WO2008138083A2

WO2008138083A2 - Process for clarification and enrichment of citrus oil

Info

Publication number: WO2008138083A2
Application number: PCT/BR2008/000132
Authority: WO
Inventors: Jefferson Ferreira Pinto; Rubens Filho Maciel; Glaucia Maria Ferreira Pinto; Maria Regina Wolf Maciel; César Benedito BATISELLA
Original assignee: Universidade Estadual De Campinas-Unicamp
Priority date: 2007-05-10
Filing date: 2008-05-09
Publication date: 2008-11-20
Also published as: BRPI0701771B1; WO2008138083A3; BRPI0701771A2

Abstract

The present invention uses the molecular distillation technique, with the use of low temperatures, for the clarification and enrichment of citrus oils in order to increase the concentrations of the components of interest in the obtained distillated stream and residue stream. The quantitative composition of the distillate and the residue in relation to the components of interest can be adjusted by experimental changes in the sense of concentrating or reducing the presence of compounds by varying essentially the evaporator temperature and the feed flow rate. In the example described in the present invention, non volatile compounds were eliminated by 99.5% in the distillate and concentrated in 523% in the residue. The concentration of the most volatile compounds in the distillate reached +137% and the elimination of the least volatile compounds reached -95%. The concentration of the least volatile compounds in the residue reaches +1237% and the elimination of the most volatile compounds reached -98%.

Description

Specification of Patent of Invention for "PROCESS FOR CLARIFICATION AND ENRICHMENT OF CITRUS OIL"

The present invention relates to a process for clarification and enrichment of oils from citrus fruits (citrus oils), using molecular distillation without the use of solvents and at such temperatures and pressures that enables to obtain fractions enriched with volatile compounds and fractions enriched with non-volatile compounds, substantially increasing the added value of the obtained oil.

Description of the prior art

Large amounts of citrus oils are used in food and cosmetic industries. These oils are commonly produced through cold expression, as a byproduct of the citrus juice industry. Orange oil, the most abundant product due to the large production of orange juice, may contain, in the volatile fraction, more than 95% of terpene hydrocarbons, especially limonene. In orange oil, there are about 300 different compounds, many of which are the cause of undesirable color and residues. These compounds, when used as an additive for other products, contribute very little to the flavor and aroma and can be somewhat unstable. The products of its breakdown are detrimental to the flavor of the resulting product containing the oil. Owing to the above and the increasing demand for contaminant-free and high-quality products, there has been a growing interest in the development of techniques which allow for obtaining the fractionation and clarification of essential oils. Furthermore, the clarified and enriched oil can achieve a much higher marketing value than raw oil.

The chemical composition of orange juice, in quantitative terms, may vary a lot depending on the origin and kind of the orange employed, harvest, crop conditions, season of the year, irrigation, etc. The constitution of citrus oil may be divided essentially into the volatile fraction, constituted primarily by terpene hydrocarbons, aldehydes, ketones, alcohols, esters, carboxylic acids, and oxides, and the non-volatile fraction, comprised primarily of flavonoids, carotenoids, coumarins, pectins, and alkaloids.

Commonly used procedures used for clarifying and enriching citrus oils comprise vacuum distillation, alcohol extraction, extraction with alcohols, use of a solvent having different polarities, preparative chromatography, and, most recently, extraction using supercritical fluid. These processes have drawbacks, such as the use of organic solvents which must be subsequently removed, thermal degradation of the product due to the high temperature employed (specially in processes like distillation) and high operational and development costs, such as in the case of extraction using supercritical fluid.

Clarification processes used for orange oil include ultrafiltration, addition of oxidizing agents and activated carbon, filtration with diatomaceous earth, microfiltration and membranes, but such processes do not lead to very satisfactory results.

US5558893 discloses a process for obtaining citrus oil substantially free of pesticides using molecular distillation. The obtained citrus oil can be used a an additive for foods, improving aroma and flavor characteristics, as well as an additive for perfumes, soaps, lotions, and similar products. Although it describes the employment of molecular distillation, the main objective of this work is obtaining fractions of pesticide-free oil, what can only be attained with the use of temperatures in the range of 8O⁰C (176⁰F) to 135⁰C

(275⁰F). Substances which are of interest and that contribute towards increasing the added-value of the obtained oil are degraded at such temperatures.

US2003/0203090 discloses the obtainment, through distillation carried out at 200⁰C (392⁰F), of orange oil with a higher content of the terpene valencene. According to the invention, the obtainment of an orange juice fraction having higher valencene content along with the treatment of the obtained fraction with alkalis, results in a oil free of substances which cause bad odor resulting from the distillation process. The obtained oil can be utilized directly as an addictive in fragrances. Said invention, although results in obtaining an oil having a low content of substances which cause bad odor, chooses to remove them after their formation and, as mentioned, has the compound valencene as the main component for enriching the obtained oil.

CN 1107007 discloses orange juice processing steps aiming at obtaining and separating coloring substances present in the oil. According to the described process, the orange juice is subjected to low temperatures (6 to 8⁰C, or 42.8 to 46.4⁰F) for 60 to 80 hours, filtered for removing crystals, deaerated and subjected to distillation at pressures of 0.85 to 0.96 Torr and temperatures from 9O⁰C to 11O⁰C (194⁰F to 23O⁰F).

In the present invention, molecular distillation arises as an advantageous alternative which is able, at the same time, to clarify and enrich the obtained citrus oil in the resulting fractions of the process. The process described by the present invention allows for obtaining a distillate stream composed of the citrus oil fraction clarified and enriched with volatile compounds of interest and a residue stream composed of the fraction enriched with the non-volatile compounds, including those responsible for the coloring of the oil.

Objects of the invention

An object of the present invention is to provide a process for the clarification and enrichment of citrus oil substantially free of impurities.

Another object of the present invention is to obtain distillate and residue streams using the process according to the present invention.

A further object of the present invention is to provide a process for the production of citrus oil clarified and enriched with volatile compounds using the process of the present invention as well as to provide a process for producing citrus oil enriched with non-volatile compounds using the process of the present invention.

Summary of the invention

This invention relates to a process using molecular distillation for clarification and enrichment of citrus oil obtained generally as a byproduct in the production of citrus juice. The molecular distillation subject of this invention can be carried out in a falling film molecular distillator, as well as in a centrifugal molecular distillator, having, as a result, the formation of two citrus oil fractions enriched with non-volatile substances or volatile substances. This invention discloses, for the first time, the use of molecular distillation with the function of clarification and enrichment of citrus oil, reducing the processing time to a few minutes and enabling the use of said process for the continuous obtainment of high value- added citrus oil.

Description of the Drawings

Figure 1 shows a centrifugal molecular distillator.

Figure 2 shows a schematic view of the centrifugal molecular distillator adapted according to the present invention.

Figure 3 shows chromatograms obtained by

High-Performance Liquid Chromatography (HPLC), (A)Sample, (B)Distillate, (C)Residue.

Figure 4 shows chromatograms obtained by Gas Chromatography (GC), (A)Sample, (B)Distillate, (C)Residue. Detailed description of the invention

Citrus fruit are widely known in the agricultural scenario, comprising, besides orange, lemon, tangerine, lime, citron and pummelo.

The orange tree (Citrus sinensis L.) is a tree of Asiatic origin, belonging to Rutaceae family. Widely-spread in the agricultural scenario, it is present in all five continents and about 70 countries. Despite the popularization of its cultivation, in order to achieve an economically-acceptable production, these plants require extra care and special techniques. In virtue of the limited use of technologies, Brazilian orchards have a productivity level considered low, representing less than half of the productivity of Florida (USA), the main competitor to Brazil in the international market. Numerous varieties make up the group of plants, wherein the most commercially exploited are the oranges "Pera", "Valencia", "Natal", "Bahia", "Baianinha", "Hamlin", "Lima", and "Piralima". In the State of Bahia, for calculation purposes, it is estimated that the average production of technically conducted plantations is of 150 fruits per plant in the fourth year, increasing to 200 in the fifth, 300 in the sixth, and 400 fruits in the seventh year of production (Source: Embrapa). Orange culture is a significant business and an important portion of the economies of various countries and European regions, such as Spain, Italy, Romania, and the area of Algarve in Portugal. On other continents, there is a significant production in South Africa, Zimbabwe, in the States of Florida and California in USA, in South America, especially in Argentina and Brazil, and the district of 'Riverina' in Murray River, Australia.

Brazil, driven by the growth in exports and the development of the citrus industry, is now the biggest worldwide producer of oranges, with State of Sao Paulo accounting for 80% of this production.

Although juice is the main product of orange, various byproducts having commercial value are obtained during its manufacturing process. Among these byproducts are essential oils, d-limonene, terpenes, aromatic liquids and citrus pulp pellets.

Essential oils have different applications in the internal and external market, which include the manufacturing of chemical products and solvents, aromas and fragrances, substances for application in paint and cosmetic industries, as a complement for animal food, and the like. In the last 10 years, Brazil has exported, on average, around 23,900 tons of essential oils. Essential oils are volatile oils which are extracted from the rinds of citrus fruits. During the juice extraction process, the oil bags of the rind are broken, releasing the product, which is then removed by means of water jets. Next, it is separated by means of centrifugation and then cooled.

Some techniques have been studied for use on the purification, clarification, and fractionation of essential oils.

For clarification, various oxidizing agents have been utilized, which did not lead do good results. The use of chloroform and activated carbon enabled the partial clarification of the oil, but has the drawbacks of using a toxic organic solvent, introducing more than one contamination source, longer preparation time and laboriousness.

Other techniques used for clarification were ultrafiltration and microfiltration, which have the drawbacks of requiring a long time for sample preparation and high cost of the consumables involved.

Among techniques used for the fractionation of orange oil, we can mention distillation and vacuum distillation, whose major disadvantages are the employment of high temperatures, which can degrade the compounds present in the oil and bring on losses of volatile compounds, in addition to requiring a long preparation time.

Adsorption and preparative chromatography techniques also are alternatives of rough separation of the essential oils, having as major drawbacks the introduction of solvents, which have to be removed subsequently and which can result in contaminations and losses, high costs of the involved material and laboriousness.

The industrial sector, in view of environmental and health restrictions, has been looking systematically for alternatives to its inputs and raw materials, seeking principally the ones of natural origin and which exhibit benefits to the human being, what implicates in better final products available on the market and the obtainment of a competitive edge.

One of the biggest challenges in getting along in face of this choose of raw materials and inputs originating from natural sources is on the obtainment of these materials itself and, mainly, on the isolation and purification thereof which assure the quality necessary for their safe application in the market.

In this context, today the obtainment of citrus oils clarified and enriched with volatile or non-volatile oils through simples and economically-feasible processes represents a challenge to be overcome. The present invention relates to the obtainment of citrus oil fractions enriched with volatile substances or non-volatile substances through the use of molecular distillation.

Molecular distillation is a special kind of distillation which occurs in high vacuum, where the evaporator and the condenser meet each other at a distance on the order of the mean free path of the evaporated molecules and the holding time of the distilled material is on the order of 1 minute. Its potential owes to the fact of enabling the obtainment of compounds having thermal sensitivity, as is the case on most of the constituents of essential oils, since, for operating in high vacuum, it utilizes lower temperatures. Moreover, there is no need for the use of solvents and it allows for separating contaminant substances by distinct volatilities and molecular weights. By using this separation technique, it is also possible to separate the bioactive compounds from other undesirable compounds through efficient separation, with minimal thermal decomposition and maximum product quality.

Further characteristics of this process are: low residence time of the processed liquid (usually less than 1 minute), use of low temperatures due to operation under high vacuum and high efficiency on mass and heat transfers.

The present invention describes, for the first time, the introduction of citrus oil substantially free of impurities, in a molecular distillator and the obtainment of a distillate stream enriched with volatile compounds while another residue stream is obtained enriched with non-volatile compounds. The invention also addresses the possibility of redistillating the formed residue in order to obtain new distillate and residue streams enriched with desired components.

The citrus oil used as the initial raw material of the invention should be substantially free of impurities. The impurities described herein include water, solvents and/or solids in suspension. The obtainment of a citrus oil substantially free of impurities is attained through filtration of liquid and/or solid impurities. The filtration of liquid impurities is carried out through filtration of the oil after the addition of a drying agent while the filtration of solid impurities is carried out by means of direct filtration in filter paper The drying agents used comprise those of molecular sieve, zeolite, and anhydrous sodium sulfate salt type. The process of clarification and enrichment according to the present invention utilizes, as a raw material, citrus oil selected from the group consisting of orange oil, lemon, tangerine, lime, citron and pummelo. Preferably, orange oil is used as an initial raw material for the process described herein.

The process of clarification and enrichment of citrus oil through the use of molecular distillation does not employ any solvent of any nature and, therefore, allows for obtaining the pure product, without the need for a step of cleaning/eliminating the solvent; does not utilizes high temperatures, thus assuring not to occur thermal degradation or losses of the volatile compounds of interest.

In the falling film molecular distillator, the citrus oil is subjected to vacuum and changes immediately into a very thin film on the surface of the evaporator, evaporating quickly. The heated walls and the high vacuum carry the most volatile compounds (which distil) to a closed inner condenser, producing, as a result, the distillate stream, while the least volatile compounds remain in the cylinder forming the residue stream, which is also a product of the process. Therefore, the resulting fractions constitute separated phases and exit individually. Depending on the application, the desired product can be either the distilled material stream enriched with volatile substances or the obtained residue stream enriched with non-volatile substances In the centrifugal molecular distillator, the centrifugal force enables to form a thin liquid film which passes through the heated disc and contacts the surface of the condenser. The lightest compounds evaporate and condensate in fractions of seconds. The residues (constituted by heavier compounds) do not evaporate and are collected in concentric collectors. The short residence time and the low operational temperatures reduce the risk of thermal decomposition of the molecules. The use of a heated central rotating disc is a mechanical way to create a thin liquid film evenly distributed. The separation degree is a function of the difference between molecular weights of the mixture to be separated. The bigger is the difference between molecular weights, the higher is the separation. In mixtures having similar molecular weights, the obtained purity can be low making it necessary to perform consecutive distillations.

The purity of the distillate also depends on the thickness of the film/mass diffusivity. The absence of air molecules (high vacuum) also allows the distilled molecules to reach the condenser easily, what reduces the return of molecules to the surface of the liquid present in the evaporator (non-equilibrium process).

Molecular distillators used in the present invention comprise falling film molecular distillators or centrifugal molecular distillators. For the application proposed in the present invention, preferably the centrifugal molecular distillator is used. Figure 1 shows a centrifugal molecular distillator where it can be seen the feed and exit temperature controls 20, the feed and exit flow rate control 21 , the vacuum control 22, the evaporator temperature control 23, the sample feed vessel 24, the rotor/evaporator 25, the condenser 26, and the distillate 27 and residue 28 exit pipes. Figure 2 schematically shows the centrifugal molecular distillator adapted to the present invention.

The centrifugal molecular distillator usually operates under pressures of about 10 ³-10^"4 Torr, being efficient for compounds having molecular weights ranging from 150 to 4000, providing high flow rates and low cost. The centrifugal molecular distillator is comprised by a mechanical vacuum pump 1 , a oil-diffusion vacuum pump 2, a cold trap for vacuum for protecting the vacuum pump 3, a pressure valve, a condenser 4, a rotor 5, a rotor/evaporator heating 6, a fine adjustment valve 7, a high vacuum valve 8, a trap valve 9, a sample vessel 10, sample conducting pipes 11 with heating mantle and thermocouple for temperature control, a distillate 13 and residue 14 vessel, distillate 15 and residue 16 exit channels involved by heating mantle and thermocouple for output temperature control and coarse adjustment valve 17. Although any falling film molecular distillator or centrifugal molecular distillator can be used in the process according to the present invention, some modifications were made on the centrifugal molecular distillator of the present invention in order to allow the clarification and enrichment of citrus oil using a continuous stream of raw material, with the consequent obtainment of continuous streams of distillate and residue. These adaptations were related to the installation of a direct displacing pump 12 for continuous feeding and the installation of a direct displacing pump provided with check valves 18 in order to allow products to exit without losing vacuum, enabling to work with continuous process flow. The introduction of these pumps also allows the vacuum to remain constant during operation and be kept in the optimized operating range. The modifications described herein on the molecular distillator are liable to be carried out in any molecular distillation apparatus.

Molecular distillation does not makes the use of solvents of any nature and allows to work with low temperatures, thus avoiding the possibility of introducing more contaminants, loss of purity, sample degradation and loss of volatile compounds. Furthermore, molecular distillation still have the advantages of being fast (sample residence time is lesser than 1 minute), not involving any consumables, and not being laborious or destructive.

The process according to the present invention can be described as follows: the input and output temperature of citrus oil in the molecular distillator is adjusted; the condenser temperature is adjusted; the mechanical pump responsible for obtaining a low internal pressure of the molecular distillator is turned on, wherein it must be operated only when pressure is under or equal to 0.5 Torr; liquid nitrogen is placed on the trap of the mechanical pump to prevent volatile compounds from reaching the pump; the evaporator temperature is adjusted; the rotor is turned on by adjusting the rotation of the same; and the citrus oil sample substantially free of impurities is introduced directly into the feed of the molecular distillator. Distillate and residue fractions are collected in the distillate and residue streams, respectively. The sample input temperature (feeding) should be kept controlled and constant in order to ensure the sample will enter in the system under suitable conditions for undergoing clarification and enrichment process. The optimized range of feeding temperature of the citrus oil in the molecular distillator according to the present invention is between 3O⁰C and 5O⁰C (86⁰F and 122⁰F). The feeding temperature preferably used is of 3O⁰C (86⁰F). The temperature applied to the sample on the time of distillation, known as evaporator temperature, is one of the most important factors on determining how will the fractionation occurs and what will be the quality of the clarification. The distance between the evaporator and the condenser must be of the mean free path of molecules such that residence time is the lowest as possible and that degradations, reactions, or combinations between molecules do not occur. As low the evaporation temperature is, lower will be the degradation caused on the thermally unstable compounds, but if the same is too low and the vacuum is not suitable the result will not be satisfactory. For proper clarification and obtainment of fractions enriched with citrus oils, the evaporator of the molecular distillator should operate at a temperature from 30⁰C to 5O⁰C (86⁰F to 122⁰F) for an adjusted internal pressure in the range of 0.3 Torr to 0.5 Torr. Preferably, the temperature of the evaporator should be set to 3O⁰C (86⁰F) under a pressure of 0.3 Torr. The temperature of the condenser should be kept constant from the beginning to the end of the process ensuring the collection of the suitable fraction of the condensed sample. For the present invention, condenser temperatures in the range of 1 O⁰C to 4O⁰C (5O⁰F to 104⁰F) are used. Nevertheless, preferably, the temperature of 1O⁰C (5O⁰C) is used. The output temperature of the residue and distillate streams should be controlled and kept constant to ensure that the sample fractions, upon exiting the system, do not suffer changes in its physicochemical properties and are still able to be collected with its proper characteristics. In the present invention, the output temperature should be set within the range of 3O⁰C to 5O⁰C (86⁰F to 122⁰F) and, preferably, should be set to 3O⁰C (86⁰F).

For obtaining enriched fractions as described in the present invention, the rotating speed of the rotor of the centrifugal molecular distillator used should be of 1350 rpm to 1730 rpm. Preferably, the rotor is operated at a rotating speed of 1750 rpm.

By means of modifications made on the centrifugal molecular distillator previously described, the continuous clarification and enrichment of orange oil samples was rendered possible. The optimized sample feed flow rate in the molecular distillator of the present invention is of 2.5 to 10 ml/min. and, preferably, it is operated at a flow rate of 5 ml/min. Further steps of residue redistillation may be introduced if it is desired to fractionate the product with other qualitative and quantitative compositions.

In the present invention, the clarification and enrichment of orange oil through centrifugal molecular distillation and obtainment of distillate and residue streams were evidenced by means of analyses utilizing high- performance liquid chromatography (HPLC), gas chromatography with flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometer (GC- MS). The evaluation of the non-volatile compounds, specially carotenoids, flavonoids, coumarins, and pectins and alkaloids, was carried out by HPLC while the qualitative and quantitative determination of the volatile fraction was carried out by GC- FID and GC-MS. The regions delimitated by the peaks resulting from the analyses carried out by HPLC shown in Figure 3 are proportional to the total amount of non-volatile substances detected in the sample (Figure 3A), residue stream (Figure 3C), and distillate stream (Figure 3B). Nonvolatile substances comprise flavonoids, carotenoids, coumarins, pectins, and alkaloids. As it can be seen, the concentration of non-volatile substances in the residue (Figure 3C) is markedly superior to the concentration of nonvolatile substances in the sample (Figure 3A). The fraction corresponding to the distillate stream (Figure 3B) has shown to be substantially free of non-volatile compounds. The results of HPLC show that the initial content of non-volatile compounds liable for coloring was eliminated in the distillate stream by, at least, 99.5% and was concentrated in the residue stream by, at least, 523% as compared to the orange oil sample employed in the experiment. Results obtained through the use of gas chromatography are shown in Figure 4. The initial orange oil sample (Figure 4A), the residue stream (Figure 4C), and the distillate stream (Figure 4B) were analyzed. Compounds which are more volatile are represented by the peaks with lower holding time. Compounds identified by GS-MS by elution order were: alpha pinene, sabinene, mircene, felandrene, non-identified limonene, nonanal, linalool, cineole, careno, citronellal, decanal, neral, geranial, dodecanal, cariofilen, beta-copaeno, farnesene, retinal, valencene, beta- sinensal, alpha-sinensal. Peaks having a holding time lower than 2.2 min. are resultant from the solvent. The comparison of the obtained chromatogram of the distillate (Figure 4B) with the chromatogram of the sample (Figure 4A) shows that compounds having a holding time lower than 10 minutes (more volatile compounds) were concentrated, what can be verified by the larger delimited area by the respective peaks, while compounds having a holding time higher than 10 minutes had their concentration reduced.

The residue chromatogram (Figure 4C) compared with the sample chromatogram (Figure 4A), shows that compounds having a holding time lower than 8 minutes had their concentration decreased, while compounds having a holding time higher than 8 minutes had their concentration increased, wherein some compounds which were only slight visible in the sample became significant in the residue. The results obtained by gas chromatography show that distillated stream concentrated the most volatile compounds, specially alpha-pinene, limonene, sabinene, mircene, and linalool, and that residue stream concentrated the least volatile compounds, like valencene. The quantitative composition of terpenes of the distillate and residue can be easily adjusted by experimental changes in the sense of concentrating or decreasing the presence of compounds by varying the evaporator temperature and the feed flow rate. The concentration of the most volatile compounds in the distillate stream, when orange oil was used, was of +137% and the elimination of the least volatile compounds was of -95%. The concentration of the least volatile compounds in the residue stream was of +1237% and the elimination of the most volatile compounds reached -98%.

The chromatographic evaluation conditions were the following:

• for HPLC, uPorasil column of 300 x 3.9 mm, mobile phase constituted by ethanohhexan 50:50, v/v; flow rate of 2 mL/min., wavelength of 254 and 315 nm, room temperature; Waters equipment, UV detector 2480. For GC-FID, DB-17 column of 0.25 mm x

30 m x 0.5 μm; injector temperature of 250⁰C, column temperature from 50°C/122°F (2 minutes) to 250°C/482°F

(5°C/minute or 41°F/minute), detector temperature of 25O⁰C; helium as carrier gas; equipment: GC Varian Star 3600 Cx.

For GS-MS, Varian Foctor Four column of 0.25 mm x 15 m x 0.25 μm; injector temperature of 25O⁰C, column temperature from 50°C/122°F (2 minutes) to 250°C/482°F (5°C/minute or 41°F/minute); interface temperature of 15O⁰C; helium as carrier gas; equipment: GC Varian Star 3600 Cx Satun 2000 GC/MS/MS.

Claims

1. A process for clarification and enrichment of citrus oil substantially free of impurities, characterized in that it comprises the following steps:

a) introducing citrus oil in a molecular distillator; and

b) obtaining a distillate stream enriched with volatile compounds and a residue stream enriched with nonvolatile compounds.

2. Process for clarification and enrichment of citrus oil, according to claim 1 , characterized in that the citrus oil is selected from the group consisting of orange oil, lemon oil, grapefruit oil and tangerine oil.

3. Process for clarification and enrichment of citrus oil, according to claim 2, characterized in that the citrus oil is orange oil.

4. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 3, characterized in that the impurities comprise water, solvents and/or solids in suspension.

5. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 4, characterized in that the citrus oil substantially free of impurities is obtained by filtration of liquid and/or solid impurities.

6. Process for clarification and enrichment of citrus oil, according to claim 5, characterized in that the filtration of liquid impurities is carried out by means of a drying agent.

7. Process for clarification and enrichment of citrus oil, according to claim 6, characterized in that the drying agent is selected from agents of the type comprising molecular sieve, zeolite and anhydrous sodium sulfate salt.

8. Process for clarification and enrichment of citrus oil, according to claim 5, characterized in that the filtration of solid impurities is carried out by means of gravity in a filter paper.

9. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 8, characterized in that it comprises a step of redistillating the residue after step b).

10. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 9, characterized in that the molecular distillator is selected from the group consisting of falling film molecular distillator and centrifugal molecular distillator.

11. Process for clarification and enrichment of citrus oil, according to claim 10, characterized in that the molecular distillator comprises a direct displacing pump (12) and a direct displacing pump having check valves (18).

5 12. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 11 , characterized in that the feeding temperature of the molecular distillator is from 30°C/86°F to 50°C/122°F.

13. Process for clarification and enrichment ofo citrus oil, according to claim 12, characterized in that the feeding temperature of the molecular distillator is of 30°C/86°F.

14. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 13,5 characterized in that the pressure in the interior of the molecular distillator is lower or equal to 0,5 Torr.

15. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 14, characterized in that the evaporator temperature of theo molecular distillator is from 30°C/86°F to 50°C/122°F for a pressure of 0.3 Torr to 0.5 Torr.

16. Process for clarification and enrichment of citrus oil, according to claim 15, characterized in that the evaporator temperature of the molecular distillator is of 30°C/86°F for a pressure of 0.3 Torr.

17. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 16, characterized in that the condenser temperature of the molecular distillator is from 10°C/50°F to 40°C/104°F.

18. Process for clarification and enrichment of citrus oil, according to claim 17, characterized in that the condenser temperature of the molecular distillator is of 10°C/50°F.

19. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 18, characterized in that the output temperature of the molecular distillator is from 30°C/86°F to 50°C/122°F.

20. Process for clarification and enrichment of citrus oil, according to claim 19, characterized in that the output temperature of the molecular distillator is of 30°C/86°F.

21. Process for clarification and enrichment of citrus oil, according to claims 10 or 11 , characterized in that said molecular distillator is a centrifugal molecular distillator.

22. Process for clarification and enrichment of citrus oil, according to claim 21 , characterized in that the rotation speed of the rotor of the centrifugal molecular distillator is from 1350 rpm to 1750 rpm.

23. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 22, characterized in that the volatile compounds of the distillate stream comprise terpene hydrocarbons, aldehydes, ketones, alcohols, esters, carboxylic acids and oxides.

24. Process for clarification and enrichment of citrus oil, according to any one of claims 1 to 23, characterized in that the non-volatile compounds of the residue stream comprise flavonoids, carotenoids, coumarins, pectins and alkaloids.

25. Distillate stream characterized in that it is obtained by means of a process as defined in any one of claims 1 to 24.

26. Distillate stream, according to claim 25, characterized in that it comprises citrus oil clarified and enriched with volatile compounds.

27. Distillate stream, according to claim 26, characterized in that the citrus oil is orange oil.

28. Residue stream characterized in that it is obtained by means of a process as defined in any one of claims 1 to 24.

29. Residue stream, according to claim 28, characterized in that it comprises citrus oil enriched with nonvolatile compounds.

30. Residue stream, according to claim 29, characterized in that the citrus oil is orange oil.

31. A process for producing citrus oil clarified and enriched with volatile compounds, characterized in that it comprises the use as defined in any one of claims 1 to 24.

32. A process for producing citrus oil clarified and enriched with volatile compounds, characterized in that it comprises the use of the process as defined in any one of claims 1 to 24.

33. Citrus oil, characterized in that it is obtained by means of the process as defined in claims 31 or 32.

34. Citrus oil, according to claim 33, characterized in that it is orange oil.