CA1172655A - Process to maintain bland taste in energy efficient oil deodorization systems - Google Patents
Process to maintain bland taste in energy efficient oil deodorization systemsInfo
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- CA1172655A CA1172655A CA000368204A CA368204A CA1172655A CA 1172655 A CA1172655 A CA 1172655A CA 000368204 A CA000368204 A CA 000368204A CA 368204 A CA368204 A CA 368204A CA 1172655 A CA1172655 A CA 1172655A
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- Prior art keywords
- oil
- temperature
- deodorized
- flavor
- hot
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
- C11B3/00—Refining fats or fatty oils
- C11B3/12—Refining fats or fatty oils by distillation
- C11B3/14—Refining fats or fatty oils by distillation with the use of indifferent gases or vapours, e.g. steam
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- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Microbiology (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Fats And Perfumes (AREA)
Abstract
ABSTRACT
This invention relates to an improved high temperature oil deodorization process for optimum bland taste and flavor maintenance. The process comprises a selective temperature control quenching step of the hot, freshly deodorized oil. This step comprises selectively utilizing a cooling means to quench hot, freshly deodorized oil down to a pumpable bland flavor-stable processing temperature (PBFSPT) within a selected time, preferably within a few seconds, so that the hot deodorized oil can dwell dormant in an energy efficient deodorization system.
The oil can then be pumped through heat interchargers without bland oil flavor degradation or can be held at the PBFSP temperature for longer critical dormant times without flavor degradation.
This invention relates to an improved high temperature oil deodorization process for optimum bland taste and flavor maintenance. The process comprises a selective temperature control quenching step of the hot, freshly deodorized oil. This step comprises selectively utilizing a cooling means to quench hot, freshly deodorized oil down to a pumpable bland flavor-stable processing temperature (PBFSPT) within a selected time, preferably within a few seconds, so that the hot deodorized oil can dwell dormant in an energy efficient deodorization system.
The oil can then be pumped through heat interchargers without bland oil flavor degradation or can be held at the PBFSP temperature for longer critical dormant times without flavor degradation.
Description
~ 1 ~2655 PROCESS TO MAINTAIN BLAND
TASTE IN ENERGY EFFICIENT
OIL DEODORI~ATION SYSTEMS
Edward S. Seguine Background of the Invention In order to build superior taste into edible oil products, they must undergo certain processing steps.
The most important, from a finished flavor standpoint, is deodorization. Since the senses of taste and smell are closely linked, deodorization also improves the flavor of the product. The finished product is ideally a bland oil.
About the middle of the last century, deodorization of fats was practiced in Europe by blowing steam through the heated oils. Prior to the turn of the century, steam blowing was used in connection with evacuation for the improvement of fats used in margarine products.
About 1900 David Wesson, in the United States, designed a greatly improved steam-vacuum deodorizer. The system success~ully avoided air contamination, which is one of the important prere~uisites of ~his high-temperature ;~ treatment. The process was never patented, but its secrecy was so effectively guarded that for a great ~; 20 many years competitive efforts failed to match the quality of the products that were treated in the Wesson system.
In addition to improved batch processes, semi-continuous and continuous deodorizers were later developed. ~he theoretical aspects of steam stripping are governed by RaouLt's law and Dalton's law.
Vernon Young in an article published in Chemistry and Industry Sept. 16, 1978, p~. 692-703, provides an excellent review of processing currently in use for refining and modifying oils and fats.
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~ 172~55 High temperature deodorization systems require large ~mounts of energy, but they can be designed for heat recovery to save energy. For e~ample, a deodorizing system modification for heat recovery and steam refining of palm oil is reported by Gavin et al in J. Am. Oil Chemists Soc., November 1973 (Vol. 50), pp. 466A-472A~
Also, U.S. Patent 3,607,670, ~ing, Sept. 12, 1971, relates to a deodorization process in which the heat exchange between incoming cold oil and outgoing hot oil takes place within an enclosed vessel.
The problem of bland oil regression (degradation), however, is a drawback to energy efficient deodorization systems, and paxticularly prior art modified systems where hot, freshly deodorized oil i5 held dormant, dwells or is pumped out of the deodorizer at too high a temperature. Such oils degrade from a bland ta~te to a scorched or rubbery taste, or degrade to various other $i~vors which are less than bland.
Thus, there was a need to in~ent a process whereby optimum heat is utilized and the bland taste of deodorized oil is maintained in energy efficient systems.
It is~an obje~t of the present invention to prevent degradation of ~land flavor in hot, freshly deodorized oil in high temperature deodorization systems where said oil is held dormant fox further processing.
It is another object of the present invention to provide a method to maintain optimum good taste and bland flavor in freshly deodorized oil.
Another object of the present invention is to maximize heat recovery in high temperature deodorization systems while maintaining bland deodorized oil flavor.
Other objects will become apparent in the light of the disclosuxe.
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1 ~726~5 : Brie Descriptlon of the Draw ng The Figure is a pictorial schematic of a contin-; uous deodorizer unit ln which this invention is illustrated.
Summary of the Invention In view of the above-stated need, the present invention provides a high temperature edible oil deodorization process which utilizes a vacuum deodoriza-tion system, said process comprising the steps of:
(a) stripping odoriferous constituents from said : o.il at a high temperature to provide a hot, : freshly deodorized oil having a bland flavor, : ~ said hot, freshly deodorized oil having a ~ temperature of above an outgoing oil bland flavor-stable temperature; and (b~ cooling said hot, freshly deodorized oil to ~: a storage temperature;
the lmprovement comprising utilizing a cooling : means to quench said hot, freshly deodorized oil to a pumpable outgoing oil bland flavor-stable processing : ~ temperature.
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Furthermore, the present invention provides a process for utilizing heat and xecovering energy in , :~
hot, freshly deodorized outgoing oil in a deodorization system wherein the hot deodorized outgoing oil is utilized to warm up cold undeodorized incoming oil via a heat interchanger means, said process comprising the steps ~ of:
: : (a) deodorizing said incoming oil at a temperature ;~ 30 of ahout 425F to about 520F to provide said ~:~ hot, freshly deodorized oil having a tempera-ture above a hot pumpable outgoing oil bland : flavor-stable processing temperature;
: (b) utilizing a cooling means to quench said hot, freshly deodorized outgoing oil to said hot, pumpable outgoing oil bland flavor-stable processing temperature of from about 480F to about 340F dependinq on the type of oil and dormant time prior to coolingi and ~ 1 7265~
(c) passing said hot, pumpable outgoing oil through said heat interchanger means to warm up said cold undeodorized incoming oil.
Detailed Description of the Invention S mis invention relates to an i~pro~E~t in a high t~rature edible oil, deodorization process which utilizes a vacuum deodorization system, said process comprising the steps of:
`~ ~a) stripping odoriferous constituents from said oil at a high temperature to provide a hot, freshly deodorized oil having a bland flavor, said hot, freshly deodorized oil having a . temperature of abo~e an outgoing oil bland : fla~or-stable process temperature; and (b) cooling said hot, freshly deodorized oil to a storage te~perature, the improvement comprising utilizing a cooling means to quench said hot, freshly deodorized oil to a p~lmpable (outgoing oil) bland flavor-stable processing t~mperature (PBFSPT).
The invention further relates to a deodorization syste~ which operates with said hot, freshly deodorized oil at a high oil temperature of from about 425F to about 520F, and at a pressuxe of from about 0.1 mm o : 2S mercury to about 30 mm of mercury absolute pressure :: prior to said quenching, and wherein said outgoing oil is quenched to said pumpable bland flavor-stable proces-: sing temperature of from about 480F t~ about 340F, and wherein ~aid quenched oil is further cooled via : 30 heat interchanger means within 30 seconds to about 10 minutes after said ~llench, and wherein said deodorization temperatuxe and said pumpable temperature, and said time be~ore said further cooling are interdependent upon the type o~ oil being processed and the type of deodorization system being use-~.
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Preferably, the oil is deodorized at a high oil temperature of from about 460F to about 490F, and the outgoing oil is quenched to a pumpable temperature below about 446F within a quench time of about a fraction of a second to about S0 seconds.
In a preferred embodiment, the process of this invention preferably comprises the steps of:
(a) feeding said hot incoming oil into a deodoriza-tion vacuum column, deodorizing said incoming oil at an oil deodorization temperature of from about 446F to about 520F by passing super-heated stripping steam countercurrently through a separate upper deodorizing section of said column, said hot, freshly deodorized oil dropping into a separate lower reservoir of said column;
(b) utilizing said separate lower oil-sealed reservoir in said column as a conduit for said hot, deodorized outgoins oil as it passes into said lower reservoir to be pumped;
~ 20 (c) utilizing a cooling means in said lower - reservoir to quench the temperature of said hot, freshly deodorized outgoing oil down to said pumpable oil temp-erature of below about 446F within a quench time of ; about a fraction of a second to about 50 seconds.
The preferred cooling means for quenching the oil is previously deodorized cooled quenching oil brought in contact with said hot, fxeshly deodorized oil.
Preferably, the quenching oil is directly mixed with said hot outgoiny oil as the hot outgoing oil passes into said lower, oil-sealed reservoir. Furthermore, the preferred hot, freshly deodorized outgoing oil has a temperature o from about 460F to about 490F when it passes into t~e lower, oil-sealed reservoir, and said quenching oil has a maximum temperature of about 140F. In another preferred embodiment, a pool or outgoing oil in said oil-sealed reservoir is agitated with stripping steam.
~ ~7~6~5 The deodorizaticn steam temperature is not critical, and can r~nge from about the boiling point of water at the inlet pressure to about 600~F. Water can even be introduced in lieu of steam, since the water would be immediately vaporized and heated to the deodorization temperature by contact with the hot deodorized oil in the lower portion of the deodorization column 1 and any other hot materials which the water contacts. It cools the apparatus and makes deodorization less efficient.
On the other hand, steam at a temperature in excess of about 600F can scorch the oil, and it is unnecessary to use such high temperature steam. It is preferred that the steam temperature be within about 20F of the oil temperature; cooler steam cools the oil, and hotter steam is unnecessary. Thus, the preferred temperature of ~team is broadly from about 410F to about 540F;
when the oil is within the preferred temperature range of from about 460F to about 490F, the preferred steam temperature ranges fxom about 440F to about 510F.
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2n Throughout this specification reference is made to steam as the deodorization agent. Steam is highly pre-ferred for this purpose as it is readily a~ailable in high purity and because it does not injure the oils being deodorized. Other deodorization agents can be used, however, ~or example, gases which are inert under the conditions of the process, such as nitrogen or hydrogen.
` Oxygen and air are unsuitable, however, as they would cause oxidation and degradation of the oils being deodoriæed.
The deodorization chamber per se and its COmpQnents can be any type of packed vapor-liquid contacting cham-ber, such as those which are well known in the chemical ;~ en~ineering art. See, for example, R. H. Perry et al, eds., Chemical Engineers' Handbook (McGraw-Hill, 4th ed., 1963), p-. 18-25 to 18~53; J. S. Ec~ert et al, Chemical Engineering Progress 54, No. 1, 70-75 tJanuary 1958~, 57, No. 9, 54-58 (September 1961), 59, No. S, 76-82 ; (May 1963), and 62, No. 1, 59-67 ~January 1966); and K. E. Porter, Chemistry and Industrv 182~89 (Eeb. ~, -~ 1 72~55 : 1967). These references also describe various kinds of packing materials which can be used.
The edible oils which can be deodorized by the process of this invention include various substances of plant or animal origin which consist predominantly of glyceryl esters of fatty acids, e.g. triglycerides, in-cluding both those commonly called "oils" which are : liquid at atmospheric pressure and room temperature, andthose commonly called "~ats" which are solid or semi-solid under these conditions, but liquid at the tempera-ture of heat-bleaching and deodorization (i.e. about 350F to 520F). Preferred oils are tallow, lard, and the common ~dible vegetable oils used for the production : : of salad oil and shortenings, e.g. cottonseed, peanut, safflower, palm, soybean, rapeseed, sunflower, corn, and coconut oils. The invention is particularly applicable ; to the heat efficient deodorization of sunflower seed oil.
The selectlon:of a pumpable bland flavor-stable :; 20 processing temperature~within the range of about 480F
: to about 340F is interdependent on the type of edible oil belng processed and the dormant oil times of the ~:~z~ deodorization system being used.
Preferably, the bland flavor-stable outgoing oil : : :: 25 is pumped at a temperature above about 340F for heat recovary via heat interchanger means.
The improved process of this invention is designed for utilizing heat and recovering energy in hot, freshly deodorized outgoing oil in a deodorization system wherein the hot deodorized outgoing oil is utilized to warm up cold undeodorized incoming oil via :~ a heat interchanger means, said process comprising the : steps of:
(a) deodorizing said incoming oil at a temperature of about 425F to about 520F to provide said hot, freshly deodorized oil having a temperature above a hot , ~
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pumpable ougoing oil bland flavor~stable processing temperature;
(b) utilizing a cooling means to quench said hot, freshly deodorized outgoing oil to said hot, pumpable outgoing oil bland flavor-stable processing temperature of ~rom about 480F to about 340~; and (c) passing said hot, pumpable outgoing oil through said heat interchanger means to warm up said cold undeodorized incoming oil.
Industrial Applicatlon The method of this invention is useful in all types of deodorization processes which can be modified to:
(1) quench the emperature of the hot, freshly deodor-ized oil to a bland oil fla~or-stable temperature before pumping the hot oil through a heat interchanger to warm up cold incoming oil. Thus, it will be clear to those skilled in the art that an important principle of this invention is that hot, freshly deodorized oil must be quenched to its bland flavor-stable temperature before O it can be held dormant for further processing.
The term "dormant oil" is defined herein as hot ;~ deodorized oil, held in a tray or reservoir as a pool without sparging or significant steam stripping or simply oil that is being pumped. Dormant oil can be oil that dwells in an oil-sealed reservoir. Dormant oil can be oil pumped through a l-ine or heat inter-; changer. Dormant dèodorized oil held beyond its crit-ical dormant time at a temperature above its bland flavor-stable temperature, will degrade. The term "dormant time" as used herein technically refers to the time freshly deodorized oil dwells in a deodorization process that is no longer being sparged or stripped.
The term ~Ipumpable bland flavor-stable processing temperature of a deodorized oil" refers herein to a temperature or temperature range at which hot deodorized oil can be held "dormant'l or pumped without loss of its bland flavor. There is a maximum pumpable bland flavor-stable processing temperature for each particular oil and each oil has a unique dormant process time-~ 17~BS5 temperature interdependency wherein said dormantpxocess time increases as the temperature decreases.
The term "~uenched oil" as used herein refers to hot, freshly deodorized oil that has been cooled to its PBFSPT. The term "quench time" is that time re~uired to reduce the temperature for the deodorization temp-erature to the PBFSPT. There is a critical quench time for each particular oil and each oil has a unique critical process quench time - PBFSP temperature inter-dependency wherein said critical quench ~rocess timeincreases as the hot deodorization temperature decreases.
Therefore, the specific process or system used is also a factor in selecting times and temperatures since the equipment limitations will determine the requisite time that the oil is held "dormant" at various processing temperatures. Hot oil selectively quenched to its maximum bland flavor-stable processing temperature can be safely ~ ~imped through heat inter~hangers which utilize the heat of the hot outgoing oil to warm up rold incoming oil.
The incoming oil of this invention is refined and bleached oil or oil which has b~en processed with one or more of the following processes: refined, bleached, hydxogenated, winterized, dewaxed, interesterified, etc.
For a more detailed disclosure of the types of refined and processed oils useful as incoming oil for the present invention, the reader is referred to U.S. Patent 4,035,402, Levine, dated July 12, 1977 Steam-vacuum deodorization is preferred. The process consists o~ steam stripping or steam distilling of the volatile odori~erous constituents at elevated temperature and reduced pressure.
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$ 5 ~ he most common shape of the batch deodorizer is a cylindrical vessel two to four ,imes as high as it is wide. Provision is made to heat the oil internally or externally by steam, direct firing, or "Dowtherm"TM
S vapor. "Dowtherm" is a eutectic mixture of diphenyl and diphenyl oxide which is reportedly more suitable than steam because of the high temperature range that is required for deodorization. The vacuum equipment consists of multistage steam ejectors with barometric condensers. Stripping steam is introduced at the bottom by means of spiders or orifice plates. Good steam dis-tribution is essential, as it provides the additional advantage of effective agitation. The classical batch deodorization cycle usually is from 4 to 8 hours.
lS Batch deodorization systems can be modified to recover the heat of the hot, deodorized oil by determining the oil's bland, flavor-stable temperature and quenching the oil to that temperature with a cooling means. The ` hot quenched deodorized oil can then be safely pumped to heat cooler incoming oil. Some sparging of the hot, deodorized oil for agitation is preferred.
A semi-continuous system designed by the Girdler Corporation has found laxge-scale application. It consists essentially of~a large cylindrical vessel contai~ing five pans. A motor-operated timing device opens and closes valves automatically. They regulate the flow of product from the higher to the next lower pan. The oil is preheated and de-aerated in the top pan.
In the second pan the temperature of the charge is in-; 30 creased to about 240C. Deodorization is mainly carried out in the third and fourth pans. In the last pan the temperature is reduced by water cooling while the product continues to be steam stripped under vacuum. The total operating time is about 2-1/2 hours. In a modified system, heat recovery can be accomplished by determining the bland, flavor-stable processing temperature of the oil and following the guidelines set out herein.
1~ t , ! 1 72655 Several continuous deodorizers also are widely used. The system manufactured by Foster Wheeler Cor-poxation consists essentially o a vertical stainless steel column provided with trays and bubble caps. The oil, cascading from top to bottom, moves counter-currently to the ascending steam. U.S. Patent 3,542,653, Lowrey et al, Nov. 24, 1970, relates to an apparatus and process for continuous heat-bleaching and high temperature steam deodorization of edible oils.
As stated above, in some processes some steam stripping of the "dormant" hot deodorized oil is pre-ferred durin~ the quenching step for agitation while the hot oil is dwelling prior to being pumped. It provides agitation and also assures the maintenance of optimum bland oil flavor in some systems. Less s eam is needed for this agitation than i~ required for deodorization.
This invention is mainly described hexein in the context of a continuous deodorization process. However, will be apparent to those skilled in the art, in the light of this disclosure, that the principles of this invention are equally applicable to modified batch and semi-continuous deodoxization processes which are modified to utilize the heat of the outgoing hot deodorized oil to ~ ~ save energy. The hot deodorized oil in a modified system ; must be quenched if it is to be momentarily held dormant, e.g. as a pool in a vacuum oil-sealed reservoir means prior to pumping it to heat interchangers.
The Figure shows a deodorizing unit 1 having a hot incoming oil feed inlet 2. The deodorixation unit 1 comprises packing 3 supported on a screen means 3a, which are standard items in the art. The hot incoming oil 2 is treated with super-heated stripping steam 20 in the upper cham~er 22 inside the unit 1 to sparge and strip out odor-forming matter from the oil. The unit 1 also has a separate lower cooling reser~oir 5 containing a pool of dormant hot deodorized outgoing oil 6. The reservoir 5 receives a steady stream of hot, freshly deodorized oil 21 falling from the upper chamber 22 ~ 172BS5 of the unit 1. There the hot, freshly deodorized oil 21 is cooled to a bland flavor-stable processing tempera~ure by the quenching oil 23 in the lower reservoir 5 before it is pumped through the heat interchanger means 24 wherein cold incoming oil 25 is warmed by the hot quenched deodori2ed oil 6 before said incoming oil 25 is finally heated with a high tempPrature heating means 26. The hot quenched deodorized oil is finally cooled to 120F-140F by a cooler means 27 which is preferably a water cooler The means 24, 26 and 27 pxeferably comprise a battery of heaters or heat interchangers.
For a detailed disclosure of deodorization systems in general, pac~ing, bubble caps, residence times, etc.
~ which are not inconsistent with this invention, reference ;~ 15 is made to U.S. Patent 3,542,653, of Lowrey et al, dated November 24, 197Q~
The figure illustrates a system whereby heat is recovered and the bland flavor of the deodorized oil is maintained. The quenched deodorized oil 6 after passing ~ 20 through the heat interchanger means 24 is further cooled :~ ~ia cooler 27 to a packing (storage) safe temperature of about 120F to 140F, which cooled oil 23 can also be used as ~uenching oil 23.
.The continuous deodorization unit quench, "CDU
quench" method is a preferred embodiment of this invention.
~: The preferred method comprises showering recycled cooled deodorized quenchiny oil 23 through a quenching means 28 onto a pool of quenched deodorized oil 6 in the cooling ~ reservoir 5 to quench and agitate the hot, freshly deod-~ 30 ori~ed oil 21 as it drops into said oil pool 6. The hot, ;~ freshly processed deodorizPd oil 21 is rapidly quenched to a bland flavor stable processing temperature oil wit.hin a fraction of a second. Additional agitation of ~ the quenched oil 6 can be provided by stripping steam 20a :~ 35 or water ~imply injected into the pool of oil. An alter-native quenching means for cooling the hot, freshly deodorized oil comprises injecting the quenching oil directly into the oil pool 6.
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As stated earlier, the preferred pumpable bland flavor-stable temperature of a particular oil varies from oil to oil and rom system to system. The maximum temperature at which hot deodorized oil can be pumped to recover heat in a deodorization process while the bland flavor of the freshly deodorized oil is maintained, is pxeferred. The preferred bland flavor-stable temp-erature, from an ener~y efficient standpoint, is the maxim~m temperature of the hot deodorized outgoing oil at which the bland oil flavor is maintained in a heat recovery step. In a preferred embodiment the maximum - heat of the hot deodorized oil is used in a heat inter-changer means to save energy.
An alternative to a direct oil-to-oil quench is submerged internal heat e~changer coils which are used ~ to ~uench the hot, freshly processed deodorized oil in ;` reservoirs like reservoir 5, shown in the Figure. Such types of heat exchangers must cool the hot oil down to its bland flavor-stable processing temperature fast enough to maintain optimum good taste and bland flavor in deodorized oil, i.e. within the critical quench time.
Alternate methods and equipment for quenching hot, freshly deodorized oiI to bland flavor stable temperature, other than an oil-sealed lower cooling reservoir like 5 ~;~ 25 are contemplated as within the scope of this invention.
Typical examples of such devices are found in: "Deod-orization 1975", C~ T. Zehnder, Journal of American Oil - Chemists' Socie~y, June 1976 (Vol. 53), and Gavin et al, J. Am. Oil Chemlsts' Society, ~Jovember 1973, pp. 46~A-477A (Vol. 50).
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It was surprisingly discovered that hot, freshly deodorized oils having too hi~h a temperature to be safely pumped could be quenched to a slightly lower but 3s bland fla~or-stable temperature to avoid flavor degrada-tion before pumping. Sunflower seed oil is a very difficult oil to deodorize. It is preferably deodorized at a high temperature of about 490F to about 460F in a continuous deodorizer. The freshly deodori~ed sunflower seed oil must .,, ~ . i ~ ~ 72~5 be quenched in a CDU to its flavor process stable temperature of about 445F to about 410F within a quench time of about a fraction of a second to within about S0 seconds.
Again, it has been discovered that hot, freshly processed deodori~ed oil which has optimum good taste (a bland flavor) will degrade ~ L if held dormant at too high a temperature without sparging (stripping) under vacuum. Hot, freshly deodorized sunflower seed oil at high deodorization temperatures held dormant for just a few seconds can show degradation. It was surpris-ingly discovered that hot quenched deodorized sunflower - seed outgoing oil having a temperature below about 445F
i~ a CDU, as illustrated, maintains its optimum good taste and bland flavors, but unquenched freshly deodor-ized outgoing sunflower seed oil shows degradation when held dormant. Short dormant (dwell) times, e.g. about 60 seconds and less, in a continuous pool in a reservoir like reservoir 5 and associated piping to cooler 24 of a CDU at high deodorization temperatures is enough to significantly degrade the oil, if not quenched. Similar degradation would happen in modified batch and semi-continuous processes so designed to recover the maximum heat of the freshly deodorized oil.
In a CDU system, as shown in the ~igure, sunflower seed oil can be deodorized at a temperature of fro~
about 446F to about 510F, and preferably 460F to 490F.
The hot, freshly deodorized outgoing oil 21 dribbles out of the upper chamber 22 down into the lower reservoir.
Thus, hot, freshly deodorized outgoing oil 21 is quenched in resexvoir 5 with ~uenching oil 23 to a temperature ; of below about 445F, its bland flavor-stable temperature.
It is preferably quenched to a temperature of about 410F
+ 5F within a quench time of about a fraction o a second The hot~ freshly deodorized oil i preferably quenched by mixing it with 120-140F prior deodorized quenching oil 23. This step in a CDU is preferably ac-complished by spraying a shower o~ the quenching oil 23 into the lower reservoir 5 of a CDU system whereby the ? ~,.
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~ 1 72655 hot and cooled oils are contacted, mixed and a~itated.
j The quenched deodorized outgoing oil 6 in the , reservoir 5 can then be safely pumped out for further cooling, e.g. via a heat interchanger cooler 24 and then further cooled via cooler 27 to a packing or storage ~ stable temperature of about 130F ~ 10F. The oil is j then pumped to a storage tank, packed or recirculated ' to the cooling reservoir S as cool quenching oil 23.
eat interchanger cooler 24 is preferably designed ' 10 to also heat up incoming oil 25 and thereby save energy.
The ratio of quenching oil to hot, freshly i deodorized oil, needed to quench to a bland flavor-.f stable processing temperature, will vary depending on the respective oil temperatures, dwell times and the f 15 particular deodorization process being applied.
, The bland flavor-stable processing temperature for ~;, a particular oil within a particular dwell time for a particular system can be determined by trial and error.
The critical factor is to determine the pumpable bland , 20 flavor-stable processing temperature (PBFSPT) of the oil ' being processed. One method of determining the PBFSPT
would be to withdraw a series of samples of hot,' freshly' deodorized oil from a batch deodorization system at decreasing temperatures and quenching them to various 25 temperatures at increasing times. Soybean oil, for example, has a maximum PBFSPT of about 480F in a CDU
.f : ~ ~ , ' system as shown in the Figure. Soybean oil call be deodorized at a temperature as high as 510F.
- Procedure to Determine the PBFSPT
The following describes a procedure used to determine the PBFSP,T of deodorized oils. Equipment is ~' a 20 lb. capacity b'atch deodorizer under which is mounted a small stainIess steel sample vessel connected by two valves. The sample vessel is also vented up to the top of the deodorizer via a valved vent linè. The procedure ~' for its operation is: inlet oil is charged into the ; dPodorizer and deodorized at desired temperature and time to achieve a suitably bland flavor. Bland flavor , ~ , .
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is verified by withdrawing an oil sample into the sample vessel and immersing the sample vessel into an ice bath while it is connected to the deodorizer and opening the vent line to the top of the deodorizer to equalize the pressures. Both valves connecting the sample vessel with the deodorizer itsel are then opened, allow-ing oil to freely drain from the deodorizer through the two valves and into the sample vessel. Cooling of the oil draining into the sample vessel is almost instan-10 taneous, as its walls are essentially held at ice bath conditions by the external ice bath. The sample of deodorized oil thus withdrawn is then tasted by expert oil evaluators to determine that it is suitably bland.
This sample is the flavor control. When testing, the 15 sample vessel is not precooled in an ice bath; but rather, the sample is first withdrawn and, after withdrawal, the sample vessel is cooled in an ice bath, which cooling is ; not commenced until a few seconds after sample withdrawal, e.g. 2, 5, 10, 15 or 30 seconds or more. The tempera-P 20 ture of the deodorized oil is reduced to various temp-eratures to provide several different sampling temper-atures. This process is repeated for several different quenching times and several different sampling tempera-tures to produce a map of flavor grades versus the con-25 trol. This map o time and temperature allows one to select the PBFSPT by giving the artisan an understanding of the time at which the oil can be held at a specified ; temperature before it starts to degrade.
Examples 1-9 The specific conditions of Examples 1-9 are set out in Table I. The equipment used is illustrated in the Figure. Undeodorized, refined and bleached sunflower seed incoming (inlet) oil was used for each run. Super-heated stripping steam 20 was introduced at a rate of about 0.5% by weight of the incoming oil 2. The steam is introduced via steam inlet 20 below the screen 3a level and is drawn through the upper chamber 22 via ~ vacuum source 30.
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~ 17~B55 As shown in the Figure, some additional sparging steam 20a can be introduced below the surface of the pool of quenched oil 6 in the reservoir 5 for agitation and good measure. Column operating pressures of about 5 mm of mercury absolute pressure maximum were maintained at the top of the column with a maximum operating pressure differential (~ P) across the column of about 24 mm of mercury. Preferably, a ~P of about 15 mm of mercury are maintained. A ~ P of about 30 mm of mercury is not too high. Results of several runs under various condi-tions are shown in Table I.
The temperature of the hot incoming oil 2 approxi-mates the temperature o~ the hot, freshly deodorized oil 21 in each run. The residence time of oil in the upper chamber 22 of the unit is about a minute and the residence time of t~le oil in reservoir 5 plus pumping time to interchanger 24 of the unit is about 1 to 2 minutes.
, ~ _ The ratios of the quenching oil to hot, freshly deodorized oil fed into the system were adjusted to achieve the desired pool temperature shown in the Table.
The pool temperatures of Examples 2, 3, 4, 7, 8 and 9 illustrate some~preferred PSFSPTs of this invention.
TABLE_I
Run Incoming Oil Quench Oil Pool Temperature Temperature Temperature DOF
1 484F No Quench (480F) 7.1
TASTE IN ENERGY EFFICIENT
OIL DEODORI~ATION SYSTEMS
Edward S. Seguine Background of the Invention In order to build superior taste into edible oil products, they must undergo certain processing steps.
The most important, from a finished flavor standpoint, is deodorization. Since the senses of taste and smell are closely linked, deodorization also improves the flavor of the product. The finished product is ideally a bland oil.
About the middle of the last century, deodorization of fats was practiced in Europe by blowing steam through the heated oils. Prior to the turn of the century, steam blowing was used in connection with evacuation for the improvement of fats used in margarine products.
About 1900 David Wesson, in the United States, designed a greatly improved steam-vacuum deodorizer. The system success~ully avoided air contamination, which is one of the important prere~uisites of ~his high-temperature ;~ treatment. The process was never patented, but its secrecy was so effectively guarded that for a great ~; 20 many years competitive efforts failed to match the quality of the products that were treated in the Wesson system.
In addition to improved batch processes, semi-continuous and continuous deodorizers were later developed. ~he theoretical aspects of steam stripping are governed by RaouLt's law and Dalton's law.
Vernon Young in an article published in Chemistry and Industry Sept. 16, 1978, p~. 692-703, provides an excellent review of processing currently in use for refining and modifying oils and fats.
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~ 172~55 High temperature deodorization systems require large ~mounts of energy, but they can be designed for heat recovery to save energy. For e~ample, a deodorizing system modification for heat recovery and steam refining of palm oil is reported by Gavin et al in J. Am. Oil Chemists Soc., November 1973 (Vol. 50), pp. 466A-472A~
Also, U.S. Patent 3,607,670, ~ing, Sept. 12, 1971, relates to a deodorization process in which the heat exchange between incoming cold oil and outgoing hot oil takes place within an enclosed vessel.
The problem of bland oil regression (degradation), however, is a drawback to energy efficient deodorization systems, and paxticularly prior art modified systems where hot, freshly deodorized oil i5 held dormant, dwells or is pumped out of the deodorizer at too high a temperature. Such oils degrade from a bland ta~te to a scorched or rubbery taste, or degrade to various other $i~vors which are less than bland.
Thus, there was a need to in~ent a process whereby optimum heat is utilized and the bland taste of deodorized oil is maintained in energy efficient systems.
It is~an obje~t of the present invention to prevent degradation of ~land flavor in hot, freshly deodorized oil in high temperature deodorization systems where said oil is held dormant fox further processing.
It is another object of the present invention to provide a method to maintain optimum good taste and bland flavor in freshly deodorized oil.
Another object of the present invention is to maximize heat recovery in high temperature deodorization systems while maintaining bland deodorized oil flavor.
Other objects will become apparent in the light of the disclosuxe.
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,~ ,. .
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1 ~726~5 : Brie Descriptlon of the Draw ng The Figure is a pictorial schematic of a contin-; uous deodorizer unit ln which this invention is illustrated.
Summary of the Invention In view of the above-stated need, the present invention provides a high temperature edible oil deodorization process which utilizes a vacuum deodoriza-tion system, said process comprising the steps of:
(a) stripping odoriferous constituents from said : o.il at a high temperature to provide a hot, : freshly deodorized oil having a bland flavor, : ~ said hot, freshly deodorized oil having a ~ temperature of above an outgoing oil bland flavor-stable temperature; and (b~ cooling said hot, freshly deodorized oil to ~: a storage temperature;
the lmprovement comprising utilizing a cooling : means to quench said hot, freshly deodorized oil to a pumpable outgoing oil bland flavor-stable processing : ~ temperature.
: : :
Furthermore, the present invention provides a process for utilizing heat and xecovering energy in , :~
hot, freshly deodorized outgoing oil in a deodorization system wherein the hot deodorized outgoing oil is utilized to warm up cold undeodorized incoming oil via a heat interchanger means, said process comprising the steps ~ of:
: : (a) deodorizing said incoming oil at a temperature ;~ 30 of ahout 425F to about 520F to provide said ~:~ hot, freshly deodorized oil having a tempera-ture above a hot pumpable outgoing oil bland : flavor-stable processing temperature;
: (b) utilizing a cooling means to quench said hot, freshly deodorized outgoing oil to said hot, pumpable outgoing oil bland flavor-stable processing temperature of from about 480F to about 340F dependinq on the type of oil and dormant time prior to coolingi and ~ 1 7265~
(c) passing said hot, pumpable outgoing oil through said heat interchanger means to warm up said cold undeodorized incoming oil.
Detailed Description of the Invention S mis invention relates to an i~pro~E~t in a high t~rature edible oil, deodorization process which utilizes a vacuum deodorization system, said process comprising the steps of:
`~ ~a) stripping odoriferous constituents from said oil at a high temperature to provide a hot, freshly deodorized oil having a bland flavor, said hot, freshly deodorized oil having a . temperature of abo~e an outgoing oil bland : fla~or-stable process temperature; and (b) cooling said hot, freshly deodorized oil to a storage te~perature, the improvement comprising utilizing a cooling means to quench said hot, freshly deodorized oil to a p~lmpable (outgoing oil) bland flavor-stable processing t~mperature (PBFSPT).
The invention further relates to a deodorization syste~ which operates with said hot, freshly deodorized oil at a high oil temperature of from about 425F to about 520F, and at a pressuxe of from about 0.1 mm o : 2S mercury to about 30 mm of mercury absolute pressure :: prior to said quenching, and wherein said outgoing oil is quenched to said pumpable bland flavor-stable proces-: sing temperature of from about 480F t~ about 340F, and wherein ~aid quenched oil is further cooled via : 30 heat interchanger means within 30 seconds to about 10 minutes after said ~llench, and wherein said deodorization temperatuxe and said pumpable temperature, and said time be~ore said further cooling are interdependent upon the type o~ oil being processed and the type of deodorization system being use-~.
1 ~ ~2~5~
Preferably, the oil is deodorized at a high oil temperature of from about 460F to about 490F, and the outgoing oil is quenched to a pumpable temperature below about 446F within a quench time of about a fraction of a second to about S0 seconds.
In a preferred embodiment, the process of this invention preferably comprises the steps of:
(a) feeding said hot incoming oil into a deodoriza-tion vacuum column, deodorizing said incoming oil at an oil deodorization temperature of from about 446F to about 520F by passing super-heated stripping steam countercurrently through a separate upper deodorizing section of said column, said hot, freshly deodorized oil dropping into a separate lower reservoir of said column;
(b) utilizing said separate lower oil-sealed reservoir in said column as a conduit for said hot, deodorized outgoins oil as it passes into said lower reservoir to be pumped;
~ 20 (c) utilizing a cooling means in said lower - reservoir to quench the temperature of said hot, freshly deodorized outgoing oil down to said pumpable oil temp-erature of below about 446F within a quench time of ; about a fraction of a second to about 50 seconds.
The preferred cooling means for quenching the oil is previously deodorized cooled quenching oil brought in contact with said hot, fxeshly deodorized oil.
Preferably, the quenching oil is directly mixed with said hot outgoiny oil as the hot outgoing oil passes into said lower, oil-sealed reservoir. Furthermore, the preferred hot, freshly deodorized outgoing oil has a temperature o from about 460F to about 490F when it passes into t~e lower, oil-sealed reservoir, and said quenching oil has a maximum temperature of about 140F. In another preferred embodiment, a pool or outgoing oil in said oil-sealed reservoir is agitated with stripping steam.
~ ~7~6~5 The deodorizaticn steam temperature is not critical, and can r~nge from about the boiling point of water at the inlet pressure to about 600~F. Water can even be introduced in lieu of steam, since the water would be immediately vaporized and heated to the deodorization temperature by contact with the hot deodorized oil in the lower portion of the deodorization column 1 and any other hot materials which the water contacts. It cools the apparatus and makes deodorization less efficient.
On the other hand, steam at a temperature in excess of about 600F can scorch the oil, and it is unnecessary to use such high temperature steam. It is preferred that the steam temperature be within about 20F of the oil temperature; cooler steam cools the oil, and hotter steam is unnecessary. Thus, the preferred temperature of ~team is broadly from about 410F to about 540F;
when the oil is within the preferred temperature range of from about 460F to about 490F, the preferred steam temperature ranges fxom about 440F to about 510F.
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2n Throughout this specification reference is made to steam as the deodorization agent. Steam is highly pre-ferred for this purpose as it is readily a~ailable in high purity and because it does not injure the oils being deodorized. Other deodorization agents can be used, however, ~or example, gases which are inert under the conditions of the process, such as nitrogen or hydrogen.
` Oxygen and air are unsuitable, however, as they would cause oxidation and degradation of the oils being deodoriæed.
The deodorization chamber per se and its COmpQnents can be any type of packed vapor-liquid contacting cham-ber, such as those which are well known in the chemical ;~ en~ineering art. See, for example, R. H. Perry et al, eds., Chemical Engineers' Handbook (McGraw-Hill, 4th ed., 1963), p-. 18-25 to 18~53; J. S. Ec~ert et al, Chemical Engineering Progress 54, No. 1, 70-75 tJanuary 1958~, 57, No. 9, 54-58 (September 1961), 59, No. S, 76-82 ; (May 1963), and 62, No. 1, 59-67 ~January 1966); and K. E. Porter, Chemistry and Industrv 182~89 (Eeb. ~, -~ 1 72~55 : 1967). These references also describe various kinds of packing materials which can be used.
The edible oils which can be deodorized by the process of this invention include various substances of plant or animal origin which consist predominantly of glyceryl esters of fatty acids, e.g. triglycerides, in-cluding both those commonly called "oils" which are : liquid at atmospheric pressure and room temperature, andthose commonly called "~ats" which are solid or semi-solid under these conditions, but liquid at the tempera-ture of heat-bleaching and deodorization (i.e. about 350F to 520F). Preferred oils are tallow, lard, and the common ~dible vegetable oils used for the production : : of salad oil and shortenings, e.g. cottonseed, peanut, safflower, palm, soybean, rapeseed, sunflower, corn, and coconut oils. The invention is particularly applicable ; to the heat efficient deodorization of sunflower seed oil.
The selectlon:of a pumpable bland flavor-stable :; 20 processing temperature~within the range of about 480F
: to about 340F is interdependent on the type of edible oil belng processed and the dormant oil times of the ~:~z~ deodorization system being used.
Preferably, the bland flavor-stable outgoing oil : : :: 25 is pumped at a temperature above about 340F for heat recovary via heat interchanger means.
The improved process of this invention is designed for utilizing heat and recovering energy in hot, freshly deodorized outgoing oil in a deodorization system wherein the hot deodorized outgoing oil is utilized to warm up cold undeodorized incoming oil via :~ a heat interchanger means, said process comprising the : steps of:
(a) deodorizing said incoming oil at a temperature of about 425F to about 520F to provide said hot, freshly deodorized oil having a temperature above a hot , ~
:
:
~ 1 ~26~
pumpable ougoing oil bland flavor~stable processing temperature;
(b) utilizing a cooling means to quench said hot, freshly deodorized outgoing oil to said hot, pumpable outgoing oil bland flavor-stable processing temperature of ~rom about 480F to about 340~; and (c) passing said hot, pumpable outgoing oil through said heat interchanger means to warm up said cold undeodorized incoming oil.
Industrial Applicatlon The method of this invention is useful in all types of deodorization processes which can be modified to:
(1) quench the emperature of the hot, freshly deodor-ized oil to a bland oil fla~or-stable temperature before pumping the hot oil through a heat interchanger to warm up cold incoming oil. Thus, it will be clear to those skilled in the art that an important principle of this invention is that hot, freshly deodorized oil must be quenched to its bland flavor-stable temperature before O it can be held dormant for further processing.
The term "dormant oil" is defined herein as hot ;~ deodorized oil, held in a tray or reservoir as a pool without sparging or significant steam stripping or simply oil that is being pumped. Dormant oil can be oil that dwells in an oil-sealed reservoir. Dormant oil can be oil pumped through a l-ine or heat inter-; changer. Dormant dèodorized oil held beyond its crit-ical dormant time at a temperature above its bland flavor-stable temperature, will degrade. The term "dormant time" as used herein technically refers to the time freshly deodorized oil dwells in a deodorization process that is no longer being sparged or stripped.
The term ~Ipumpable bland flavor-stable processing temperature of a deodorized oil" refers herein to a temperature or temperature range at which hot deodorized oil can be held "dormant'l or pumped without loss of its bland flavor. There is a maximum pumpable bland flavor-stable processing temperature for each particular oil and each oil has a unique dormant process time-~ 17~BS5 temperature interdependency wherein said dormantpxocess time increases as the temperature decreases.
The term "~uenched oil" as used herein refers to hot, freshly deodorized oil that has been cooled to its PBFSPT. The term "quench time" is that time re~uired to reduce the temperature for the deodorization temp-erature to the PBFSPT. There is a critical quench time for each particular oil and each oil has a unique critical process quench time - PBFSP temperature inter-dependency wherein said critical quench ~rocess timeincreases as the hot deodorization temperature decreases.
Therefore, the specific process or system used is also a factor in selecting times and temperatures since the equipment limitations will determine the requisite time that the oil is held "dormant" at various processing temperatures. Hot oil selectively quenched to its maximum bland flavor-stable processing temperature can be safely ~ ~imped through heat inter~hangers which utilize the heat of the hot outgoing oil to warm up rold incoming oil.
The incoming oil of this invention is refined and bleached oil or oil which has b~en processed with one or more of the following processes: refined, bleached, hydxogenated, winterized, dewaxed, interesterified, etc.
For a more detailed disclosure of the types of refined and processed oils useful as incoming oil for the present invention, the reader is referred to U.S. Patent 4,035,402, Levine, dated July 12, 1977 Steam-vacuum deodorization is preferred. The process consists o~ steam stripping or steam distilling of the volatile odori~erous constituents at elevated temperature and reduced pressure.
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$ 5 ~ he most common shape of the batch deodorizer is a cylindrical vessel two to four ,imes as high as it is wide. Provision is made to heat the oil internally or externally by steam, direct firing, or "Dowtherm"TM
S vapor. "Dowtherm" is a eutectic mixture of diphenyl and diphenyl oxide which is reportedly more suitable than steam because of the high temperature range that is required for deodorization. The vacuum equipment consists of multistage steam ejectors with barometric condensers. Stripping steam is introduced at the bottom by means of spiders or orifice plates. Good steam dis-tribution is essential, as it provides the additional advantage of effective agitation. The classical batch deodorization cycle usually is from 4 to 8 hours.
lS Batch deodorization systems can be modified to recover the heat of the hot, deodorized oil by determining the oil's bland, flavor-stable temperature and quenching the oil to that temperature with a cooling means. The ` hot quenched deodorized oil can then be safely pumped to heat cooler incoming oil. Some sparging of the hot, deodorized oil for agitation is preferred.
A semi-continuous system designed by the Girdler Corporation has found laxge-scale application. It consists essentially of~a large cylindrical vessel contai~ing five pans. A motor-operated timing device opens and closes valves automatically. They regulate the flow of product from the higher to the next lower pan. The oil is preheated and de-aerated in the top pan.
In the second pan the temperature of the charge is in-; 30 creased to about 240C. Deodorization is mainly carried out in the third and fourth pans. In the last pan the temperature is reduced by water cooling while the product continues to be steam stripped under vacuum. The total operating time is about 2-1/2 hours. In a modified system, heat recovery can be accomplished by determining the bland, flavor-stable processing temperature of the oil and following the guidelines set out herein.
1~ t , ! 1 72655 Several continuous deodorizers also are widely used. The system manufactured by Foster Wheeler Cor-poxation consists essentially o a vertical stainless steel column provided with trays and bubble caps. The oil, cascading from top to bottom, moves counter-currently to the ascending steam. U.S. Patent 3,542,653, Lowrey et al, Nov. 24, 1970, relates to an apparatus and process for continuous heat-bleaching and high temperature steam deodorization of edible oils.
As stated above, in some processes some steam stripping of the "dormant" hot deodorized oil is pre-ferred durin~ the quenching step for agitation while the hot oil is dwelling prior to being pumped. It provides agitation and also assures the maintenance of optimum bland oil flavor in some systems. Less s eam is needed for this agitation than i~ required for deodorization.
This invention is mainly described hexein in the context of a continuous deodorization process. However, will be apparent to those skilled in the art, in the light of this disclosure, that the principles of this invention are equally applicable to modified batch and semi-continuous deodoxization processes which are modified to utilize the heat of the outgoing hot deodorized oil to ~ ~ save energy. The hot deodorized oil in a modified system ; must be quenched if it is to be momentarily held dormant, e.g. as a pool in a vacuum oil-sealed reservoir means prior to pumping it to heat interchangers.
The Figure shows a deodorizing unit 1 having a hot incoming oil feed inlet 2. The deodorixation unit 1 comprises packing 3 supported on a screen means 3a, which are standard items in the art. The hot incoming oil 2 is treated with super-heated stripping steam 20 in the upper cham~er 22 inside the unit 1 to sparge and strip out odor-forming matter from the oil. The unit 1 also has a separate lower cooling reser~oir 5 containing a pool of dormant hot deodorized outgoing oil 6. The reservoir 5 receives a steady stream of hot, freshly deodorized oil 21 falling from the upper chamber 22 ~ 172BS5 of the unit 1. There the hot, freshly deodorized oil 21 is cooled to a bland flavor-stable processing tempera~ure by the quenching oil 23 in the lower reservoir 5 before it is pumped through the heat interchanger means 24 wherein cold incoming oil 25 is warmed by the hot quenched deodori2ed oil 6 before said incoming oil 25 is finally heated with a high tempPrature heating means 26. The hot quenched deodorized oil is finally cooled to 120F-140F by a cooler means 27 which is preferably a water cooler The means 24, 26 and 27 pxeferably comprise a battery of heaters or heat interchangers.
For a detailed disclosure of deodorization systems in general, pac~ing, bubble caps, residence times, etc.
~ which are not inconsistent with this invention, reference ;~ 15 is made to U.S. Patent 3,542,653, of Lowrey et al, dated November 24, 197Q~
The figure illustrates a system whereby heat is recovered and the bland flavor of the deodorized oil is maintained. The quenched deodorized oil 6 after passing ~ 20 through the heat interchanger means 24 is further cooled :~ ~ia cooler 27 to a packing (storage) safe temperature of about 120F to 140F, which cooled oil 23 can also be used as ~uenching oil 23.
.The continuous deodorization unit quench, "CDU
quench" method is a preferred embodiment of this invention.
~: The preferred method comprises showering recycled cooled deodorized quenchiny oil 23 through a quenching means 28 onto a pool of quenched deodorized oil 6 in the cooling ~ reservoir 5 to quench and agitate the hot, freshly deod-~ 30 ori~ed oil 21 as it drops into said oil pool 6. The hot, ;~ freshly processed deodorizPd oil 21 is rapidly quenched to a bland flavor stable processing temperature oil wit.hin a fraction of a second. Additional agitation of ~ the quenched oil 6 can be provided by stripping steam 20a :~ 35 or water ~imply injected into the pool of oil. An alter-native quenching means for cooling the hot, freshly deodorized oil comprises injecting the quenching oil directly into the oil pool 6.
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~ î726~
As stated earlier, the preferred pumpable bland flavor-stable temperature of a particular oil varies from oil to oil and rom system to system. The maximum temperature at which hot deodorized oil can be pumped to recover heat in a deodorization process while the bland flavor of the freshly deodorized oil is maintained, is pxeferred. The preferred bland flavor-stable temp-erature, from an ener~y efficient standpoint, is the maxim~m temperature of the hot deodorized outgoing oil at which the bland oil flavor is maintained in a heat recovery step. In a preferred embodiment the maximum - heat of the hot deodorized oil is used in a heat inter-changer means to save energy.
An alternative to a direct oil-to-oil quench is submerged internal heat e~changer coils which are used ~ to ~uench the hot, freshly processed deodorized oil in ;` reservoirs like reservoir 5, shown in the Figure. Such types of heat exchangers must cool the hot oil down to its bland flavor-stable processing temperature fast enough to maintain optimum good taste and bland flavor in deodorized oil, i.e. within the critical quench time.
Alternate methods and equipment for quenching hot, freshly deodorized oiI to bland flavor stable temperature, other than an oil-sealed lower cooling reservoir like 5 ~;~ 25 are contemplated as within the scope of this invention.
Typical examples of such devices are found in: "Deod-orization 1975", C~ T. Zehnder, Journal of American Oil - Chemists' Socie~y, June 1976 (Vol. 53), and Gavin et al, J. Am. Oil Chemlsts' Society, ~Jovember 1973, pp. 46~A-477A (Vol. 50).
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It was surprisingly discovered that hot, freshly deodorized oils having too hi~h a temperature to be safely pumped could be quenched to a slightly lower but 3s bland fla~or-stable temperature to avoid flavor degrada-tion before pumping. Sunflower seed oil is a very difficult oil to deodorize. It is preferably deodorized at a high temperature of about 490F to about 460F in a continuous deodorizer. The freshly deodori~ed sunflower seed oil must .,, ~ . i ~ ~ 72~5 be quenched in a CDU to its flavor process stable temperature of about 445F to about 410F within a quench time of about a fraction of a second to within about S0 seconds.
Again, it has been discovered that hot, freshly processed deodori~ed oil which has optimum good taste (a bland flavor) will degrade ~ L if held dormant at too high a temperature without sparging (stripping) under vacuum. Hot, freshly deodorized sunflower seed oil at high deodorization temperatures held dormant for just a few seconds can show degradation. It was surpris-ingly discovered that hot quenched deodorized sunflower - seed outgoing oil having a temperature below about 445F
i~ a CDU, as illustrated, maintains its optimum good taste and bland flavors, but unquenched freshly deodor-ized outgoing sunflower seed oil shows degradation when held dormant. Short dormant (dwell) times, e.g. about 60 seconds and less, in a continuous pool in a reservoir like reservoir 5 and associated piping to cooler 24 of a CDU at high deodorization temperatures is enough to significantly degrade the oil, if not quenched. Similar degradation would happen in modified batch and semi-continuous processes so designed to recover the maximum heat of the freshly deodorized oil.
In a CDU system, as shown in the ~igure, sunflower seed oil can be deodorized at a temperature of fro~
about 446F to about 510F, and preferably 460F to 490F.
The hot, freshly deodorized outgoing oil 21 dribbles out of the upper chamber 22 down into the lower reservoir.
Thus, hot, freshly deodorized outgoing oil 21 is quenched in resexvoir 5 with ~uenching oil 23 to a temperature ; of below about 445F, its bland flavor-stable temperature.
It is preferably quenched to a temperature of about 410F
+ 5F within a quench time of about a fraction o a second The hot~ freshly deodorized oil i preferably quenched by mixing it with 120-140F prior deodorized quenching oil 23. This step in a CDU is preferably ac-complished by spraying a shower o~ the quenching oil 23 into the lower reservoir 5 of a CDU system whereby the ? ~,.
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~ 1 72655 hot and cooled oils are contacted, mixed and a~itated.
j The quenched deodorized outgoing oil 6 in the , reservoir 5 can then be safely pumped out for further cooling, e.g. via a heat interchanger cooler 24 and then further cooled via cooler 27 to a packing or storage ~ stable temperature of about 130F ~ 10F. The oil is j then pumped to a storage tank, packed or recirculated ' to the cooling reservoir S as cool quenching oil 23.
eat interchanger cooler 24 is preferably designed ' 10 to also heat up incoming oil 25 and thereby save energy.
The ratio of quenching oil to hot, freshly i deodorized oil, needed to quench to a bland flavor-.f stable processing temperature, will vary depending on the respective oil temperatures, dwell times and the f 15 particular deodorization process being applied.
, The bland flavor-stable processing temperature for ~;, a particular oil within a particular dwell time for a particular system can be determined by trial and error.
The critical factor is to determine the pumpable bland , 20 flavor-stable processing temperature (PBFSPT) of the oil ' being processed. One method of determining the PBFSPT
would be to withdraw a series of samples of hot,' freshly' deodorized oil from a batch deodorization system at decreasing temperatures and quenching them to various 25 temperatures at increasing times. Soybean oil, for example, has a maximum PBFSPT of about 480F in a CDU
.f : ~ ~ , ' system as shown in the Figure. Soybean oil call be deodorized at a temperature as high as 510F.
- Procedure to Determine the PBFSPT
The following describes a procedure used to determine the PBFSP,T of deodorized oils. Equipment is ~' a 20 lb. capacity b'atch deodorizer under which is mounted a small stainIess steel sample vessel connected by two valves. The sample vessel is also vented up to the top of the deodorizer via a valved vent linè. The procedure ~' for its operation is: inlet oil is charged into the ; dPodorizer and deodorized at desired temperature and time to achieve a suitably bland flavor. Bland flavor , ~ , .
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} i726~
is verified by withdrawing an oil sample into the sample vessel and immersing the sample vessel into an ice bath while it is connected to the deodorizer and opening the vent line to the top of the deodorizer to equalize the pressures. Both valves connecting the sample vessel with the deodorizer itsel are then opened, allow-ing oil to freely drain from the deodorizer through the two valves and into the sample vessel. Cooling of the oil draining into the sample vessel is almost instan-10 taneous, as its walls are essentially held at ice bath conditions by the external ice bath. The sample of deodorized oil thus withdrawn is then tasted by expert oil evaluators to determine that it is suitably bland.
This sample is the flavor control. When testing, the 15 sample vessel is not precooled in an ice bath; but rather, the sample is first withdrawn and, after withdrawal, the sample vessel is cooled in an ice bath, which cooling is ; not commenced until a few seconds after sample withdrawal, e.g. 2, 5, 10, 15 or 30 seconds or more. The tempera-P 20 ture of the deodorized oil is reduced to various temp-eratures to provide several different sampling temper-atures. This process is repeated for several different quenching times and several different sampling tempera-tures to produce a map of flavor grades versus the con-25 trol. This map o time and temperature allows one to select the PBFSPT by giving the artisan an understanding of the time at which the oil can be held at a specified ; temperature before it starts to degrade.
Examples 1-9 The specific conditions of Examples 1-9 are set out in Table I. The equipment used is illustrated in the Figure. Undeodorized, refined and bleached sunflower seed incoming (inlet) oil was used for each run. Super-heated stripping steam 20 was introduced at a rate of about 0.5% by weight of the incoming oil 2. The steam is introduced via steam inlet 20 below the screen 3a level and is drawn through the upper chamber 22 via ~ vacuum source 30.
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~ 17~B55 As shown in the Figure, some additional sparging steam 20a can be introduced below the surface of the pool of quenched oil 6 in the reservoir 5 for agitation and good measure. Column operating pressures of about 5 mm of mercury absolute pressure maximum were maintained at the top of the column with a maximum operating pressure differential (~ P) across the column of about 24 mm of mercury. Preferably, a ~P of about 15 mm of mercury are maintained. A ~ P of about 30 mm of mercury is not too high. Results of several runs under various condi-tions are shown in Table I.
The temperature of the hot incoming oil 2 approxi-mates the temperature o~ the hot, freshly deodorized oil 21 in each run. The residence time of oil in the upper chamber 22 of the unit is about a minute and the residence time of t~le oil in reservoir 5 plus pumping time to interchanger 24 of the unit is about 1 to 2 minutes.
, ~ _ The ratios of the quenching oil to hot, freshly deodorized oil fed into the system were adjusted to achieve the desired pool temperature shown in the Table.
The pool temperatures of Examples 2, 3, 4, 7, 8 and 9 illustrate some~preferred PSFSPTs of this invention.
TABLE_I
Run Incoming Oil Quench Oil Pool Temperature Temperature Temperature DOF
1 484F No Quench (480F) 7.1
2 465F 130F 440F 8.0
3 465F 130F 410F 8.0 ~-~ 30 4 484F 120F 405F 7.6 S 468F No Quench* (460F)* 7.3 6 480F No Quench* (480F)* 7.3 7 484F 120F* 445F* 7.8 8 460F 120F* 410F* 7.7 9 486F 120F* 410F* 7.7 * Pool sparge with steam ' ;
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~ 1 72~55 Deodorized oil flavor (DOF) is subjectively evalu ated on a 10:1 grading scale with 10 being a bland oil and l having a very objectionable or strong off-flavor.
A 0.2 flavor differential is significant. As can be seen, oils deodorized without the aid of the quench system of this invention graded lower in flavor quality than all the oils deodorized using the quench system of this invention.
Compare unquenched run l with quenched run 4. They respectively had deodorized oil flavors of 7.1 and 7.6.
Both were dormant in the oil pool 6 and were pumped dormant at temperatures of 480F and 405F, respectively.
Also compare the flavors of unquenched sparged pool oil run 6 pumped at 480F with quenched, sparged pool oil run 7 pumpad at 445F which were respectively 7.3 and 7.8.
The hot, freshly deodorized oils of runs 2, 3, 4, ~`~` 7, 8 and 9 were quenched to their PBFSP temperatures within 50 seconds and probably within 10 seconds. ~he residence or dwell times in the pool 6 of reservoir 5 were each about 1-2 minutes.
~;~ Comparing run l, unquenched and dormant oil, with ,, runs 5 and 6, unquenched and steam sparged oils, gives ; ~ a direct comparison of the effect of steam sparging on oil quality. These runs had deodorized oil flavors of 7.1, 7.3 and 7.3 respectively. This comparison shows that steam sparging is directionally preferred and does improve flavor. This improvement, however, is over-shadowed by the greater flavor improvement achieved via quenching. Steam sparging is directionally better but ~; ~ optional.
In all of the runs (1-9) pool oil 6 was pumped to heat exchanger 24 whereby the cooler inlet oil 5 was warmed to save energy. Less energy was required to heat the inlet oil via high temperature heater means 26 to the desired inlet deodori ation temperature.
,~
.
~ 1 72~55 Deodorized oil flavor (DOF) is subjectively evalu ated on a 10:1 grading scale with 10 being a bland oil and l having a very objectionable or strong off-flavor.
A 0.2 flavor differential is significant. As can be seen, oils deodorized without the aid of the quench system of this invention graded lower in flavor quality than all the oils deodorized using the quench system of this invention.
Compare unquenched run l with quenched run 4. They respectively had deodorized oil flavors of 7.1 and 7.6.
Both were dormant in the oil pool 6 and were pumped dormant at temperatures of 480F and 405F, respectively.
Also compare the flavors of unquenched sparged pool oil run 6 pumped at 480F with quenched, sparged pool oil run 7 pumpad at 445F which were respectively 7.3 and 7.8.
The hot, freshly deodorized oils of runs 2, 3, 4, ~`~` 7, 8 and 9 were quenched to their PBFSP temperatures within 50 seconds and probably within 10 seconds. ~he residence or dwell times in the pool 6 of reservoir 5 were each about 1-2 minutes.
~;~ Comparing run l, unquenched and dormant oil, with ,, runs 5 and 6, unquenched and steam sparged oils, gives ; ~ a direct comparison of the effect of steam sparging on oil quality. These runs had deodorized oil flavors of 7.1, 7.3 and 7.3 respectively. This comparison shows that steam sparging is directionally preferred and does improve flavor. This improvement, however, is over-shadowed by the greater flavor improvement achieved via quenching. Steam sparging is directionally better but ~; ~ optional.
In all of the runs (1-9) pool oil 6 was pumped to heat exchanger 24 whereby the cooler inlet oil 5 was warmed to save energy. Less energy was required to heat the inlet oil via high temperature heater means 26 to the desired inlet deodori ation temperature.
,~
Claims (12)
- Claim 1. A vacuum deodorization process comprising the steps of:
(a) deodorizing edible oil at a temperature of about 520°F to about 425°F and a pressure of from about 0.1 mm to about 30 mm of mercury; and (b) quenching the deodorized oil of step (a) to a flavor-stable temperature of about 480°F to about 410°F within about 50 seconds by mixing the deodorized oil with quenching oil having a temperature substantially below the flavor-stable temperature. - Claim 2. The process of Claim 1 wherein the deodorization temperature of step (a) is about 490°F to about 460°F, and wherein the deodorized oil of step (b) is quenched to a flavor-stable temperature below about 446°F within a fraction of a second to within about 50 seconds.
- Claim 3. The process of Claim 1 wherein said edible oil is selected from the group consisting of sunflower seed oil, soybean oil safflower seed oil and corn oil.
- Claim 4. The process of Claim 3 wherein said process is continuous.
- Claim 5. A vacuum deodorization process comprising the steps of:
(a) deodorizing oil with super-heated stripping steam at a temperature of from about 520°F to about 446°F and a pressure of about 0.1 mm to about 30 mm of mercury absolute; ana (b) quenching the freshly deodorized oil of step (a) to a bland, flavor-stable temperature of from about 410°F to about 446°F in a fraction of a second to within about 50 seconds by mixing said oil with deodorized quenching oil, said quenching oil having a temperature-substantially below said flavor-stable temperature. - Claim 6. The process of Claim 5 wherein said deodorized oil of step (a) has a temperature of about 490°F to about 460°F and said quenching oil has a maximum temperature of about 140°F.
- Claim 7. The process of Claim 1 wherein step (b) further comprises agitating the deodorized oil with sparging steam while cooling.
- 19 Claim 8. The process of Claim 5 wherein said oil is a refined and bleached sunflower seed oil.
- Claim 9. An improved deodorization process comprising the steps of:
(a) deodorizing edible oil at a temperature of about 520°F to about 425°F at a pressure of about 0.1 mm to about 30 mm of mercury absolute pressure to provide deodorized oil;
(b) quenching said deodorized oil to a flavor-stable temperature of about 480°F to about 410°F within about 50 seconds by mixing said oil with deodorized quenching oil, said quenching oil having a temperature substantially below said flavor-stable temperature; and (c) passing the quenched oil through a heat interchanger means to further cool the quenched oil and simultaneously to warm undeodorized oil and thercby save energy. - Claim 10.A deodorization process comprising the steps of:
(a) passing oil into a deodorization vacuum column, wherein said oil is deodorized at a temperature of from about 520°F to about 446°F by passing steam countercurrently througn said oil;
(b) passing the hot deodorized oil into a separate reservoir of said deodorization vacuum column; and (c) quenching said hot deodorized oil to a temperature below about 446°F within abnut 50 seconds by mixing said oil with deodorized quenching oil having a temperature below 140°F. - Claim 11. The process of Claim 3 wherein said process is semi-continuous.
- Claim 12. The process of Claim 3 wherein said process is a batch process.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US11095980A | 1980-01-10 | 1980-01-10 | |
| US110,959 | 1980-01-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1172655A true CA1172655A (en) | 1984-08-14 |
Family
ID=22335862
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000368204A Expired CA1172655A (en) | 1980-01-10 | 1981-01-09 | Process to maintain bland taste in energy efficient oil deodorization systems |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0032434B1 (en) |
| CA (1) | CA1172655A (en) |
| DE (1) | DE3166218D1 (en) |
| PH (1) | PH16859A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4826702A (en) * | 1986-06-17 | 1989-05-02 | Q.P. Corporation | separate type dressing |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE8500480L (en) * | 1985-02-04 | 1986-08-05 | Alfa Laval Food & Dairy Eng | PROCEDURE FOR HEAT METER WASTE PURIFICATION OF VEGETABLE OIL |
| GB9804479D0 (en) * | 1998-03-02 | 1998-04-29 | Chemtech International Ltd | Stripping of volatile substances from less volatile fluids |
| WO2015181341A1 (en) | 2014-05-28 | 2015-12-03 | Drei Lilien Pvg Gmbh & Co. Kg | Method for refining lipid phases, and use |
| CN109628204A (en) * | 2018-12-29 | 2019-04-16 | 金华市农业科学研究院 | A kind of Luzhou-flavor tea seed oil preparation method of deodorization |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2621196A (en) * | 1948-10-28 | 1952-12-09 | Kraft Foods Co | Method of deodorizing glyceride oils |
| US3607670A (en) * | 1968-02-26 | 1971-09-21 | French Oil Mill Machinery | Method and apparatus for deodorizing glyceride oils within a single vessel using counter current indirect heat exchange and direct superheated steam injection |
| DE2039531C3 (en) * | 1970-08-08 | 1978-08-31 | Fried. Krupp Gmbh, 4300 Essen | Process for the semi-continuous deodorization or hardening of edible oil |
| US4036865A (en) * | 1973-07-18 | 1977-07-19 | Metallgesellschaft Aktiengesellschaft | Semicontinuous process for deodorizing oils |
| GB1532007A (en) * | 1975-11-19 | 1978-11-15 | Leva M | Apparatus for deodorizing fats and oils |
-
1981
- 1981-01-09 DE DE8181300082T patent/DE3166218D1/en not_active Expired
- 1981-01-09 CA CA000368204A patent/CA1172655A/en not_active Expired
- 1981-01-09 PH PH25074A patent/PH16859A/en unknown
- 1981-01-09 EP EP81300082A patent/EP0032434B1/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4826702A (en) * | 1986-06-17 | 1989-05-02 | Q.P. Corporation | separate type dressing |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0032434A2 (en) | 1981-07-22 |
| EP0032434B1 (en) | 1984-09-26 |
| DE3166218D1 (en) | 1984-10-31 |
| EP0032434A3 (en) | 1981-09-23 |
| PH16859A (en) | 1984-03-22 |
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