CH674014A5 - - Google Patents

Description

DESCRIPTION The present invention relates to an antioxidant extract of a plant from the labiaceae family and its preparation process. The plant of the labiaceae family is preferably chosen from sage, rosemary, thyme, oregano, peppermint, spearmint, monarda and marjoram.

It has been known for a number of years that members of the labiaceae family, the mint family, comprising herbs also known as sage, rosemary, thyme, peppermint, etc., contain substances which delay the discoloration of paprika and other natural colors, reduce the rate at which pork fat, and more particularly sausage, becomes rancid, and prevent the oxidation of fat in poultry, in other meats and cooked food, among other food materials.

The use of spices, herbs and various forms thereof is not new in the art in this regard. Ma-10 veety (US Patent No. 2,124,706) describes this concept in 1938. Crude extracts from these herbs or the herbs themselves were used to achieve the expected effect. No practical, simple method of measuring the activity of the herb or the extract, in particular with regard to its aroma, has been described and the application has been found to be limited.

More recently, various techniques have been developed to give a less flavoring extract, both in liquid and powder form. The pulverulent form (United States Patent No. 4,363,823 to Kimura) is obtained by extraction of a residue of fresh herbs or previously steam distilled using, for example, a alcohol and by evaporation of the alcohol to form a pasty substance. Alternatively, the solventless extract can be added to boiling water, which dissolves the water soluble products extracted and will leave the insoluble products, including antioxidants, in the form of a precipitate which can be filtered. , dried and sprayed. If the precipitate is thoroughly washed with water, the hygroscopic material is removed and the resulting dry powder, containing certain flavorings, antioxidants, as well as fats and waxes, will not harden in the presence of moist air. There is no choice of non-polar solvents, because it is necessary to dry the spent herb residue.

Viani (US Pat. No. 4,012,531) uses the direct extraction of dried herbs (rosemary and sage) 35 with an aqueous basic solution, at a pH between about 7 and 11.5 and preferably 9, to separate the antioxidant materials from the herb substrate. Viani points out (column 2, line 23) that this upper pH limit is not critical, since it prevents the separation of pro-oxidant, strongly acidic substances from rosemary. The alkaline extract can be used as it is, dried, or extracted in a water-immiscible solvent, such as methylene chloride after acidification. Viani extract has a very slight rosemary odor (Example 1, column 5, line 57).

45 Nakatani (United States patent no.

4,450,097) modifies this process by first extracting the dried grass with a non-polar organic solvent such as hexane, separating the hexane, distilling off volatile essential oils from water by steam distillation. an aqueous dispersion, cooling and separating the rosemary extract insoluble in water. This deodorized extract is then dissolved in ether, washed with acid, the ether solution then being extracted with sodium bicarbonate at a pH of at least 10.5. Apparently, using bicarbonate, the pro-oxidant, weakly acidic fraction described by Vian is not extracted from ether in water. Nakatani also specifies that the rosemary leaves can first be steam distilled to separate the essential oils, and then extracted with a non-polar solvent, the extract being refined as above. (It will be noted that the purified extract of the present invention greatly simplifies the processes mentioned above, since it reduces the emulsions and the particulate matter, and simplifies the pH separations).

Berner (U.S. Patent No. 3,732,111) 65 uses an edible fat to extract the dried herb, separates the essential oil from the extract dissolved in fat, and then uses this deodorized extract in the fat as an antioxidant. This process has the major drawback of

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wasting a significant amount of edible fat in the exhausted grass, and not allowing the extract to be concentrated,

Chang (U.S. Patent No. 3,950,266) extract of rosemary leaves dried with an organic solvent, separate the solvent, mix the extract with an edible oil of high boiling point or non-volatile , such as soybean oil, and steams the resulting mixture to remove the aroma of rosemary, leaving the antioxidant moiety without flavor. It also molecularly distills the fluid, before or after bleaching with vegetable charcoal, to obtain a concentrated antioxidant. In addition, Chang shows that contacting the extract with solvents of higher and lower polarity makes it possible to concentrate the antioxidant fraction in the solvent of higher polarity using column chromatography. The Chang method has the major drawback compared to the Berner method of providing a concentrated antioxidant which can be used in a large number of applications in which the fat used by Berner would be harmful.

Bracco (U.S. Patent No. 4,352,746) uses the discoveries of Chang and Berner to carry out a process applicable to both herb extracts in fat and solvent, This process is also applicable to leaves rosemary distilled with water vapor and rosemary containing essential oil. In Bracco's invention, the oil extract, or the solvent extract, after separation of the solvent is suspended in oil, is micronized, and then carbonized in the presence of water by a treatment. thermal. The charred suspension is passed through a sieve to separate the charred material, the fluid fraction then being molecularly distilled to obtain an antioxidant fraction concentrated in the Chang manner. However, Bracco believes that his invention allows him to use less oil than Chang, compared to grass. Thus, its oil can contain 5 to 20 equivalent% of the starting plant material, compared to 1-2% for the Chang process (column 4, line 65). It is assumed that this improvement is due to the carbonization step, which separates the materials which obstruct the molecular distillation apparatus.

In a more recent patent, Kimura (U.S. Patent No. 4,380,506) describes a process for the separation of oil-soluble and oil-insoluble active fractions (Example 3) from the extract of herbs. He uses mixtures of ethanol-hexane ranging from 2% to 95% ethanol in hexane for the extraction of sage, and shows that all these mixtures are very effective extraction solvents. By adding the extract, dissolved in the mixture of extraction solvents, to water it can separate the rosemary extract into a portion soluble in hexane and into a portion insoluble in hexane. The portion soluble in hexane is also soluble in oils, and has a strong antioxidant activity. The precipitate formed, when the extract dissolved in the solvent is added to water, is insoluble in oils, weakly antioxidant (may be due to the soluble materials in hexane entrained) but can be used as an antibacterial preservative . This precipitate is not the acetone insoluble material of the present invention, which does not exhibit antibacterial properties. The Kimura process shares the drawback of the Berner process by the loss of solvent (ethanol), solvent which is mixed with the aqueous phase, and also has the drawback compared to the present invention of using an amount of solvent which is 10 times the weight of the spice used to purify the extract (examples 1 and 2), an amount which would in fact dissolve the materials "insoluble in acetone" in the hexane phase, which materials insoluble in acetone are eliminated by the present invention. Kimura nevertheless removes impurities insoluble in acetone from its hexane or other phase.

The aims of the present invention are to increase the efficiency of the natural antioxidants present in the labiaceae, preferably rosemary, to increase the production of antioxidants from the herb, to separate the undesirable and harmful substances from the herbal extract, to offer a natural extract totally soluble in oil, retaining all the natural antioxidants of the herb, to control the antioxidant activity of the extract and the aroma of the herb in specific ratios suitable for use in different types of food and in different preparation methods, to provide an extract of labiaceae which is compatible with a wide range of antioxidants ensuring a synergistic effect, to offer an extract of controlled grass from which the harmful dyes have been separated without loss of antioxidant activity, to carry out a process which is adaptable to all these objectives using a range of solvents, of the qualit acceptable food and under different extraction conditions, to make and of-fry herbal herbs, retaining all their own antioxidant properties, which are soluble in and compatible with spice extracts, oils and aromatics normally used.

According to the invention, the antioxidant extract of a plant of the labiaceae family, is characterized in that it contains less than 7.5% by weight of substances, including undesirable prooxidants, which are insoluble in acetone when the extract is diluted to a concentration of 15% w / v in acetone at a temperature of about 20 ° C.

The extract according to the invention is prepared according to the following steps: extract the plant with a solvent, separate part of the solvent up to a concentration by weight of 5 to 50% of the extract in the remaining solvent, cool the solvent and ex-35, separating the material insoluble in acetone, then the solvent.

According to the present invention, it has been found that the extraction of rosemary and other herbs by usual acceptable solvents, such as hexane, ethanol and acetone, and even by chlorinated solvents, such as methylene chloride, in a manner which maximizes the yield and the rate of extraction, followed by post-extraction precipitation of the harmful extracts from a solution of the extract, in a solvent, which preferably comprises acetone or methyl, ethyl, ketone, makes it possible to eliminate the undesirable and harmful prooxidizing matters as well as the other insoluble matters which have no antioxidant effect and which usually only serve to produce a turbidity or a cloudy in a vegetable oil medium in which they are fiso nally used.

The following examples will show

1. Separation of undesirable materials as well as (a), improving the efficiency of desirable materials and (b)

their increased solubility and fluidity.

55 2. The improvement that the elimination of undesirable acetone insoluble matter confers on the removal of the aroma by the Chang process, in particular steam and molecular distillation.

3. The separation of products soluble and insoluble in petroleum ether and the appropriate formulations of each of them for specific purposes.

4. Measuring antioxidant efficiency and aroma strength, as well as controlling their relationships.

5. The preparation of antioxidant systems which are compatible with aqueous systems, by the fact that they disperse well in water alone.

6. Elimination of a large number of handling steps required to purify the antioxidant material.

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7. Total recovery of solvents, whether edible or volatile.

8. The separation of the antioxidant fraction in a polar solvent phase, such as acetone, in which certain undesirable materials (including non-polar materials and others) are soluble under the extraction conditions but not under the purification conditions .

9. The use of the invention for the preparation of a purified extract of various herbs.

The following examples are given by way of illustration only and do not in any way constitute a limitation to the invention.

In the context of these examples the terms oleoresin and extract are synonymous. These are the materials dissolved in the solvent coming from the herb, and they are quantitatively measured by separating the solvent from the extract dissolved in it, which is also called "miscella". For example, when rosemary is extracted extensively in a Soxhlet with acetone, and the acetone is then separated from the miscella in the distillation flask, the residual material is a rosemary oleoresin or a crude extract. When the crude extract has been treated with acetone according to the present invention, the acetone soluble part, after separation of the acetone, is considered to be a "purified extract".

Example 1: Rosemary - Colorless refined antioxidant extract

120 g of crushed Portuguese rosemary are extracted in a Soxhlet with acetone and a production of 19.6 g is obtained. Part of this "crude oleoresin", a solid at room temperature, is set aside. The remainder, namely 17.4 g, is heated and stirred with 100 ml of acetone, and is then cooled to room temperature for 5 hours. It is filtered and the solid cake is washed with acetone to separate any material soluble in any acetone adhering to it. After separation of the solvent, the antioxidant fraction soluble in acetone weighs 12.3 g or constitutes 71% of the crude oleoresin. The solids weigh 5.0 g or constitute 28%, the loss being 0.1 g or 0.6%.

Part of the acetone soluble fraction (7.61 g) is redissolved in acetone and stirred for 5 hours with activated vegetable charcoal (0.76 g). After filtration and evaporation at 70 ° C. in a rotary evaporator with water suction, 7.2 g are recovered, which represents a yield of 63.5% relative to the starting oleoresin. The decrease compared to the yield of 71.0% is due to the coloring matter adsorbed on the vegetable charcoal, as well as to the loss of the lightest fractions of rosemary oil on the rotary evaporator and to the handling.

Each of these fractions is diluted in soybean oil to a concentration that would give the equivalent amount of crude oleoresin. Since the oleoresin is not mixed beforehand with a liquid support, they are first stirred in hot oil, which is then stirred in a larger amount of hot oil, which is allowed to cool. Observations on sediment and clarity are as follows: (1) oleoresins soluble in acetone are clear and free of sediment; (2) the crude oleoresin, the fraction insoluble in acetone and (3) a product prepared according to Viani and placed on the market, are not.

It will be noted that the preferred way of preparing a formulation of rosemary or any other herb consists in adding an edible liquid, such as a mono- or diglyceride, to the extraction solvent before its separation. This makes it possible to maintain the pasty extract before its separation. This makes it possible to maintain the pasty or liquid extract during its cooling, this extract not becoming a hard resin which is difficult to

redissolve. The edible liquid can be added at any time in the extraction and refining process.

It should also be noted that the steps of discoloration and separation of solids can be carried out at the same time. In the context of this example, these are carried out one after the other, this making it possible to avoid engomma-

age of vegetal charcoal which makes it more difficult to filter. Another point must be mentioned: the chlorophylls degrade into brownish pigments as a function of time, which are only sparingly soluble in oil. Since these pigments are separated by vegetable charcoal, the preferred form of the invention is a discolored extract, from which the materials insoluble in cold acetone have been separated.

The level of antioxidant activity of the extracts is measured using an instrument called Rancimat (registered trademark), which measures the time of induction (predisposition to rancidity) of an oil sample containing a known amount of extract, for example 0.1% or the equivalent, under accelerated aging conditions. The induction time 20 is measured by a clear change in the conductivity of a solution in which air is passed which is blown into the oil sample. The oil is kept at 120 ° C, and 18 liters of air are passed through it per minute.

A control is also produced at the same time, and the induction time of the control, for example 184 minutes, is subtracted from the time of induction of the test sample, for example 254 minutes, which makes it possible to obtain a number representing the increase in stability made by the sample, which will be 70 minutes. A second sample at the same concentration is then compared by the ratio of the increase in its induction time compared to that of the first sample. If, at the same concentration, the second sample increases the induction time by 80 minutes, it will be said to have an efficiency of 114% compared to the reference sample.

In this case, the stability on Rancimat of the crude oleoresin at the concentration of 0.1% is 95 minutes higher than that of the control. The fraction insoluble in acetone is prooxidant, showing an induction time at a concentration of 0.033% of 0.033% by 21 minutes less than the control. The discolored acetone-soluble oleoresin shows an increase in stability of 111 minutes at a concentration of 0.0635%, or 117% compared to the crude oleoresin. Since the yield of discolored oleoresin is 45 to 63.5% of the crude oleoresin, this refining improves the antioxidant properties of the extract by 17%.

These results demonstrate conclusively that not only does the process of the present invention make it possible to obtain a product of higher solubility, but that it also makes it possible to increase the efficiency of a given weight of rosemary by separating the prooxidants which are present in the insoluble fraction.

Example 2: Rosemary - Separation of prooxidants.

55 Rosemary is industrially extracted using a mixture of hexane and acetone (about 50-50) to obtain a standard rosemary oleoresin. Part of the solvent containing the extract (miscella) is taken in the laboratory. This miscella is divided into three portions: 1) as is; 2) boiled juice-60 to about 10-20% of the solvent content, reconstituted with acetone up to about 12% oleoresin, cooled for several hours at room temperature and filtered; 3) added with acetone as in (2), added with vegetable charcoal at a rate of 12% w / w of oleoresin, stirred for 65 hours for several hours and filtered. The solvent is separated from each sample. The production is recorded, the weights recovered being given in Table I as a percentage of the weight of the control sample (1). The Table shows that 13% of the

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weights are separated by application of the treatment (2), an additional 4.5% being separated by application of the treatment (3). The Rancimat induction times of each finished extract are determined. Again, it is considered that the yield from the unrefined extract (1) corresponds to an activity of 100%. It will be noted that the antioxidant activity increases with the separation of the undesirable prooxidants or parasites in steps (2) and (3). In other words, a concentration of 0.083% of sample (3) in the oil corresponds to 123% of the stability of a concentration of 0.1% of sample (1) in the oil.

hot hexane is a better solvent for "materials insoluble in acetone", which seem to constitute a less polar fraction than materials soluble in acetone.

In Example 2, it is mentioned that the extreme limits of materials insoluble in acetone generally encountered in rosemary extracts are between 13% and 33%. This example describes an unusual case, where the ground crushed rosemary, for some unknown reason, contains approximately

10 double the fraction insoluble in acetone usually found. This shows that the present invention is applicable to a large number of types and extracts of rosemary.

Table I Sample

Description

1 Total extract

2 Materials soluble in acetone

3 Matters soluble in acetone, discolored

Yield,%

100%

87%

83%

Quantity activity

extract equivalents

100%

117%

123%

Table II 15 Solvent (hexane / acetone) 100/0 80/20 50/50 20 0/100

Materials.

insoluble,% *

68

64

36

33

_ materials insoluble in aceton x jqq total gross extract

25

It will be noted that the quantity of materials insoluble in acetone in this example (13%) is significantly lower than that of Example 1 (33%). These two numbers represent the extremes of the concentrations of these materials generally encountered in the grass, and can be linked to the freshness, the specific cultivar, the harvest season or the geographical area. The examples show that the desirable effects of the present invention are not limited to specific types of rosemary.

Acetone insoluble material can also be separated using another food grade solvent, such as petroleum ether, such as hexane or heptane, lower alcohol, lower ester such as acetate ethyl, or another lower alkyl ketone, such as methyl ethyl ketone or the like, in which these insoluble materials are soluble in hot and insoluble in cold. However, acetone is the preferred solvent because of its cost, its ease of handling and the compatibility with which the general solvent requires extraction equipment. Note also that the present invention is not specific to the organic solvent used to prepare the crude extract, any suitable food grade solvent being acceptable.

Example 3 Effect of Different Mixtures of Solvents on the Extract

Crushed rosemary is subjected to intensive extraction in a Soxhlet using hexane, a mixture of 80% hexane and 20% acetone, a mixture of 50% hexane and 50% acetone as well as acetone alone. These represent a wide range of possible solvent polarities, and demonstrate the flexibility of the extraction solvent which can be used in the present invention. After extraction, the solvent is separated and the crude extract is then dissolved in hot acetone (8 parts), cooled and filtered. The fraction insoluble in acetone and the soluble fraction are both separated from their solvent, Table II giving the percentage of materials insoluble in acetone in the extract. The antioxidant activities of the acetone-soluble fractions are the same, which again shows that the polarity of the extraction solvent is not critical, even if

Example 4: Extraction and refining of sage.

Extract from the Dalmatian sage crushed in a Soxhlet with a mixture of hexane and acetone (70/30), the extract then being separated from its solvents. It is redissolved in hot acetone, cooled, stirred with 14% w / w vegetable char extract for 5 minutes, filtered and the solvent is separated from the filtrate. 80% of the starting weight of the oleoresin is recovered, which shows that there are much less "materials insoluble in acetone"

in this sample of sage than in a characteristic sample of rosemary. The antioxidant activity of refined, discolored oleoresin is 110% of that of the initial sample, on an equivalent weight basis. The extract is cloud free when diluted in vegetable oil.

This example shows the versatility of the invention, the 40 insoluble materials being able to increase and decrease with the type of grass, as well as with the age of the leaves, the season, the location and the specific cultivar. Two sage samples collected in early and late fall 1985 had 25% and 27%, respectively, of insoluble matter in a-45 ketone in the crude extract.

It should again be emphasized that the expression “materials insoluble in acetone” as used within the framework of the present patent simply designates a class of inert and / or harmful substances (in particular pro-oxidizing materials), which can be separated from active ingredients of the herb extract by precipitation in a cold solvent, of which acetone is the preferred member of the class. It is also possible to use a lower alcohol, for example ethyl alcohol, methyl ethyl ketone, a lower ester, or even a petroleum ether or mixtures thereof.

Example 5: Separation of active ingredients into a fraction more soluble in oil and in a fraction more soluble in water.

An additional embodiment of the present invention includes the separation of the active components of the refined oleoresin into a fraction more soluble in liquid oil and a fraction more soluble in propylene glycol or the like. The rosemary oleoresin, from which the insoluble materials in acetone have been separated, is mixed with two to five volumes of hot hexane or heptane, well stirred, allowed to cool and decant. The solvent phase is decanted from the solid phase, the two phases being separated from their solvent, 37% in yield resides in the soso fraction

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lide, and 63% in the solvent fraction. For example, the fraction of colorless solid matter is easily soluble in propylene glycol, it retains its solubility in vegetable oil and has antioxidant properties. The second fraction, namely the solvent-soluble fraction, is easily soluble in vegetable oil and less soluble in propylene glycol and has antioxidant and flavoring properties as well as residual carotenoids. The fractions, recombined, have the same activity as the refined oleoresin.

Two fractions have essentially the same antioxidant activity, which distinguishes them from the fractions obtained by Kimura. It will also be noted that the aim of the present invention is not the production of a stabilizing antimicrobial fraction, but rather of two antioxidant fractions, one containing the flavoring substances and the antioxidant activity, the other being soluble in vegetable oil and in propylene glycol but containing no flavoring substance. These two fractions can be steam distilled and mixed with mono- and / or diglycerides, etc., according to other examples given.

Note that for a person skilled in the art it is not necessary to separate the "acetone insoluble matter" before separating the oil-soluble fraction, since the desired result can be achieved by first shaking the crude extract with a hot hydrocarbon solvent, cooling and separating the solvent phase from the solids. The materials insoluble in acetone, also insoluble in the cold hydrocarbon solvent, can then be separated from the remainder of the oleoresin by stirring the fraction with acetone, as in the previous examples. In this embodiment, the process steps are reversed. Other modifications will be obvious to a person skilled in the art.

The more polar fraction can be formulated in propylene glycol or glycerin to serve as an antioxidant in an aqueous system, while the second fraction, namely the more oil-soluble fraction, can be used in an aqueous system. 'oil. This fractionation technique gives great versatility to the invention.

The propylene glycol soluble fraction and the more oil soluble fraction can also be diluted to a constant antioxidant concentration, using suitable compatible edible solvents, just as it is possible to standardize the activity of the purified extract. corresponding by dilution with oil or other suitable edible solvents. Likewise, the level of flavoring of any given formulation can be controlled by the amount of essential oil separated, or used to fortify the purified extract. The present invention therefore provides the food manufacturer with an extract standardized in terms of antioxidant activity and flavor level, as well as an extract free from haze both as such and diluted with vegetable oil. .

Example 6: Solubility characteristics of "materials insoluble in acetone" in acetone and in vegetable oil, and maximum acceptable contents in the purified extract.

As indicated in Example 1, the materials insoluble in cold acetone can constitute up to 30-40%, and sometimes up to approximately 2/3 of a grass oleoresin extracted with usual suitable food grade organic solvents. Part of the precipitate (2.6 g) of Example 1 is heated to reflux with about 40 ml of acetone, in which it is practically dissolved. The hot acetone is filtered and evaporated to recover 2.18 g of solid material.

1.84 g of this solid material are stirred with 500 ml of acetone at 40 ° C, which remains slightly cloudy. The solution is cooled to 19 ° C, stirred for an hour and a half and filtered. A total amount of 0.38 g is separated by filtration, the filtrate being only very slightly cloudy.

100 ml of this solution are placed in cap-5 sulated containers which are kept at different temperatures for 5 hours, as indicated below. In addition, one sample is diluted 1/1 with acetone, and another sample 1/1 with hexane, and held for 5 hours as indicated. The undiluted samples are filtered using Whatman # 1 paper and diatomaceous earth, most of the haze being removed. However, a very small amount passes through the paper in each case. The acetone is then evaporated to determine the solubility of "insoluble matter" at the specified temperature.

15

Holding temperature

56 ° C 20 40 ° c 19 ° C

6 ° C —2 ° C acetone 1/1 25 ß ° C acetone / he-xane very light 1/1 / 8 ° C

First of all, these results are led to demonstrate the superiority of the lower temperatures to facilitate the separation of insoluble matters, although the greatest advantage is achieved by lowering the temperature of the solution of the extract to 20 ° C or at a lower temperature and, if the equipment is available, at a temperature below 10 ° C.

Secondly, note the superiority of acetone over hexane, since apparently the insoluble materials are slightly more soluble in hexane than in acetone 40 when it is cold. Therefore, if an extraction solvent containing large quantities of hexane is chosen due to cost requirements and large volumes, it is preferable to separate practically all of it before precipitation and separation. insoluble matter.

Third, note the shortcomings of the prior art, as exemplified by Example 2 of Kimura. In this example, it extracts 50 g of rosemary with a total volume of 500 ml of solvent, formed from a mixture of 50 50 ml of ethanol and 450 ml of hexane. After discoloration, it separates the ethanol by mixing the miscella with water, and obtains a fraction soluble in hexane and its antimicrobial precipitate. Since, as indicated in Example 3, hexane is a good solvent for "materials insoluble in a-55 ketone", these would be extracted from rosemary. In the 450 ml of hexane solution after the separation of ethanol with water, at least about 0.3% would remain in solution, or about 1.25 g, which constitutes a very important part of the 1, 94 g of residue soluble in hexane obtained. According to the present invention, the 1.94 g of residue soluble in hexane are redissolved in acetone, cooled, filtered and the insoluble materials separated to recover the antioxidant fraction soluble in acetone. It is the fraction which has a high solubility in oil and which will not confer cloudiness. 65 When adding a portion of the 2.18 g of material insoluble in solid acetone prepared above to soybean oil at a concentration of 0.042%, it is necessary to heat to 140 ° C. to carry out dissolution after a

Clarity Conc.,% In Temperature at weight / vol. which the filtrate clarifies

5.5

clear 0.36

trouble

0.29

25 ° C

trouble

0.23

25 ° C

milky

0.22

25 ° C

trouble

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about 30 minutes. After cooling for 2.5 hours, a precipitate forms, the solution becoming milky overnight. Part of this solution is diluted 1/1 with soybean oil, heated to 100 ° C until the precipitate redissolves and is cooled overnight. There is a very slight haze, which would be acceptable in certain commercial applications of the extract, which indicates that a concentration of approximately 0.02 to 0.03% of materials insoluble in acetone could be tolerated in an oil. clear cooking.

Yajima (U.S. Patent No. 4,525,306), which uses a conventional discolored extract or solvent from which acetone insoluble matter has been separated (column 3) for stabilization of capsules, suggests that the preferred level of use of an extract is 0.1% to 1% w / w (column 4, lines 11, 12). A comparable level for an extract refined according to the present invention would be more than 0.5%. At this level, the extract can tolerate 0.03 / 0.5 x 100% = 6% of insoluble matter and, at a level of use of 0.4%, 7.5% of matter insoluble in acetone . This is therefore considered to be the practical upper limit of a purified liquid herb extract according to the present invention when the extract is diluted to a concentration of 15% w / v in acetone at a temperature of about 20 ° C.

When the concentration of crude extract in acetone is increased and when the precipitation temperature is lowered, more insoluble matter precipitates so that the amount of insoluble matter remaining in the purified extract is reduced. The practical upper limit of concentration is determined by the viscosity and the co-solvent effect of the other acetone-soluble constituents active in the extract. For practical applications, the upper limit of concentration of the crude extract in the solvent is approximately 50%. The concentration of use is preferably varied between around 20% and 40% without altering the quality of the product, but, with sufficient cooling and precipitation time, even a concentration of 5 to 10% will make it possible to separate most of the insoluble matter.

Example 7: Industrial extraction of rosemary, purification of the extract and determination of materials insoluble in the purified extract.

Rosemary leaves are ground and extracted continuously using a mixture of solvents consisting of half hexane and approximately half acetone, at an elevated temperature.

Part of the miscella, which is the term used for the extract in a solvent, is subjected to distillation and the concentration of extract is brought to about 50-60%. It is then diluted to a concentration of approximately 15% by the addition of acetone, it is cooled to a temperature of approximately 22 ° C. and the materials insoluble in acetone are filtered off. Glycerides (20% w / w acetone-soluble extract) and cottonseed oil (80% w / w acetone-soluble extract) are added, the solvent being followed separate. By dilution with acetone to an extract concentration of 15%, heating, refrigeration and filtration, 1.2% to 1.6% of material insoluble in acetone of the extract in oil is recovered. The liquid extract is then distilled with steam (as in Chang) to separate the essential flavoring oils. The extract gives a clear solution in oil at a content of 0.5%, and does not require heat to obtain a solution.

Another part of the miscella is separated directly from its solvent, without filtration of the insoluble matters, but with the addition of glycerides and cottonseed oil, and is then distilled with steam. The separation of essential flavoring oils takes three times as long, which shows that the separation of insoluble matter and the consequent decrease in viscosity of the extract is a great advantage in processing compared to, for example, Chang and Yajima. The extract produces a haze when added to oil at the rate of 0.5% and requires heating to dissolve it.

It should not be overlooked from this example that a commercial extract 1 ° produced according to the process of the invention will contain not less than about 1.6% of insoluble matter. If the filter is not fine enough, a certain quantity can pass through it or, if the diluted crude extract is not sufficiently cooled or that it has not been left completely hurried, the results will not be as satisfactory. In the context of the present invention, an upper limit of 7.5% of material insoluble in acetone in the extract is considered to be a practical upper limit.

Example 8: Extraction of thyme and other labiaceae and refining in the presence of an edible support.

Thyme (150 g) harvested in October 1985 in Kalamazoo, Michigan, United States of America, is extracted in a Soxhlet with acetone. After the addition of 3 g of mono- and 25 deglycerides, the acetone is separated to obtain a total of 15.1 g of crude oleoresin. This represents a yield of 8% oleoresin compared to thyme, with a characteristic odor. The oleoresin and the glycerides (15.1 g) are redissolved in 50 ml of hot acetone, they are cooled for several hours and filtered. The cake is washed with acetone, dried and 3.4 g of solid matter or 28% of the weight (of 12.1 g) of the oleoresin are obtained. The filtrate is separated from its solvent and is completely soluble in oil at a concentration of 0.2%.

This example shows that common edible solvents, such as glycerides can be present during the refining step, if this is advantageous for the manufacturer, and illustrates the versatility of the invention. This is another example of a different herb, the oil solubility of which can be improved in the same way by further processing of the crude oleoresin from the extraction solvent.

In addition, the oleoresin can be discolored, as previously described, into a brownish hue. Throughout this refining, the delicious flavor, characteristic of thyme, is preserved, if that proves desirable, or it can be eliminated by a steam distillation of the volatile flavor beforehand, if this flavor is not desirable.

Extracts from other labiaceae behave the same way when subjected to the previous treatment. An ex-50 trait of marjoram contains 26% of material insoluble in acetone, an oregano extract 37%, a spearmint extract 11%, a peppermint extract 12.5% and a monarda extract 18, 3%.

Example 9: Purification of a crude extract 55 In some cases, a crude extract can be prepared, such as for example by the Viani or Kimura method; after which it is desirable to separate the inert and prooxidants by the process of the present invention. This can be done most easily by heating the raw extract 60 with reflux with acetone, allowing the mixture to cool, filtering or decanting the liquid phase from the solid phase, and formulating the refined extract as described. Note that acetone is only the solvent that is preferably used, and that other volatile organic solvents are also ac-65 ceptable, as described above.

For example, 5 g of rosemary extract obtained according to the Viani process are refluxed, stirred with 50 ml of acetone for 30 minutes, cooled and filtered. We

674,014

8

collects 3.53 g of material soluble in acetone and 1.45 g of material insoluble in acetone. The materials soluble in acetone are brought in the form of a mixture with 5.4 g of soybean oil and 3.2 g of mono- and diglycerides which, when added to soybean oil at a level equivalent to 0.1% of the starting extract, does not cause clouding at 12 ° C overnight.

On the contrary, the starting crude extract requires a temperature of 150 ° C to obtain a total dispersion at a content of 0.1%, which dispersion remains cloudy at an extract content of 0.05%. After filtration of the hot dispersion with diatomaceous earth, it becomes clear but gives a precipitate by leaving overnight at 12 ° C.

Example 10: Mixtures of natural substances with the purified extracts, ensuring a synergistic effect.

A purified liquid extract produced according to Example 7 contains approximately one part of extract, 0.8 part of vegetable oil and 0.2 part of mono- and diglycerides. Since the amount of glycerides and vegetable oil of liquefaction, of dilution is not critical, the concentration of extract of rosemary or other labiaceae of the liquid mixture can be increased or reduced according to the needs for a particular application. This characteristic also allows the mixing in the liquid of other substances, which can have synergistic effects, in particular fat and food systems. Consequently, one of the aims of the present invention is to provide a homogeneous mixture of rosemary or labiaceae extracts with an agent ensuring a synergistic effect.

10

15

20

25

It is known that metals, such as iron and copper, when present in fats and foods, greatly accelerate the onset of rancidity. Metal purifiers, such as citric acid or EDTA, are frequently used to chelate and inactivate the metal. In the examples given below, a sufficient amount of chelating agent is added to the fat to reduce the effect of possible trace metal ions on the appearance of rancidity.

In determining the effect of synergistic agents, a given quantity of a substance, chosen from the class comprising ascorbic acid compounds, tocopherols and turmeric compounds, is mixed with the rosemary oleoresin, question above (from Example 7) and the mixture is added to the fat so that it contains 0.05% oleoresin rosemary. The amount of synergistic agent present is given as a percentage of the rosemary extract present. For example, if a liquid mixture contains 18% rosemary extract and 9% tocopherols, the synergistic agent is present at 50% of the rosemary.

BHA (butylated hydroxyanisole), the most commonly used synthetic antioxidant, is given in the Table for comparison.

The test results are evaluated using Rancimat, as described above, after accelerated aging.

Ratio of sample induction time to control in a specific fat

Witness

Rosemary

+

tocopherols * or ascorbates ** or BHA turmeric extract

Level of use

0.05

0.05

0.05

0.05 0.05

Lard Suet

1.0

6.0

> 10

1.0 7.5

> 10

9-10

5.0

Fat

Fish

Hydrogenated partially hydrogenated chicken oil

1.0

1.0

1.0

5.2

2.2

1.8

> 10

1.9

6.2 9

4.0

2.9

1.1-1.3

* 50% mixed tocopherols in vegetable oil

** ascorbyl palmitate, ascorbyl stearate or ascorbic acid may be substituted.

The Table shows that the purified rosemary extract is more effective than BHA at equal concentrations and that, when combined with an agent ensuring an effective synergistic effect in a specific fat, its usefulness is even more greatly increased. Since the liquid preparation of the present invention is in a single phase and is compatible with the agents ensuring a synergistic effect mentioned above, the purified extracts combined with an agent ensuring a synergistic effect which contain one are considered to be part of the present invention.

The product of the present invention is a new and improved form of a grass extract essentially free of cloud-forming and prooxidizing substances, which is completely soluble in oil, and which furthermore can be separated into a more soluble fraction. in oil and a fraction more soluble in water. The product of the present invention retains all the antioxidant power of the initial crude extract, and can also be treated by methods known in the art for separating volatile essential oils. It can be combined with agents ensuring a synergistic effect, and diluted with edible solvents, such as vegetable oil or glycerin, to form a liquid which is easily used in the manufacture of food. The product can be produced from a herb which has been previously distilled with steam to separate its essential oil, but if the total flavor of the herb is desirable in the refined extract, this also directly resulting of the invention, the essential oil is preserved (as in Example 8) or re-added thereafter.

55 The process for obtaining this new product is simpler and less expensive than the processes described in the prior art, such as the Nakatani, Viani, Bracco, Kimura and Berner processes, but it can also be used to greatly improve the product of these processes. 60 The process itself comprises a usual but not obvious extraction step, allows the use of a wide range of volatile solvents of food grade, and does not require the recovery of an aqueous system of a substance which produces an annoying emulsion. All 65 volatile solvents can be reused as they would normally be reused in an extraction operation, not being lost in the water or in the grass used as in the case of the Berner patent.

VS

Claims (13)

674,014 o 1. Antioxidant extract of a plant of the la-biaceae family, which contains less than 7.5% by weight of substances, including undesirable pro-oxidant substances, which are insoluble in acetone when the extract is diluted to a 15% w / v concentration in acetone at a temperature of about 20 ° C. 2. Extract according to claim 1, characterized in that the plant is chosen from sage, rosemary, thyme, oregano, peppermint, spearmint, monarda and marjoram. 3. Extract according to claim 1, characterized in that it is in separate form of fractions soluble in petroleum ether and of fractions insoluble in petroleum ether, petroleum ether in both cases being hexane or heptane. 4. Extract according to claim 1 without odor. 5. Edible solvent containing the extract according to claim 1 or 2, comprising a compound chosen from ascorbic acid, a tocopherol, and a turmeric compound. 6. Method for producing an antioxidant extract of a plant of the labiaceae family according to claim 1, which comprises the steps of extracting the plant with a solvent, of separating part of the solvent up to a concentration by weight from 5 to 50% of the extract in the remaining solvent, cooling the solvent and the extract, separating the material insoluble in acetone, then the solvent. 7. Method according to claim 6, characterized in that the solvent is acetone, in the presence or absence of a petroleum ether, preferably hexane or heptane. 8. Method according to claim 6, characterized in that the solvent is chosen from acetone, methyl ethyl ketone, lower alcohols, lower esters and petroleum ethers. 9. Method according to claim 6, characterized in that the volatile oil is separated from the plant partially or completely after the separation of the material insoluble in acetone. 10. Method according to claim 6, characterized in that it is carried out in the presence or not of an edible solvent and in that the extract is mixed with a petroleum ether, preferably hexane or heptane, the solvent phase is separated, the solvent removed, the fraction insoluble in petroleum ether is mixed with acetone and the fraction soluble in antioxidant acetone is separated from the fraction insoluble in acetone comprising undesirable oxidizing material. 11. Method according to claim 6, characterized in that the solvent is a solvent in which the material insoluble in acetone is soluble when hot and insoluble when cold. 12. Method according to one of claims 6 and 8 to 11, characterized in that the solvent is acetone. 13. Method according to one of claims 6 to 12, characterized in that the material insoluble in acetone is separated after the addition of charcoal and in the presence of an edible solvent.