Note: Descriptions are shown in the official language in which they were submitted.
~213~67
AQUEOUS-BASED STRIPPE~ ESSENCE
Barry J. Anderson, Galen E. Downton
Donald ~. Kearney, Judith A. Kennedy
,, and David A. Strang S
BACKG~OUND OF THE INVENTION
Citrus fruits have specific growing seasons. They grow
only under certain clirnatic conditions as occur in places such as
Florida, Arizona, California, Texas, Brazil, Spain, Italy, Israel
5 and Egypt. Citrus fruits, in particular orange and grapefruit,
are available only for limited periods of time during the year.
Thus, certain varieties of these fruits, especially those used for
juices, may be periodically in short supply. For instance, Florida
Valencia oranges which are used in many commercial orange juices
10 are available only from April through July. In order to have a
good quality orange juice available year round, the orange juice
must be processed for storage and distribution.
The challenge of produçing an orange juice product which is
acceptable to a broad range of consumers, involves making a
15 unique product having acceptable flavor (taste), distinctive aroma
(smell), acceptable appearance and satisfactory mouthfeel. The
aroma and flavor ingredients in oranges and other citrus fruits
affect each of these organoleptic properties. This is so even
though the aroma and flavor ingredients are present only in
20 relatively small amounts.
Since natural or fresh orange juice contains about 80% to 90%
water, the most economicai way to store and distribute the juice
is in a concentrated form. The bulk of the orange juice
commercially processed in the United States has been a frozen
25 concentrated product.
~2~3167
Most commercial concentration processes utilize evaporation
techni~ues to remove the bulk of ~he water from the juice.
However, it is widely recognized that evaporation~-techniques
result in the undesired removal or loss of volatile aroma and
5 flavor compounds alvng with the water, thereby resulting in a
significant deterioration in quality and overall aroma and flavor of
the concentrated juice. Evaporation processes involve heating the
juice under conditions which promote oxidation of the compounds
in the juice as ~ell as flavor degradation due to caramelization of
10 the sugar, browning r~actions, and other chemical reactions of
the aroma and flavor compounds, While evaporation concentration
processes are useful and effective, there is a significant loss of
aroma and flavor compounds which occurs. The industry collects
an essence material which is concentratcd from the first 10~ to
15 30% of the water removed from the juice. This essence can be
separated into an aclueous essence and an essence oil. Either can
be added back to the juice alone or as a mixture. However, the
orange juice concentrate to which the essence materials have been
added back does not contain all the highly volatile materials such
20 as ethyl butyrate, ethanol, methanol and acetaldehyde which were
present in the starting juice.
The process provided herein removes the volatiles in a
sequential manner. The most delicate aroma and flavor compounds
are removed first and therefore have less opportunity to be
25 degraded further in the process. The condensation ancJ
concentration of these volatiles are also carried out under
conditions which preserve the fidelity of the aroma and flavor
compounds. The condensed volatiles can be separated into a
limonene-based stripper oil and an aqueous stripper essence.
30 Both of these stripper compositions are distinct in their aroma
and flavor character.
The present invention produces a juice or citrus juice
concentrate which contains a substantial amount of the aroma and
flavor volatiles of the citrus juice. The volatile aroma flavor
35 condensate, or aqueous stripper essence and limonene-based
1213~;7
--3
stripper oil, which are produced by the process are added back
to a citrus concentrate to produce a superior concentrate.
An important objective achieved by the present invention
is that a natural orange juice concentrate product is prepared
5 which has the aroma and flavor of natural orange juice. The
orange juice concentrate of this invention when reconstituted
tastes like freshly squeezed juice. This same process can be
used to produce natural lemon, grapefruit, lime and tangerine
concentrates, as well as blended citrus juice concentrates.
It is an object of an aspect of this invention to
produce citrus juice concentrate which when reconstituted
tastes as good as the starting juice.
It is an object of an aspect of this invention to
produce a limonene-based stripper oil from oranges which has a
fresh aroma and flavor. The oxidation products of the natural
aroma and flavor compounds is also much lower.
It is an object of an aspect of this invention to produce
an aqueous stripper essence from orange juice which contains
the aroma and flavor compounds which give orange juice its fresh
20 quality. The compounds are primarily the ester and aldehyde
compounds. This essence is characterized by being very low in
ethanol and containing higher levels of the longer chain alde-
hydes when compared to conventional aqueous éssences.
It is an object of an aspect of this invention to produce
a citrus juice stripper oil which can be used as a flavorant
or in a citrus juice concentrate.
It is an object of an aspect of this invention to
produce an aqueous citrus juice arorna and flavor volatile con-
centrate which can be used as a flavorant in beverages,
including carbonated beverages, dry beverage mixes, alcoholic
beverages, candies, baked goods and culinary mixes.
, ~
~3167
An aspect of this invention is as follows:
An aqueous-based stripper essence derived from
oranges comprising: from about 0.01% to about 2%
ethanol and water-soluble volatile compounds, said
essence having a ratio of low-boiling water-soluble
compounds to high-boiling water-soluble compounds
of from about 0.1:1 to about 1:1.
These and other objects of this invention will
become apparent by the desçription of the invention
below.
All percentages are by weight unless otherwise
defined.
~2~31~7
BRIEF DESCRlPTiON OF THE DRAI~IINGS
Finllre 1 is a diagram of the process used to prepa,-e the
citrus juice concentrates. ~~
~igure 2 is a diagram of a stripper column.
Figures 3 throu~h 7 are typical gas chromatograms obtained
by the methods described herein.
- Figure 3 is a frozen ~range juice concentrate made according
to this invention.
Figure 4 is a limonene-based stripper oil from Valencia
1 0 oranges.
Figure 5 is an aqueous stripper essence from Valencia
oranges .
Figure 6 is a concentrated aqueous essence from oranges
using orange juice sol ids as a carrier .
Fi3ure 7 is the alcohol portion of an aqueous stripper
essence .
SUMMARY QF THE INVEI~JTION
The present invention relates to a process for removing the
aroma and flavor volatiles from citrus juices by contacting the
juice with a stripping agent, e.~. inert gas or steam, at
temperatures in the range of about 100F (37.7C) to about 160''F
(71 C) and at pressures of up to 9 inches of mercury absolute
(Hg. absolute) and preferably from about 2 to about 6 inches of
Hg. absolute. The volatiles stream is condensed at temperatures
frorn 90F (32C) to -320F (-196~C). The exact temperatures of
condensation will depend upon the pressure in the system. This
condensate can be separated into products when steam is the
stripping agent. The lighter water-insoluble phase is a
limonene-based stripper oii. The heavier, aqueous phase is an
aqueous stripper essence. This aqueous stripper essence and/or
the aqueous condensate is preferably mixed with a carrier and
concentrated to a solids content of from about 20% to about 85%
(20 to 88 Brix). Preferably, this concentration is accomplished
by freeze concentration. This aqueous stripper essence
concentrate and limonene-based stripper oil or the concentrated
~2~3~67
aroma and flavor condensate are blended with a citrus juice
concentrate. The citrus juice çoncentrate can be prepared by
any known concentration technique, but for economical purposes
it is best to concentrate it using commercial evaporation
5 techniques. Preferably, the concentrated juice is prepared from
the juice which has been stripped of its volatiles.
The concentrated citrus juice product produced by this
process contains at least 6~% of the water-soluble aroma and
flavor volatiles originally present in the juice. The condensate
10 from one juice could be blended with other juices to produce
blended juice flavors. For example, orange and lemon
concentrates and the aroma and flavor volatile concentrates from
either or both could be mixed to provide a lemon/orange
concentrate .
DEFINITIONS
"Stripper aroma and flavor condensate" is the composition
obtained by condensing the aroma and flavor volatile compounas
and the stripping agent . V~hen water is used this is an oi l-
in-water emulsion of aron.a and flavor compound,. The stripper
20 aroma and flavor condensate can be concentrated to form an aroma
and flavor concentrate.
"Limonene-based stripper oil" or "stripper oil" is the
water-insoluble fraction of the stripper aroma and flavor
condensate. The separation of the substantially water-insoluble
25 materials produces a composition which is predominantly limonene
but which contains many aroma and flavor volatile compounds.
This composition i5 characterized by the amount and proportion of
linalool and nonanal. In addition to these three aroma and flavor
compounds, this limonene-based stripper oil essence also contains
30 many other water-insoluble flavor components such as myrcene,
pinene, decanal, geranial, neral, among others. It also has low
leveis of oxidation proclucts.
"Aqueous stripper essence" is the aqueous fraction of the
stripper aroma flavor condensate containing the water-soluble
35 aroma and flavor compounds. The aqueous stripper essence of
~Z13~67
orange juice is characterized by having up to about 2% ethanol
~on~ ntr~ti~n. In addition, aqueous stripper essence of orange
juice contains the majority of the highly volatile and water-soluble
aroma and flavor components of the startiny orange juice.
"Evaporator essence oil" is the water insoluble phase of the
essence recovered during the evaporation of the stripped citrus
juice, i.e., the juice from which substantially all of the volatiles
have been removed.
"Evaporator essence" is the aqueous phase of the essence
rernoved during the evaporation of the stripped juice. Both the
evaporator essence and the evaporator essence oil are different
from "essences" which are conventionally removed from citrus
juice during evaporation concentrationO
DETAILED D~SCRIPTll~N OF THE INVENTION
Tl-~e process for preserving the fresh aroma and flavor of
citrus juices is diagrammed in Figure 1. Any citrus fruit can be
used in the practice of this invention. Thus, this process is
applicable to all the varieties of oranges, e.g. Pineapple, Hamlin,
Valencia and Parson Brown, as well as to lemons, limes,
grapefruit, tangerines, and kumquats.
The fresh juice is extracted from the fruit using
conventional juice extractors and juice finishers. The fresh juice
is passed through equipment to remove the large or sensible
pulp. 5ensible pulp has a particle size greater than about 0 . 5
mm. Juice finishers, vibrating screens, sentrifuges or any
combination of these can be used to remove the large pulp. The
sensible pulp is removed to prevent it from being macerated as it
passes through the stripper and concentrator anci to prevent it
from being oxidized or degraded during further processing steps.
The flavor, texture and appearance of the pulp is preserved so it
can be added to the concentrated product at the end of the
process. The juice which now contains pulp particles less than
O . 5 mm in size is referred to herein as "citrus juice" .
~2~3~67
Removal of Volatiles
.
The citrus juice is passed (via pump 12 ) through a device
such as a heat exchanger tl4) to quickly raise the temperature of
t.he citrus juice to the feed temperature of the strippi,ncJ column.
This temper3ture ranges from about 100F (37.7C~ to about
160F (71C), preferably temperatures of from 125F ~51.7C) to
140F (60C) are used. Any suitable means can be used to heat
the citrus juice, e.g. shell and tube, plate or spiral heat
exchangers or direct steam injection. Either low pressure steam
or hot water can be used as the heating medium in the heat
exchangers .
The hot citrus juice is then pumped into the top of a
stripper column (see Figure 2) which is operated under vacuum.
As illustrated the stripper can consist of a vertical cylindrical
vessel encompassing one or more stripping stages. Each stage
consists of a means for distributing a fine spray of juice droplets
across the whole circular cross section of the vessel (4~ and (8).
The juice is atomized so that the entire cross section of the
stripper is covered with atomized juice droplets. This can be
accomplished with pressure atomizing nozzles or by other means
such as two-fluid nozzles or spinning disk atomizers. Either
holiow or solid cone sprays can be produced.
The juice is contacted with a stripping agent such as steam,
or an inert gas, i.e., nitrogen or carbon dioxicJe, to remove or
strip away the aroma and flavor volatiles. Steam is preferred for
this purpose because many of the volatiles are soluble in or
co-distill with water and are thus easily removed. Condensation
of the aroma and fiavor volatiles is also easier to accomplish.
Steam or inert gas is introduced through tl-e bottom of the
stripper (1~). In general, from about 0.3 Ibs. to about 1.5 Ibs.
of steam are used per each pound of soluble solids in the juice.
Preferably, from 0 . 6 to 1 . 0 Ibs . of steam per Ib. of solids are
used. Cut rate is defined as the pounds of stea~ per pound of
soluble solids in the juice.
~21~67
It is important that the vapor rising in the stripper mix well
with th~ citr~ls juice spray, especially in the region near the
nozzle so that the volatilized aromatic material can be carried
away as part of the vapor stream. The partially or, completely
.. 5 stripped citrus juice is collected and pumped (via pump 16) from
the bottom of each stage. For the top stage and any intermediate
stages the citrus juice is collected on a tray (6) having a number
of openings in it to allow for the vapor from the stage below to
pass up the column and mix with the spray in each stage. The
10 opening should be covered to prevent the citrus juice spray from
passing directly into the stage below. Trays should be designed
to minimize the citrus juice holdup so that the overall exposure
time of the citrus juice to the 100F (37.7C) to 160F (71C)
temperatures can be minimized. As citrus juice is pumped from
15 one stage to another, it can be passed through heat exchangers
(18) to heat the citrus juice to a temperature above the
equilibrium temperature in the stripper so that the citrus juice
flashes as it leaves the spray nozzles in that stage. In general,
the citrus juice should not be heated above 160F (71C) for
20 longer $han a few seconds.
The quantity of volatile components removed can be
increased by increasing either the cut rate, the number of stages
or the length of each stage. The amount of additional volatiles
removed by increasing the cut rate above about 0 . 8 or 0 . 9 is
25 usually small and must be balanced against the higher cost to
remove the additional water condensed with the volatiles.
Similarly, increasing the number of stages beyond 4 or 5 does not
result in large increases in the amount of volatiles removed. The
additional residence time of the citrus juice at elevated
30 temperature can result in the creation of off-flavors in the citrus
juice. Thus, the cut rate and the number of stages used can be
varied to obtain the optimum balance of cost, volatile removal,
and minimum degradation.
Care must be taken so that the steam does not impact on the
35 surface of any citrus juice that may be collected at the bottom of
12~31~7
~he stripper. Water vapor from the added low pressure steam is
passed countercurrently through the juice spray to help remove
and carry off the volatile materials as the vapor pas~es upward
through each stage and out of the stripper. in a~dition to
5 steam, inert gases may also be used to strip the citrus juices.
Steam is preferred because the later concentration step removes
water in its essentially pure form. \Alhen other inert gases are
used, they must be separated from the volatiles using pressure
equilibration techniques. These processes can cause loss of some
Of the aroma and flavor volatiles due to the high volatility of the
aroma and flavor compounds.
The temperatures in the stripping stages can be from about
100~F (37.7C) to about 160F (71C). Temperatures above 160F
(71 C) cause some degradation of the aroma and flavor of the
juice. Preferably, the temperatures will be about 125F (51,7C)
to about 140F (60C). Each stage can be operated at a different
temperature. The temperatures can be progressively higher in
each stage, or the same in all stages.
The pressure within the stripping column can be up to 9
inches of Hg. absolute and preferably is from about 2 to about 6
inches of mercury absolute. I~/lost preferably, the stripping is
carried out at pressures of from 3 to 5 inches of mercury
absolute .
The stripped juice is pumped (20) from the last stage and is
either sent directly to an evaporcltor or concentration equipmerlt
or cooled and stored prior to evaporation. If the juice is cooled,
energy can be saved if the hot juice is used to partially heat the
incoming juice. It, in turn, is partially ccoled thereby.
RECOVERY OF VOLATILES
The aroma and flavor volatiles are passed through a demister
at the top of the stripper (2) and recovered by condensation at
temperatures of 95F (35C) to -320F (-196C). The actual
temperature of conciensation will depend upon the pressure within
the condensation system. Vihile the majority of the volatile
35 compounds in citrus juices condense around -50F (-45.5C) at
lZ13~67
--1 o--
pressures o~ 2 to 9 inches of mercury absolute, condenser
temperatures from about - 60F (-51C) to about -32~F (-196C)
are sufficient to condense substantially all of the aroma and flavor
volatiles at low pressures.
The condensation can be carried out using she~l and tube
heat exchangers, condensing in vertical tubes for the liquid
condensing, and in the shell of a U-tube exchan~er for freezing
the condensate. The liquid condensing can also be accomplished
in two or more condensers in series using cooling tower water
(24) for the first condenser (22) and refrigerated coolant (26) on
subsequent condensers (28 and 30). Refrigerated coolants such
as glycol and Freon can be used. Steam ejectors, mechanical
vaclJum pumps, or some combination can be used to reduce the
pressure and remove non-condensables.
The aroma and flavor volatile materials which have been
gently removed from the citrus juice by the stripping column are
preferably condensed in three stages. The first stage condenses
pS~imarily the water and some of the aroma and flavor volatiles,
ar d the second and third stages condense the remaining volatiles.
The first stage condenser can be at a temperature of from about
60F (15.6C) to about 95F (35C), and preferably from 60F
(15.6C) to 80F (26.7C). The second stage condenser can be
at a temperature of from about 33F (0.5C) to about 60F
(15.6C) and preferably from about 40F (4C) to about 50F
(10C). This will insure collection of most of the water and the
lesser volatile flavor and aroma rnaterials (higher boiling). The
third condenser (30) is at about -50F (-45.5C), and can be as
low as liquid nitrogen temperatures (-320F). The aroma and
flavor volatiles are condensed or collected as a frost in this
condenser. The collection efficiency of these low temperature
condensers can be improved by pre-frosting the condensing
surface using stear;7 or a steam-noncondensable gas mixture. This
provides more condensation sites for collection of the volatile
mixture .
1213167
Care must be taken to avoid losing the volatiles which are
condensed as the frost when the frost is added back to the liquid
portion of the condensate or to a carrier solution for further
concentration. One way to accomplish this recombination is to
5 coliect the frozen portion on one condenser. After ~ollecting the
frost, the condenser is isolated from the vapor system and from
the vacuum system and then filled with liquid condensate from the
first condenser. This liquid can then be recirculated through the
cryogenic condenser to melt the frost. The temperature of this
melting should be at about 35F (1C) to about 45F (7C~ so
that the volatiles dissolve directly into the cold liquid and do not
have an opportunity to volatilize.
The condensate is a mixture of water-soluble volatiles such
as ethanol, ethyl butyrate, and acetaldehyde and oil volatiles
15 such as d-limonene, myrcene, and alpha-pinene which are
relatively insoluble in water. These volatile materials are present
in a relatively stable emulsion of oil in water. Some oil may
separate. The oil and aqueous phases can be separated by
holding cold for long periods of time, by freezing and thawing,
20 or preferably by centrifuging (32) in a continuous sta;ked disc
hermetic centrifuge. Two clear phases are obtained, an aqueous
stripper essence which is nearly free of oil components and a
limonene-based stripper oil. Small quantities of a wax-like
substance are collected in the centrifuge and must be removed
25 period ical ly .
The condensed materials are stored in closed tanks with an
inert gas blanket and are preferably shielded from light to
prevent oxidation of the aroma and flavor compounds. The
aqueous aroma flavor condensate can be stored at cool
30 temperatures prior to separation or use. The limonene-based
stripper oil can be stored at low temperatures (-1 0CF) prior to
use .
Part of the water can be removed from the aqueous stripper
essence by recycling part of the material back to the top of the
35 stripper as shown in Figures 1 and 2 . This recycle stream ( 23 )
~213167
--12--
can be heated or cooled in a heat exchanger to the desired
temperature. Preferably the temperature is within about 20F
(11C) of the water temperature corresponding to the equilibrium
temperature of water at the pressure used in the stripper. In
5 the top of the stripper the recycled aroma condehsate is
distributed over packing material (3) incorporated within the top
of the stripper (2). Most types of mass transfer packing can be
used, such as Berl saddles, Raschig rings, or preferably
Goodloe-type wire mesh packing. Enough packing to give the
lO equivalent of 0.~ to 3.0 theoretical transfer units may be used.
Preferably this would be packing equivalent to about 2 transfer
units.
This recycle (rectification) process can be used to remove
from 10~ to up to 70% of the water from the aqueous stripper
15 essence and preferably up to 50~ or 60% without significant losses
of volatile materials in the juice going out the bottom of the
stripper .
The vacuum system used for the stripper column can be ar,y
commercia system capable of achieving the desired pressures,
20 including multi-stage steam ejectors, vacuum pumps, or
combinations. A liquid ring vacuum pump i5 preferred and a
preferred type is one made with stainless steel. When this type
of vacuum pump is used, the seal water can be added to the
aqueous stripper essence prior to concentration as a way of
25 recovering additional small quantities of valuable volatile
components. In addition a small packed column scrubber may be
used after the liquici ring vacuum pump to remove virtually all of
the valuable volatile materials from the exiting gas stream. ~hen
the scrubber is used, the cold water ~or other liquid) used as
30 the scrubbing fluid can also be used as the seal fluid for the
liquid ring vacuum pump in a countercurrent fashion.
lZ13~67
--13--
Aqueous-based Stripper Essence Concentration
Both the condensate , rom the stripper and the aqueous
stripper essence which is separated from this stripper condensate
are dilute water solutions of the volatile aroma an,cl flavor
5- compounds from citrus juice. In order to obtain an aroma and
flavor composition that can be economically stored for long periods
of time or which can be added to a frozen concentrate without
causing too much dilution, it is necessary to remove most of the
water. When steam is used as the stripping agent, the volatiles
usually comprise less than 2~ of the composition. The water must
be removed in a manner which retains essentially all of the
volatile aroma and flavor materials and which avoids oxidation and
degradation of the aroma and flavor compounds.
There are several methods which can be used to accomplish
the concentration of the aroma and flavor condensate or the
aqueous-based stripper essence, if it has been separated.
Reverse osmosis, low temperature vacuum distillation and freeze
concentration can be used. Vacuum low temperature distillation
exposes the volatile aroma and flavor materials to heat, therefcre,
degradation reactions that are accelerated by even this low
temperature ~about 161~F) may occur. The time the aroma and
flavor condensate is exposed to temperatures above 160GF should
be minimized during low temperature distillation. Freeze
concentration and reverse osmosis are preferred methods herein.
In order to concentrate the volatiles in the water solution a
carrier is usually added. A carrier is not required when vacuum
distillation is useci to concentrate the aroma flavor condensate.
Any material which is acceptable for food use and compatible
with citrus juice can be used as the carrier. Because of the
attraction between the aroma flavor volatiles and the citrus juice
its`elf, it is preferred to use the juice as a carrier.
The carrier can be juice, carbohydrates, edible acids, salts
of edible acids, soluble proteins or mixtures thereof. The sugars
which occur naturally in citrus juices are preferred carbohydrate
35 carriers. Preferably, the sugars will be in about the same ratios
~2~3~67
.
--14-
as are present in the starting juice. Thus, for orange juice
volatiles a carrier comprising 50~ sucrose, 2596 giucose and 25%
fructose could be used. Non-metaboiizabie sugars such as
~ maltose, and other sugars such as lactose, ribose, xylose can be t~,
- _~ 5 used. In addition, the sugar aicohols such as xylitol and ~r~l
are also acceptable as carriers. Polymeric carbohydrates such as
pectins, dextrins and starch can also be used.
Edible acids also function as ~arriers. Citric acid is
preferred since it naturally occurs in citrus juices. Other acids
such as malic, fumaric, and acetic acids can be usecl or salts of
these acidsO The taste of the acid will also control the level to
- which it can be addcd as a carrier.
A carrier solution which simulates the solids in orange jUiC2
is an aqueous solution of 4% to 6~ sucrose, 2~ to 3~ fructose, 2%
to 3~ glucose, 0.2~ to 0.7~ citric acid, and 0.196 to 0.2% potassium
(as a salt). These percentages are the weight percent in the
carrier solution before addition of the aroma flavor condensate.
The carrier is added to the aqueous stripper essence, or the
aroma and flavor cor,densate, at a level of from about 1~ to about
50~. The aroma flavor condensate and carrier composition
preferably has a sol ids concentration of from about 1% to about
8% .
The citrus juice carrier can be easily obtained by diverting
3 small portion of the citrus juice either from the feed to the
stripper, from the devolatilized juice leaving the stripper, or from
the concentrated devolatilized juice stream. The citrus juice
stream can be from 1% to 5~ of the total juice flow to the
concentrator .
A preferred method of concentrating the aqueous stripper
essence condensate is to remove the water by freeze
concentratic>n . Freeze concentration requi res the presence of
sufficient material to suppress the freezing point. Therefore, it
is necessary to mix the aroma flavor condensate composition with
a small amount of a carrier which will depress the freezing point
of the aroma flavor condensate.
~Z~3~L~7
Before the carrier and aroma flavor condensate solution
enters the freeze concentrator, any material having a particle si~e
greater than about 80 microns is removed. High speed
centrifugation can be useci to remove these particres, which
includes pulp. This prevents plu~ging of the filters and wash
columns in the freeze concentration equipment. Evaporator
essence or other aroma and flavor compounds can also be added
to the soiution before the freeze concentration.
Examples of an apparatus for use in freeze concentration is
the Grenco freeze concentration unit available from 5renco B.V.,
The Netherlands, the FMC freeze concentration units available
from FMC Corporation, and Struthers freeze concentration units.
Other companies which supply freeze concentration equipment
are C~l (Concentration Specialists, Inc. 3 of Andover, Mass. anci
Chicago Bridge ~ I ron Works.
The object is to remove essentially pure water from the
aqueous stripper essence to forra a concentrated aroma and flavor
and carrier composition. The aql~eous stripper essence can be
freeze concentrated to about 25% and then freeze dried to a
hiyher concentration, e.g. up to 85Q6. The free7e drying must be
done under conditions such that the frozen aqueous stripper
essence does not liquify during the freeze drying process. The
aqueous stripper essenc~ should be held below its eutectic
tempcratu re .
Other methods of concentrating the aqueous stripper essence
carrier solution are reverse osmosis or a combination
ultrafiltration/ reverse osmosis process. Water is removed from
the aroma flavor condensate carrier solution. In this case, the
volatile aroma and flavor materials remain with the carrier, i.e.
3~ juice or sugar solids, while the water passes through the
raembrane. See for example U.S. 3,743,513 issued to Tulin ~1973)
which describes reverse osraosis concentration of juices.
The aqueous stripper essence composition when combined
with a carrier can be concentrated from about ~o~ to about 85~.
Preferably the aroraa flavor concentrate will have a concentration
~21~3~67
--16--
in the range of about 20% to 50%, and most preferably in the
r~naes nf 25~ to 35~.
A typical concentrated aqueous stripper essence from orange
juice which has been concentrated using orange juice solids as a
5 carrier has the following composition of volatile aroma and flavor
compounds in the headspace:
Compounds % of Total Volatiles
in Headspace
Acetaldehyde O . 40 to 3 . 5
Methanol O .15 to 1 . 55
Ethanol 4 . 00 to 47 . O
Ethyl butyrate O . 25 to 2 . 50
Hexanal 0.05 to 0.35
Alpha-pinene O .18 to O . 32
Myrcene 0.70 to 1.65
Limonene trace to 90 . O
These are selected compounds, many others are also present,
as is evident from Figure 6.
The level of methanol and ethanol are lower than commercial
essences. The level of alpha-pinene, myrcene, limonene are
higher than commercial essences.
Optionally, the starting juice or carrier solution can be
pasteurized. The feed material is heated to a temperature of from
about 176F (80C) to about 203F (95~C) for from about 5 to
z5 about 12 seconds. The feed is then rapidly cooled to a
temperature of about 32F (0C) to about 40F (4.4C). This
system used to pasteurize the juice or carrier must be c10s2d and
must be conducted in a manner such that the juice is not exposed
to an oxidative atmosphere.
Evaporation of the Stripped Juice
The stripped juice is concentrated by conventional
evaporation techniques.
Ideally the evaporation economically removes water to
increase the concentration of the juice to 60~ Brix or higher
.
~213~67
(about 60~6 to about 75% sugar solids). The juice can be stored
safely and economically at these concentrations. In addition, the
evaporation step will collect any aroma and flavor materials which
were not removed in the strippin~ step. In addition, the
5- evaporation should be carried out in the manner tha~t artificial,
cooked or manufactured flavors are minimized.
Preferably, a multi-stage, multi-effect vacuum evaporator
such as the TASTE (thermally accelerated short time evaporator)
is used. This type of evaporator is common in the Florida citrus
10 industry. The temperature profile used in this invention is
controlled so that the maximum juice temperature is about 160'iF
(71C) to about 210~F (98.9C). A noticeable "cooked" flavor
develops in citrus juice concentrate even with the short residence
time of these evaporators when the juices exceed this
15 temperature. The evaporators can be operated using either
forward flow or mixed flow. The vessel where the steam is
flowing is called an effect. The vessel where the juice flows is
the stage. Forward flow occurs when the juice is fed to the same
vessel as the steam and then follows a path through different
20 vessels in parallel to the vapor flow. Mixed flow occurs when the
juice is introduced to one of the intermediate vessels where it is
evaporated by vapor generated in a preceding vessc-l. After
partial concentration the juice is then fed to the first vessel
where it is evaporated using fresh steam, Evaporation takes
25 place in one or more stages following the feed stage and also
following the first effect.
In each case, forward or mixed flow, the steam and the
vapor flow in the first effect and in subsequent effects, in the
same pattern. The vapor starts at the highest pressure and ends
30 at the stage with the lowest pressure. Any suitable vacuum
system can be used to remove non-condensables, but typically
this will be a multi-stage steam ejector system. The process is
operated at pressures of about 2 inches to about 4 inches of
mercury absolute.
12131~7
-1 8-
ln a multiple effect evaporator, steam is used on!y on th~
first effect and each subsequent effect is heated by vapor
evaporated in the preceding stage. This vapor is primarily water
but it also contains voiatile materials originally in the citrus juice.
5 These volatiles can be recovered by removing part o~ the vapors
from the heating side of the evaporation effect. This removal
- stream is passed through a series of fractionators, condensers,
and coolers to obtain a cold li~uid essénce rich in volatile
fractions. This procedure is commonly practiced in the citrus
10 industry.
The evaporator essence collected in the process herein is
significantly different from the commercial essences since most of
the highly volatile materials have previously been removed fro~n
the juice in the stripper.
15This evaporator essence can be added back to the
concentrated citrus product in the blend tank or added to the
aqueous stripper essence prior to the concentration step. If the
water content of the evaporator essence is high, or if the
evaporator essence is to be stored, then it is more economical to
20 concentrate this evaporator essence.
The evaporated concentrate is cooled and can either be
pumped to a blend tank and mixed v,lith other components of the
product or further chilled to about 18F (-7.8~C) and stored in
tanks or drums under an inert gas atn osphere such 3S nitrogen
25 or carbon dioxide. These storage tanks should be shielded fror~
light to prevent oxidative degradation of the concentrate.
Other means of concentrating the stripped citrus iuice can
be used. These wouid include reverse osmosis, freeze drying or
freeze concentration. Economically, however, it is better to use
3~ an evaporation technique especially since the stripped citrus juice
does not contain many aroma and flavor volatiles and therefore
there is no need to utilize a method which would retain these
volati les .
3167
.. ,9
B lending
The aqueous stripper essence concentrate and the
limonene-based stripper oil essence prepared above can be
blended with concentrated stripped juice, sensible pulp, water,
peel oil, or other aqueous essence to make a citrus juice
concentrate product. These various components are preferably
blended as follows. First add the sensible pulp to the mix vessel
alon~ with most of the water calculated to reach the final desired
concentration. Next add all of the aqueous stripper essence
concentrate and enough of the evaporated concen~rate to raise the
concentration of the mix to from about 12 Brix to about 30 Brix
(Sg6-40% of the evaporated concentrate). To this mixture add the
aqueous essence and limonene-based stripper oil and other flavor
oils and mix until oil is thoroughly dispersed. The remainder of
the evaporated concentrate and water can then be added and
m ixed .
The aqueous stripper essence or aqueous stripper essence
concentrate ancl limonene-based stripper oil are added back to the
concentrated stripper juice (or to any citrus juice concentrate) at
levels which impart the aroma and flavors of fresh juice. A
20-30 ~rix aqueous stripper essence concentrate that is added
to a 65 Brix evaporated concentrate will be from about 1% to
about 25% of the total product. In general, it will be from about
2% to about 20% of the product.
The limonene-based stripper oil will be from about 0.005"6
(v/v) to about 0.018% (v/v) based on single strength juice, i.e.
the dilutccl concentrate. Other peel or essence oils can also be
added to the product.
Figure 3 is a gas chromatogram of the headspace of a frozen
orange juice concentrate prepared with aqueous stripper essence,
limonene-based stripper oil, and concentrated stripped orange
juice. The solids concentration in the concentrate is about 41~6.
The concentrated juice can be packed in cans, foil-lined
containers, bottles, etc. To insure long-term oxkJative stability,
the packaging materials should be impermeable to oxygen.
1213~67
--2~--
Additional Iy, the concentrate can be packed under an inert
atmosphere such as nitrogen.
Both quantity and size of the pulp affect the consumer
acceptability of orange juice concentrates. Prefera~ly, the
5 amount of pulp will be 6% to 12% (volume/volume) ha~ing a size
less than 0 . 5 mm . and 1~ to 3% having a size 0 . 5 to 2 . 0 mm .
These pulp percentages are measured by standard citrus industry
method s .
Orange Juice Aroma and Flavor Condensates
Gas chromatographic analysis of the volatile portion of
orange juice indicates that there are at least 250 compounds, and
probably considerably more present in the volatile portion of the
orange juice. Complete identification of all of these volatile
compounds has not yet been achieved. The volatile compounds
15 which are believed responsible for the fresh ~roma and flavor
character of the citrus juice concentrate are composed of alcohols,
carbonyls, acids, esters, terpenes, and other volatile
hydrocarbons. The low boiling fraction contains large amounts of
methanol, ethanol and acetaldehyde. Other key low boiling
20 compounds are ethyl butyrate and hexanal. The aroma flavor
condensate obtained from the stripping of orange juice contains at
least 60~ of the flavor and aroma compounds which were present
in the original juice.
~IVhen steam is used as the stripping agent the aroma and
25 flavor condensate can be separated into two phases: an aqueous
stripper essence and a limonene-based stripper oil.
The limonene-based stripper oil is different from essence oil,
peel oil and juice oil. Juice oil is the water-insolublP oil obtained
by centrifuging fresh juice. This limonene stripper oil is less
30 oxidized and contains higher chain length aldehydes than
conventional oils.
Aqueous-based Stripper Essence
The aqueous-based stripper essence comprises the aqueous
phase of the aroma flavor condensate obtained from stripping
35 fresh orange juice with steam. It contains the water-soluble
lZ13167
orange juice aroma and flavor volatile compounds in a very dilute
solution. The aqueous-based stripper essence has from about
~.0l% to about 2% ethanoi. Figure 7 is a gas chromatogram of the
alcohol fraction of an aqueous-based stripper essence from
.5 Valencia oranges.
The essence is characterized by having a ratio of low-boiling
(highly volatile) water-soluble components to high-boiling (lower
volatile) water-~oluble components of from about 0. 1: 1 to about
l: l . Preferably, this ratio will be in the range of from about
0.2:1 to about 0.3:1.
The aqueous stripper essence is analyzed by the direct
injection gas chromatographic procedure described later. The gas
chromatographic procedure uses a column which separates the
materials by adsorption. An internal standard, cyclohexanone, is
used. The materials which elute before the cyclohexanone are the
lower molecular weight compounds and thus are the low-boiling
compounds. Those which elute after the cyclohexanone are the
high-boiling compounds. To determine the ratio of these two
compositions, the total area or total concentration of the
low-boiling materials is divided by the total concentration of the
high-boiling materials. Methanoi, ethanol and acetaldehyde are
not included in this ratio because of their high concentration
relative to the other components. The internal standard is not
added to either composition. Figure 5 is a chromatogram of an
aqueous stripper essence from Valencia oranges.
The aqueous stripper essence has a concentration range of
aroma and flavor materials as illustrated in Table 1. Many other
volatiles are present as is evident from the chromatogram.
TABLE 1
A typical aqueous stripper essence from orange juice has the
foliowing composition:
f' ';~
3~i7
--22--
~oncentration
Gomponent ppm lu g/ml essence)
Hexanal 0 . ~ to 3 . 5
Ethyl butyrate 4.0 to 7.0
t-2-hexenal trace
3-hexene~l-ol trace
Hexanol trace
Octana 1 3 . 0 to 6 . 0
Octanol trace to 2 . 5
Linalool 6 . 0 to 15 . 0
Nonana1 trace
Alpha-terpineol trace to 2.0Q
d-ca rvone trace
Geraniol trace
Geranial 1,0 to 3.0
Valencene 0 to 4.0
Myrcene trace to 3.0
d-limonene trace to 72
Ethanol 0.01~ to 2$.
Methanol 0 . 01~ to 0 . 5~
Acetaldehyde 0 . 01~ to l . 5%
The extremely Icw levels of the six carbon hydrocarbons is
important. The t-2-hexenal, 3-hexene-1-ol, hexanol and hexanal
contribute to the "green" or apple-like aroma of certain essences.
The fact that these materials are at very low concentrations or
are absent in this aqueous stripper essence makes it taste less
"green" and more citrusy or orange-like than conventional
products .
Limonene-based Stripper Oi l
The limonene-based stripper oil is the water-insoluble
fraction of the stripper aroma fiavor condensate. This
composition contains the water-insoluble aroma flavor compounds
in a limonene matrix.
:lZ~3167
--23-
~ lhen orange js~ice is stripped of its volatiles, the
limonene-based stripper oil essence composition comprises a
minimum of about 695 (mg/ml) of limonene. The composition is
further characterized by comprising less than 1.1 mg/ml of
5 linalool and less than 1.1 mg/ml of nonanal, the ratio of nonanal
to linalool being from about 0.5:1 to about 4:1. Preferably, the
ratio of nonanal to linalool will be between 0.5:1 and 2:1.
The limonene-based stripper oil of orange juice is fruity and
most faithful to the flavor of orange juice. It is higher in its
10 concentration of longer chain aldehydes. This may contribute to
its more mellow or mild flavor,
A typical limonene-based stripper oil essence derived from
orange juice has a density of between 0.75 and 0.9 g/ml.
A typical limonene-based stripper oil essence comprises the
15 following amounts of representative compounds listed in Table 2:
12~3~67
-24-
TA BLE 2
~n~n~n~ntc Concentration (mg. /ml. )
Ethyl Butyrate 0 .15 to 0 . 75
alpha-pinene 2.20 to 7.00
Sabinene 0 . 40 to 4 . 50
Myrcene 15.0 to 20.0
Octanal 1.50 to 3.00
d-Limonene 695 to 800
gamma~terpinene 0.02 to 0.08
Octanol 0 to 0 . 20
Linalool 0 . 30 to 1 .10
Nonanal 0 . 30 to 1 .10
Citronellal 0.10 to 0.75
alpha-terpineol trace to 0.20
Decanal 3.5 to 5.75
Neral 0.15 to 0.60
d-carvone trace to 0.20
Geraniol trace to 0.7
Geranial 0.01 to 1.0
Perillaldehyde 0.10 to 0.30
Dodecanal 0.31 to 0.72
Valencene 10 . 0 to 25 . 0
Nootkatone 0.25 to 2.0
Figure 4 is a gas chromatogram of a limonene-bas~d stripper
25 oil from Valencia oranges.
The limonene-based stripper oil has a fresher flavor than
conventional essence oils, including "juice oil" which is obtained
by centrifuging juice. This is primarily due to the
nonanal: linalool ratio. The ratio of the sum of the alcohols to the
30 sum of the aldehydes is also important, it is from about 7 :1 to
about 28:1 long chain aldehydes to long chain alcohols.
The sum of the aldehydes is obtained by adding the
concentration of the following materials: octanal; hexanal;
citronellal; decanal; neral; geranial; perillaldehyde, and
~213167
dodecanal . The sum of these materials ranges from 7. 5 to 11
mg/ml .
The sum of the alcohols is obtained by adding the
conoentration of the following materials: octanol, linalool and
S geraniol. This concentration ranges from 0.40 to 1.1 mg/ml.
The oxidation products, alpha-terpineol and d-carvone are
also lower in the limonene-based stripper oil than in most
conventional essence oils. The sum of the concentration of the
oxidation products: linalool, alpha-terpineol, d~carvone,
lO geraniol. and nootkatone is lower than conventional essence oils.
The range is frc~n .50 mg/ml to 2.75 mg/ml. Conventional
essence oils contain from 3.3 to 126 mg/ml of these products.
The lack of oxidation products is an indication of the
non-degrading manner in which these materials were removed from
15 the orange juice.
EXAMPLE I
The pulp greater than 0.5 mm. is removed from Valencia
orange juice (1000 Ibs. of 12,5 ~rix) by a Brown A~iC juice
finisher. The juice is stripped in a 1 0-inch diameter 2 stage pilot
20 plant stripping column. Thé juice is heated (with low pressure
steam) in a heat exchanger from 35F (1.7C) to 125F (51.7C)
and is sprayed into the first stage of the stripper through a TF8
FCN 303 Bete fog nozzle at 20 psig pressure. The juice is
collected about halfway down the column and pumped out and
25 through a second heat exchanger to raise the temperature to
1 40~F (60C) . This reheated juice is then sprayed into the
stripper a second time through a TF10 FCN 303 Bete fog nozzle.
At this temperature, the juice ~lashes to the stripper equilibrium
temperature of 125F ~51.7"C). The stripped juice is pumped
30 from the bottom of the column and cooled to 50F (10C) and
stored in drums until enough material to evaporate has been
col lected .
The stripping column is operated at a pressure of 4 inches
Hg. absolute. Juice is stripped at a rate of 250 Ibs. /hr. Steam
j!
~2~3167
--26--
is sparged into the bottom of the column (about 30 Ib. /hr. ) and
passed countercurrent to the juice to aid in removing and
carrying off the volatile aroma and flavor materials. The
stripping steam $ogether with water which flashed in the second
5 stage and the stripped volatile aroma materials are cohdensed in a
series of condensers. The first condenser operates at 70F
(21 C~ and at 4 inches Hg . absolute and condenses most of the
water and some of the volatiles. The second condenser operates
at 35'~F (1.7C) and at 4 inches Hg. absolute and condenses more
10 water and volatiles while the last condenser operates at -60F
(-51C) and at 4 inches Hg. absolute and condenses virtually all
the remaining water and volatile materials. Previous tests in
which two liquid nitrogen cooled traps in series are added to the
system after the -60F (-51 C) ~ondenser indicated only trace
15 amounts of condensable materials indicating substantially complete
condensation in the first three condensers. At the conclusion of
the stripping run, a portion of the liquid condensate collected
from the first two condensers is poured into the third condenser
to melt and dicsolve the frozen mater al. This mixture is then
20 carefully added to the remainder of liquid condensate from the
run .
Gas chromatographic analyses for the aromatic volatile
materials show the following resul 's in comparing the amount
removed (feed juice and stripper bottoms) and the amount
25 recovered in the condensate.
As ~O of Component
Present in Feed Juice
Removed Recovered
Acetaldehyde94 73
Ethyl butyrate 98 62
Methanol 77 69
Ethanol 81 75
12~3167
,. --27--
The removal and recovery of the highly volatile n aterials of
which these are an example means that the aroma flavor
condensate will contribute importantly to the "fresh" flavor. The
difference between the amount removed and that recovered in the
5 condensate can be explained on the basis of exposure of volatile
materials during transfer between vessels. It would be expected
that recovery would be cioser to the removal in a well-designed
closed collection system such as would be used for continuous
commercial operation,
1 0 The stripper bottoms are concentrated in a five-stage, five
effect TASTE pilot plant model from Gulf Machinery
Corp. evaporator operated in a mixed flow mode. The product
temperature profile is 145F (62.8C), 127F (52.8~C), 185F
(85C), 1~5F (73.9C), 103F (39.4C). Essence is recovered
15 from the shell of the fourth effect (boil-off from the feed).
Pressure in the evaporator ranged from 2 inches Hg. absolute at
the ejector to about 21 inches Hg. absolute in the third stage.
The stripper bottoms are concentrated from 12.7 Brix to 65
Brix and 0.4 Ibs. of essence are collected for each 100 Ibs. of
20 bottoms fed. The feed rate to the evaporator is 950 Ib. /hr.
The aroma condensate from the stripper is blended with
stripper bottoms to form a mixture of 4 ~rix concentration to
feed to the freeze concentrator, In this example, aroma
condensate from the Valencia juice is b!ended with aroma
25 condensate from both Hamlin ancl Pineapple juices which are
stripped in the same way, This is done to obtain enough aroma
condensate feed material to easily operate the pilot-sized
continuous freeze concentrator (Grenco Model VJ-8).
Pulp is removed from the starting juice for freeze
30 concentration in a bowl-type centrifuge (Westfalia Corp., Model
~SB-7-06-576) operatiny at a speed of 9500 rpm. Nitrogen is
passed into the bowl of the centrifuge during the separation.
The separated serum is poured into a refri~erated supply tank
helcJ at 32F (0C) and equipped with a 90 micron filter at the
35 exit. The aroma flavor condensate is added to the serur,~. The
1213~67
-28-
sugar solids concentration of the serum/condensate solution is 4%.
The tank i~ shielded from the light. A nitrogen gas blanke' is
continually maintained in t~e supply tank.
A Grenco freeze concentration unit, Model ~8, ,is fed from
5 the refrigerated supply tank. The refrigeration unit and
recirculation pump circulating the serum/condensate from the
recrystallizer through the scraped wall heat exchanger are started
and the serum/condensate is cooled down to 28F (-2.2C).
Cooling down the serum/condensate solution to 28F (-2.2C) and
10 formation of recrystallized ice is achieved after 2 hours at which
point also the removal of ice via the wash column is started.
After removal of the ice from the unit the solid concentration
begins to increase steadily to reach a concentration of 25% after a
7 hour period. At this point the aroma flavor concentrate is
15 removed.
The aroma flavor concentrate which is obtained represents a
concentration of volatile aroma and flavor materials about 60 times
that hund in the starting juice.
GC analysis of the aroma condensate feed material, the aroma
20 flavor concentrate, and the water removed indicated that about .
99% of the most volatile components (acetaldehyde, methanol,
ethanal and ethyl butyrate) remained in the concentrate.
The aroma flavor concentrate was added back to the
concentrate at 16% of the final solution. Pulp was added (8.7~)
25 and the peel oil level was adjusted to 0.010% (v/v). The
aromatized concentrate was packaged in zip lock cans.
EXAA/IPLE H
The aroma flavor condensate was mixed with sucrose to make
a solution of approxir,lately 6 . 2P6 concentration of sucrose. This
30 solution was concentrated using a DDS lab module 20 reverse
osmosis apparatus available from Niro Atomizer. An HR-98 (DDS,
polysulfone-polyamide composite mcmbrane) was used. The
volatiles plus carrier solution was concentrated at 60F and 50
bars pressure. The final concentration was 25.8%.
3~;7
--29--
The aroma flavor concentrate prepared in this manner
retained 85~ of the volatiles. This aroma flavor concentrate is
blended with an evaporated concentrate to produce superior
orange juice concentrate which when diluted to single strength
5 tastes like fresh orange juice.
EXAMPLE l l I
- Valencia orange juice which had been extracted usiny B rown
AMC extractors was finished in Brown AMC finishers to remove
pulp larger than about 0.5 mm. A portion of this juice was
10 pumped to a 3-stage production stripping column at the rate of
25, 000 Ibi hr .
Thc juice was heated to 130F before entering the first stage
where it was sprayed into the stripper through 7-3/8" stainless
steel pipe nipples. Since the juice was slightly above the
15 equilibrium temperature and c.ince it contained some dissolved air
which would come out of solution, the expanding released air and
small quantities of flashed water vapor caused the juice coming
from the pipe nipples to be sprayed, the spray covering the
entir~ cross section of the stripper. Juice was collected from the
20 first tray and pumped through a second heat exchanger where it
was reheatecl to 1 30F and resprayed, this time through
7TF14FCN Bete Fog nozzles. The juire from the second stage was
pumped through a pipeline containing a direct injection steam
nozzle and was reheated to a temperature of 145F and flashed
25 into the stripper as in the first stage. The juice from the bottom
of the stripper was pumped through a plate an~ frame heat
exchanger to be cooled by the incoming juice before being pumped
to the TASTE evaporator feed tank.
Culinary steam was sparged into the stripper near the
30 bottom, at a rate which when combined with all of the flashed
vapor would give a cut rate of 0. 8 Ib steam/ Ib of sugar solids .
Since the Valencia juice in this example was at 12.2 E~rix, tl-e
total steam flow was 244U Ib/ hr.
Thc vapors passed up through the stainless steel wire gauze
35 mist eliminator and about 1 ,t of Goodloe-type wire gauze type
lZ13167
--30-
packing to a 2-stage shell and tube condenser. The first staye
was cooled with cooling tower water at about 85F and the second
stage was cooled using 35F glycol so that the condensate was
pumped from the second stage at a temperature of a~out 38F.
5 The condensate, which is a mixture of water and wa!ter-insoluble
phases, was collected in a cold wall condensate collection tank and
blanketed with nitrogen gas. The vapors from the second stage
cooled condenser passed through one of two low temperature
condensers. These condensers used liquid ammonia as the
10 refrigerant at about -50F. The vapors were condensed as frost
on the shell side of the tubes which had previously been
pre-frosted with steam. These two condensers were used
alternately; while one was condensing, frost was removed from
the other by pumping condensate from the condensate collection
15 ~ank through it.
When a condensate collection tank was full, the essence
condensate was pumped through a DeLaval S~194 stacked disc
hermetic centrifuge at a rate of about 5 gpm. The, entrifuge
continuously separated the ess~nce condensate into two clear
20 streams. The limonene-based s.ripper oil was takcn off as the
light component and collected under nitrogen gas in 5 gallon lined
pails. These pails were stored zt -10F when full. The heavier
ac~ueous stripper essence was pumped to a cold wall storage tank
and held at 35-40F under nitrogen until concentrated in the next
25 step.
Part of the stream of stripped juice pumped from the bottom
of the stripper earlier had been passed through a continuous
stacked disc centrifuge to reduce the pulp content to about 0. 56
v/v, This depulped juice was used as a carrier and was blended
30 with the aqueous stripper essence to form a 4 t~rix feed stream
for the freeze concentrator. The concentrated stripper essence
exi~ing the freeze concentrator was 25 Grix. The water (ice)
removed contained less than 5% of the volatile materials fed to the
freeze concentrator. This aqueous stripper essence concentrate
35 was collected in a cold wall tank and held at about 28F until
:i2~3167
being pumped into nitrogen flashed 35 gallon essence drums. The
aqueous stripper essence concentrate was stored and frozen at
-10F.
The stripper bottoms are pumped through an Al~a-Laval type
5 SRPX-417-HGV stacked disc centrifuge to reduce the sinking pulp
level to meet the requirements of the State of Florida Departr,lent
of Citrus. Pulp removed from part of this stream to make serum
for the freeze concentrator is added back to the main stream flow
prior to centrifuging.
The stripper bottoms were concentrated to 65 Brix in an
8-stage, 6-effect TASTE evaporator manufactured by Gulf
lAachinery Co. The evaporator was operated using mixed flow
and the temperatures leaving each stage were about: (1) 172F;
(2) 205F; l3) 193F; (4) 154F; (5) 137F; ~6) 106"F; (7)
15 103GF; and (8) 104F. The concentrate was stored at -10F in
55-gallon drums using two polyethylene bag liners.
Evaporator essence was collected from the first boil-off using
an essence collection system furnished by Gulf l~llachinery Co.
After collection the essence was allowed to separate into 2 phases
20 and was decanted to give an aqueous evaporator essence and an
evaporator essence oil.
Gas Chromato~raphic Headspace Analysis
For investigation of aroma volatiles fror~ orange juice,
headspace samples were taken by passing helium over the orange
25 juice samples to be analyzed. The automated purge and trap
headspace analytical system consists of a Hewlett Packard 7675A
purge and trap sampler and a Hewlett Packard 5880A capillary
column gas chromatograph.
A 1 ml. sample of orange juice is placed into a sampling
30 contain r (15 ml. volume culture tube) equipped with a
Teflon~ coated stirring bar. After equilibration in a water bath
(27 ~ 1 C) for 5 minutes with magnetic stirring, the volatile
compounds were swept into a room temperature adsorption tube
~Z~3~67
--32-
filled with Tenax, a porous polymer, at a helium rate of 10
ml. /min. for 1 minute. This hydrophobic polymer selectively
absorbs the organic volatiles and the helium stream containing
water is vented to atmosphere. Then the Tenax tube was flushed
5 one more minute with clean, dry helium gas ( 10 ml . min ., flow
rate) to remove water from the trap. This water can cause
clogging problems by ice formation in the cold trapping system of
the capillary column.
Tenax is a porous polymer based on 2,6-diphenyl-p-
10 phenylene oxide available from the Applied 5cience Division of~ilton Roy Co. This porous polymer is used because it is
hydrophobic, shows excellent thermal stability, and does not react
with most organic aroma volatiles. The adsorption tube is filled
with 200 mg. of Tenax (80/100 mesh) and a small plug of glass
15 wool a~ each end to keep the adsorbent in place. Before use, the
Tenax tube is always cleaned for 16 minutes at 250C in a stream
of dry helium gas (10 ml./min.).
Sample injection into a capillary column was performed via
desorption of the Tenax trap and reconcentration of the desorbed
20 sample onto the first portion (2 inches) of the capillary column.
Thermal desorption was effected by heating the Tenax tube to
200C for 8 minutes with helium flowing through it at a flow rate
of 2.7 ml. /min. The front portion of the capillary column is
located inside a trap cooled with liquid nitrogen (-1 50C) . The
25 sample is swept from the Tenax tube onto the capillary column
where it condenses out in a narrow band at liquid nitrogen
temperature. For injection of sample snto capillary column, after
cooling, this cold trap was heated very rapidly: it takes about
20 seconds to reach 140C and the temperature is held at 140GC
30 for 1 minute. The helium switching valves and the cooling and
heating sequences of the cold trap were controlled automatically in
a pre-programmed mode.
The column used in this experiment is a Durawax-3 fused
silica capillary column (J~J Scientific, Inc., 0.32 mm. I.d x 60 m.
35 length). Durawax-3 is a stabilized liquid phase which contains
f ~
~213~67
--33--
50% of Carbowax-20M and 50% of methyl silicone. The carrier gas
flow (He) at the capillary column outlet was 2.7 ml./min. (linear
gas velocity = 34.5 cm./sec. at 40C). The injection port and
flame ionization detector temperatures were set at 1 80C and
5- 220C, respectively. The column oven temperature 4as held at
50C for 18 minutes, raised to 70C at 1.5C/min., then raised at
5C/min. to 145C and held for 8 minutes.
The compounds were identified by the retention times of
peaks obtained for known standards using the technique of
10 co-injection and peak enhancement. Integration of peak area was
obtained by use of Hewlett-Packard 5880A series terminal, level
four. This automated headspace analytical system provides good
precision for most of the aroma compounds lpercent relative
standard deviation = 5.0 - 14.7%, n = 6). Orange juice samples
15 were analyzed as single strength, and concentrated aroma
condensate and aqueous essences were diluted with water to reach
the linear range of the gas chromatographic detector response.
Figures 3 and 6 are representative chromatograms of a
frozen orange juice concentrate product and of a concentrated
20 aqueous essence.
~213~67
--34--
Gas Chromatographic Method_
B. Aqueous Stripper Essence Analysis
3. Sample preparation
Standa rd Sol ution ~ -
.
Absolute ethanol (10 ml.) is added to a 50 ml.'- ~olumetric
flask. Th~ components listed in Table 1 are added. After all of
these components are added to the flask, the solution is diluted
to 50 ml. with ethanol.
Table 1
Composition of Standard Mixture
Volume of ppm (wt./wt.)
ComponentsPu~e Comp~ ng~ in Calibration
Hexanal 50 4.07
Ethyl butyrate 150 13.18
Hexanol 50 8.14
Octanal 50 4.06
t-2-Hexenal 50 4.25
3-Hexene-1-ol 50 4.24
Alpha-pinene 50 4.29
Beta-pinene 50 4.32
Myrcene 100 8.13
Octanol 100 8.21
Limonene 200 16.82
Linalool 150 13.00
Nonanal 50 4.13
alpha-Terpineol 100 9.34
L)ecanal 50 4.15
Citral 100 8.89
d-carvone 50 4.80
3~ Geraniol 25 2.22
Valencene 50 4.21
2 Internal Standard Solution
.
A small volume (2-3 ml.) of distilled water is added to a 10
ml. of volumetric flask. Cyclohexanone (25 ~I) is added and the
35 water/cyclohexanone mixture is brought to volurne with distilled
water .
.
~213~L67
--35--
3. 159~ Ethanol Solution
Pipette t S ml . of absolute ethanol into 100 ml . of volurnetric
flask and bring the ethanol to volume with distilled water. This
standard should be in a sealed container.
4. Preparation of Calibration Mixture
Bring 15~ ethanol solution, internal standard solution and
standard mixture to room temperature. Pipette 4 ml . of 1 5g6
ethanol solution into a 2 dram vial using S ml. glass pipette.
Spike with 20 ~ul internal standard solution and 20Jul of standard
o mixture. Insert syringe needle to bottom of vial when adding
standard mixture because it will climb up the inside wall of the
glass container. Cap the container tightly and place it in an
ultrasonic bath for 10 minutes to thoroughly mix. Remove the
container from the bath, invert several times and inject 1 Jul into
15 G . C . The calibration mixture must be used as soon as it is
made .
5. Analytical Sample Preparation
Rinse 5 ml. glass pipette with the sample twice. Pipette 4
ml. of sarr,ple into 2 dram vial and spike with 20 jul of internal
20 standard solution. Cap tl-e sample container tightly and place in
ultrasonic bath for 10 minutes. Invert the sample several times
and inject 1 )JI into G. C.
b. Analytical Procedure
A Hewlett-Packard 5880A Gas Chromatograph equipped with a
25 capillary column injector is used, A level 4 data terminal with
basic program and tape cartridge are attached to ol>tain a
computer read out of the data.
~2~3~67
~36--
1. Conditions for HP 5880A G.C.
Air flow rate :250 ml. /min.
Hydrogen flow rate : 30 ml. /min .
Nitrogen flow rate : 30 ml. /min. (make up gas)
Helium flow rate : 3 ml. /min. (caPrier gas)
( 13 . 5 psi setting )
Split flow :3 mlO /min.
Septum purge flow : 3 ml . Imin.
DB-5 fused silica capillary column
(0.32 mrn. x 30 m., J~W Scientific)
straight direct injection liner
chart speed: 0. 5 cm. /min .
Att: 2~ 0
2. Temperature Profile
Oven temperature 40C, limit of 405CC. The oven is heated
at 40C for 5 minutes.
The oven is then programmed to rise 2.0C/min. to a
temperature of 140C. Then the oven rises at 6.0C/min. .o a
final value of 260C, and is held there for 10 minutes.
3. Calibration of instrument
Inject 1 ,~l of calibration mixture into the G.C. Thc
calibration spectra should show the following peaks:
1~13167
Calibration Table
Retention
Peak Time Amt/Area Name
" (resF~onse factor '-
X10 )
11.031 1.77 Hexanal
2 11.222 2.49 Et . Butyrate
3 14.739 2.22 t-2-hexenal
4 15.040 2.1 ~ 3-hexene-1 -ol
16.047 1.98 Hexanol
6 17.761 2.10 Cyclohexanone
7 21.130 1.84 Alpha-Pinene
8 24.642 1.60 Beta-Pinene
9 25.893 1.611 Myrcene
26.805 1.45 Octanal
11 28.949 1.16 Limoner-e
12 32.342 1.66 Octanol
13 34.712 1.44 Linalool
14 35.062 1.46 Nonanal
41.904 1.64 Alpha-Terpineol
16 42.976 1.24 Decanal
17 45.663 1.81 Neral
18 45.936 1.52 d-Carvone
19 45,619 2,00 Geraniol
4'.330 1.35 Geranial
. 21 61.200 1.34 Valencene
4. Calculations:
Relative Peak Area =
Peak Area of Component
Peak Area of Internal Standard
Relative Response Factor =
Response Factor of Component (ar.~t/area)
Response Factor of Internal Standard (amt/area)
Amount o~ Component (mg/ml) =
(Relative Peak Area) (Kelative Response Factor) (Amount
I nte rna I Standa rd )
Fi~3ure 5 is a representative chromatogram.
~13~67
-38-
C~ Quantitative Analysis of Orange Oil Essence
_y Capillary Column Gas Chromatography
This method provides a direct injection of oil essence ints a
capillary column ~as chromatograph and automaticalli calculates
5 absolute amount (mg./ml.) and weight % of calibratedi- components.
Two internal standards (propyl benzene and Cl0 FAME lFAME is
methyl decanoate]) are used to calculate relative response factors.
When pure components are not available, a component of similar
structure was used to calcul~te a response factor. This
10 procedure does not need an adjustment to compensate for the
non-volatile components in oil essence because each component is
calibrated individually. This method is good only for orange oil
essence (cold pressed orange oil, stripper oil, commercial orange
oil essence, etc. ) . If this technique is to be applied to other
15 types of citrus oil ~grapefruit, lemon, etc. ) only one internal
standard (propyl benzene) is used.
Internal Standard Solution
Add a small volume (10-20 ml. ) of ethyl acetate into 100 ml.
of volumetric flask and spike with 300 jul of propyl benzene and
20 100 JJI of C10 FAME. Bring to volume with ethyl acetate. Store
this solution at low temperature (-20C to -40C). An alternate
method of preparation is to mix propyl benzene and C1 0 FAME in
a 3:1 ratio (3 ml. propyl benzene to 1 ml. C10 FAME) and spike
400 )~I of this mixture to 100 ml. or ethyl acetate as above. Store
25 at -2 0 C to -40 C .
~Z~3~67
39-
Standard Solution
Volume of itlg/ml
Components Pure Compound (,~ n Calibration
Alpha-pinene 400 3 . 73
Beta-pinene 100 i.94
" Myrcene 2000 17, 42
Octanal 450 4 . 02
Limonene 85000 777.10
Alpha-terpinene 50 . 46
10 Octanol 100 . 90
Linalool 300 2 . 84
Nonanal 100 . 90
Citronellal 100 .93
Alpha-terpineol 100 l . 02
15 Decanal 600 5.4G
Citral (neral) 80 .77
D-carvone 50 . 52
Geraniol 50 . 48
Citral lgeranial ~ 120 1 .16
20 Perillaldehyde 50 . 45
Dodecanal 1 OG .91
Valencene 100 . 91
Nootkatone 50 . 46
Ethyl butyrate 200 1.22
25 Ethanol 200 1 . 22
Procedure
A Hewlett Packard 5880A G.C. with Capillary column injector
i5 used. The instrument is equipped with a level 4 data terminal
with basic program and tape cartridge.
30 Procedure
A. Conditions for HP 5880A G._
Air: 250 ml/min.
Hydrogen: 30 ml/min.
Nitrogen: 30 ml/min.
3s Helium: 3 ml/min. (13.5 psi setting)
Splitflow: 150 ml/min.
Septum pu rge: 3 ml / mi n .
DB5 Fused silica capillary coiumn (.32 mm x 30 m, J~'J
Scientific) Chart Speed:0.5 cm/min.
Attn 2~1
;~2~3:1~i7
. --40--
-
Temperature Profi!e
Initial oven temperature = 40C with a limit = 405C. The
oven is equilit~rated for one minute. The oven is programmed to
rise at 2 . 00C/ min . to a final value of 1 40C . The program is
.. 5 then changed to have the oven rise 6.00C/min. to a final value
of 260C and held there for 10 minutes.
Calibration of Instrument
Add 1 ml. of standard mixture and 1 ml. of internal
standard solution into a 1 dram vial. Inject 1 Jul of calibration
10 mixture when G . C . is ready and begin the run . After
chromatogram (calibration mixture run) is completed, check for
proper identification of peaks and retention times.
Analvtical Samr~le Preparation
Rinse 2 ml. glass pipette with the sample, twice. Pipette
15 1 ml. of oil sample and 1 ml. of internal standard solution into a
2 dram vial. Inject 1 ~ul of this solution using the solvent plug
technique. If the sample is not analyzed immediately it can be
stored at low temperature (4C) for several days without any
changes .
~2~ 6~
-41 -
Calibration Table
Retention
Peak Time Amt/ Area Name
. - (response Factor
X10 )
21.038 5.40 A l pha- Pi nene
2 22.631 4.91 Propyl-Benzene
3 24.545 5.01 Beta-Pinene
4 25.840 7.25 Myrcene
26.728 6.25 Octanal
6 29.459 5.42 Limonene
7 31,397 5.02 Gamma-Terpinene
8 32.273 7.04 Octanol
9 34,662 6.42 Linalool
1 0 35.005 8.71 Nonanal
11 38.891 7.44 Citroneilal
12 41.852 6.99 Alpha-Terpineol
13 42.941 10,8 Decanal
14 45.629 7.29 Neral
46.578 6.69 ci-Carvone
1 6 47.1 90 8.21 Geraniol
17 47.800 6.42 Geranial
18 48.182 5.88 Perillaldehyde
19 51.662 7.18 C10 FAME
57.207 10.3 i~odecanal
21 61.228 7.62 Valencene
22 69.871 5.91 Nootkatone
23 24.327 5.40 5abinene
24 11.090 9.58 Ethyl-Butyrate
1.575 12.6 Ethanol
26 58.129 6.48 Caryophellen
~2~3~7
--42--
Calculations:
Relative peak area = peak area ~f component
peak area of internal standard
Relative response factor =
S Response factor of component
~esponse factor ot internal standard
Amount of component (mg/ml) =
(Relative peak area)(Relative response factor)(Amount
f of internal standard)
Figure 4 is a representative chromatogram.
C. Alcohol analysis of aqueous essence by çapillary column gas
chromatography
This method provides direct injection of aqueous essence into
a capillary column gas chromatograph and automatically calculates
15 the absolute amount ~mg/ml) and weight percent of ethanol and
methanol. The methanol cluantitation will be the sum of methanol
and acetaldehyde as these compounds co-elute. Acetonitriie is
used as an internal standard and relative response factors are
calculated from its concentration which must remain constant for
20 all samples and calibration mixtures. In this way the system can
make adjustments to ,the calculations which compensate for any
variation in amount of sample introduced. This method is good
for both commercial and aqueous stripper essences, but they must
be diluted to a concentration of less than 1 mg/ml ethanol.
~13~67
--43--
-
Procedu__
Conditions for HP 5880A G . C.
Air flow rate: 250 ml/rnin.
Hydrogen flow rate: 30 ml/min.
.. .
Nitrogen flow rate: 30 ml/min.
Heli~Jm flow rate: 3 ml/min. (13.5 PSI setting3
Split flow: 150 ml/min.
Septum purge: 3 ml/min.
DB5 fused silica capillary column (.32 mm x 30 m, J~iV
10 Scientific)
Chart speed 1 cm/min.
Attn 21`2
Temperature Profile
Initial oven temperature = 40C with an oven limit of 405C.
15 and an equilibration time of 1 minute. The oven was heid at a
ternperature of 40C for three minutes, then prograrnmed at a ~ ate
of 10C/min. to 80C and held there 1 r~ inute.
Calibration of I nstrument
Add approximately 70 ml of distilled water to a 100 ml
20 volumetric flask. Spike with 5 ,ul methanol, ~0 )JI ethanol, and 20
~ul acetonitrile (internal standard) using a S and a 25 ~ul syringe
respectively. Bring to volume with distilled water and inject 1 ~ul
vvhen C . C. is read. After run is completed, enter known amount
(mg/ml) of ethanol and methanol in calibration table and have
25 integrator calculate response factor s (arnt/area) .
The calibration spectra should show the following peaks:
3~67
--44--
List of Calib_ation Table
Retention Amt/ a rea
- Name Time (response factor)
methanol 1 . 31 5 . 70 x 10 4
ethanol 1 . 52 4 .16 x 10
Analytical Sample Preparation
(1 ) for aqueous stripper essence: rinse â 2 ml glass pipette
with sample twice. Pipette 1 ml of sample into a 4 dram vial and
add 9 ml distilled water using a 10 ml graduated pipette. Spike
lO with 2JUI of acetonitrile. Inject 1 Jul into the G.C.
(2) for commercial aqueous essence: rinse 2 ml glass pipette
with sample twice. Pipette 0.5 ml of sample into a 100 ml
volumetric. Bring to volume with distilled water and spike with
20,u1 of acetonitrile. Inject 1 ,ul into the G.C.
15 Calculations:
Relative peak area =
Peak area of component
Peak area of internal standard
Relative response factor =
Response factor of componen .
~esponse factor of internal standard
Amount of component (mg/ml) =
(Relative peak area)(Relative response factor)~Amount
of internal standard)
25 Figure 7 is a representative chromatogram.
