AU594129B2 - Process for production of useful products from citrus fruit peel - Google Patents

Description

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594129 Form

AUSTPALIA

PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. CI: Application Number: 6 3'J Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority o 0o 04 a IRelated Art:

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0 a a This document contains the amendments made under Section 49 and is correct for printing.

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'4 '0 DIVIDED FROM 11308/83 0 *0 0 TO BE COMPLETED BY APPLICANT Name of Applicant: TROPICANA PRODUCTS, INC.

?\dd.'ess of Applicant: t V (C C Actual Inventor: t r P.O. Box 338 Bradenton Florida 33506

U.S.A.

Mr James M BONNELL AUUIess for Service: CLEMENT HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

Complete Specification for the invention entitled: "PROCESS FOR PRODUCTION OF USEFUL PRODUCTS FROM CITRUS FRUIT PEEL" 1 II j The following statement is a full description of this invention, including the best method of performing it known to me:- PF/CPlF/2/80 L. ii BACKGROUND OF THE INVENTION The present invention is directed to the processing of solid citrus frL'uit-derived waste to provide useful products, as well as a medicament comprised of solvent-extracted citrus fruit peel.

One of the major problems encountered over the years with respect to the production of citrus fruit products such as orange juice, orange concentrate and orange sections has been the disposal of the various waste products including the orange peel, seeds, rag and pulp. For many years these materials were believed to be of little practical value and accordingly were simply disposed of as waste without being processed in any way.

In recent years, however, it has been found that a 0 certain of these waste materials the peel) could be further processed to provide an excellent and highly nutritious 0 00 o cattle feed. Unfortunately, while the use of such processed 04 0 wastes did help to alleviate a portion of the waste disposal 004o problem, the processing of the wastes to provide cattle feed was S not as economically attractive as had been hoped.

SAccordingly, efforts have recently been made to process such waste materials to provide products which are suitable for *J V human as well as animal consumption. It is also desirable .to provide a diverse range of products from the processing of such c~* materials in order to take full advantage of the raw materials contained therein.

Unfortunately, the waste materials are not easily processed in an attempt to meet these ends. For example, U.S.

Patent 2,215,944 discloses a process where the orange peel is treated with lime to provide a product suitable for use as cattle

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-2i::i i. .rl J- :-4 $7r' i feed. However, the use of lime is not advantageous as it generally yields a bitter tasting product. In addition, the pectin which is present in the peel is destroyed or damaged during processing with lime, thus removing one of the desirable components in the peel from the standpoint of human and animal consumption. However, the peel is difficult to process without the use of lime or related materials magnesium or aluminum-containing compounds) since it is very slimey. The processed peel is also difficult to dry due to the cellular structure of the peel which is usually rendered less intact through contact with materials such as lime.

In addition, the peel contains a substantial amount of L various sugars which are desirably removed from the peel in order to reduce the caloric content of the finished product. The bO sugars are very hygroscopic and, if present in significant amounts, also render the processed peel very difficult to dry.

The peel also contains significant amounts of essential oils naturally occurring volatile oils) which are the odor .0 00. and/or flavor component of the peel. The essential oils can provide bitter or unpleasant taste sensations and are thus t desirably removed from the peel.

As an alternative to lime processing, waste peels have been washed with water to remove portions of the sugars and bad flavors present. Such aqueous washing does not, however, remove much of the essential oils which are present. Carotenoid pigments also remain in the product, and after a short period of time, oxidize to produce an unpleasant "haylike" flavor. The water-washed products are also difficult to press in order to remove excess water. The finished product thus generally ~13 i 1 r -3contains an unreasonably high water content 85 percent by weight or greater), rendering the product expensive to dry. An additional waste material in the form of the wash water is also created which is difficult to treat due to the presence of the sugars and other peel-derived components which have been extracted from the peel.

It is therefore desirable to provide an improved process for the treatment of the waste materials derived from the processing of oranges in order to produce a variety of useful products in addition to those which are suitable for human and animal consumption. It is also desirable to provide a process which is more attractive economically as well as more efficient i than the processes conventionally employed in the orange 1o*o processing industry.

o o0 In recent years, it has also been found that certain 0o 4 components of the peel pectin) possesses properties which enabled the pectin to be advantageously employed in the control of serum cholesterol. Such advantages have been reported in the literature in recent years, such as, for example, in The Tampa 9 Tribune Times, April 30, 1978, p. 3-E; Food Product Development, April, 1978, pages 81-88; Sarasota Herald-Tribune, August 6, 1977, page 9-C; Bradenton Herald, July 19, 1978, p. 6-C; St.

Petersburg Times, October 16, 1977, page 22B; The Tampa Tribune, 2 August 6, 1977, page 7B; The Chemurgic Digest, May 15, 1944, rz pages 119-121. i1 j Pectin has also been discussed in the patent literature with respect to its various therapeutic effects. See, for example, U.S. Patent Nos. 2,139,139; 2,145,016; 2,294,016; -4i.

i~4T-ri 2,333,950; 2,481,804; 2,481,805; 2,865,757; 3,190,756; and 3,306,819.

However, the therapeutic administration of pectin per se has frequently resulted in the occurrence of various side effects such as intestinal cramping and abdominal distension. It is therefore desirable to provide an improved method of administration of pectin whereby such side effects can be reduced or minimized.

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0 9 i BRIEF DESCRIPTION OF THE DRAWING The Figure schematically depicts the process of the present invention wherein citrus fruit-derived waste is treated to provide a variety of products.

DETAILED DESCRIPTION OF THE INVENTION The process of the present invention will be described in conjunction with the Figure. For the purposes of the present invention, citrus fruit is used in the usual sense and intended to include oranges, grapefruit, lemons, limes, and tangerines.

For ease of discussion, however, the present invention will be discussed in terms of orange peel. In accordance with the process of the present invention, waste orange peel is provided which consists of waste from a conventional process such as the processing of oranges to provide orange juice. The peel is fed to and coarsely ground in a suitable mill 2 such as a hammer mill. The peel is ground to an extent such that the peel is substantially broken up.

The ground orange peel is then preferably passed to a steam blanching zone 4 wherein it is contacted with steam for o 00 er a 0 0 00 00 04 00D o a o O o ®a oa o 10 00 o 0 0 0 60 04 0 00 04 0 00 0 0 o 00 0 i t0 4 0 4 several minutes, followed by extrusion in a screw finisher 6.

The peel is contacted with steam in the steam blanching zone for about 5-15 minutes to soften the peel and render it more amenable to extrusion in the screw finisher. The screw finisher serves to remove any seeds, stems or leaves which may have been included with the peel waste, as well as rendering the peel more finely divided. Naturally, the more finely divided the peel is, the more effective will be the solvent extraction process.

As noted above, combination of the steam blanching and extrusion steps is not solely applicable, however, to processes wherein orange peels are processed. Advantageously, these steps also enhance the extractive processing of various types of citrus fruit-derived peels grapefruit peel,. lemon peel, lime peel, etc.) by rendering the peels more amenable to extraction with various types of aqueous or non-aqueous liquids water, lower alcohols, lower ketones, etc.). The use of a screw finisher is not critical to practice of the present invention and the ground peel from the mill 2 may be passed directly to the mixing zone 8.

The peel is then passed to mixing zone 8 wherein it is admixed with a suitable liquid such as the non-aqueous solvent hereinafter described or a portion of the extract 10 from the solvent extraction step to form a slurry. The slurried peel extrudate 12 is then subjected to solvent extraction in the extraction zone 14, wherein the peel extrudate is contacted with sufficient quantities of a non-aqueous solvent 16 to provide the desired degree of extraction.

In order to be suitable for use in the process of the present invention, the non-aqueous solvent must be wateri T:

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miscible. Sugar must also be soluble in an aqueous solution of the solvent. The solvent preferably has a relatively low boiling point in order to enable the solvent to be easily recovered from an aqueous solution. To further ease the recovery of the solvent, the solvent preferably does not form an azeotrope with water. Non-aqueous solvents which are suitable for use in the present invention include lower alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, or isopropyl alcohol, etc.; lower ketones such as dimethylketone, methylethylketone, etc.; and mono and dialkyl ethers of ethylene glycol or their esters such as acetates. Methyl alcohol is the preferred solvent as it does not form a azeotrope with water while also having a relatively low 0 boiling point. Advantageously, methyl alcohol also dissolves 09 oil-soluble insecticides which may be present on the peel. The above list of suitable solvents is non-inclusive, and one of 0a00 ordinary skill in the art can readily determine which non-aqueous solvents are suitable for use in the present invention.

The extruded peel may be contacted with the non-aqueous o 0 solvent in the extraction zone 14 by any manner and for a sufficient period of time suitable to extract substantially all S' of the desired components from the peel. While countercurrent extraction in multiple stages 18 has been illustrated in the Figure, batch solvent extraction operations are also appropriate and do not detract from the benefits achieved by the present invention. Countercurrent extraction is, however, the preferred method of extraction.

It should be noted that the non-aqueous solvent 16 which is fed to the countercurrent extraction zone 14 is preferably substantially undiluted substantially nonr i i: t

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-7- "1' 77 1 i i ":i oo o S0 0 0 9 o 0 0 «1 c 0 fi0f 0 0 0.0 0 o0 o 00 0' t> 4 0 0 0 06 O 000 O 00O 4 0D ol O t aqueous or commercial grade in purity). The solvent may be derived from an external source or may consist of a solvent fraction which has been recycled from subsequent processing steps as will be more fully discussed hereinafter. The solvent may be diluted with minor amounts of water less than about percent by weight of water based on the weight of the total solution) without adversely affecting the effectiveness of the extraction process.

As the solvent 16 contacts the slurried peel in the last stage of the countercurrent extraction zone, the essential oils and oil-soluble components carotene, chlorophyll, flavanones, etc.) which are present in the peel are extracted therefrom. Water is also gradually remove.d from the peel during the extraction process as the solvent passes from stage to stage in the extraction zone. As the water content of the extraction solution increases, the water-soluble components various sugars, citric acid, some salts) present in the peel are also removed. The removal of the strongly flavored essential oils from the peel enables products to be produced from the treated peel which are useful in a variety of applications without being hindered by the presence of a strong orange flavor.

The solvent extracted peel 20 which exits from the extraction zone 14 thus contains little sugar, is low in essential oils less than about 0.005 percent by weight based on dry solids), and consists substantially of protopectin cellulose and pectin). The concentration of the sugars which were originally present is generally reduced to below about percent by weight based on the weight of the dry solids. The pectin which is present in the peel is substantially unaffected -8-

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4, z' r I by the extraction process such that the dried processed peel will normally contain at least about 30 percent by weight of pectin.

Importantly, the water holding capacity of the peel is not impaired as a result of the extraction process.

The solvent extracted peel 20 is then dried in drying zone 22 by suitable means such as by contact with superheated solvent vapor to remove any solvent and moisture which may remain. The peel may be additionally dried under a vacuum to ensure bubstantially complete removal of the solvent and/or moisture. The dried, desolventized peel product is then preferably ground in a milling zone 24 by suitable means such as a hammer mill to a size appropriate for its intended use, o examples of which are given below. For ex.ample, the processed peel can advantageously be ground sufficiently to pass through an ;o 80 mesh screen using a micropulverizer, with the finely ground O t peel being bagged for storage or shipment.

S 0 The solvent-extracted peel product of the present invention advantageously contains little sugar, is low in etherextractable substances including essential oils, lipids, fats and 0" caretenoid pigments and consists substantially of protopectin (a combination of cellulose and pectin). The amount of ether extracts present in the peel is determined by AOAC Procedure No.

7.056 (direct method) or No. 7.057 (indirect method). More specifically, the peel product contains less than about 5 percent by weight of sugars and less than about 0.6 percent by weight of ether extractable solids. Preferably, the peel product contains less than about 0.01 percent by weight, and most preferably less than about 0.005 percent by weight, of essential oils (one of the ether-extractable substances.) The pectin which is present in -9- 4: ij 4 r

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BC B 4 4 the peel is substantially uneffected by the extraction process such that the peel will generally contain at least about percent by weight of pectin, and preferably at least 33 percent by weight of pectin, as determined by Medallion Laboratories of 9000 Plymouth Ave., Minneapolis, Minnesota 55427, U.S.A.

The process of the present invention thus produces a solvent-extracted citrus fruit peel which possesses the ability to reduce and/or prevent an increase in serum cholesterol when orally administered to a patient suffering from a disadvantageously high level of serum cholesterol. In order to achieve the intended decrease and/or prevent an increase in levels of serum cholesterol in the patient, amount of up to about grams of pectin in the form of the peel product of the present invention administered daily may be required, although the amounts required for each individual can vary greatly.

The peel product of the present invention may be orally administered by various means such as with an inert diluent or an edible carrier, enclosed in hard or soft capsule form, compressed into tablets or incorporated directly into various foods in particulate form. Capsules or tablets will generally contain a dosage of about 0.5 gram.

While not wishing to be bound by the following, it is bElieved that the pectin-containing peel product of the present invention can be administered with a minimum of side effects, due to the fact that the pectin is not administered alone but in conjunction with a significant amount of fiber also contained in the peel. The presence of the fiber is believed to enhance the p op, 4 4

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*4II 4 4~ body's tolerance to the presence of the pectin such that the incidence of intestinal disturbances, etc. is reduced.

The liquid extract 26 which exits from the extraction zone contains several orange peel-derived compounds which may be eventually separated therefrom to provide additional useful products. A major portion of the liquid extract comprises the non-aqueous solvent 60 to 65 percent by weight). Other components which are present include the alcohol-soluble components such as essential oil (of which d-limonene predominates), bioflavanoids such as hesperidin, carotenoid pigments, and chlorophyll.

In order to effect separation of the essential oils and other alcohol-soluble components from the extract, the extract is fed into a separation zone 28 wherein it is substantially diluted with externally-supplied water 30 or recycled desolventized extract 32. Upon suitable dilution, the alcohol-soluble essential oils which are present (along with chlorophyll and carotenoid pigments) are rendered insoluble such that an emulsion is formed. The essential oils can be agglomerated and easily removed from the extract by suitable means such as centrifugation as a separate highly colored product 34 which also contains chlorophyll and the carotenoid pigments. The chlorophyll and the carotenoid pigments can be subsequently removed from the oils by distillation if so desired.

Normally, the amount of aqueous diluent which need be added to the extract to effect adequate separation of the soluble oils comprises at least about 15 percent by weight of the extract, and most preferably about 20 percent by weight.

Sufficient diluent need only be added, however, to ensure i

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adequate separation of the essential oils without excessively diluting the extract with the aqueous solution. The addition of an excessive amount of diluent, while having no adverse effect upon the separation of the oils from the extract, may place an unnecessary burden upon any separation equipment downstream of the separation zone 28.

The fact that the alcohol-soluble essential oils can be easily rendered insoluble by dilution of the extract with an aqueous diluent is indeed surprising. Normally, the removal of essential oils from such solutions by means such as fractional distillation is extremely difficult due to the azeotropic nature of the solution. However, it has been found that the dilution of the extract with an aqueous diluent causes. the essential oils which are in solution to readily separate therefrom, whereupon they can be easily separated by suitable means such as o0 o0 o o centrifigation.

o e The solvent which remains in the extract is then 040 S removed by suitable means such as steam distillation in stripping zone 36. The solvent 38 which is recovered from the extract may be recycled to the extraction zone 14 for the treatment of o 4U* S, additional waste peel.

After the non-aqueous solvent has been removed from the t extract, the orange peel-derived bioflavanoids remaining therein are rendered insoluble due to the lessened concentration of solvent in the extract and will precipitate out of solution. The bioflavanoids may thus be easily recovered as a separate product by filtration in filtration zone 42.

A portion of the desolventized and filtered extract 44 may be recycled to the centrifuge zone 28 to serve as the i' ,ir*s~e i

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-12previously-described aqueous diluent 32. The remainder of the extract may, however, be further processed to provide a purified sugar syrup product.

Specifically, the remainder of the extract may be passed through an ion exchange zone 46 to remove any remaining impurities. Advantageously, the extract may be sequentially contacted with a strong acid ion exchange resin, a weak base ion exchange resin, and a weak acid ion exchange resin. The extract may then further purified by being passed through a bed of activated carbon (not depicted). As a result of this purification treatment, an extract 48 in the form of a sugar syrup is produced which basically consists of an aqueous solution of sucrose, dextrose, levulose and a few trace impurities.

The process of the present invention thus produces a variety of products which have multiple uses. The processed peel exhibits substantial water retention and may be used as a o medicament (as discussed above), thickener, emulsifier, or aeoo 0: stabilizer. For example, the peel product in a finely ground state may be used as a viscosity intensifying agent in drilling mud, as a coagulant in the processing of sugar to remove solids from a cloudy solution, etc. The peel product in a finely ground oI 4 Sstate may be used to maintain freshness and moisture in baked goods such as bread, doughnuts, cakes and cookies. The processed peel reduces spoilage by inhibiting mold formation. Generally, amounts in the range of about 1 to 3 percent by weight based on the weight of the baked goods is sufficient to provide the desired results. The sugar syrup product may be employed as a wholly natural sweetening agent in an appropriate comestible such as fruit juice, baked goods, etc.

iu~ -13- I~ EXAMPLE 1 Six hundred forty pounds of orange peel are ground in a hammer mill to a maximum particle size of about 2cm x 2cm x 3mm. The pulverized peel is then charged into a solvent extraction cell wherein it is contacted with an aqueous extractive solution comprising about 95 to 99 percent by weight of methanol. The extractive solution is circulated through the pulverized orange peel for about 15 minutes, after which time the peel has been contacted with about 1250 to 1300 pounds of the methanol-containing solution. At the end of the 15 minute extraction period, the extract. e solution comprises about 67 to 72 percent by weight of methanol.

The above is repeated using 1250 to 1300 pounds of fresh methanol yielding an extractive solution of 89 to 92 percent nethanol. This is again repeated using 1250 to 1300 pounds of fresh methanol yielding an extractive solution of 96 to 98 percent methanol.

The orange peel is removed from the extraction cell, allowed to drain, and dried in a steam tube drier ti produce an orange flour. The orange flour prodict is light tan in color and consists of about 96 pounds of finely divided orange peel which has a water holding capacity of 10.6 grams of water per gram of flour. A representative analysis of the major components of the orange flour product (basis dry solids) is set fort in Table I below: o 50 o os o 4 0 '44, 00 46 t d i I t t<; -14i;.

I::ij TABLE 1 Example 1 Orange Flour Composition by wt) Crude Fiber Protein Moisture Fat (Acid Hydrolysis) Ash Sucrose 18.20 5.92 5.12 2.15 3.48 1.79 Acid Detergent Fiber Neutral Detergent Fiber Pectin Pentosan Fructose Glucose 26.6 27.7 32.0 26.4 0.87 0.84

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o o 9 0 9 *o 9 @999 9 0 0 .c 9 *r 9 9 9 9909 IOt *I 9 *I 0 *04 The 1250 to 1300 pounds of solution used in the extraction of the orange peel the liquid extract) are then combined with sufficient desolventized extract to render the mixture cloudy, indicating that the essential oils present have separated from solution and that an emulsion has formed. The mixture is centrifuged and an oily fraction separated from the extract. The oily fraction is distilled under a vacuum of 5 mm Hg absolute to yield a clear, water white, pleasant smelling citrus oil and a solid residue which contains carotenoid pigments and chlorophyll.

The remaining portion of the diluted extract is stripped of the methanol contained therein by steam stripping.

Upon cooling, the desolventized extract is filtered to recover crude hesperidin rendered insoluble by the removal of the methanol.

The desolventized extract which remains is sequentially percolated through an ion exchange column which contains the strong acid ion exchange resin IR120 (marketed by Rohm and Haas), an ion exchange column containing the weak base ion exchange g 4 i r G l i; resin A-37 (marketed by Diamond Alkali an ion exchange column containing the weak acid ion exchange resin IR84 (marketed by Rohm and Haas), and a bed of activated charcoal. The resulting liquid product is adjusted to a concentration of brix to yield a sugar syrup.

EXAMPLE 2 A quantity of orange peel is collected in a drum and contacted with steam for about ten minutes until it is rendered soft. The softened peel is then passed through a screw finisher equipped with a 0.040 inch screen. The extruded peel is then pulped to form a puree. An 8.8 pound portion of the puree is subjected to countercurrent extraction with the extracted peel being dried to yield a peel product comprising 1.23 pounds of dry solids. The liquid extract is processed in the same manner as described in Example 1 so as to recover the essential oils and bioflavanoids therefrom as well as provide a sugar syrup product.

a o 9 o «o 6 e o er 9 e 09 9o 0* 09+ a 0 9 0 0 00 94 99 9 i EXAMPLE 3 Raw peel prepared according to Example 1 is subjected to countercurrent solvent extraction by being fed to a countercurrent solvent extraction zone at a rate of pounds/minute. Substantially undiluted methanol (at least percent) is fed to the extraction zone at a rate of pounds/minute. Extracted orange peel exits from the extraction zone at a rate of 4.5 pounds/minute (pressed weight) and spent methanol exits from the extraction zone at a rate of 20.5 pounds/minute. The composition of each of the above streams is set forth below: t i -16- TABLE II Composition of Feed and Product Streams Durinq Countercurrent Extraction Raw Orange Peel: Extracted Orange Peel: 7.5 lbs water ibs insoluble solids Ibs soluble solids 10.0 Ibs total 0.2 lbs water lbs insoluble solids trace of soluble solids 2.8 lbs methanol lbs total o 0 0 4 @4 44 4 4 4* 44 4 .44,0 Spent Alcohol: 7.3 lbs 1.0 lbs 12.2 Ibs 20.5 lbs water soluble solids methanol total li. The extracted orange peel is processed in a manner similar to that described in Example 1 to provide an orange flour S having a composition corresponding to that set forth in Table I.

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Claims (1)

1. 9.99 4 49 4 41 i 0 '040 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: i. A process for the recovery of useful products from citrus fruit peel comprising: subjecting the citrus fruit peel to countercurrent solvent extraction in a solvent extraction zone with a solution comprising a non-aqueous water-miscible solvent selected from the group consisting of lower alcohols, lower ketones, and mono and dialkyl ethers of ethylene glycol, said solution as it is fed to said solvent extraction zone comprising said water-miscible solvent in either undiluted or diluted with minor amounts (as herein defined) of water, said peel being contacted with said solution for a period of time sufficient to provide an aqueous extract containing substantially all of the sugars, essential oils and bioflavanoids from the peel which are present therein; removing said solvent-extracted peel from contact with said solution; and drying the solvent extracted peel to produce a solid product which is high in cellulose and pectin. 2. The process of claim 1 further comprising diluting said extract from the solvent extraction step with sufficient aqueous diluent to render insoluble the essential oils contained in the extract; separating the essential oils from the extract; removing the non-aqueous solvent from the extract to render insoluble the bioflavanoids present in the extract; separating the insoluble bioflavanoids from the 0044 9 r t 4c 4r 1 40 41 0 Sra 01 j 1 r 4 81 extract; and t ,1 r 19 purifying the resulting extract to produce a sugar syrup product. 3. The process of claim 1 wherein the non-aqueous water-miscible solvent is methyl alcohol. 4. The process of claim 1 wherein the solution comprising the non-aqueous water miscible solvent comprises less than 15 percent by weight of water based on the weight of the solution. The process of claim 1 wherein the citrus fruit is selected from the group consisting of oranges, grapefruit, ft4A I 9 ft Oft? ft. ft ft 4 0' lemons, limes and tangerines. 6. The are removed from #6 *I Ivt ftI El IL 7. The are removed from process of claim 1 wherein the essential oils the extract by centrifugation. process of claim 9L wherein the bioflavanoids the extract by filtration. process of claim I wherein said peels comprise a W i:ill 8. The orange peels. 9. The solid solvent-extracted peel product produced by the process of claim 1. The sugar syrup product produced by the process of claim 2. DATED this 6th day of March 1987 TROPICANA PRODUCTS, INC. By Its Patent Attorneys: CLEMENT HACK CO ri