BACKGROUND

Essential oils provide natural flavors and fragrance in concentrated form, and they are widely used in the preparation of products including foods, beverages, perfumes, pharmaceuticals, air fresheners, aromatherapeutics, and cosmetics. Such oils are extracted, for example, from fruit peels or other plant parts (fruit pulp, leaves, stems, roots, seeds, etc.) by various methods that release the oils from plant structures containing them. In some cases, additional compounds are present in the essential oil compositions. Such additional compounds may be undesirable or unnecessary for the oil's intended use. Selective removal of unwanted compounds can improve the usability of an oil.

Furthermore, selective removal of compounds unnecessary for the oil's intended use allows use of the removed compounds in other products.

SUMMARY

Methods for the treatment of essential oil compositions are described herein. One method involves the steps of contacting an essential oil composition with an effective amount of an activated carbon, and separating the activated carbon from the treated essential oil. The essential oil composition can be a fruit oil composition such as a citrus oil composition. A treated essential oil prepared by this method can contain a selected amount of one or more components, such as chlorophyll, carotenoid, or fiavonoid. The method can further include the step of recovering the components adsorbed to the activated carbon.

A further method described herein involves separating chlorophyll from an essential oil composition. This method involves the steps of contacting the essential oil composition containing chlorophyll with activated carbon, and separating the activated carbon from the treated essential oil. The essential oil composition can be a fruit oil composition such as a citrus oil composition.

An additional method described herein involves isolating one or more components from an essential oil composition. This method involves the steps of contacting an essential oil composition with activated carbon, separating the activated carbon from the treated essential oil, and recovering the components adsorbed to the activated carbon. The components adsorbed to the activated can be recovered, for example, by eluting the components from the activated carbon with a polar solvent.

The details of one or more aspects of the methods and compositions are set forth in the description below. Other features, objects, and advantages will be apparent from the description and from the claims.

DETAILED DESCRIPTION

Methods for the treatment of essential oil compositions and essential oils produced by these methods are described. Specifically, the methods involve contacting an essential oil composition with an adsorbent material then separating the treated essential oil from the adsorbent material. The methods described herein can be used, for example, to enhance the acceptability, usability, or stability of essential oils for the food processing industry. Furthermore, the methods can be used to extract compounds from an essential oil composition so that the compounds can be used in the relative absence of the essential oil component of the composition. Thus, provided herein is a method for treating an essential oil composition including the steps of contacting an essential oil composition with an adsorbent material and separating the adsorbent material from the treated essential oil. Optionally, the essential oil composition is a fruit oil composition. For example, the fruit oil composition is a citrus oil composition such as lemon, orange, Mandarin orange, grapefruit, tangerine, and lime or a citrus-related oil composition such as kumquat. By way of example, the citrus oil composition can be extracted from fruit at various stages of ripeness - from very ripe to very unripe (i.e., green). Unripe fruit contains higher levels of chlorophyll than ripe fruit, and the oil composition extracted from unripe fruit will contain higher levels of chlorophyll as compared to oil composition extracted from ripe fruit. Depending on the intended application for an essential oil composition, it may be desirable to remove a portion of the chlorophyll (i.e., not all of the chlorophyll) or all of the chlorophyll from the essential oil composition. For example, an excessively green lemon oil composition might impart an undesirable green tint to a beverage that is intended to be colorless. This situation may be remedied by removal of a part, i.e., less than all, of the chlorophyll from the composition. As another example, the presence of chlorophyll in a Mandarin orange oil composition reduces the oxidative stability of a beverage or other product prepared from the oil, so it may be desirable to remove all or a high percentage of the chlorophyll from a green Mandarin orange oil composition. The methods are designed to allow customization of the level of removal or retention of one or more components (e.g., chlorophyll, flavonoids, carotenoids) from an essential oil composition by adjusting the amount of adsorbent material added to the essential oil composition.

Thus, provided herein is a method for treating an essential oil composition comprising contacting the essential oil composition with an effective amount of the adsorbent material and separating the adsorbent material from the treated essential oil, wherein the treated oil has a selected amount of one or more additional compounds (e.g., chlorophyll, flavonoid, carotenoid). The effective amount of an adsorbent material is determined by the type and characteristics of the adsorbent material, the volume of essential oil composition, the type of essential oil composition, the degree of ripeness of the source of the essential oil composition, and the amount and identity of the additional compounds desired in the treated oil. Thus, it is difficult to identify an exact amount of adsorbent material to be used in treating a specific essential oil composition. However, one of skill in the art can identify the preferred amount using routine experimentation based on the desired characteristics of a treated essential oil.

The selected amount of the one or more additional components (i.e., the components remaining in the treated essential oil) includes 0.1-100% of the amount in the untreated essential oil composition. The percentage of various components in the treated essential oil can be the same or different from each other. For example, a higher amount of adsorbent material reduces the amount of chlorophyll in the treated essential oil. The selected amount of chlorophyll can be, for example, 1%, whereas the selected amount of carotenoid or other additional component can be the same (e.g., 1%), higher (e.g., 50%), or lower (e.g., 0.1%) than the percentage of chlorophyll.

Adsorbent materials include activated carbon, amorphous silicas, bleaching earth, fuller's earth, and diatomaceous earth (alternately known as diatomite, diahydro, kieselguhr, kieselgur and celite). Activated carbon (alternatively known as activated charcoal or activated coal) is a highly porous form of carbon with a large surface area. Amorphous silicas include silica gels, precipitated silicas, dialytic slilicas and fumed silicas that have high surface areas. Similarly, the earths listed above have highly porous structures with large surface areas. The porous structures of these adsorbent materials provide environments upon which compounds can adhere. In the case of activated carbon, compounds are bound by Van der Waals forces and/or London dispersion forces. Thus, activated carbon will bind certain compounds or components of a composition and not bind other compounds or components of the composition.

The preparation of the adsorbent materials described herein is well known and such materials are commercially available. For example, activated carbon can be obtained

100 from commercial sources such as Carbon Activated Corporation (Orchard Park, NY) and Mead/Westvaco (Glen Allen, VA); various amorphous silicas can be commercially obtained from Evonik Industries AG (Essen, Germany); and various diatomaceous earths can be commercially obtained from Perma-Guard, Inc (Albuquerque, New Mexico). The adsorbent materials useful with the methods described herein include activated carbon

105 with at least 150 m ² /g surface area. Similarly, adsorbent materials with at least 200 m ² /g, at least 300 m ² /g, at least 400 m ² /g, at least 500 m ² /g, at least 600 m ² /g, at least 770 m ² /g, at least 800 m ² /g, at least 900 m ² /g, at least 1000 m ² /g, at least 1100 m ² /g, at least 1200 m ² /g, at least 1300 m ² /g, at least 1400 m ² /g, at least 1500 m ² /g, at least 1600 m ² /g, at least 1700 m ² /g, at least 1800 m ² /g, at least 1850 m ² /g, at least 1900 m ² /g, at least 1950 m ² /g, at

110 least 2000 m ² /g surface area are useful. Further, adsorbent materials useful with the methods described herein have between 150 and 2000 m ² /g surface area. Similarly, adsorbent materials with between 500 and 1950 m ² /g, between 1000 and 1900 m ² /g, or between 1200 and 1850 m ² /g surface area. As a further example, activated carbon useful in the disclosed method has a surface area between 1400 and 1800 m ² /g. In addition to

115 large surface areas as a general parameter, the adsorbent materials useful with the methods described herein can demonstrate large internal surface areas. These large internal surface areas are preferably accessible to molecules of the sizes that are to be removed from the essential oil composition. For example, pores or other access points large enough to permit access of molecules such as chlorophyll are useful. One of skill in the art can

120 empirically determine the preferred adsorbent material (activated carbon versus silica, for example) and its characteristics (e.g., surface area) using knowledge in the art and the methods taught herein based on the desired outcome.

Untreated essential oil compositions including citrus oil compositions such as lemon, orange, Mandarin orange, grapefruit, tangerine, and lime oil compositions or a

125 citrus-related oil composition such as kumquat — contain a complex mixture of compounds including, for example, limonene and photosynthetic molecules such as chlorophyll, carotenoids, and flavonoids. Such essential oil compositions can be derived or extracted from whole fruit or portions thereof (e.g., peel or pulp) using available equipment and methods (e.g., by expression). For example, such essential oil compositions can be

130 obtained by cold-pressing or machine abrasion techniques. In cold-pressing and machine abrasion, the plant material, e.g., peels, is manipulated to help release the oil compositions and then pressed or otherwise manipulated to help remove the oil compositions from the plant material. With either cold-pressing or machine abrasion, the oil can be separated from the plant material by, for example, centrifugation, filtration, or decanting. Due to the

135 nature of these extraction techniques, the oil compositions collected from these methods often contain other plant matter and components, such as, for example, chlorophyll, carotenoids, and flavonoids as discussed above. Other techniques such as distillation and solvent extraction are also possible.

Without wishing to be bound by theory, certain adsorbent materials useful in the

140 methods described herein adsorb chlorophyll readily but adsorb other components such as carotenoids and flavonoids less readily. Thus, by way of example only, if the preferred outcome is a treated essential oil relatively devoid of chlorophyll, but containing carotenoids and/or flavonoids, the essential oil composition is treated with a lower volume of activated carbon than if the desired outcome is a treated essential oil relatively devoid

145 of all chlorophyll, carotenoid, and flavonoid. Thus, provided herein is a method for separating chlorophyll from a essential oil composition, including the steps of contacting an essential oil composition containing chlorophyll with an adsorbent material, the adsorbent material capable of adsorbing chlorophyll, and separating the adsorbent material from the treated essential oil. The method can further comprise adsorbing chlorophyll

150 and, optionally, one or more additional components of the essential oil composition in a selected amount.

The selected amount of the chlorophyll or other components adsorbed to the adsorbent material or present in the treated essential oil can be determined using a variety of methods. For example, the treated essential oil can be visually examined (e.g., for

155 removal of sufficient green tint and/or stability of the color over a selected period of time or upon exposure to light), smelled (e.g., for a pleasant aroma and/or stability of the aroma over a selected period of time or upon exposure to light), or tasted (e.g., for a pleasant taste and/or stability of the taste over a selected period of time or upon exposure to light). Visual examination can include, for example, manual or computer aided comparison to

160 color standards. Other standard analytical and chemical techniques can also be performed to verify that the selected amount of the chlorophyll or other components is adsorbed to the adsorbent material or is present in the treated essential oil. Thus, methods such as liquid or gas chromatography, UV- Vis or IR spectroscopy, elemental analysis, or mass spectrometry, and the like, can be used to assess the treated oil. Further, the level of

165 oxidation/stability of an essential oil composition can be assessed using chemical analysis before and after a period of time or before and after exposure to light.

The methods described herein involve contacting an essential oil composition with an adsorbent material then separating the treated essential oil from the adsorbent material. Various methods and apparatuses for contacting a composition such as an essential oil

170 composition with an adsorbent material are available. For example, an essential oil composition and an adsorbent material can be combined in a mixer to form a slurry, then the treated essential oil and the adsorbent material can be separated. The treated essential oil can be decanted from the absorbent material after sedimentation/precipitation or, optionally, after centrifugation. Further, an essential oil composition can be filtered

175 through a column containing an adsorbent material. When a column is used, the essential oil composition is injected or poured onto the column and the treated essential oil is eluted from the column, optionally, under pressure. Such methods can be performed in batch or continuous modes with replacement or regeneration of the adsorbent material as needed. Also provided herein is a method of isolating one or more components from an

180 essential oil composition comprising contacting an essential oil composition with an adsorbent material, separating the adsorbent material from the treated essential oil, and recovering the components adsorbed to the adsorbent material. When the one or more components include chlorophyll, carotenoid, and flavonoid the components are recovered from the adsorbent material using a polar solvent. Polar solvents useful in removing

185 adsorbed components are selected from the group consisting of methanol, acetone, ethanol, butanol, propanol, isopropanol, methylene chloride (dichloromethane), suitable mixtures thereof, and the like. Selective removal of one or more adsorbed components over one or more other components may be possible through solvent selection or derivatization of the adsorbed components. Recovery of components adsorbed to the

190 adsorbent material during the treatment of essential oils is also possible, i.e., as a recovered by-product of the essential oil treatment process.

Provided herein are essential oils made by the methods disclosed. Thus the essential oils have a selected amount of chlorophyll and/or other components according to the desired use. Also provided are compositions comprising one or more components 195 selected from the group consisting of chlorophyll, carotenoid, and/or flavonoid as made by the methods taught herein. The treated essential oils and/or the selected components isolated from the essential oil composition as provided herein are optionally used, for example, as colorants, flavorants, or fragrances. The treated essential oils or the components of the essential oil composition are preserved by drying, cooling, or freezing

200 for subsequent use or are immediately added to other compositions, e.g., drinks, foods, perfumes, medications, or the like. The components of the essential oil composition can be further prepared or treated, for example, by concentration, separation, or purification (if more than one component is present).

The compositions, apparatus, and methods of the appended claims are not limited

205 in scope by the specific compositions, apparatus, and methods described herein, which are intended as illustrations of a few aspects of the compositions, apparatus, and methods of the claims and any compositions, apparatus, and methods which are functionally equivalent are within the scope of this disclosure. Various modifications of the compositions, apparatus, and methods in addition to those shown and described herein will

210 become apparent to those skilled in the art and are intended to fall within the scope of the appended claims. Further, while only certain representative combinations of the compositions, apparatus, and of the method steps disclosed herein are specifically described, other combinations of the apparatus components and method steps will become apparent to those skilled in the art and also are intended to fall within the scope of the

215 appended claims. Thus a combination of components or steps may be explicitly mentioned herein; however, all other combinations of components and steps are included, even though not explicitly stated. The term comprising and variations thereof as used herein is used synonymously with the term including and variations thereof and are open, non- limiting terms.