CA2082422C - Hydrogenated frying fat with extended frylife - Google Patents
Hydrogenated frying fat with extended frylife Download PDFInfo
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- CA2082422C CA2082422C CA002082422A CA2082422A CA2082422C CA 2082422 C CA2082422 C CA 2082422C CA 002082422 A CA002082422 A CA 002082422A CA 2082422 A CA2082422 A CA 2082422A CA 2082422 C CA2082422 C CA 2082422C
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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
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23D—EDIBLE OILS OR FATS, e.g. MARGARINES, SHORTENINGS, COOKING OILS
- A23D9/00—Other edible oils or fats, e.g. shortenings, cooking oils
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
- C11C3/00—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom
- C11C3/12—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by hydrogenation
- C11C3/123—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by hydrogenation using catalysts based principally on nickel or derivates
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Abstract
A hydrogenated frying fat with extended frylife is made by: (a) hydrogenating an edible liquid oil having a starting iodine value between 95 and 150 by reacting the liquid oil with hydrogen in the presence of 0.01 % to 0.4 % hydrogenation catalyst by weight of the oil, where the hydrogenation reaction is conducted at a temperature between 320 °F (160°C) and 500°F (260 °C) and a pressure between 0 psig and 100 psig until the iodine value of the oil after hydrogenation is between 50 and 90, and where during the hydrogenation reaction the temperature of the oil is between 440 ° F (227 ° C) and 500 ° F (260 ° C) for a time of at least minutes and until the desired endpoint is reached; then (b) cooling the oil, filtering the oil to remove the catalyst, storing the oil at a temperature of 110 °F (43°C) to 220 °F (104 °C), and deaerating the oil; and then (c) deodorizing the oil by heating it at a temperature between 530 ° F (277 °C) and 650° F (343 °°C), at a pressure between 0.5 mm Hg and 50 mm Hg, for a time between 5 seconds and 35 minutes, while stripping the oil with a stripping medium in tthe amount of 0.1 % to 20 % by weight of the oil.
Description
HYDROGENATED FRYING FAT WITH EXTENDED FRYLIFE
BACKGROUND OF THE INDENTION
1. Field of the Invention This invention relates to hydrogenated frying fats and to a method for making the fats by high temperature hydrogenation and deodorization.
BACKGROUND OF THE INDENTION
1. Field of the Invention This invention relates to hydrogenated frying fats and to a method for making the fats by high temperature hydrogenation and deodorization.
2: Descri tion of the Related Art U.S. Patent 4,789,554 to Scavone et al., issued December 6, 198,8, discloses a high temperature deodorization process used to purify and increase the frylife of edible oils. Deaerated oil is deodorized at a temperature between 530°F {277°C) and 650°F (343°C) for a time between 5 seconds and 15 minutes. Tocopherols and related structures believed to be deleterious to frylife are removed. The patent does not discuss hydrogenation.
U.S. Patent 2,602,806 to Jacob, Jr., et al., issued July 8, 1952, discloses a hydrogenation process for triglycerides inn which the hydrogenation is conducted at temperatures up to 545°F (285°C).
U.S. Patent 2,621,191 to Thurman, issued December 9, 1952, discloses a deodorization process for glyceride oils conducted at temperatures between 500°F (260°C) and 600°F
(316°C). Hydrogenation of the oils is done at a temperature of about 400°F or less.
U.S. Pateni: 3,732,266 to Dudrow, issued May 8, 1973, discloses a method for hydrogenating oils at a temperature between about 240°F (116°C) and about 450°F
(232°C).
U.S. Patent: 4,260,643 to Cochran, issued April 7, 1981, discloses triglycerides hydrogenated by a two-step process, where the first: hydrogenation step is carried out at SUUSTITUTE SHEET
z WO 91/17667 ~ °~ a ~ PCT/US91/02685 325°F-460°F (:163°C-238°C) and the second hydrogenation step is carriE:d out at 340°F-460°F (171°C-238°C).
U.S. Patent 3,555,058 to Going et al., issued January 12; 1971, discloses a special catalytic hydrogenation process. The temperature of reaction is said to vary between about 150°F (66°C) and about 500°F
(260°C) .
The above-mentioned Scavone et al. '554 patent discloses a mEahod for increasing the frylife of edible oils by deodorizing the oils at high temperatures between 530 ° F (277 ° C) and 650 ° F (343 ° C) and under other specified conditions. However, the Scavone et al. patent does not teach or suggest that a particular high temperature hydrogenation process used in combination with the deodorization process can have an additional effect in improving fryl.ife.
Other of the above-mentioned patents disclose hydrogenation;processes carried out at high temperatures.
However, the patents do not suggest that the method of hydrogenation can affect the frylife of edible fats.
Moreover, the patents do not suggest that the optimum frylife can be obtained in fats by processing the fats in a high temperature deadorization process combined with a high temperature hydrogenation process.
It is, therefore, an object of an aspect of the present invention to provide a method for improving the frylife of edible fats by use of a specific high temperature deodorization process in combination with a specific high temperature hydrogenation process.
It is another object of an aspect of the present invention to provide the hydrogenated fats that have improved fryl:ife, and that are characterized by low levels of tocopherols and high levels of trans-isomers.
These and other objects of the invention will become evident from the disclosure herein.
~r All part:, percentages and ratios used herein are by weight unless otherwise defined.
SUMMA~tY OF THE INVENTION
The invention is s process for making a hydrogenated frying fat with extended frylife comprising:
(a) hydrogenating an edible liquid oil having a starting iodine value between about 95 and about 150 by reacting the liquid oil with hydrogen in the presence of about 0.01% to about 0.4% hydrogenation catalyst by weight of the oil, wherein the hydrogenation reaction is conducted at a temperature between about 320°F
(160°C) and about 500°F (260°C) and a pressure between about 0 prig and about 100 psig until the iodine value of the oil after hydrogenation is between about 60 and about 80, and wherein during the hydrogenation reacaion the temperature of the oil is between about 460°F (238°C) and about 500°F (260°C) for a time of at least about 5 minutes to produce a frying fat containing at least about 40% traps-isomers; then (b) cooling the oil, filtering the oil to remove the catalyst, storing the oil at a temperature of about 110°F (43°C) to about 220°F (104°C:), and deaerating the oil; and then (c) deodorizing the oil by heating it at a temperature between about 530°F (277°C) and about 650°F (343°C), at a pressure between about 0.5 mm Hg and about 50 mm Hg, for a time between about 5 seconds and about 35 minutes, while stripping the oil with steam in the amount of about 0.1% to about 20% by weight of the oil.
>~;
~' -3a-The presE:nt invention also relates to a hydrogenated frying fat with extended frylife, wherein the hydrogenated fat has an iodine value between about 50 and about 90, and wherein the hydrogenated fat contains at least about 35% traps-isomers, preferably at least about 40o traps-isomers.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
1. Discoverv of Frylife Benefit from Hydrogenation It has now been discovered that a high temperature hydrogenation process can increase the frylife of an edible frying fat. Moreover, when the high temperature hydrogenation process described herein is combined with a particular high temperature deodorization process, it has been discovered that the frylife of the resulting frying fat is improved over that of a fat undergoing the high temperature deodorization process alone. Although not intending to be bound by theory, it is believed that a higher level of traps-isomers in the frying fat, which results from the high temperature hydrogenation process, is involved in the improved frylife benefit of the invention.
2. Hydro eq nation Hydrogenation is a means of saturating oils by the addition of hydrogen to the double bonds (unsaturated or ethylenic bonds) of an oil or fat by reaction with hydrogen in the presence of a metal catalyst. The hydrogenation reaction is accompanied by the simultaneous isomerization, both positional and geometrical, of the unsaturated bonds, producing both traps-isomers and cis-isomers.
Both Swern, Bailey's Industrial Oi) and Fat Products, 3rd ed., 1964, pp. 305-313 and 793-886, and Swern, Bailey's Industrial Oil and Fat Products, Uol. 2, 4th ed., 1982, pp.
5-69, discuss the hydrogenation process in general.
Beckmann, "Hydrogenation Practice", JAOCS, Uol. 60, No. 2, February 1983, pp. 282-290, discusses hydrogenation ', practice, equipment, process controls, and catalysts.
For hydrogenation t o take place, gaseous hydrogen, liquid oil, and the solid catalyst must be brought together at a suitable temperature. In the usual type of equipment, a suspension of catalyst and oil is agitated in a closed vessel in an atrnosphere of hydrogen. ';
SUBSTITUTE SNEET
~a ~' Hydrogenation, like other chemical reactions, is accelerated by an increase in temperature or pressure.
Also, as the temperature of reaction is increased, the formation of traps unsaturation increases almost linearly. ', The effect of pressure on isomerization is limited, and the rate of increase in the formation of traps isomers is less at higher pressures.
Commercial hydrogenation plants are essentially divided between "recirculation" systems, in which agitation and dispersion of hydrogen within the oil are achieved by continuously recycling hydrogen in large volumes through the reactor, and the newer "dead-end" systems in which the reactor is supplied only with as much hydrogen as is absorbed, and where dispersion of the hydrogen is assisted by mechanical agitatiord. Any type of commercially ' acceptable processing operation, including batch hydro-genation, continuous processing, recirculation systems, and "dead-end" systems, may be utilized with the hydrogenation process described herein. For a thorough discussion of hydrogenation equipment, see Swern, Bailey's Industrial Oil and Fat Products, Uol. 2, 4th ed., 1982, pp. 27_37.
The starting oil for the hydrogenation process of the present invention can be any edible liquid vegetable, animal or marine oil or blend of oils which has an iodine value of from about 95 to about 150. The preferred oil is a polyunsaturated vegetable oil having fatty acid chains containing at least 14 carbon atoms. Preferred vegetable oils include soybean, corn, cottonseed, sunflower seed, safflower, olive, peanut, coconut, palm, rapeseed, palm oil olefin, and canolc~ oil. More preferred oils include soybean, sunflower seed, palm oil, peanut oil, canola oil, corn oil, cottonseed oil, safflower oil, and mixtures thereof. The most preferred oils are soybean oil and canola oil, and mixtures thereof, A blend of i:wo or more oils may be used to obtain the desired initial -iodine values and the desired stability in ~UB~TITCITE SNEET
WO 91/17667 R~l ~~ ~a ~~ ~ø ~' , PCT/US91/02685 the oil after hydrogenation. The oils may be blended either prior to or following hydrogenation. Oils with high iodine values, such as liquid soybean oil, are useful in limited amounts when blended with oils that have been hydrogenated to control the consistency and solids content of the final product.
The oil is mixed with any conventional hydrogenation catalyst known to the hydrogenation industry. Finely divided metallic nickel catalysts are well known for use in the hydrogenation of vegetable oils. Such catalysts are usually deposited on carriers such as Kieselguhr, aluminum oxide, silicate and the like.
Nickel catalysts can lose their activity, or be deactivated, due to the poisoning action of certain chemical substances, such as sulfur, phosphorus, chlorine, zinc, and compounds of the same. For the hydrogenation process of the present invention, it is preferred to use a nickel catalyst, a partially deactivated nickel catalyst, or mixtures thereof. Sulfur-treated catalysts are particularly suitable for use since they promote the rapid development of traps isomers during hydrogenation. See, e.g. Okonek, Douglas V., "Nickel-Sulfur Catalysts For Edible Oil Hydrogenation,"
printed as Chapter 5 of Hydrogenation: Proceedings of An ADCS Colloquium, edited by Robert Hastert, 1987.
The hydrogenation catalyst used in the present invention is utilized at a concentration of from about 0.01%
to about 0.4%, preferably from about 0.02% to about 0.3%, catalyst by weight of the oil. The amount of catalyst used is dependent upon the rate of reaction to be attained and other variables such as temperature and pressure, and the starting oil.
The time of the total hydrogenation reaction is not critical. The reaction is generally carried out for from about 30 minutes to about 8 hours, and preferably from about 1 hour to about 4 hours. The pressure ranges from about 0 ~UBST'TC~~T~ SHEET
WO 91/17667 ~Cf/US91/02685 c ac«~~~
uW.~
psig to about 1.00 psig, and preferably from about 0 psig to about 80 psig.
The hydrogenation reaction is conducted at a temperature bei:ween about 320°F (160°C) and about 500°F
(260°C). In order to obtain the frylife improvement benefit of the present invention, during the hydrogenation reaction the temperature of the oil must be between about 440°F
(227°C) and about 500°F (260°C) for a time of at least about minutes, and preferablly at least about 8 minutes. It is preferred that the oil be held for these times at temperatures between about 460°F (238°C) and about 500°F
(260°C), and most preferably between about 470°F (244°C) and about 500°F (260°C).
The method used to control the temperature of the reaction varies. with the processing equipment. Since hydrogenation is an exothermic reaction, it may be necessary to cool the rea~~tion by some suitable means, such as a heat exchanger. However, if the vessel is not well insulated or is in a large unheated area, the system may lose heat quickly enough that the heat generated by the exothermic reaction will not be sufficient to maintain the reaction temperature. In this case, it is necessary to apply additional heat by some suitable means, such as heating coils, a heating jacket o r heat exchangers.
The reaction is terminated when the iodine value (IU) ', reaches a value of from about 50 to about 90, and preferably from about 60 to about 80. The endpoint of the reaction is chosen so that 'the product has the solids content profile desired in that particular product. The solids content can be expressed at different temperatures, in terms of a "Solids Contents. Index" (SCI) or "Solid Fat Index" (SFI) which are measured by what is essentially the test described in the Journal of the American Oil Chemists' Society, March 1954, Vol. XXXI, pp. 98-103. The test involves a dila-tometric measurement of ithe amount by which a fat expands when heated from a specific temperature to complete melting.
rUHSTITUT~ SHEET
WO 91/17667 , ~ ~x? ~~ ~,, ~, PCT/US91/02685 _g_ ~~ The hydrogenation reaction is generally ended by stopping the flow of hydrogen to the reactor. When the hydrogen flow is stopped, in order to exclude oxygen from the hot oil until it is cooled, generally either the reactor is pressurized with nitrogen or the reactor is kept under a vacuum.
After the hydrogenation reaction is ended, the oil is cooled down from the high temperatures of hydrogenation and stored at a temperature of about 110°F (43°F) to about 220°F
(104°C), preferably about 140°F (60°C) to about 180°F
(82°C), prior to deodorization. The oil is kept warm enough to avoid the formation of solids, but not too hot because higher temperatures could cause off-flavors and would waste energy.
It is also important after hydrogenation and before deodorization to remove the hydrogenation catalyst by filtering the oil. Further, the oil must be deaerated before it undergoes deodorization, preferably to a level of less than about 0.10% by volume of dissolved oxygen. The order of these processing steps is not critical, but usually the oil is first cooled, then filtered, and then stored, and immediately prior to deodorization the oil is deaerated.
As discussed hereinabove, the fat after hydrogenation has an iodine value (I.V.) of from about 50 to about 90, preferably from about 60 to about 80. The I.V. of a fat or oil indicates the number of grams of Iodine equivalent to halogen absorbed by a 100 gram sample. Because the halogen absorbance is due to the double bonds present in the fatty acid residues attached to the glycerides, the I.V. of a fat or oil can give a general indication of solids content at a given temperature. As the fatty acid residues become more saturated, the fat or oil increases in solids content. In general, the lower the I.V. of a given fat or oil, the greater will be the solids content at a given temperature.
The I.V. of a fat or oil can be determined by the ROCS
Official Method Col. 1-25, also known as the Wijs method.
suesT~T~~~ sH~E~
WO 91/17667 ~"~" PCT/US91/02685 _g_ Approximate iodine values may be determined by measurement of the refractive index of the oil, since for each given oil. a linear correlation between iodine value and refractive index can be determined. This method allows a relatively quick and easy determination of the proper endpoint of the hydrogenation. ', The contEant of trans-isomers of unsaturated fatty acids in the hydrogenated frying fat of the present invention is measured by infrared spectrometry. The method used is. identical to that described by Madison et al. in "Accu:rate Determination of Trans Isomers in Shortening and Oils by Infrared Spectrophotometry, " in J.
Amer. Oil Chem. Soc., Vol. 59,,No. 4 (April, 1982), pp.
178-81 with two exceptions: 1) the method utilized in the present invention employed a Nicolet, Model 20DXC, Infrared Speci=rometer (Nicolet Instrument Corporation, Madison, WI) which was equipped with a deuterated triglycine-sulfate detector and used in lieu of a Beckman IROl2 spectrophotometer; and 2) methyl stearate was replaced with methyl oleate as a calibration standard to be used with methyl elaidate in the construction of the calibration curve.
3. Deodoriza.tion The deodorization process used in the present invention is hike that described in U. S. patent 4, 789, 554 to Scavone, et al., issued December 6, 1988. The present deodorization process differs from the Scavone et al.
process in tha~~t longer deodorization times are permitted.
In this deodorization process, the oil is deodorized by heating it at a temperature between about 530°F (277°C) and about 650°F (343°C), at a pressure between about 0.5 mm Hg and about 60 mm Hg, for a time between about 5 seconds and about 35 minutes, while stripping the oil with a stripping medium in the amount of about 0.1% to WO 91/17667 ~« - PCT/US91/02685 about 20% by weight of the oil, preferably about 0.5% to about 20%, more preferably about 1% to about 50.
At col. :3, line 17 to col. 5, line 4 of the above-mentioned Scavone et al. patent, the inventors discuss deep-frying, t:he undesirable color darkening that occurs in frying fat: over time, and the theory behind why the deodorization process works to provide improved frylife.
At col. 5, line 5 to col. 7, line 19, Scavone et al.
discuss the various stripping factors and their interrelation:ahip in providing a deodorization process that results in optimum frylife of the frying fat.
Briefly, standard deodorization is accomplished when the volatile odoriferous components in a fat or oil are removed as well as when the free fatty acids are lowered from approximately 0.08% to 0.02%. The theoretical relations which govern the continuous deodorization process are a:~ follows:
Vl KP"S
VZ PO
where:
K - an Experimentally determined coefficient. In general, using similar packed column continuous deodorization equipment, values for K of about 4 for free fatty acid deodorization and values for K of about 65 for removal of materials deleterious to frylife have been observed. Regardless of the equipment, the relative values should remain constant (e. g.
65/4 ) . In equipment where the steam and oil contacting is not as efficient, such as in a thin: film Evaporator, K values for materials deleaerious to frylife as low as 1.0 have been observed. In contrast, in equipment where WO 91/17667 ~ ~ -° PCT/US91/02685 -10a-contacting efficiency is extremely efficient, K values as high as about 200 have been obsE:rved for materials deleterious to frylife.
P" vapor pressure of the pure compo nent to = be removed.
S molar steam rate.
-P absolute pressure.
-O molar oil rate.
-V1 initial molar concentration in the oil of the =
component to be removed.
VZ final molar concentration in the oil of the =
component to be removed.
Thestripping factor, f, is defined as V1 KP"S
f =- - 1 -VZ PO
The stripping factor is a measure of the amount or strength of the stripping. More extreme conditions are needed to remove components of low vapor pressure in the oil than are needed for components of higher vapor pressure. In a typical deodorization process, the combination of: temperature (as it influences free fatty acid vapor pressure), pressure, steaming rate and oil rate are fixed so that the combination results in a stripping factor of 3, the desired level of stripping to remove fatty acids.
In contrast, the components that have now been found to be detrimental to frylife require much stronger stripping conditions. The stripping factor must be greater than about 0.0 for materials of much lower vapor pressure than that of fatty acids. Such dramatic stripping conditions are required because the components now thought to be deleterious to frylife, components from the group of tocopherols, tocotrienols, sterols WO 91/17fi67 PCT/US91/02685 -lOb-(preferably c:holesterol), trace pesticides, and other trace quinone-type structures, have low vapor pressures in oil of not more than about 0.1 mm Hg at 500°F (277°C) and not more than about 2 mm Hg at 600°F (343°C).
Further description is provided in the aforementioned Scavone et al patent.
In a preferred embodiment of the invention, during the deodorization, the molar ratio of steam to oil is between about 0.05 and about 9.7, and the combination of stripping parameters is selected so that the stripping factor "f" is greater than about 0.6, where f = KP"S/PO, and wherein "'.K" is a constant between about 1 and about 200, "P"" (the vapor pressure, of the component to be stripped) is not more than about 0.1 mm Hg at 500°F
(277°C) and not more than about 2 mm Hg at 600°F (343°C), "S" is the molar steam rate, "P" is the absolute pressure, and "O" is the molar oil rate.
In any cleodorization process, it is important to deaerate the oil before it undergoes deodorization.
Scavone et al. discuss a deaeration method at col. 8, line 15 to co:l. 8, line 37.
After the oil is deaerated, it is deodorized by stripping it with steam or another stripping medium at high temperatures and under vacuum. The temperature can range between 530°F (277°C) and about 650°F
(343°C), preferably between about 550 ° F ( 288 ° C) and about 630 ° F
(333°C), and lthe time of deodorization is between about seconds and about 35 minutes. More preferred times in order of increasing preference are: about 30 seconds to about 30 minutes, about 30 seconds to about 25 minutes, about 30 seconds to about 20 minutes, and about 30 seconds to about 15 minutes. At col. 8, line 38 to col.
9, line 51, the Scavone et al. patent discusses deodorization temperatures, times, pressures and stripping conditions. After the oil is deodorized in a - 1Oo continuous deodorizer, it is rapidly cooled to a temperature below about 480°F (249°C), preferably below about 370°F (188°C), in a short time to avoid an increase in side reaci~ions in the oil. In a semicontinuous deodorizer, the oil is cooled in one or two trays to a temperature of about 150'°F (66°C) before leaving the deodorizer.
Any type of deodorization equipment known to the art is suitable for use in the present deodorization process.
The wU yI/I766-m , PCT/L~S9I/026''r8:
~~ -11-Scavone et al. patent describes various types of deodoriza-tion equipment and processes at col. 9, line 59 to col. 11.
line 28. A continuous deodorizing unit is preferred for use with the invention.
U.S. Patent 2,602,806 to Jacob, Jr., et al., issued July 8, 1952, discloses a hydrogenation process for triglycerides inn which the hydrogenation is conducted at temperatures up to 545°F (285°C).
U.S. Patent 2,621,191 to Thurman, issued December 9, 1952, discloses a deodorization process for glyceride oils conducted at temperatures between 500°F (260°C) and 600°F
(316°C). Hydrogenation of the oils is done at a temperature of about 400°F or less.
U.S. Pateni: 3,732,266 to Dudrow, issued May 8, 1973, discloses a method for hydrogenating oils at a temperature between about 240°F (116°C) and about 450°F
(232°C).
U.S. Patent: 4,260,643 to Cochran, issued April 7, 1981, discloses triglycerides hydrogenated by a two-step process, where the first: hydrogenation step is carried out at SUUSTITUTE SHEET
z WO 91/17667 ~ °~ a ~ PCT/US91/02685 325°F-460°F (:163°C-238°C) and the second hydrogenation step is carriE:d out at 340°F-460°F (171°C-238°C).
U.S. Patent 3,555,058 to Going et al., issued January 12; 1971, discloses a special catalytic hydrogenation process. The temperature of reaction is said to vary between about 150°F (66°C) and about 500°F
(260°C) .
The above-mentioned Scavone et al. '554 patent discloses a mEahod for increasing the frylife of edible oils by deodorizing the oils at high temperatures between 530 ° F (277 ° C) and 650 ° F (343 ° C) and under other specified conditions. However, the Scavone et al. patent does not teach or suggest that a particular high temperature hydrogenation process used in combination with the deodorization process can have an additional effect in improving fryl.ife.
Other of the above-mentioned patents disclose hydrogenation;processes carried out at high temperatures.
However, the patents do not suggest that the method of hydrogenation can affect the frylife of edible fats.
Moreover, the patents do not suggest that the optimum frylife can be obtained in fats by processing the fats in a high temperature deadorization process combined with a high temperature hydrogenation process.
It is, therefore, an object of an aspect of the present invention to provide a method for improving the frylife of edible fats by use of a specific high temperature deodorization process in combination with a specific high temperature hydrogenation process.
It is another object of an aspect of the present invention to provide the hydrogenated fats that have improved fryl:ife, and that are characterized by low levels of tocopherols and high levels of trans-isomers.
These and other objects of the invention will become evident from the disclosure herein.
~r All part:, percentages and ratios used herein are by weight unless otherwise defined.
SUMMA~tY OF THE INVENTION
The invention is s process for making a hydrogenated frying fat with extended frylife comprising:
(a) hydrogenating an edible liquid oil having a starting iodine value between about 95 and about 150 by reacting the liquid oil with hydrogen in the presence of about 0.01% to about 0.4% hydrogenation catalyst by weight of the oil, wherein the hydrogenation reaction is conducted at a temperature between about 320°F
(160°C) and about 500°F (260°C) and a pressure between about 0 prig and about 100 psig until the iodine value of the oil after hydrogenation is between about 60 and about 80, and wherein during the hydrogenation reacaion the temperature of the oil is between about 460°F (238°C) and about 500°F (260°C) for a time of at least about 5 minutes to produce a frying fat containing at least about 40% traps-isomers; then (b) cooling the oil, filtering the oil to remove the catalyst, storing the oil at a temperature of about 110°F (43°C) to about 220°F (104°C:), and deaerating the oil; and then (c) deodorizing the oil by heating it at a temperature between about 530°F (277°C) and about 650°F (343°C), at a pressure between about 0.5 mm Hg and about 50 mm Hg, for a time between about 5 seconds and about 35 minutes, while stripping the oil with steam in the amount of about 0.1% to about 20% by weight of the oil.
>~;
~' -3a-The presE:nt invention also relates to a hydrogenated frying fat with extended frylife, wherein the hydrogenated fat has an iodine value between about 50 and about 90, and wherein the hydrogenated fat contains at least about 35% traps-isomers, preferably at least about 40o traps-isomers.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
1. Discoverv of Frylife Benefit from Hydrogenation It has now been discovered that a high temperature hydrogenation process can increase the frylife of an edible frying fat. Moreover, when the high temperature hydrogenation process described herein is combined with a particular high temperature deodorization process, it has been discovered that the frylife of the resulting frying fat is improved over that of a fat undergoing the high temperature deodorization process alone. Although not intending to be bound by theory, it is believed that a higher level of traps-isomers in the frying fat, which results from the high temperature hydrogenation process, is involved in the improved frylife benefit of the invention.
2. Hydro eq nation Hydrogenation is a means of saturating oils by the addition of hydrogen to the double bonds (unsaturated or ethylenic bonds) of an oil or fat by reaction with hydrogen in the presence of a metal catalyst. The hydrogenation reaction is accompanied by the simultaneous isomerization, both positional and geometrical, of the unsaturated bonds, producing both traps-isomers and cis-isomers.
Both Swern, Bailey's Industrial Oi) and Fat Products, 3rd ed., 1964, pp. 305-313 and 793-886, and Swern, Bailey's Industrial Oil and Fat Products, Uol. 2, 4th ed., 1982, pp.
5-69, discuss the hydrogenation process in general.
Beckmann, "Hydrogenation Practice", JAOCS, Uol. 60, No. 2, February 1983, pp. 282-290, discusses hydrogenation ', practice, equipment, process controls, and catalysts.
For hydrogenation t o take place, gaseous hydrogen, liquid oil, and the solid catalyst must be brought together at a suitable temperature. In the usual type of equipment, a suspension of catalyst and oil is agitated in a closed vessel in an atrnosphere of hydrogen. ';
SUBSTITUTE SNEET
~a ~' Hydrogenation, like other chemical reactions, is accelerated by an increase in temperature or pressure.
Also, as the temperature of reaction is increased, the formation of traps unsaturation increases almost linearly. ', The effect of pressure on isomerization is limited, and the rate of increase in the formation of traps isomers is less at higher pressures.
Commercial hydrogenation plants are essentially divided between "recirculation" systems, in which agitation and dispersion of hydrogen within the oil are achieved by continuously recycling hydrogen in large volumes through the reactor, and the newer "dead-end" systems in which the reactor is supplied only with as much hydrogen as is absorbed, and where dispersion of the hydrogen is assisted by mechanical agitatiord. Any type of commercially ' acceptable processing operation, including batch hydro-genation, continuous processing, recirculation systems, and "dead-end" systems, may be utilized with the hydrogenation process described herein. For a thorough discussion of hydrogenation equipment, see Swern, Bailey's Industrial Oil and Fat Products, Uol. 2, 4th ed., 1982, pp. 27_37.
The starting oil for the hydrogenation process of the present invention can be any edible liquid vegetable, animal or marine oil or blend of oils which has an iodine value of from about 95 to about 150. The preferred oil is a polyunsaturated vegetable oil having fatty acid chains containing at least 14 carbon atoms. Preferred vegetable oils include soybean, corn, cottonseed, sunflower seed, safflower, olive, peanut, coconut, palm, rapeseed, palm oil olefin, and canolc~ oil. More preferred oils include soybean, sunflower seed, palm oil, peanut oil, canola oil, corn oil, cottonseed oil, safflower oil, and mixtures thereof. The most preferred oils are soybean oil and canola oil, and mixtures thereof, A blend of i:wo or more oils may be used to obtain the desired initial -iodine values and the desired stability in ~UB~TITCITE SNEET
WO 91/17667 R~l ~~ ~a ~~ ~ø ~' , PCT/US91/02685 the oil after hydrogenation. The oils may be blended either prior to or following hydrogenation. Oils with high iodine values, such as liquid soybean oil, are useful in limited amounts when blended with oils that have been hydrogenated to control the consistency and solids content of the final product.
The oil is mixed with any conventional hydrogenation catalyst known to the hydrogenation industry. Finely divided metallic nickel catalysts are well known for use in the hydrogenation of vegetable oils. Such catalysts are usually deposited on carriers such as Kieselguhr, aluminum oxide, silicate and the like.
Nickel catalysts can lose their activity, or be deactivated, due to the poisoning action of certain chemical substances, such as sulfur, phosphorus, chlorine, zinc, and compounds of the same. For the hydrogenation process of the present invention, it is preferred to use a nickel catalyst, a partially deactivated nickel catalyst, or mixtures thereof. Sulfur-treated catalysts are particularly suitable for use since they promote the rapid development of traps isomers during hydrogenation. See, e.g. Okonek, Douglas V., "Nickel-Sulfur Catalysts For Edible Oil Hydrogenation,"
printed as Chapter 5 of Hydrogenation: Proceedings of An ADCS Colloquium, edited by Robert Hastert, 1987.
The hydrogenation catalyst used in the present invention is utilized at a concentration of from about 0.01%
to about 0.4%, preferably from about 0.02% to about 0.3%, catalyst by weight of the oil. The amount of catalyst used is dependent upon the rate of reaction to be attained and other variables such as temperature and pressure, and the starting oil.
The time of the total hydrogenation reaction is not critical. The reaction is generally carried out for from about 30 minutes to about 8 hours, and preferably from about 1 hour to about 4 hours. The pressure ranges from about 0 ~UBST'TC~~T~ SHEET
WO 91/17667 ~Cf/US91/02685 c ac«~~~
uW.~
psig to about 1.00 psig, and preferably from about 0 psig to about 80 psig.
The hydrogenation reaction is conducted at a temperature bei:ween about 320°F (160°C) and about 500°F
(260°C). In order to obtain the frylife improvement benefit of the present invention, during the hydrogenation reaction the temperature of the oil must be between about 440°F
(227°C) and about 500°F (260°C) for a time of at least about minutes, and preferablly at least about 8 minutes. It is preferred that the oil be held for these times at temperatures between about 460°F (238°C) and about 500°F
(260°C), and most preferably between about 470°F (244°C) and about 500°F (260°C).
The method used to control the temperature of the reaction varies. with the processing equipment. Since hydrogenation is an exothermic reaction, it may be necessary to cool the rea~~tion by some suitable means, such as a heat exchanger. However, if the vessel is not well insulated or is in a large unheated area, the system may lose heat quickly enough that the heat generated by the exothermic reaction will not be sufficient to maintain the reaction temperature. In this case, it is necessary to apply additional heat by some suitable means, such as heating coils, a heating jacket o r heat exchangers.
The reaction is terminated when the iodine value (IU) ', reaches a value of from about 50 to about 90, and preferably from about 60 to about 80. The endpoint of the reaction is chosen so that 'the product has the solids content profile desired in that particular product. The solids content can be expressed at different temperatures, in terms of a "Solids Contents. Index" (SCI) or "Solid Fat Index" (SFI) which are measured by what is essentially the test described in the Journal of the American Oil Chemists' Society, March 1954, Vol. XXXI, pp. 98-103. The test involves a dila-tometric measurement of ithe amount by which a fat expands when heated from a specific temperature to complete melting.
rUHSTITUT~ SHEET
WO 91/17667 , ~ ~x? ~~ ~,, ~, PCT/US91/02685 _g_ ~~ The hydrogenation reaction is generally ended by stopping the flow of hydrogen to the reactor. When the hydrogen flow is stopped, in order to exclude oxygen from the hot oil until it is cooled, generally either the reactor is pressurized with nitrogen or the reactor is kept under a vacuum.
After the hydrogenation reaction is ended, the oil is cooled down from the high temperatures of hydrogenation and stored at a temperature of about 110°F (43°F) to about 220°F
(104°C), preferably about 140°F (60°C) to about 180°F
(82°C), prior to deodorization. The oil is kept warm enough to avoid the formation of solids, but not too hot because higher temperatures could cause off-flavors and would waste energy.
It is also important after hydrogenation and before deodorization to remove the hydrogenation catalyst by filtering the oil. Further, the oil must be deaerated before it undergoes deodorization, preferably to a level of less than about 0.10% by volume of dissolved oxygen. The order of these processing steps is not critical, but usually the oil is first cooled, then filtered, and then stored, and immediately prior to deodorization the oil is deaerated.
As discussed hereinabove, the fat after hydrogenation has an iodine value (I.V.) of from about 50 to about 90, preferably from about 60 to about 80. The I.V. of a fat or oil indicates the number of grams of Iodine equivalent to halogen absorbed by a 100 gram sample. Because the halogen absorbance is due to the double bonds present in the fatty acid residues attached to the glycerides, the I.V. of a fat or oil can give a general indication of solids content at a given temperature. As the fatty acid residues become more saturated, the fat or oil increases in solids content. In general, the lower the I.V. of a given fat or oil, the greater will be the solids content at a given temperature.
The I.V. of a fat or oil can be determined by the ROCS
Official Method Col. 1-25, also known as the Wijs method.
suesT~T~~~ sH~E~
WO 91/17667 ~"~" PCT/US91/02685 _g_ Approximate iodine values may be determined by measurement of the refractive index of the oil, since for each given oil. a linear correlation between iodine value and refractive index can be determined. This method allows a relatively quick and easy determination of the proper endpoint of the hydrogenation. ', The contEant of trans-isomers of unsaturated fatty acids in the hydrogenated frying fat of the present invention is measured by infrared spectrometry. The method used is. identical to that described by Madison et al. in "Accu:rate Determination of Trans Isomers in Shortening and Oils by Infrared Spectrophotometry, " in J.
Amer. Oil Chem. Soc., Vol. 59,,No. 4 (April, 1982), pp.
178-81 with two exceptions: 1) the method utilized in the present invention employed a Nicolet, Model 20DXC, Infrared Speci=rometer (Nicolet Instrument Corporation, Madison, WI) which was equipped with a deuterated triglycine-sulfate detector and used in lieu of a Beckman IROl2 spectrophotometer; and 2) methyl stearate was replaced with methyl oleate as a calibration standard to be used with methyl elaidate in the construction of the calibration curve.
3. Deodoriza.tion The deodorization process used in the present invention is hike that described in U. S. patent 4, 789, 554 to Scavone, et al., issued December 6, 1988. The present deodorization process differs from the Scavone et al.
process in tha~~t longer deodorization times are permitted.
In this deodorization process, the oil is deodorized by heating it at a temperature between about 530°F (277°C) and about 650°F (343°C), at a pressure between about 0.5 mm Hg and about 60 mm Hg, for a time between about 5 seconds and about 35 minutes, while stripping the oil with a stripping medium in the amount of about 0.1% to WO 91/17667 ~« - PCT/US91/02685 about 20% by weight of the oil, preferably about 0.5% to about 20%, more preferably about 1% to about 50.
At col. :3, line 17 to col. 5, line 4 of the above-mentioned Scavone et al. patent, the inventors discuss deep-frying, t:he undesirable color darkening that occurs in frying fat: over time, and the theory behind why the deodorization process works to provide improved frylife.
At col. 5, line 5 to col. 7, line 19, Scavone et al.
discuss the various stripping factors and their interrelation:ahip in providing a deodorization process that results in optimum frylife of the frying fat.
Briefly, standard deodorization is accomplished when the volatile odoriferous components in a fat or oil are removed as well as when the free fatty acids are lowered from approximately 0.08% to 0.02%. The theoretical relations which govern the continuous deodorization process are a:~ follows:
Vl KP"S
VZ PO
where:
K - an Experimentally determined coefficient. In general, using similar packed column continuous deodorization equipment, values for K of about 4 for free fatty acid deodorization and values for K of about 65 for removal of materials deleterious to frylife have been observed. Regardless of the equipment, the relative values should remain constant (e. g.
65/4 ) . In equipment where the steam and oil contacting is not as efficient, such as in a thin: film Evaporator, K values for materials deleaerious to frylife as low as 1.0 have been observed. In contrast, in equipment where WO 91/17667 ~ ~ -° PCT/US91/02685 -10a-contacting efficiency is extremely efficient, K values as high as about 200 have been obsE:rved for materials deleterious to frylife.
P" vapor pressure of the pure compo nent to = be removed.
S molar steam rate.
-P absolute pressure.
-O molar oil rate.
-V1 initial molar concentration in the oil of the =
component to be removed.
VZ final molar concentration in the oil of the =
component to be removed.
Thestripping factor, f, is defined as V1 KP"S
f =- - 1 -VZ PO
The stripping factor is a measure of the amount or strength of the stripping. More extreme conditions are needed to remove components of low vapor pressure in the oil than are needed for components of higher vapor pressure. In a typical deodorization process, the combination of: temperature (as it influences free fatty acid vapor pressure), pressure, steaming rate and oil rate are fixed so that the combination results in a stripping factor of 3, the desired level of stripping to remove fatty acids.
In contrast, the components that have now been found to be detrimental to frylife require much stronger stripping conditions. The stripping factor must be greater than about 0.0 for materials of much lower vapor pressure than that of fatty acids. Such dramatic stripping conditions are required because the components now thought to be deleterious to frylife, components from the group of tocopherols, tocotrienols, sterols WO 91/17fi67 PCT/US91/02685 -lOb-(preferably c:holesterol), trace pesticides, and other trace quinone-type structures, have low vapor pressures in oil of not more than about 0.1 mm Hg at 500°F (277°C) and not more than about 2 mm Hg at 600°F (343°C).
Further description is provided in the aforementioned Scavone et al patent.
In a preferred embodiment of the invention, during the deodorization, the molar ratio of steam to oil is between about 0.05 and about 9.7, and the combination of stripping parameters is selected so that the stripping factor "f" is greater than about 0.6, where f = KP"S/PO, and wherein "'.K" is a constant between about 1 and about 200, "P"" (the vapor pressure, of the component to be stripped) is not more than about 0.1 mm Hg at 500°F
(277°C) and not more than about 2 mm Hg at 600°F (343°C), "S" is the molar steam rate, "P" is the absolute pressure, and "O" is the molar oil rate.
In any cleodorization process, it is important to deaerate the oil before it undergoes deodorization.
Scavone et al. discuss a deaeration method at col. 8, line 15 to co:l. 8, line 37.
After the oil is deaerated, it is deodorized by stripping it with steam or another stripping medium at high temperatures and under vacuum. The temperature can range between 530°F (277°C) and about 650°F
(343°C), preferably between about 550 ° F ( 288 ° C) and about 630 ° F
(333°C), and lthe time of deodorization is between about seconds and about 35 minutes. More preferred times in order of increasing preference are: about 30 seconds to about 30 minutes, about 30 seconds to about 25 minutes, about 30 seconds to about 20 minutes, and about 30 seconds to about 15 minutes. At col. 8, line 38 to col.
9, line 51, the Scavone et al. patent discusses deodorization temperatures, times, pressures and stripping conditions. After the oil is deodorized in a - 1Oo continuous deodorizer, it is rapidly cooled to a temperature below about 480°F (249°C), preferably below about 370°F (188°C), in a short time to avoid an increase in side reaci~ions in the oil. In a semicontinuous deodorizer, the oil is cooled in one or two trays to a temperature of about 150'°F (66°C) before leaving the deodorizer.
Any type of deodorization equipment known to the art is suitable for use in the present deodorization process.
The wU yI/I766-m , PCT/L~S9I/026''r8:
~~ -11-Scavone et al. patent describes various types of deodoriza-tion equipment and processes at col. 9, line 59 to col. 11.
line 28. A continuous deodorizing unit is preferred for use with the invention.
4. Crvstallizina and Packa4in4 The hydragenated and deodorized frying fat of the present invention can be processed after deodorization by various conventional means well known in the art for processing conventional frying fats, and it can be packaged in an,y type. of suitable container. In general, conventional methods of preparing the frying fat for packaging in cans or similar containers, or for packaging in a bulk cube, involve the steps of (1) heating the frying fat to a temperature (e.g. 39'- 93'C; I00'-200'F) above the melting point of its solid components to form a melt; (2} injecting edible gas such .as nitrogen (e. g. 10-25 volume percent) into the melt;
(3) passing the melted frying fat through a scraped wall heat exchanger (e.g. to 7'-26.7'C; 45'-80'F), to form a super-cooled mixture containing small crystals; (4) continuing crystallization into the plastic state while mildly agitating in one or more stages; (5) filling into suitable containers; and then, if desired, (6} tempering at a con..<;tant temperature (e.g. 27'-32'C; 80'-90'F) while at rest for several hours (e. g. 12-60 hours).
When it is desired to make sheets of frying fat instead of cans or cubes, the processing conditions are changed as follows. First, no nitrogen is injected into the frying fat. Second, crystallization is allowed to take place at rest in a resting tube, instead of being crystallized with agitation. After the resting tube, the fat is extruded onto parchment papery cut to size, and then packed.
Some methods and apparati for final processing are described in the following U.S. Patents: 2,430,596 to Ziels et al. (assigned to Lever 8ros. Co.), issued November 11, 1947; 2,614,937 to i;Gs:.r~'~
8aur et al. (assigned to The Procter & Gamble Co.), issued October 21, 1952; 2,801,177 to Lutton (assigned to The Procter & Gamble Co.), issued July 30, 1957; 3,102,814 to Thompson (assigned to Lever Bros. Co.), issued September 3, 1963; 3,253,927 to Going et al. (assigned to The Procter &
Gamble Co.), is;sued May 31, 1966; and 3,597,230 to Colby et al. (assigned t.o The Practer & Gamble Co.), issued August 3, 1971.
80,000 pounds of refined and bleached soybean oil having an iodine value of about 130-133 is placed into a batch hardening unit and heated under vacuum to about 330°F
(166°C). 50 pounds of a standard nickel catalyst and 50 pounds of a sulfur-poisoned nickel catalyst are added.
Hydrogen gas is then bubbled through the batch hardening unit at a pressure of about 50 pounds per square inch-gauge (hereinafter "psig"). The hydrogenation reaction takes place, and the temperature rises to 470°F (243°C). When the iodine value of the product reaches about 71-72, the reaction is ended by stopping the flow of hydrogen, and the product is cooled and then filtered to remove the hydrogenation catalyst. The hydrogenated oil is held at a temperature of 140°-180°F (60°-82°C) prior to deodorization.
The hydrogenated oil is deaerated by placing it into a standard semicontinuous tray deodorizer under a vacuum of less than about 5 mm Hg. The oil is heated to a temperature of about 550°F (288°C). Next the oil is stripped with about 2-3% steam by weight of the oil, for a time of about 20 minutes. Then the deodorization process is stopped and the oil is cooled i:o about 150°F (66°C) prior to leaving the deodorizer.
The hydrogenated and deodorized oil is lastly pumped through and cooled in a scraped wall heat exchanger and then formed into 5-lb. sheets.
SUBSTITCI~TE SHEET
WO 9I/17667 PC1/C'S91/0268:
The product has the following characteristics:
Iodine value: about 71-72 % traps-isomers: about 50%
saturates: about 21%
Solid fat index: 56% at 50'F (10'C), 43% at 70'F
(21'C), 36% at 80'F (27'C), 17% at 92'F (33'C), and 1.5% at 104'F (40'C) In a more preferred process, the oil of Example 1 hereinabove would be hydrogenated as described hereinabove, and then deodorized in a continuous deodorization apparatus as described in Example 1 of U.S. Patent 4,789,554 to Scavone et al., issued December 6, 1988, XAMP E
SAMPLE-A .
A refined and bleached soybean oil is hydrogenated and deodori zE~d as descri bed i n Exampl a 1, wi th the fol 1 owi ng changes. 57,000 pounds of oil is placed into a batch hardening unit. The oil is heated under vacuum to 325'F
(163'C) instead of 330'F (166'C) before adding the catalyst.
During the hydrogenation reaction, the temperature rises to 435°F (224'C) instead of 470'F (243'C). The reaction is ended when the product reaches an iodine value of 71-72.
The oil is later pumped through and cooled in a scraped wall heat exchanger and formed into 5-lb. sheets.
The product has the following characteristics:
Iodine value: 71-72 traps-'isomers: 48%
saturates: 22%
Solid fat index: 57% at 50'F (10'C), 44% at 70'F
(21'C), 38% at 80'F (27'C), 20% at 92'F (33'C), and 2% at 104'F (40'C).
,.._., WO 91/17667 ~;; PC.'T/US91/02685 SAMPLE B
A refined and bleached soybean oil is hydrogenated as described in Example 1, with the following changes. A
15,000-lb. batch is made instead of an 80,000-lb. batch. 4 lbs. of a standard nickel catalyst is used, and no sulfur-poisoned catalyst is used. The oil is heated to about 300°F
(149°C) before it is hydrogenated. During the hydrogenation reaction, the temperature increases to 500°F (260°C). The hydrogenation reaction proceeds until the product reaches an iodine value of about 61. After hydrogenation, the "Sample B" product is blended with liquid soybean oil (iodine value of 107) in a ratio of 78% Sample B to 22% liquid oil. The blend is then deaerated, and then deodorized essentially as described in Example 1 of the Scavone et al. '554 patent, but at a temperature of 600°-605°F (316°-319°C).
The blend is later pumped through and cooled in a scraped wall heat exchanger and either formed into 5-lb. sheets or packed into a bulk 50-lb. cu be.
The blend has the following characteristics:
IodinE~ value: about 71 traps-isomers: 31%
saturates: 29%
Solid fat index: 46% at 50°F (10°C), 39% at 70°F
(21°C;i, 37% at 80°F (27°C), 28% at 92°F
(33°C), ', and lEi% at 104°F (40°C) .
SAMPLE C
A refined and bleached soybean oil is hydrogenated as described in Example 1, except that a 57,000-lb. batch is made instead of an 80,000-lb. batch. Also, 30 lbs. of a standard nickel catalyst is added when the oil is heated to 270°F (132°C). Then the oil is further heated to 320°F
(160°C), and then hydrogenated using a hydrogen pressure of 30 psig. During the hydrogenation reaction, the temperature increases to 450°F (232°C). The reaction is ended when the SUBSTITt~E SNEET
9j Ll f i e~,. "fr ; ~, oil reaches an iodine value of about 60. After hydrogenation, the "Sample C" product is blended in a ratio of 73% Sampl a C to 27% 1 i quid soybean of 1 ( IU 107) . The blend is then deaerated and deodorized as described in Example 1 hereinabove. The blend is later pumped through and cooled in a scraped wall heat exchanger and either formed into 5-lb. sheet.s or packed into a bulk 50-lb. cube.
The blend has the following characteristics:
Iodine value: about 73 trams-isomers: 36%
saturates: 27%
Solid fat index: 47% at 50°F (10°C), 40% at 70°F
(21°C), 37% at; 80°F (27°C), 25% at 92°F
(33°C), and 11% at 104°F (40°C).
Frylife Measurements 100% Sample A:
Frylife: 9.24 days*
Tocopherol: 0.~'~ mg./g, traps-isomers: 48%
Hydrogenation temperature (maximum): 435°F (224°C) ~1'BSTITBTE SHE T
WO 91/17667 ~ r~, ~ , ~ ~ f , 1- PCT/US91/02685 r.~ ~~.~
78% Sample B/22% I-107 liguid soybean oil Frylife: 9.13 days Tocopherol: 0.17 mg./g.
trans-isomers: 31%
Hydrogenation temperature (maximum): 500°F (260°C) 7~% Sample C/27% I-107 liguid soybean oil Frylife: 8.34 days Tocopherol: 0.25 mg./g.
trans-isomers: 36%
Hydrogenation temperature (maximum): 450°F (232°C) * The frylife measurement for Sample A is actually 10.99 days . However, Sampl a A was measured i n a di fferent frylife test than Samples B and C, and data shows that the difference in these two tests causes the same oil product to differ from one test to the other by a factor of 1.19. Hence: 10.99 days . 1.19 = 9.24 days.
Discussion of Frylife Results The 73% Sample C/27% I-107 soybean oil mixture has a frylife of 8.34 days, which is not as good as the frylives of the other products. This demonstrates that adding the 27% liquid I-107 soybean oil has a diluting effect on the frylife benefit obtained, even though the liquid oil has undergone a high temperature deodorization process (550°F, 288°C). Accordingly, it is seen that hydrogenating according to the present invention in combination with deodorizing according to the high temperature deodorization conditions of the present invention, produces a better frylife than using high temperature deodorization alone.
The best frylife would have occurred if the hydrogenated product had not been diluted with the liquid oil, and if the deodorization step had been conducted at about 600°F (316°C) instead of 550°F (288°C).
Sample A is hydrogenated at 435°F (223°C), whereas Sample B is hydrogenated at 450°F (232°C). A higher ~IIBSTITtITE SHEET
WO 91/17667 r', ~r~., ~~,, 1PCT/US91/02685 hydrogenation temperature as for Sample B improves the frylife. On the other hand, Sample B is diluted 78/22 with the liquid oil, whereas Sample A is not diluted, which would provide Sample A with a frylife advantage. The frylife measurements show that Sample A has a frylife of 9.24 days, while 78% Samp'~e B/22% liquid oil has a similar frylife of 9.13 days. In view of these results, it is believed that the percentage of traps-isomers is also hawing an effect on the frylife. Sample A has a higher traps-isomer content of 48% traps verst;;s 31% traps for the Sample B mixture. This shows that higher traps-isomer content may cause an increase in the frylife of a frying oil.
Also, Samples A and C are deodorized at 550°F (288°C), while Sample B is deodo~~ized at 600°F (316°C). One would expect the product deodorized at 600°F (316°C) to have a longer frylife. (SamplE~ B having a longer frylife than Sample C is expected.) Also, Sample A has a higher tocopherol content, which would have been expected to reduce the frylife. That Sample A has about the same frylife as Sample B (9.24 vs. 9.13 days) is attributed to the higher percentage of traps-isomers, developed by the high hydrogenation temperature, and to the fact that Sample A was not diluted with the liquid Iv-107 oil.
SU~STIT~TE SHEET
(3) passing the melted frying fat through a scraped wall heat exchanger (e.g. to 7'-26.7'C; 45'-80'F), to form a super-cooled mixture containing small crystals; (4) continuing crystallization into the plastic state while mildly agitating in one or more stages; (5) filling into suitable containers; and then, if desired, (6} tempering at a con..<;tant temperature (e.g. 27'-32'C; 80'-90'F) while at rest for several hours (e. g. 12-60 hours).
When it is desired to make sheets of frying fat instead of cans or cubes, the processing conditions are changed as follows. First, no nitrogen is injected into the frying fat. Second, crystallization is allowed to take place at rest in a resting tube, instead of being crystallized with agitation. After the resting tube, the fat is extruded onto parchment papery cut to size, and then packed.
Some methods and apparati for final processing are described in the following U.S. Patents: 2,430,596 to Ziels et al. (assigned to Lever 8ros. Co.), issued November 11, 1947; 2,614,937 to i;Gs:.r~'~
8aur et al. (assigned to The Procter & Gamble Co.), issued October 21, 1952; 2,801,177 to Lutton (assigned to The Procter & Gamble Co.), issued July 30, 1957; 3,102,814 to Thompson (assigned to Lever Bros. Co.), issued September 3, 1963; 3,253,927 to Going et al. (assigned to The Procter &
Gamble Co.), is;sued May 31, 1966; and 3,597,230 to Colby et al. (assigned t.o The Practer & Gamble Co.), issued August 3, 1971.
80,000 pounds of refined and bleached soybean oil having an iodine value of about 130-133 is placed into a batch hardening unit and heated under vacuum to about 330°F
(166°C). 50 pounds of a standard nickel catalyst and 50 pounds of a sulfur-poisoned nickel catalyst are added.
Hydrogen gas is then bubbled through the batch hardening unit at a pressure of about 50 pounds per square inch-gauge (hereinafter "psig"). The hydrogenation reaction takes place, and the temperature rises to 470°F (243°C). When the iodine value of the product reaches about 71-72, the reaction is ended by stopping the flow of hydrogen, and the product is cooled and then filtered to remove the hydrogenation catalyst. The hydrogenated oil is held at a temperature of 140°-180°F (60°-82°C) prior to deodorization.
The hydrogenated oil is deaerated by placing it into a standard semicontinuous tray deodorizer under a vacuum of less than about 5 mm Hg. The oil is heated to a temperature of about 550°F (288°C). Next the oil is stripped with about 2-3% steam by weight of the oil, for a time of about 20 minutes. Then the deodorization process is stopped and the oil is cooled i:o about 150°F (66°C) prior to leaving the deodorizer.
The hydrogenated and deodorized oil is lastly pumped through and cooled in a scraped wall heat exchanger and then formed into 5-lb. sheets.
SUBSTITCI~TE SHEET
WO 9I/17667 PC1/C'S91/0268:
The product has the following characteristics:
Iodine value: about 71-72 % traps-isomers: about 50%
saturates: about 21%
Solid fat index: 56% at 50'F (10'C), 43% at 70'F
(21'C), 36% at 80'F (27'C), 17% at 92'F (33'C), and 1.5% at 104'F (40'C) In a more preferred process, the oil of Example 1 hereinabove would be hydrogenated as described hereinabove, and then deodorized in a continuous deodorization apparatus as described in Example 1 of U.S. Patent 4,789,554 to Scavone et al., issued December 6, 1988, XAMP E
SAMPLE-A .
A refined and bleached soybean oil is hydrogenated and deodori zE~d as descri bed i n Exampl a 1, wi th the fol 1 owi ng changes. 57,000 pounds of oil is placed into a batch hardening unit. The oil is heated under vacuum to 325'F
(163'C) instead of 330'F (166'C) before adding the catalyst.
During the hydrogenation reaction, the temperature rises to 435°F (224'C) instead of 470'F (243'C). The reaction is ended when the product reaches an iodine value of 71-72.
The oil is later pumped through and cooled in a scraped wall heat exchanger and formed into 5-lb. sheets.
The product has the following characteristics:
Iodine value: 71-72 traps-'isomers: 48%
saturates: 22%
Solid fat index: 57% at 50'F (10'C), 44% at 70'F
(21'C), 38% at 80'F (27'C), 20% at 92'F (33'C), and 2% at 104'F (40'C).
,.._., WO 91/17667 ~;; PC.'T/US91/02685 SAMPLE B
A refined and bleached soybean oil is hydrogenated as described in Example 1, with the following changes. A
15,000-lb. batch is made instead of an 80,000-lb. batch. 4 lbs. of a standard nickel catalyst is used, and no sulfur-poisoned catalyst is used. The oil is heated to about 300°F
(149°C) before it is hydrogenated. During the hydrogenation reaction, the temperature increases to 500°F (260°C). The hydrogenation reaction proceeds until the product reaches an iodine value of about 61. After hydrogenation, the "Sample B" product is blended with liquid soybean oil (iodine value of 107) in a ratio of 78% Sample B to 22% liquid oil. The blend is then deaerated, and then deodorized essentially as described in Example 1 of the Scavone et al. '554 patent, but at a temperature of 600°-605°F (316°-319°C).
The blend is later pumped through and cooled in a scraped wall heat exchanger and either formed into 5-lb. sheets or packed into a bulk 50-lb. cu be.
The blend has the following characteristics:
IodinE~ value: about 71 traps-isomers: 31%
saturates: 29%
Solid fat index: 46% at 50°F (10°C), 39% at 70°F
(21°C;i, 37% at 80°F (27°C), 28% at 92°F
(33°C), ', and lEi% at 104°F (40°C) .
SAMPLE C
A refined and bleached soybean oil is hydrogenated as described in Example 1, except that a 57,000-lb. batch is made instead of an 80,000-lb. batch. Also, 30 lbs. of a standard nickel catalyst is added when the oil is heated to 270°F (132°C). Then the oil is further heated to 320°F
(160°C), and then hydrogenated using a hydrogen pressure of 30 psig. During the hydrogenation reaction, the temperature increases to 450°F (232°C). The reaction is ended when the SUBSTITt~E SNEET
9j Ll f i e~,. "fr ; ~, oil reaches an iodine value of about 60. After hydrogenation, the "Sample C" product is blended in a ratio of 73% Sampl a C to 27% 1 i quid soybean of 1 ( IU 107) . The blend is then deaerated and deodorized as described in Example 1 hereinabove. The blend is later pumped through and cooled in a scraped wall heat exchanger and either formed into 5-lb. sheet.s or packed into a bulk 50-lb. cube.
The blend has the following characteristics:
Iodine value: about 73 trams-isomers: 36%
saturates: 27%
Solid fat index: 47% at 50°F (10°C), 40% at 70°F
(21°C), 37% at; 80°F (27°C), 25% at 92°F
(33°C), and 11% at 104°F (40°C).
Frylife Measurements 100% Sample A:
Frylife: 9.24 days*
Tocopherol: 0.~'~ mg./g, traps-isomers: 48%
Hydrogenation temperature (maximum): 435°F (224°C) ~1'BSTITBTE SHE T
WO 91/17667 ~ r~, ~ , ~ ~ f , 1- PCT/US91/02685 r.~ ~~.~
78% Sample B/22% I-107 liguid soybean oil Frylife: 9.13 days Tocopherol: 0.17 mg./g.
trans-isomers: 31%
Hydrogenation temperature (maximum): 500°F (260°C) 7~% Sample C/27% I-107 liguid soybean oil Frylife: 8.34 days Tocopherol: 0.25 mg./g.
trans-isomers: 36%
Hydrogenation temperature (maximum): 450°F (232°C) * The frylife measurement for Sample A is actually 10.99 days . However, Sampl a A was measured i n a di fferent frylife test than Samples B and C, and data shows that the difference in these two tests causes the same oil product to differ from one test to the other by a factor of 1.19. Hence: 10.99 days . 1.19 = 9.24 days.
Discussion of Frylife Results The 73% Sample C/27% I-107 soybean oil mixture has a frylife of 8.34 days, which is not as good as the frylives of the other products. This demonstrates that adding the 27% liquid I-107 soybean oil has a diluting effect on the frylife benefit obtained, even though the liquid oil has undergone a high temperature deodorization process (550°F, 288°C). Accordingly, it is seen that hydrogenating according to the present invention in combination with deodorizing according to the high temperature deodorization conditions of the present invention, produces a better frylife than using high temperature deodorization alone.
The best frylife would have occurred if the hydrogenated product had not been diluted with the liquid oil, and if the deodorization step had been conducted at about 600°F (316°C) instead of 550°F (288°C).
Sample A is hydrogenated at 435°F (223°C), whereas Sample B is hydrogenated at 450°F (232°C). A higher ~IIBSTITtITE SHEET
WO 91/17667 r', ~r~., ~~,, 1PCT/US91/02685 hydrogenation temperature as for Sample B improves the frylife. On the other hand, Sample B is diluted 78/22 with the liquid oil, whereas Sample A is not diluted, which would provide Sample A with a frylife advantage. The frylife measurements show that Sample A has a frylife of 9.24 days, while 78% Samp'~e B/22% liquid oil has a similar frylife of 9.13 days. In view of these results, it is believed that the percentage of traps-isomers is also hawing an effect on the frylife. Sample A has a higher traps-isomer content of 48% traps verst;;s 31% traps for the Sample B mixture. This shows that higher traps-isomer content may cause an increase in the frylife of a frying oil.
Also, Samples A and C are deodorized at 550°F (288°C), while Sample B is deodo~~ized at 600°F (316°C). One would expect the product deodorized at 600°F (316°C) to have a longer frylife. (SamplE~ B having a longer frylife than Sample C is expected.) Also, Sample A has a higher tocopherol content, which would have been expected to reduce the frylife. That Sample A has about the same frylife as Sample B (9.24 vs. 9.13 days) is attributed to the higher percentage of traps-isomers, developed by the high hydrogenation temperature, and to the fact that Sample A was not diluted with the liquid Iv-107 oil.
SU~STIT~TE SHEET
Claims (11)
1. A process for making a hydrogenated frying fat with extended frylife comprising:
(a) hydrogenating an edible liquid oil having a starting iodine value between about 95 and about 150 by reacting the liquid oil with hydrogen in the presence of about 0.01% to about 0.4% hydrogenation catalyst by weight of the oil, wherein the hydrogenation reaction is conducted at a temperature between about 320°F
(160°C) and about 500°F (260°C) and a pressure between about 0 psig and about 100 psig until the iodine value, of the oil after hydrogenation is between about 60 and about 80, and wherein during the hydrogenation reaction the temperature of the oil is between about 460°F (238°C) and about 500°F (260°C) for a time of at least about 5 minutes to produce a frying fat containing at least about 40% trans-isomers; then (b) cooling the oil, filtering the oil to remove the catalyst, storing the oil at a temperature of about 110°F (43°C) to about 220°F (104°C), and deaerating the oil; and then (c) deodorizing the oil by heating it at a temperature between about 530°F (277°C) and about 650°F (343°C), at a pressure between about 0.5 mm Hg and about 50 mm Hg, for a time between about 5 seconds and about 35 minutes, while stripping the oil with steam in the amount of about 0.1% to about 20% by weight of the oil.
(a) hydrogenating an edible liquid oil having a starting iodine value between about 95 and about 150 by reacting the liquid oil with hydrogen in the presence of about 0.01% to about 0.4% hydrogenation catalyst by weight of the oil, wherein the hydrogenation reaction is conducted at a temperature between about 320°F
(160°C) and about 500°F (260°C) and a pressure between about 0 psig and about 100 psig until the iodine value, of the oil after hydrogenation is between about 60 and about 80, and wherein during the hydrogenation reaction the temperature of the oil is between about 460°F (238°C) and about 500°F (260°C) for a time of at least about 5 minutes to produce a frying fat containing at least about 40% trans-isomers; then (b) cooling the oil, filtering the oil to remove the catalyst, storing the oil at a temperature of about 110°F (43°C) to about 220°F (104°C), and deaerating the oil; and then (c) deodorizing the oil by heating it at a temperature between about 530°F (277°C) and about 650°F (343°C), at a pressure between about 0.5 mm Hg and about 50 mm Hg, for a time between about 5 seconds and about 35 minutes, while stripping the oil with steam in the amount of about 0.1% to about 20% by weight of the oil.
2. A process according to Claim 1 wherein during the hydrogenation reaction the temperature of the oil is between about460°F (238°C) and about 500°F (260°C) for at least about 8 minutes.
3. A process according to Claim 1 wherein the hydrogenation catalyst is selected from the group consisting of nickel catalysts, partially deactivated nickel catalysts, and mixtures thereof.
4. A process according to Claim 1 wherein the liquid oil is selected from the group consisting of soybean oil, corn oil, sunflower seed oil, palm oil, peanut oil, canola oil, cottonseed oil, safflower oil, and mixtures thereof.
5. A process according to Claim 4 wherein the liquid oil is selected from the group consisting of soybean oil and canola oil, and mixtures thereof.
6. A process according to Claim 1 wherein the oil is deodorized at a temperature between about 550°F
(288°C) and about 630°F (333°C).
(288°C) and about 630°F (333°C).
7. A process according to Claim 1 wherein the oil is deodorized for a time between about 30 seconds and about 20 minutes.
8. A process according to Claim 7 wherein the oil is deodorized for a time between about 30 seconds and about 15 minutes.
9. A process according to Claim 1 wherein from about 1% to about 5% steam is used during the deodorization.
10. A process according to Claim 1 wherein during the deodorization the molar ratio of steam to oil is between about, 0.05 and about 9.7, and wherein the combination of stripping parameters is selected so that the stripping factor "f" is greater than about 0.6, where f = KP v S/PO, and wherein "K" is a constant between about 1 and about 200, "P v" (the vapor pressure of the component to be stripped) is not more than about 0.1 mm Hg at 500°F (277°C) and not more than about 2 mm Hg at 600°F (343°C), "S" is the molar steam rate, "P" is the absolute pressure, and "O" is the molar oil rate.
11. A process according to Claim 1 wherein the oil is deaerated before deodorization to a level of less than about 0.10% by volume of dissolved oxygen.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52308890A | 1990-05-14 | 1990-05-14 | |
| US523,088 | 1990-05-14 | ||
| PCT/US1991/002685 WO1991017667A1 (en) | 1990-05-14 | 1991-04-22 | Hydrogenated frying fat with extended frylife |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2082422A1 CA2082422A1 (en) | 1991-11-15 |
| CA2082422C true CA2082422C (en) | 2002-04-16 |
Family
ID=24083613
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002082422A Expired - Fee Related CA2082422C (en) | 1990-05-14 | 1991-04-22 | Hydrogenated frying fat with extended frylife |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0528850A4 (en) |
| CA (1) | CA2082422C (en) |
| WO (1) | WO1991017667A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7585990B2 (en) | 2003-07-31 | 2009-09-08 | Cargill, Incorporated | Low trans-fatty acid fat compositions; low-temperature hydrogenation, e.g., of edible oils |
| EP1656439A4 (en) | 2003-07-31 | 2010-11-10 | Cargill Inc | Low trans-fatty acid fat compositions; low-temperature hydrogenation, e.g., of edible oils |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| LU78622A1 (en) * | 1977-12-02 | 1979-06-13 | Labofina Sa | CATALYSTS AND HYDROGENATION PROCESS |
| US4260643A (en) * | 1979-03-28 | 1981-04-07 | Bunge Edible Oil Corporation | Triglyceride compositions |
| NL8302198A (en) * | 1983-06-21 | 1985-01-16 | Unilever Nv | MARGARINE FAT MIX AND METHOD FOR PREPARING SUCH A FAT MIX. |
| US4789554A (en) * | 1985-12-05 | 1988-12-06 | The Procter & Gamble Company | High temperature vacuum steam distillation process to purify and increase the frylife of edible oils |
-
1991
- 1991-04-22 CA CA002082422A patent/CA2082422C/en not_active Expired - Fee Related
- 1991-04-22 EP EP19910908630 patent/EP0528850A4/en not_active Withdrawn
- 1991-04-22 WO PCT/US1991/002685 patent/WO1991017667A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0528850A1 (en) | 1993-03-03 |
| EP0528850A4 (en) | 1993-04-14 |
| CA2082422A1 (en) | 1991-11-15 |
| WO1991017667A1 (en) | 1991-11-28 |
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