimed in any of claims 1 to 5, characterized in that maltodextrin is added to the extract after the treatment with alcohol or acetone.

7. A process as claimed in any of claims 1 to 6, characterized in that drying is carried out in vacuo or by spray drying.

8. A process as claimed in claim 1, characterized in that the ground valerian roots are extracted three times at a temperature of 70°C, the aqueous extract is concentrated at a temperature of 48°C under a vacuum of 10 4 Pa and then 2.10 3 to obtain a dry matter content of approximately 14%, ethanol or acetone is added so that an alcohol or acetone content of 50% is obtained, the mixture is left standing at ambient temperature for 12 hours and then centrifuged, 5 maltodextrin is added to the water-alcohol or water-acetone mixture in a quantity sufficient to give a ratio by weight of 1:1 of dry matter of the water-alcohol or water-acetone mixture to maltodextrin and the whole is dried at 50’C under a vacuum of the order of 10 3 Pa. 0

9. A process according to claim 1 for the preparation of a deodorized powder-form extract of valerian roots substantially as hereinbefore described by way of Example.

10. A deodorized powder-form extract of valerian roots whenever prepared by a process as claimed in any of the preceding claims. TOMKINS & CO.