WO2014072282A1

WO2014072282A1 - Recovery of caffeine and bioactive fraction from coffee

Info

Publication number: WO2014072282A1
Application number: PCT/EP2013/073032
Authority: WO
Inventors: Frederico Mora; Johanna Hendrika Schoonman; Thierry Labrunie
Original assignee: Nestec S.A.
Priority date: 2012-11-08
Filing date: 2013-11-05
Publication date: 2014-05-15

Abstract

The present invention relates toa process for recovering caffeine and bioactive compounds from coffee by contacting a coffee extract with an adsorbent to adsorb caffeine and bioactive compounds and subsequently recovering adsorbed compounds by contacting the adsorbent with an aqueous liquid and collecting at least two fractions of the aqueous liquid.

Description

RECOVERY OF CAFFEINE AND BIO ACTIVE FRACTION FROM COFFEE

Field of the invention The present invention relates to a process of recovering caffeine and bioactive compounds from coffee by adsorbing caffeine and bioactive compounds on an adsorbent following by desorption and collection of at least two fractions of the desorbed material. Background

Coffee beans are rich in many substances with biological effects, e.g. caffeine and polyphenols, such as chlorogenic acids and their lactones, some of which may act as antioxidants. Many of these bioactive compounds are extracted during normal extraction of coffee with water and may exert biological effects in individuals consuming the resulting coffee brew. In some occasions, and by some consumers, the effect of caffeine is not desired, and to satisfy such consumers decaffeinated coffee products, coffee products wherein the content of caffeine has been removed, totally or in part, are produced. Several methods exist for the removal of caffeine from coffee beans. The caffeine removed may be used as an ingredient e.g. in other beverage and/or food products. Caffeine may e.g. be removed from green coffee beans extracting the coffee beans with water, and treating the extract with an adsorbent with a high specificity for caffeine. The solids left in the extract after caffeine has been adsorbed may then be returned to the green coffee beans, e.g. by allowing the extracted, and dried, green coffee beans to absorb the extract from which caffeine has been removed Such as method is e.g. disclosed in US patent No. 5,208,056. The caffeine may be desorbed from the adsorbent and used for other purposes. However, most adsorbents will also adsorb a number of other green coffee compounds which are not intended to be removed from the coffee beans, e.g. aroma precursor compounds and polyphenols. This problem may to some degree be avoided by pre-saturating the adsorbent with these compounds. Nevertheless, when the caffeine is desorbed from the adsorbent it is not pure and needs to be purified afterwards to be useful as an ingredient. The impurities removed are usually discarded. WO 2011/011418 discloses a crude caffeine complex obtained as the un-purified complex of caffeine and other compounds remaining after removal of caffeine from coffee beans, and the use of such a crude complex as an ingredient. However, some of the compounds of the crude caffeine complex may have different benefits and used than others, so a fractionation may be needed or desired. It may especially be desirable to be able to separate the group of polyphenols, which have antioxidant effects, and caffeine, which has stimulating effects. The uses of polyphenols, e.g. in health products, food supplements and the like, is often different from caffeine which is normally used in products such as energy drinks. There is thus a need for simple and cost effective ways of obtaining pure caffeine from decaffeination of coffee beans, as well as ways of separating the additional bioactive compounds removed by decaffeination, especially the polyphenols.

Summary of the invention The inventors have found that the compounds adsorbed by an adsorbent used for decaffeination of an aqueous extract of coffee beans, apart from caffeine, comprises polyphenols which may be useful as an ingredient, e.g. in food and beverage products. Furthermore, they have found that adsorbed compounds from the decaffeination process can be desorbed with an aqueous liquid, and that polyphenols are desorbed faster than caffeine, so that a first polyphenol rich fraction may be collected, followed by a second caffeine rich fraction. In this way a simple and cost efficient fractionation of the adsorbed compounds may be achieved by desorbing the adsorbed material with an aqueous liquid, and collecting at least two fractions, a first fraction and a second fraction. Accordingly, the invention relates to a method of recovering bioactive compounds and caffeine from coffee, the method comprising: a) extracting coffee beans with an aqueous liquid to obtain an aqueous extract of coffee; b) contacting the aqueous extract of coffee obtained in step a) with an adsorbent to adsorb caffeine and bioactive compounds; and c) recovering adsorbed compounds from the adsorbent of step b) by contacting the adsorbent with an aqueous solution, and collecting a first fraction of the aqueous solution, the first fraction being rich in polyphenols, followed by collecting a second fraction of the aqueous solution, the second fraction being rich in caffeine. Brief description of the figures

Figure 1 shows the cumulated caffeine (total amount of caffeine in the total amount of aqueous liquid used for desorption) over time (dark line) and the cumulated solids (including caffeine and polyphenols) over time for the 1000L scale (light line) for the experiments reported in example 1.

Figure 2 shows the cumulated caffeine over time (dark line) and the cumulated solids (including caffeine and polyphenols) over time for the 3L scale (light line) fro the experiments reported in example 1.

Detailed description of the invention

According to the present invention coffee beans are extracted with an aqueous liquid. Coffee beans may be the beans from any coffee plant (Coffea), e.g. Arabica coffee (Coffea arabica), and/or Robusta coffee (Coffea canephora). The coffee beans may be green (raw) or roasted, or may have been subjected to any other suitable treatment, e.g. a heat treatment as disclosed in WO 2011/073052. In a preferred embodiment the coffee beans are green coffee beans. The coffee beans may be whole or ground, the coffee beans are preferably whole beans. The extraction may preferably from part fo a process for decaffeination of coffee beans, such as e.g. the process disclosed in US patent No. 5,208,056. The aqueous liquid may e.g. be water or an extract of coffee beans. If an extract of coffee beans is used, the concentration of coffee solids, except caffeine, may preferably be so high that substantially only caffeine is removed from the coffee beans. In a preferred embodiment, the aqueous solution used to extract the coffee beans is an aqueous extract of coffee from which caffeine has been removed. The coffee beans may for example be extracted in an aqueous liquid which is re-circulated until it is saturated with coffee solids. During the recirculation the coffee extract may be contacted with an adsorbent to remove caffeine.

The coffee extract is contacted with an adsorbent to adsorb caffeine and other bioactive compounds. The adsorbent may be any suitable adsorbent, such as e.g. activated char coal, activated alumina, silica gel, clay minerals, zeolites or a polymer resin such as a molecularly imprinted polymer. The adsorbent may have been loaded with coffee solids other than caffeine to reduce the amount of non-caffeine solids removed from the coffee extracts, e.g. by contacting the adsorbent with a caffeine free coffee extract. In this case, the adsorbent may only adsorb minor amounts of bioactive compounds other than caffeine.

Adsorbed compounds are recovered from the adsorbent by contacting the adsorbent with an aqueous liquid. The aqueous liquid is preferably water, but may also contain compounds such as weak protic acids, and halogenated and non-halo genated organic solvents. By water is meant water that is substantially free of other components, especially organic solvents such as e.g. ethanol. The contacting may be done as a batch operation or as a continuous operation where used aqueous liquid is continuously collected and new aqueous liquid is supplied, the aqueous liquid may be circulated over the adsorbent and any other suitable way of contacting may be used. The contacting may be performed at any suitable temperature, e.g. at a temperature between about 120°C and about 170°C. The inventors have found that with an aqueous liquid, preferably water, polyphenols are desorbed faster than caffeine. This means that fractions of aqueous liquid collected early in the desorption process will be rich in polyphenols as compared to fractions collected later, which will be relatively rich in caffeine. By rich in polyphenols or rich in caffeine is meant that a fraction comprises a higher ratio of polyphenols or caffeine, respectively, out of the total solids in the fraction, as compared to the ratio of polyphenols or caffeine, respectively, in the total of the adsorbed solids. According to the invention, a first fraction of the aqueous solution is collected, the first fraction being rich in polyphenols, followed by collection of a second fraction of the aqueous solution, the second fraction being rich in caffeine. To obtain the desired composition of the collected fractions, desorption of specific compounds of interest, e.g. caffeine or polyphenols, may be followed by monitoring the concentration of the compound(s) of interest, e.g. the concentration in percent of total solids desorbed. The period of collection of each fraction may thus be controlled based on the desorption pattern of each fraction. The process of the invention is not restricted to the collection of a first and second fraction, only. As many fractions as desired may be collected, e.g. depending on the intended use and required composition and purity of compounds, as well as the desired degree of recovery of specific compounds.

In a preferred embodiment of the invention, the collection of the first fraction of the aqueous solution is terminated before the concentration of caffeine in the total amount of aqueous solution used for desorption has reached 40% by weight of total dry matter, such as before the concentration of caffeine in the total amount of aqueous solution used for desorption has reached 50%> more preferably 60%>, by weight of total cumulated dry matter. In another preferred embodiment, the collection of the second fraction of the aqueous solution is started after the concentration of caffeine in the total amount of aqueous solution used for desorption has reached 40%> by weight of dry matter, such as the concentration of caffeine in the total amount of aqueous solution used for desorption has reached 50%>, more preferably 60%>, by weight of cumulated dry matter. In a further preferred embodiment, the collection of the first fraction is terminated before the cumulated amount of caffeine in the first fraction has reached 50% by weight of total cumulated dry matter.

The collected fractions may be subjected to any subsequent treatments suitable for their intended use. They may e.g. be concentrated, e.g. by removing water, e.g. with evaporation or filtration, and they may be subjected to further purification steps to further purify and/or separate specific compounds or groups of compounds. The collected fractions may also be dried. In a preferred embodiment, the method of the invention comprises drying the first fraction rich in bioactive compounds obtained in step c), or part of this fraction, to produce a dry composition of bioactive compounds. In another preferred embodiment, the method of the invention comprises drying the second fraction rich in caffeine obtained in step c), or part of this fraction, to produce a dry preparation of caffeine.

The bioactive compounds and the caffeine obtained by the method of the invention may have many uses, e.g. as ingredients of food supplements, food products, beverage products, pet food products, skin care products, medical products, and medical food and beverage products. In a preferred embodiment, the method of the invention further comprises using the first fraction obtained in step c) as an ingredient of a food supplement, a food product, a pet food product, or a beverage product. Suitable beverage products are e.g. coffee products, such as e.g. soluble coffee, and roast and ground coffee, e.g. roast and ground coffee in capsules; cocoa beverages; malt beverages; fruit or vegetable juice based beverages; and milk based beverages. Suitable food products are e.g. confectionary products, e.g. chocolate products; sports nutritional products, e.g. energy bars; infant nutrition products;

EXAMPLES

Example 1

A green coffee extract of total solid content 5% (TC: mass of matter in a coffee solution defined as the weight (w) of the dried coffee residue expressed as a percentage of the original coffee solution or suspension in weight/weight percent (w/w%)) and caffeine concentration of 0.5 (w/w%) was contacted with a fixed volume of active carbon (3L and 1000L) for lOhr. After this contacting, the non adsorbed coffee extract was displaced with 1 bed volume of water. The active carbon was then washed with water at 150°C for 24h to recover the adsorbed solids. The concentration of caffeine and the concentration of total solids were monitored throughout the experiment.

Figure 1 shows the cumulated caffeine (total amount of caffeine in the total amount of aqueous liquid used for desorption) over time (dark line) and the cumulated solids (including caffeine and polyphenols) over time for the 1000L scale (light line). It is to note that 10 sets of experiments were performed and for clarity only one figure is used.

Figure 2 shows the cumulated caffeine over time (dark line) and the cumulated solids (including caffeine and polyphenols) over time for the 3L scale (light line). It is to note that 10 sets of experiments were performed and for clarity only one figure is used.

Claims

1. A method of recovering bioactive compounds and caffeine from coffee, the method comprising:

a) extracting coffee beans with an aqueous liquid to obtain an aqueous extract of coffee; b) contacting the aqueous extract of coffee obtained in step a) with an adsorbent to adsorb caffeine and bioactive compounds; and

c) recovering adsorbed compounds from the adsorbent of step b) by contacting the adsorbent with an aqueous solution, and collecting a first fraction of the aqueous solution, the first fraction being rich in polyphenols, followed by collecting a second fraction of the aqueous solution, the second fraction being rich in caffeine.

2. The method of claim 1, wherein the collection of the first fraction of the aqueous solution is terminated before the concentration of caffeine in the total amount of aqueous solution used for desorption has reached 40% by weight of total dry matter.

3. The method of any one of claims 1 and 2, wherein the collection of the second fraction of the aqueous solution is started after the concentration of caffeine in the total amount of aqueous solution used for desorption has reached 40%> by weight of dry matter.

4. The method of any one of claims 1-3, wherein the collection of the first fraction is terminated before the cumulated amount of caffeine in the first fraction has reached 50% by weight of total cumulated dry matter.

5. The method of any one of claims 1-4, wherein the coffee beans being extracted are green coffee beans.

6. The method of any one of claims 1-5, wherein the aqueous solution used to extract the coffee beans in step a) is an aqueous extract of coffee from which caffeine has been removed.

7. The method of any one of claims 1-6, wherein the adsorbent is activated charcoal.

8. The method of any one of claims 1-7, wherein contacting of the adsorbent with an aqueous liquid in step c) is performed at a temperature between about 120°C and about 170°C.

9. The method of any one of claims 1-8, wherein rinsing of the adsorbent in step c) is performed with water.

10. The method of any one of claims 1-9, further comprising drying the first fraction rich in bioactive compounds obtained in step c), to produce a dry composition of bio active compounds.

11. The method of any one of claims 1-10, further comprising drying the second fraction rich in caffeine obtained in step c), to produce a dry preparation of caffeine.

12. The method of any one of claims 1-11, further comprising using the first fraction obtained in step c) as an ingredient of a food supplement, a food product, or a beverage product.