rssutr IPRICE 82.50

i\l lri yi.it,:\l li 9-i!!1.!-fl Or I Jii{ Vi C-[,J

plant are successfu l ly s tabi l ised

d J r i n g m a n u l a c l u r e a n d . s u b -

s e q r e n t l y . d u r i n g d i s t r i b u t i o n

and storage.

T n i s n e w s l e r t e r r e v i e w s t h i s

impor iant aspect of A loe.

ALOE VERAThe Crucial lmportance of Correct Processing

By Dr . G. Lawrer rce P lasket t B A. , Ph .D , C .Chem , F R I C

T h e a l l - i m p o r t a n t b i o m e d i c a l

act iv i t ies o{ a loe ju ices and

exl racts depend c ' i t ica l ly L Pora p p l v i n g s t r i c t r u l e s o f P r ocessing and handl ing. Th ese

detefmine whether or not the

labi le b iochemicals in the l iv ing

BIOMT,DICAT INTORMATION SERVICES tTD23 Chapel Street , Camelford, Cornwall. PL 37 9PJ

L-

Introcluction

Gett ing oneself supplied with good Aloe veraExtract is not so easy as one might think. Oneproblem is that the Aloe Industry has been veryprone, unfortunately, to misleading practices, withsuppliers often diluting the valuable Aloe Extractswith water to increase their profits - even to theextent of selling virtually pure water as Aloe. In othercases suppliers have extended the elitracts with acombination of water and maltodextrin - a cheapcarbohydrate product from corn starch - just tomake it look as though the solids component ofthe Aloe has not been diluted. That is one of theproblems with Aloe and it will be dealt with fully inNews le t te rNo l l .

The other major obstacle to getting really genuineAloe does not relate to dishonesty, but rather tolack o f knowledge or a lack o f t igh tness o fmanagement control in the Aloe processingoperations. The problem is that many of the activeingredients of Aloe are distinctly labile, that is tosay, that if you subjectthem to even slightly adversecondit ions, then they spontaneously undergochemical changes which cause them to lose thebiomedical activity, which is what the purchaser ofAloe is trying to buy.

The Active Principles of Aloe and theirSurvival of Processing

The known active principles of Aloe are (1) Plantsterols (2) Natural salicylates (3) The enzymebradyk in inase (4 ) A probab le unknownantihistamine substance (5) Plant hormones of thegroup known as auxins (6) Plant hormones of thegroup known as gibberel l ins (7) The specialcarbohydrate of Aloe, known as "glucomannan",

which in reality represents several active principles,because i t compr ises f rac t ions o f d i f fe ren tmolecular weights which have different effects.These active principles have been discussedalready in lssues 1 , 2 and 4.

It is clear that these various active principles havediffering degrees of lability, i.e. will vary in theirsusceptibility to inactivation under conditions ofprocessing. Indeed, since they are of a number ofwidely differing chemical types we can be sure thatsome types of processing operation will adverselyaffect.one active principle and another type ofprocessing operation will adversely affect differentactive principles. This makes the problem complex,because different parts or aspects of the productbecome vulnerable at dif ferent stages of theprocessing operations.

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The Steps in Aloe Processing and theVulnerabilig of Biomedical Activity

When we come to consider the steps in processingwe have to consider that there are two mainproducts involved, either gel or whole leaf extract,and that different processing steps are needed foreach of these products. However, they both beginin the same way, with harvesting the leaves andtransport off the field to a place where the first stepsof processing are carried out. Usually there will alsobe a holding period when the delivered leaves areawaiting processing. What is important here is (1)the t ime taken from the moment of cutt ing toreaching storage (2) the conditions under whichthe leaves are transported from the field to the plant(3) the conditions of storage during the holdingtime, especially whether these involve cold storage. g

Large American producers of Aloe vera have donework monitoring the changes in biological activitywith time and holding conditions. They have shownthat there is significant loss of activity if the cutleaves are kept at ambient temperature for morethan 6 hours after harvest and that if the leaves arekept beyond that time, then the level of activity goeson falling and reaches zero after about 24 hours.They found that although cold storage slows therate of loss of activity, it cannot prevent it altogether.All this means that the leaves, after being gatheredfrom the field, should be transported into coldstorage as quickly as possible, preferably wellunder the six hours required for deterioration tostart, and should be kept cold. Processing shouldbegin as soon as possible, i .e., holding t imesshould always be minimized. Moreover, theprocessing should also be completed as quicklyas possible. A guideline has been suggested thatthe overall time from cutting to the completion ofprocessing should not exceed 36 hours, even whencold storage is employed. Obviously, these criteriaput certain pressures upon process operators.Meeting these criteria calls for well organisedlogistics and careful management and if these arenot provided then standards can slip and productof a lower grade will be turned out. The deteriorationwhich occurs will be partly through spontaneousdecomposition but is has also been shown that inthe cut leaf, upon standing, enzymes within the cutleaves remain active and start to reduce theconcentration of active principles. Clearly then, acareless processor could quite easily completelydestroy the biomedical activity of his Aloe beforeeven starting to process it.

The Processing Sequence

As soon as processing starts, the leaf must bedesrgnated either for gel or for whole leaf extract. lfit is for gel the leaf will be cut to dissect the centralgel from the outer rind. This may be done either byhand cutting or by machinery. Obviously, the handand mechanical versions of the process cannot beexactly the same. The machine elitraction of thegel is bound to be just a little more "hit or miss"and as a result the gel e),tracted by this methodusually contains rather more of the exudatematerials (e.9. aloin), than hand dissected gel. lfthe leaf is to be for whole leaf extract, then it isground up in a mill without any previous dissection.After these processes, the clear juice has yet to beobtained. In the case of the gel this involves onlygrinding the gel tissue, which then disintegrates toyield mostly fluid with a little fibre floating in it. Thegel is of such a high water content that it convertsmainly into liquid. Some manufacturers remove thefloating fibre, but others do not, since it containssome of the activity of the original gel and might aswell be consumed with the liquid. In the case of thewhole leaf, the extract has to be expressed fromthe mass of fibrous leaf fragments under pressure.This is actually quite hard to do because there isso much fibre relative to the quantity of free liquidavailable. Thereafter the extract must be passedon to a chillerto reduce its temperature. These stepsare illustrated in Figure 1.

Leaf Breakclown and Cellulase En4gme

The process of disintegrating the whole leaf has to

be watched quite closely. First ly, in a poorlycontrolled operation it would be easy for the millingto raise the temperature significantly. The Aloe leafis tough and fibrous. Plenty of energy has to beused to break it down to fine fragments. Suchmechanical energy becomes dissipated as heat.Secondly, the separation of the liquid elitract fromthe pulp, because there is so much fibre, is almostimpossible unless a processing aid is added. Theprocessing aid is the enzyme cellulase, which iscapable of breaking down some of the cellulosefibre, and this makes separation of the liquid a greatdeal easier There is a price to be paid, however,because the cellulase is also capable of breakingdown the glucomannan constituent of Aloe whichis such a key active principle for its biologicalactivity. As to whether or not any detrimentalbreakdown of valuable glucomannan occurs, isdependent upon the length of time for which theAloe is exposed to the effects of active cellulaseand the amount of cellulase enzyme used. lf excesscellulase is used, or if the active enzyme is left toolong in contact with the Aloe, then very detrimentalbreakdown of the glucomannan may occur. Onceagain it is a matter of controlling carefully the timeand conditions of contact between the Aloe andthe enzyme. The cellulase should not be regardedas being inevitably harmful, for it is not. Theglucomannan, as was stated above, occurs indifferent versions, and any sample of Aloe willcontain a cross-section of glucomannans havingdifferent molecular weights (for the non chemist,this can be regarded as being much the same asmolecules of different sizes\. The cellulase can

Pre-Processing Flow

Whole Leof

--+ ->Leaf Harvest Leaf Washirrg

Sanitizing Dip

Figure I

Chiller

][]'ilTi l 11l] i l

,lllllll-

ToProcessingPulp

\ Extractor

\ , ,- r -1 'ffiffi" l

r*iGei

Extractor

Mill

Gel Fillet

@ Copyright 1996 Biomeclical Information Services Ltcl.

convert some of the large glucomannan moleculesinto rathei smaller ones. This may actually improvesome of the biomedical properties of Aloe - becausethe glucomannan of different molecular sizes havedifferent biological activities. Howevel clearly, if theprocess of degradation by cellulase were permittedto go too fa( the effects would be wholly detrimentalas al l biological act ivi ty would eventual ly bedestroyed by the continuing action of the enzyme.Once again. here. we are looking at a good processwhich is potential ly l iable to abuse by the i l l -informed or careless operator. By using too muchcellulase in his enthusiasm to make the separationstage easier, and by leaving the enzyme in contactfo r too long, he cou ld we l l ru in h is p roduc tcompletely so far as its biomedical activities areconcerned. Note , though, tha t th is wou ldnonetheless still be an honest Aloe product in thesense that it would be composed wholly of Aloewith no dilution or adulteration. This processor'ssin would be carelessness or ignorance rather thanfraud. Nonetheless, the purchaser is going to bethe loser, that is certain.

Management Will and Process Know-

how

Please note that since it is possible {or a processorto make such grave errors that would ruin theproduct, either pre-processing errors or processlngerrors, the number of times that these errors aremade to a milder degree is likely to be considerable.lf that happens, it would most probably havd theeffect of reducing biomedical activity rather thanextinguishing it altogether. lt really does seemreasonable to expect that the industry is likely tobe making these lesser errors quite often in thoseplants which are subject to fairly poor process orquality control, resulting in delivery to the consumerof less than what he or she is paying for. Only thetechnically aware companies that also have goodlaboratory capabilities are likely to be in a positionto meet all the known processing criteria. Obviouslythey also require to have the management will andability to do so, bearing in mind that standards arealways inclined to slip a bit unless watched andsafeguarfled very carefully from the top of thebusiness by people who are also prepared toallocate the resources necessary to both attain andmaintain high standards.

Carbon Filtration

Moving on now to further processing of theseparated liquids, the whole leaf extract needs topass through a filtration stage employing activatedcharcoal (carbon filtration stage). This is neededbecause the who le lea f ex t rac t unavo idab ly

O Copyrisht 1996 Biomedical Information SeNices Ltcl

contains the materials of the Aloe exudate fraction- the fraction which contains the phenols, such asthe laxative anthraquinone substance "aloin". Thisfraction must be substantially removed to avoidhaving a product with bitter taste and laxative action.Passing through the carbon filter does this mosteffectively. Users of Aloe can usually be fairlyconfident that whole leaf extract, as opposed to thegel, will have had the exudate fraction effectivelyremoved, reducing its concentration in the productto only trace. The gel has a naturally low level ofthese anthraquinones - low enough that they willnever cause a laxative effect. For that reasonproducers of gel products may or may not decideto carbon filter their material. As a result, it is morepossible that one may buy a gel product containingperceptible anthraquinone components, than awhole leaf extract.

OThis technology of carbon filtration permits Aloewhole leaf extract to be used, whereas that wouldnot be possible without the carbon filtration step. ltwould be precluded altogether by the unacceptablyh igh leve ls o f an thraqu inones and re la tedcomDounds in the unfiltered extract. This explainswhy historically most of the market for Aloe juiceshas been satisfied until now with the fluid from thegel. As noted above, the gel dissected by hand ismore aloin-free than that which is pressed out bymechanical means because the dissection is moreexact and it is easier to avoid contamination withthe fluid exuding from the rind.

So far as the cafbon filtration stage is concerned inthe processing of whole leaf, the reader will readily .perceive that it is entirely unavoidable. but it does 9have a orice attached to it in term of some loss ofactivi ty. Init ial ly, the whole leal extract has awonder fu l l y h igh leve l o f b io log ica l ac t i v i t ycompared to the ge l (assuming tha t a l l theprocessing criteria have been well observed to thispoint), l t also has a high sol ids concentrat ioncompared to gel. lt is always surprising to anyonenew to the {ield, that the concentration of solublesolids in Aloe vera gel is only 0.5 - 0.6%. This reflectsthe fact that this plant is a succulent well adaptedto living in fairly arid places. lts adaptation consistsof storing great amounts of water in its tissues. Allits tissues are adapted to this function, but the gelmost particularly so, and hence it consists mainlyo{ water. However, the whole leaf extract containsfrom 1 .0 to 2.0% solids. Typically the level of solidsit contains is about two and a half to three timeshigher than the gel. Not surprisingly, the whole leafextract, when processed according to good criteria,offers more of the all-important biomedical activitythan does the gel, sometimes almost twice asmuch. Naturally, its activity level does not usually

rise quite as much as its solids level compared tothe gel. lt appears that by making the whole leafextract, one obtains a certain yield of act iveprinciples from the rind part of the leaf. This extraactivity gained is not quite so high on an "activityper gram" basis because the rind also containssome inactive materials. However, it is more inabsolute terms. The conditions of carbon filtrationmust be watched very carefully, however, sincecarbon filtration always reduces biomedical activityby at least a little. The filtered elitract is thereforerather less strong biomedically than it was beforefiltration. Since one has no cholce about doing thefiltration step, this loss must be accepted. However,it should be minimized by observing carefullyprocess controls over the filtration operation. Sothis is another area in which the unalert or carelessprocessor can lose the Aloe's act ivi ty. There

$ continues to be a certain debate within the industryas to whether gel or whole leaf extract is better.Often the gel is favoured just out of long habit orbecause people have the affection for it as thematerial of tradit ion, or the material they havealways worked with. Sometimes people favour gelbecause they have had experience only with poorlyprocessed whole leaf extracts. However, this authorinterprets the evidence shown to him by the Industryas clearly indicating the higher biomedical activityof the whole leaf extract when the correctprocessing parameters are applied. That does notmean that the gel is easy to process, that too issubject to the vulnerability of its active principles -for they are - substantial ly the same activeprinciples.

,,-l Pasteurization

After carbon filtration, the whole leaf extract ispassed on to be Pasteurized. So is ihe gel after itsmilling stage. This involves heating to 65 degreesCentigrade for 15 minutes or to rather highertemperatures for much shorter times. Whilst heaiingthe e)dracts at all is undesirable, the Pasteurizationcannot be avoided. Aloe gel or whole leaf extract,more or less free from aloin, is not itself able to killbacteria or inhibit their growth. For marketing anddistribution these products need to be protectedfrom growth of bacteria and yeasts. This is doneby a combination of two steps, the Pasteurizingprocess and the addition of preservatives (referredto as "sanitizers" in America), of which potassiumsorbate is the commonest example . Th isPasteurizing is not signif icantly harmful to theproduct so long as the proper process parametersare observed. What is perhaps much less desirableis the tendency for some operators to Pasteurizesome of the product more than once. This, basicallyis the resu l t o f care lessness . o r incor rec t

management of particular batches. This occurswhen, once the Pasteurizing has been carried out,the extract again becomes infected with highnumbers of micro-organisms which multiply out ofcontrol. lt is only likely to happen when a batch,once Pasteurized, is allowed to stand too long orunder poor conditions. Obviously, one can acceptthat the heat treatment involved in Pasteurizing isinherently less than desirable. However, when it isdone twice, obviously any damage to the productis multiplied. lt is not only damage from the repeatedheat exposure, but also the destructive effects ofthe bacteria while they are being allowed to grow.Sloppy, poorly supervised working conditions fosterthis kind of enor and it really needs to be controlledan. l et . rnn6. l

Once the Pasteurizing has been done, the productis ready to go forward as finished product. This willbe finished product of a type called "one to one".That means that its concentration is the naturalconcentrat ion for the part icular product. l f theproduct is gel, it will go forward at this stage at asolids concentration of only 0.5 to 0.6%. lf it is wholeleaf extract, the solids concentration will be i .0 or2.0%. Sometimes this expression "one to one" canlead to confusion in the Industry. For example, aproducer of unconcentrated whole leaf elitract at asol ids content of 1.5o/o may decide to cal l theproduct "3 to 1 " on the basis that in terms of solidsit is three times stronger than a gel. lt really is notcorrect practice to do that because its activity,although higher than that of a gel will not be threetimes higher. In any case, the proper designationfor such a product is really a "1 to 1 whole leafextract" because that is what it is. and its chemicalcomponents are qualitatively different from thoseof a "3 to 1" gel. This will be discussed further inlssue 1 1 .

Concentration by Evaporation

lfthe intention is to prepare a concentrate, either ofgel or whole leaf e)tract, the "1 to 1" material is fedto an evaporator. A concentrate can easily beprepared using quite low evaporator temperatures.However, the more concentrated the liouid is tobecome, the more heat will be needed to bringabout that level of concentration in the evaoorator.4 "40 to 1" concentrate of gel should have a solidsconcentration of 2Oo/" and a "40 to 1 " concentrateof whole leaf extract will be really strong and shouldbe from 40% to 80% solids. This seems to be takingthe concentration step too far

This author favours the use of modest levels ofconcentration but has has certain reservationsaboutthe making of really strong concentrates like

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40 to 1. The first reason {or this is real concern thatthe evaporator temperature will go too high anddamage the biomedical properties of the Aloe. Intact, the temptation is constantly there during theconcentrating of Aloe in the evaporation, to let thetempera ture go too h igh . The h igher thetemperature goes, the faster the process goes andthe lower will be the costs of the operation. Indeed,keeping the evaporator temperature down, as isneeded to optimize the product, will also limit theprocessing capacity of the plant. lf there is muchmaterial waiting to be processed, that will imposean understandable pressure upon the productionmanager. Almost inevitably some productionmanagers will yield to the obvious temptation. Thehigher the final concentration of the Aloe solids, thehigher the evaporator's working temperature willhave to go to perform the necessary degree ofevaooration within an economic time-scale.

The second reason why high concentrates areundesirable is that the sensitive biomedically activecarbohydrates are damaged not only by heat butalso by increasing concentrations of mineral saltsAloe contains mineral salts which represent asignif icant proport ion of i ts dry matter. As theextracts are concentrated, the salts reach higherand higher concentrations, causing progressivelygreater damage to the glucomannans. Given thecontent of metal ions in the product at its naturalstrength, as about 20% of total solids, and allowingfor the presence also of non-metal ions such asphosphate, the salts concentration in 40 to 1 AloeGel could be of the order of 6-7"/o and in 40 to 1Whole Leaf Extract could be as much as 20o/oThese concentrat ions produce very high ionicstrength which can certainly alter the molecularproperties of the Aloe Glucomannan.

Spray-Drying and Freeze-Drying

The final processing stage, which may or may notbe applied is drying. This author regards the dryingstep as inherently undesirable and thinks it shouldnever be used at all unless it is tor an applicationwhich can only use dry material. ln making driedproduct, it is an economic necessity to concentratethe product maximally in the evaporator beforedrying, with all the damage which that entails. Thenthe drying process itself will add its own quantumof further damage to biological activity. lf the dryingprocess applied is spray-drying, then we havemaximum heat application during the drying andhence maximum damage. Moreover, the spraydrying step often requires the addit ion of aprocessing aid - usually maltodextrin - that cheapextender from corn starch - which may or may notbe declared as an ingredient on the product label.

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The best way of drying is freeze drying, becausethe product is spared in this way from high heat.However, it is still true that maximum evaporationhas to be applied first. The best product which canbe obtained at all in a dry condition is a freeze-dried product prepared directly from a "1 to 1"extract without evaporation. However, no suchproduct is likely ever to be offered on the marketsince the drying costs on this basis simply couldnot be born. These various further process optionsare illustrated in Figure 2. Consumers in the U.K.and Europe, taking supplies of Aloe from U.S.A.and Mexico, or from Australasia, will often find, ifthey enquire deeply enough, that they are buyingdried product (perhaps even spray-dried product)which has been shipped dry to save freight costsand then reconstituted with added water, back toa 1 to 1" o r to a concent ra te s t rength . The \consumer can thus be deeply deceived. because Vthere is no comparison between a fresh "1 to 1"extract or, say, a"2 to 1" or 10 to 1 concentrate,and a produc t wh ich has been comple te lydehydrated and then re-constitdted, especially ifthe drying method was spray.drying.

Conclusion

I t is obvious that an honest but incompetentprocessor of Aloe could easily produce a genuinely100% Aloe which would be devoid of biomedicalac t iv i t y . Th is wou ld happen th rough e i therignorance or a lack of attention to detail in theprocessing operations. ls the consumer gettingwhat he or she wants in such a case? In terms ofgetting pure 100% Aloe the answel is obviously _"yes". In terms of buying biomedical activity. viz., \)the potential to cure or alleviate illnesses, equallyobviously the answer is "no". In the ultimate case,the consumer is actually getting nothing worthwhilefor the money at all - no more than if the supplierwere putting pure water into the bottle and passingit off as Aloe.

ls it likely that the Industry is widely peopled withsuch incompetent and ignorant suppliers? Theanswer to that is "no". This writer feels sure thatfew go so far as to entirely inactivate previouslyactive product. ls it likely that the Industry is widelypeopled with suppliers who, through ignorance andsomewhat substandard competence, part ial lyinactivate their Aloe through avoidable errors? Theanswer to that, this author thinks, is "yes". lt isalmost bound to be the case because there is noauthority responsible for monitoring and policingth is s i tua t ion . B io -assays ( i .e . b io log ica lmeasurements of activity) are available for (1) theanti-inflammatory efiect, (2) the healing effect and(3) the immunostimulant effect. They could all be

Figure 2 Processing Plont Operations

Raw l:l productsGels

&- Filter AM I- - - -- -- - -- - -rE , - aGE f .,.!ry-

LiouidConcdntrate

-t

It

ConcentrationMixingKettle

IITSTPasteurization/

FlashCooling

SprayDriedPowder

FreezeDriedPowder

monitored by lhese available bio-assays. Yet thatis not the accepted way of control l ing Aloe.Individual companies, if they are big enough andsoph is t i ca ted enough, have the means o fmonitoring these activities in their products, but itis entirely up to them whether they do it or not. Towhatever e)dent they are doing it, this is iust for theirown information. There is no reouirement for themto publish the results. Even less is there anyrequirement for them to use these bio-assays asquality control procedures and to reiect batcheswhich fail to come uo to a certain standard inrespect of biological activities. Hence there isabsolutely no guarantee for the consumer that theproducts he or she will buy will possess the highlydesirable biological activities that are reported inthe scientific and medical literature as belongingto Aloe, nor that they will attain a certain minimumvalue in resoect of these biolooical activities.

Th is s i tua t ion is oOv io 'us ty comple te lyunsatisfactory. The work of the International AloeScience Council based in Dallas, Texas, is laudable.They will provide Certification of products as beinggenuine Aloe. However, whilst one should give themevery credit for seeking to upgrade their criteria forthe genuineness of Aloe, the present criteria leavemuch to be desired. They depend upon certainconven ien t marker subs tances wh ich A loecontains, such as, for example, calcium and malicacid. These requirements gloss over the fact thatcalcium and malic acid have no role whatsoever in

prov id ing t hebiological activities ofAloe and are merely" i n c i d e n t a l "

c o m D o n e n t s .Moreover. thedetermined fraudstercou ld eas i l y adde i ther ca lc ium ormal ic ac id to h isprod uct to make i tlook genuine when itis not. These additiveswould be er:tremelycheap to add. Sincethey carry nobiological activity ofthe kinds we look forin Aloe, it would stillbe a f raud u len tproduct with eitherze to o f a muchreduced b io log ica lactivity. Moreover, theCertification from theAloe Science Council

does not guarantee that the product is 100% Aloeor anything like it. Products with only 15o/" or 2oo/oAloe may gain certification.

It is obviously an urgent matter to have in-plantquality control based upon biological activity,certification based only upon biological activity and,indeed, random testing of products on thesupplier's shelf, based upon biological activity. Untilthis happens, the buyer's only protection is to buyfrom a supplierwhom he or shetrusts tothoroughlyresearch the origins of his product in the producingcountry to independently monitor processing thereand to prgvide good storage and distribution, freefrom dilution and adulteration at all times. Thosebuyers in the U.K. and Europe who are notmultinationals with their own plantations, can bedoubly at risk because their national suppliers arethemselves dependent upon overseas producersand middlemen whom they cannot easily control.These buyers can be secure, however, providedthey fully check out their complete line of supplyand the validity of the production processes. Andone should not assume either, that multinationalsare necessarily free from wrong practices, justbecause they are multinational. Adherence to trulygood practices requires the commitment ofmanagement f rom the top down in suchorganisations.

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