CA2120442A1 - Microcrystalline phosphates as oxidation inhibitors for lipids, especially lipidic foods - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Solid phosphate particles, less than 38 microns in size on their largest dimension, are shown to be effective oxidation retardants for fats and oils, and especially fatty and oily foods and ingredients of foods. Their suspensions in a lipid in which they are insoluble are especially useful. They greatly enhance the effectiveness of natural antioxidants, and are therefore particularly useful in making natural antioxidant systems at least as effective as the synthetic antioxidants now commonly employed.

Description

2~2~L42 MICROCRYSTALLINE PHOSPHATES AS OXIDATION INHIBITORS
FOR LIPIDS, ESPECIALLY LIPIDIC FOODS

FIELD OF THE INVENTION
Microcrystalline phosphates as oxidation inhibitors for fats, oils, and especially fatty and oily foods and ingredients of foods such as flavorings or colorings, in which they are insoluble. Suspensions or dispersions thereof in lipid media, especially of nontoxic edible phosphates in edible oleagenous media, in which they are also insoluble.

BACKGROUND OF THE INVENTION AND PRIOR ART
Phosphates have been used for many years for the purpose of water retention in meats, emulsification, and the sequestering of metals in aqueous systems. Three kinds of phosphates are commonly used in foods, these being orthophosphates, pyrophosphates, and tripolyphosphates.
Long-chain polyphosphates and metaphosphates are less commonly used, but are nevertheless a sub;ect of this invention. A description of these classes of phosphates, and their current uses in foods, is well described in Food Technology 44, 80-92 (April 1990).
All of these phosphates are considered water soluble and become a part of the aqueous phase under the conditions of use. A typical description is provided in Stauffer Chemical's data sheets for CurAfosTM phosphate blends, the Stauffer trademarked product for a granular blend of sodium phosphates, copies of five ~5) of those data sheets being provided herewith.

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2120~42 -While not anti-oxidants ~ se, since they have no capability of neutralizing free radicals or de-energizing singlet oxygen, in aqueous phases phosphates do sequester iron and other transition metals, and thereby may inhibit the catalytic oxidation induced by these metal ions in aqueous systems. They are not used in a lipid media or in lipids ~ se, in which they are insoluble.
Since all of the phosphates are polyvalent, they can be used to buffer a food at a pH between about 4.6 and 9, and very often their combinations are designed to do just that, as well as to take advantage of the different emulsi-fying and water-binding properties of the different forms.
Phosphates are available in granular form, these being the easiest to work with in the solid state. Since they are dissolved in water in the food, the particle size is desirably large, like granulated sugar and salt, for handling purposes.

OBJECTS OF THE INVENTION
It is an object of the present invention to provide a method for the inhibition of oxidation in fats, oils, and especially in fatty and oily foods and ingredients of foods, by the employment of microcrystalline phosphate particles of less than 38 microns on their largest dimen-sion. Another object is the provision of such particles and a method of making the same. A further object is the provision of suspensions or dispersions of such particles in lipid media in which they are insoluble. Another object of the invention is to provide fats and oils, especially fatty and oily foods and ingredients of foods, stabilized against o~idation by the employment of such phosphate particles of less than 38 microns on their largest dimen-sion, and a method for such stabilization. Additional .. :, :- , . :

' ,'' ' ~ '' ~ . ' 212~4~2 objects of the invention include the provision of suspen-sions or dispersions of such solid microcrystalline phos-phate particles in lipid media, in which they are insolu-ble, together with other natural and/or synthetic antioxi-dants. Further objects of the invention will become apparent hereinafter, and still others will be obvious to one skilled in the art to which this invention pertains.

THE PRESENT INVENTION
It has been found that, when the above-described types of phosphates are ground to a particle size of less than 38 microns on their largest dimension, preferably suspended in an oil or other lipid medium in which they are insolu-ble, they behave as antioxidants in oils and fats and other lipid media, including especially oily or fatty foods and ingredients of foods, in which they are also insoluble.
Critical to this invention is the particle size, since the commercial solid phosphates themselves are ineffective in lipid media. This surprising antioxidant effect has no ready explanation, for phosphates are unable to reduce lipid radicals or hydroperoxides as do common phenolic antioxidants.
When combined with natural antioxidants, such as those derived from tea or Labiatae or tocopherols, strong syner-gism is found to be produced. This also occurs with the less than 38 micron-sized ascorbic acid particles, in media in which they are insoluble. The preparation and antioxi-dant properties of microcrystalline ascorbic acid particles of less than 38 microns on their largest dimension are disclosed in my copending application Serial No.
07/717,926, filed June 20, 1991 and now allowed, and in my published PCT application W0 93/00015 published January 7, 1993. In retrospect, this synergism might be conjecturally ~ .
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212~2 explained by the phosphates increasing the rate at which the true antioxidants neutralize the free radicals, perhaps by some form of catalytic surface activity, thereby slowing the exponential chain propagation process.
The following Examples show the preparation of various types of solid phosphate particles less than 38 microns in size on their largest dimension, their action alone and when suspended in a lipid medium in which they are insolu-ble, and synergistic combinations with various natural antioxidants. Synergism also occurs when combined with synthetic antioxidants, since their ability to terminate free radicals in lipids mimics that of the natural antioxi-dants. The microcrystalline phosphates also ha~Je applica-tion in essential oils, gum bases, and rubber, which are subject to similar oxidative processes. The Examples also show the enhancement of stabilization and synergistic effects when non-ionic emulsifiers are present.

SUMMARY OF THE INVENTION
My invention then comprises, inter alia, the follow-ing, individually or in combination:
Solid phosphate particles of less than 38 microns in size on their largest dimension, wherein the phosphate is selected from orthophosphate, metaphosphate, polyphosphate, and pyrophosphate, and mixtures thereof, such particles which are less than 10 microns on their largest dimension, such solid phosphate particles suspended in a lipid medium in which they are insoluble, such suspensions wherein the medium is an edible medium, any of such products wherein the phosphate is a non-toxic edible phosphate, any of such " ~
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212~2 products in combination with a tocopherol, a Labiatae extract, or solid ascorbic acid or tea catechin particles of less than 38 micron size on their largest dimension, or a synthetic antioxidant, any of such products comprising a non-ionic surface-active agent, and such products wherein the non-ionic surface-active agent is selected from the group consisting of lecithin, mono- and di-glycerides, acylated mono- and di-glycerides, tartaric acid esters of mono- and di-glycerides, and caproic-capryl-ic acid polyglycerides.
Further, a fat, oil, fatty food or food ingredient substrate stabilized against oxidation with any such composition, and such a stabilized substrate wherein the substrate includes a carotenoid.
Also, a method of stabilizing a fat, oil, food, or food ingredient substrate which includes the step of combining the substrate with any such composition, and such a method wherein the substrate includes a carotenoid.
Moreover, a method of making phosphate particles of less than 38 microns in size on their largest dimension, comprising the step of milling commercial phosphate parti-cles in a lipid medium until the size of the individual particles thereof is reduced to less than 38 microns on their largest dimension, and such a method wherein the size of the particles is reduced to less than about 10 microns on their largest dimension.

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METHODOLOGY AND TERMS EMPLOYED
An art accepted method of measuring the antioxidant activity of a substance employs the RancimatTM to ascertain the induction time of a given lipid using a given dose of the antioxidant, generally with 18 liters of air per hour blowing through the lipid held at a constant temperature selected for the specific lipid. The Rancimat measures conductivity of an aqueous solution which captures the volatile oxidation products formed as the lipid, i.e., fat, oxidizes. The results are reported as the ratio of the induction time of the test sample to the control, the higher the ratio, the more stable the fat. The results correlate very well with other standard measures of rancid-ity development, such as the active oxygen method, organo-leptic evaluations, and so forth.
Synergism also occurs with the phosphate preparations of this invention. It is defined as the increase in induc-tion time over the control of a sample containing two antioxidants divided by the sum of the increase in induc-tion time over the control when testing the two antioxi-dants separately. Strong synergism is an additional unex-pected property of the inventive phosphate preparations of the invention.

Glossary of Terms This glossary describes abbreviations and other technical terms and apparatus which may sometimes be referred to in one way or another in this specification.

Abbreviation Technical Term BHA butylated hydroxy anisole BHT butylated hydroxy toluene GMO glycerol mono-oleate -. . .
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212(~2 so soy oil SM0 sorbitan mono-oleate ST0 sorbitan trioleate SMS sorbitan monostearate 8-1-0 octaglycerol mono-oleate 10-l-CC decaglycerol mono-capric-caprylate RM rosemary extract, especially HerbaloxTM
product of Kalsec, Inc., Kalamazoo, Michigan Peroxide Value: This is also a standard test for evaluation of the degree to which an oil has been oxidized.
Labiatae Extract: The solvent extract of a Labiatae herb, and preferably rosemary, sage, or thyme, especially rosemary. The preferable form is that described in Todd USP 4,877,635, and standardized to an antioxidant strength of about twice that of BHT in soy oil, under the standard RancimatTM conditions. It is commercially available in the form of HerbaloxTM.
RancimatTM: An instrument which measures the induction time of an oleogenous substrate, usually at 120 degrees Celsius and at 18 liters of air per hour. This is an accepted methodology for determining relative strengths of preparations of antioxidants. The effectiveness is ex-pressed as the induction time of the sample divided by the induction tims of the control, as a percent.
Svnergism: As defined in McGraw-Hill Dictionary of Scientific and Technical Terms: "An action where the total effect of two active components is greater than the sum of their individual effects."
Surface-Active Agent: In the context of this specifi-cation, it represents a nonionic surface-active agent, especially one taken from the class consisting of:
a. mono and di glycerides of fatty acids, b. polyglyceride esters of fatty acids, .-.. ~

21204~2 c. mono and diglyceride esters further esterified with a dibasic organic acid taken from the class consisting of citric, lactic, and tartaric acids, d. acetylated mono and diglyceride esters further esterified with a dibasic organic acid taken from the class consisting of citric, lactic, and tartaric acids, e. sorbitan esters of fatty acids, f. propylene glycol esters of fatty acids, and g. lecithin, and equivalents thereof.
h. caproic-caprylic acid polyglycerides RM Rosemarv Extract: The extract used is HerbaloxTM, which is a commercial product available from Ka]sec, Inc., standardized as to antioxidant activity, and comprising about 20~ active antioxidant compounds.

DETAILED DESCRIPTION OF THE INVENTION
The following Examples are given by way of illustra-tion only, and are not to be construed as limiting.

Exam~le 1. Preparation of a suspension or dispersion of less than 38 micron sized phosphate particles in a medium in which they are insoluble.
(a) 318 g of sodium acid pyrophosphate and 1270 g of vegetable oil were added to a pebble mill and ground for 24 hours. The size of the particles in the dispersion was less than 38 microns on their largest dimension. A portion was withdrawn, and grinding continued until the particles were less than 10 microns on the largest dimension. While essentially all of the particles need to be less than 38 microns in size for this invention to be effective, it is preferred that they be less than 10 microns in size.

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` 212~2 (b) The same procedure was used employing an approxi-mately equal mixture of sodium acid pyrophosphate, sodium polyphosphates, and sodium ortho and metaphosphates, with the same results.
(c) A granular sodium acid pyrophosphate was ground in a mortar and pestle, and the powder sieved through a screen to separate out particles less than 38 microns in size.
These particles were used in Example 5 below.
Potassium salts of the phosphates can be substituted for the sodium salts if sodium reduction is an objective.
Alternatively, calcium or other non-toxic salt may be used.
The above products were used as representative of food-grade phosphates in the following examples.

Example 2. Stabilization of animal fat, and synergism with antioxidants.
A freshly-rendered poultry fat (chicken) was dosed with the preparation of Example l(a) to give in the fat, 200 ppm of sodium acid pyrophosphate particles of less than 38 micron size on their largest dimension.
The fat was also dosed with 0.1% W/W HerbaloxTX (a commercial rosemary extract made by Kalsec, Inc., which is representative of Labiatae extracts). It was also dosed with 200 ppm of the phosphate preparation plus 0.1% W/W of HerbaloxTM for evaluation of synergism.
The results are given in Table I.
TABLE I. Induction Times and Synergism of Microcrystalline Phosphates and Rosemary Extract.
Induction Ratio to ~ syn-Time Control eraism (a) Control chicken fat 1.29 1.00 (b) 0.1~ phosphate of Ex.l(a) 2.30 1.78 ~c) 0.1% Herbalox 4.10 3.18 (d) (b) + (c) 8.83 6.84 97 ~v 5~",~ ' ~,i' . , '.
:i~'.'. , --- 2120~2 The synergism of 97~ is an exceptionally powerful enhancement of antioxidant power. The synergistic combina-tion of HerbaloxTM and microcrystalline phosphate substan-tially outperforms the synthetic antioxidants BHT and BHA
at their legal limits in this fat.
Similarly, synergism is found with tocopherols, as well as with microcrystalline ascorbic acid particles of less than 38 microns in size on their largest dimension prepared according to my aforesaid copending application, as well as with solid tea catechin particles of less than 38 microns on their largest dimension or tea catechins solubilized as shown in the following.
* * *

Preparation 1. Preparation of a preferred form of green tea extract to be used in lipid antioxidant preparations.
(a) Dried green tea leaves are exhaustively extracted with methanol substantially free of water, preferably less than about 7~ to 9%. This is important to the improved process for making the catechins used in this invention.
Ethanol or other lower alkanols, which azeotrope with water, are not the preferred solvent, but may be employed.
(b) Methanol is removed from the extract, following the addition of sufficient water during the distillation for the purpose of keeping the mass liquid. The extract thus made at this point, if both water and solvent were removed, would be about 30% to 40% catechins, 10% caffeine, and 20%
or more fat-soluble substances and pigments, including chlorophyll. (c) The extract is partitioned between the aqueous phase and a hydrocarbon solvent which boils below 200 C., preferably hexane. (d) The solvent layer is removed, the aqueous layer again partitioned against the hydrocarbon solvent to remove traces of lipids, and again <.

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-' 2120~2 separated. (e) The pH of the water layer is then adjusted to an acidic pH between 1 and 6, preferably 2.5 to 4.5, and optimally 3 to 4, and a water-soluble salt, preferably a non-toxic salt such as sodium or potassium chloride, sodium citrate, or sodium sulfate, added to a concentration of at least 0.2%, optimally between 5~ and 30%, W/W of the water to salt out the catechins. (f) The catechins are then extracted from the water phase using ethyl acetate or other water-immiscible solvent preferably selected from lower alkanols, lower alkyl ketones, and lower-alkyl lower-aliphatic acid esters. (g) The ethyl acetate or other water-immiscible solvent solution is used as such, or desolventized to make a powder. These in turn are used to make the lipid antioxidant preparations of this invention.
Steps (c) and (d) are essential only when all tea lipids are to be eliminated.
This general process was followed: 100 gms. of green tea was extracted with anhydrous methanol, enough water added to keep the mass liquid, methanol evaporated at a temperature below 80 C to give a thick liquid extract, 90ml of hexane added, the mixture agitated, the water-insoluble hexane phase separated from the water phase, the water phase again extracted with 30 ml of hexane, the hexane phase separated, 10 g of sodium chloride or other suitable salt added to the water layer and the pH ad~usted to 3.5 with phosphoric acid, and the aqueous phase then extracted twice with 150 ml of ethyl acetate or other suitable water-immiscible solvent. The ethyl acetate was evaporated at a temperature below 80 C., yielding a dry solid catechin-rich fraction weighing 14.7 gms.
This preferred process differs from the prior art in requiring a substantially anhydrous lower alkanol, e.g., less than about 7% to 9~ water being present in the alco-f ",,~ ' ' ' ", 2120~ ~2 holic solvent, and most preferably less than 5~; the elimination of chloroform by the use of a hydrocarbon solvent, and criticality in adjusting the pH of the aqueous solution prior to ethyl acetate or other water-immiscible solvent extraction to between 1 and 6, and preferably 3 to 4, in the presence of a water-soluble salt for salting the catechins out of the aqueous phase. It goes without saying that the salt addition and pH adjustment can be carried out simultaneously or in either order.
While the foregoing is considered to be the preferred method of preparation of the water-soluble antioxidant fraction, variations suitable for specific equipment will be apparent to one skilled in the art. Although hexane is the preferred hydrocarbon solvent, other aliphatic hydro-carbons, such as heptane, and terpenes such as limonene, are acceptable.
Ethyl acetate can be replaced by other solvents which are immiscible with the aqueous phase, preferably selected from lower alkanols, lower-alkyl ketones, and lower-alkyl esters of lower-aliphatic acids, such as methyl ethyl ketone, acetone, butanol, and other lower aliphatic acid esters of lower alcohols such as isopropanol, e.g., isopro-pyl acetate, and the like.

Pre~aration 2. Preparation of less than 38 micron sized tea catechin solids in a medium in which they are insolu-ble.
45 g of catechins from the tea solid powder extract, prepared as in Preparation 1 above by evaporation of ethyl acetate from a solution thereof, were stirred into 270 g of soy oil and placed in a pebble mill. The mill was rolled for 72 hours, by which time the granular tea antioxidant particles were less than 38 microns in size on their ,.: .
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- 21204~2 largest dimension, and more than 60% less than 10 microns in size on their largest dimension. The homogeneous paste was separated from the pebbles, and was ready for use as such or further diluted with soy oil or other fat or fat-soluble solvent.

Preparation 3. Preparation of less than 38 micron sized tea catechin solids from a solution of catechins.
150 ml of an ethyl acetate solution containing 25 g catechins was added to 150 g of soy oil, and desolventized.
The desolventized product, containing lumps of catechins and liquid soy oil, was placed in a pebble mill and ground to less than 38 microns in size on the largest dimension of the catechin particles. It had the physical appearance of the product of Preparation 1.
While pebble milling is a preferred procedure for particle size reduction, since it does not overheat the solids during grinding, other methods of size reduction known to the art are acceptable. Other vegetable and animal oils and fats are as suitable as soy bean oil for suspending the particles of catechins, for the catechin particles are insoluble in all of these lipids.

Preparation 4. Preparation and antioxidant properties of a fatty alcohol solution of tea catechins.
The dry powder of Preparation 1 was added to a C-12 fatty alcohol and warmed and agitated to give a 2.7% W/W
solution of catechins. Since the C-12 alcohol is semisolid at ambient temperatures, the solution is warmed with agitation to effect dissolution. It remains stable for more than one year. Since the C-12 alcohol is lipid in nature, being fat soluble and water insoluble, it is ~ . .
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~` 212~42 unexpected that the catechins should form a stable solution therein.
Other fatty alcohols, e.g., C-8 to C-18, may be used.
However, above C-14, the melting points are inconveniently high for most applications, and below C-10 the coconut flavor becomes objectionable in many applications. There-fore C-12 to C-14 fatty alcohols are preferred.
The stabilizing effect of the 2.7% W/W solution was evaluated by adding 0.3% W/W to various oils and fats, to give 80 ppm catechins in the lipid. The induction times of the oils and fats were then compared with unstabilized oils using the Rancimat technique. Results are given in Table IP.
TABLE IP. Effectiveness of 80 ppm tea catechins dissolved in C-12 fatty alcohol in inhibiting oxidation of typical oils and fats, by Rancimat ratio of induction time to control.

lipid Rancimat Ratio soy oil 1.75 corn oil 1.50 almond roasting oil 2.10 canola oil 1.62 peanut oil 1.94 palm oil 1.58 coconut oil 4.68 chicken fat 5.05 While powerful in all the above substrates, the very great effectiveness at less than 100 ppm in coconut oil and poultry fat is particularly surprising, and best explained by the solubilizing effect of the fatty alcohol.
End of Preparations :-. . . - : -- ~120~2 * * *
Example 3. Protective effect in poultry fat.
The phosphate preparation of Example l(a) was dosed into chicken fat at 0.1% W/W. Furthermore, 200 ppm of powdered iron complex was dosed into the fat to ascertain if iron by itself, in the soluble form of ferric acetyl acetonate, is a pro-oxidant. An additional sample, con-taining 0.1% W/W of the phosphate and 200 ppm of this iron complex, was prepared. Induction times were determined and the results are presented in Table II.

Table II. Effect of phosphate, iron, and their combina-tion, upon the stability of chicken fat.
Induction Ratio to Time Control Control 1.29 1.00 200 ppm phosphate 2.30 1.78 200 ppm iron complex 0.80 0.62 200 ppm each of phosphate and iron complex 0.84 0.65 The results demonstrate that the phosphates positive effect cannot be due to the sequestering of trace amounts of metals in the fat.

Exam~le 4. Synergism with HerbaloxTM and other antioxi-dants.
Using the same poultry fat, the synergism between the HerbaloxTM at 0.1% W/W and the less than 38 micron phosphate at 200 ppm was an astounding 200~. When 200 ppm powdered iron metal was also present, the induction time declined by only 13%, and the positive synergism remained. Since rosemary contains nothing known to chelate iron, there is no explanation of why the induction time should have declined so little in the presence of iron, particularly ~,, ~ .: . ~ ;
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21204~2 when it declines by the sum of about 23% in each case when iron is combined with the phosphate or HerbaloxTM individu-ally. The combination is a new and powerful synergistic mixture for commercial poultry fats.
Other powerful and multiple synergistic effects can be achieved. In lard, for example, a mixture of 2.0 g of the 2.7% W/W catechin solution in C-12 alcohol, 4 g of Herb-aloxTM, 0.75 g of mixed tocopherols, 5 g of 20% W/W mixed phosphates, and 5 g of 15% W/W ascorbic acid, the latter two being solids of less than 38 microns in size on their greatest dimension, in vegetable oil, was dosed in at 0.165~ W/W. The increase in induction time, over the sum of the increases in induction time if the constituents had been used alone, was over 250%, resulting in synergism greater than 150%.
When lecithin is added to the above mixture, so as to result in a dose in the lard of 0.18% W/W of the original mixture and 0.2~ W/W lecithin, the induction time is further increased, demonstrating that non-ionic emulsifiers enhance the synergistic effect.

Example 5. Criticality of particle size.
The less than 38-micron powder of Example l(c) and the granular phosphate from which it was derived were separate-ly dosed into lard at 200 ppm and induction times deter-mined.
The granular phosphate had no effect, whereas the microcrystalline phosphate increased the induction time by 45%. This demonstrates the criticality of the particle size according to the present invention.

~, , 2120~42 Example 6. Phosphate Mixtures The <38 micron si~e phosphate mixture prepared in Example l(b) is added to lard to give a concentration of 200 ppm. The induction time is increased from 1.95 to 3.01 hours, to give a ratio of 1.54, demonstrating that mixtures of phosphates are also effective. This allows the practi-tioner to design mixed phosphate systems, including synergistic systems, for stabilizing foods, food ingredi-ents, and other lipids and lipid-like materials.
The unground phosphates were ineffective in increasing the induction time of the lard, demonstrating the criti-cality of the <38 micron particle size for their effective-ness as antioxidants in lipids.

ExamDle 7. The effect of lecithin upon the effect of phosphates.
An improvement in effectiveness occurs when non-ionic surface-active agents are used in conjunction with the phosphate products of the invention. These include leci-thin, mono- and di-glycerides, acetylated mono- and di-gly-cerides, caproic-caprylic acid polyglycerides, and tartaric acid esters of mono- and di-glycerides. Although lecithin may not be preferred in some applications due to its tendency to discolor the oil, it is particularly effective when used with the microcrystalline phosphates of the present invention.
Thus, 20~ by weight of soy bean mixed lecithins were admixed into the mixed phosphate preparation of Example l(b) and the composition evaluated in menhaden oil and lard. The induction times increased 7~ and 17~ respec-tively over those for samples dosed with phosphate parti-cles alone.

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21~04~2 Such non-ionic surface-active agents are particularly useful in enhancing synergism when the phosphates are combined with other antioxidants, such as tea catechins of <38 micron particle size or tea catechins solubitized as shown in the foregoing, Labiatae antioxidants, <38 micron ascorbic acid particles as disclosed in my previously-identified allowed application, tocopherols, and synthetic antioxidants such as BHA, BHT, TBHQ (Tertiary butylated hydroquinone), propyl gallate, and ethoxquin.
Combinations with a surface-active agent are particu-larly desirable if a carotenoid pigment present in a lipid medium is to be protected.

Conclusion: A novel and effective phosphate product, consisting essentially of less than 38 micron-sized phos-phate particles, and preferably less than 10 micron-sized phosphate particles, has been found to inhibit oxidation of lipidic mate~ials, including both animal and vegetable oils and fats, especially fatty and oily foods and food ingredi-ents such as flavorings and colorings, especially when suspended in a lipid medium in which the particles are insoluble. The product shows strong synergistic properties with anti-oxidants, even though it cannot be considered an anti-oxidant ~er se. Its action does not appear to be that of chelation of trace metals, but rather is unexplained.
Its effectiveness may be increased by the addition of non-ionic surface-active agents, and particularly lecithin.
It is particularly useful in the form of synergistic natural antioxidant combinations, but enhances the activity of synthetic antioxidants as well.
* * *
It is to be understood that the invention is not to be limited to the exact details of operation, or to the exact : .

compositions, methods, procedures, or embodiments shown and described, as obvious modifications and equivalents will be apparent to one skilled in the art, and the invention is therefore to be limited only by the full scope which can be legally accorded to the appended claims.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

An antioxidant composition consisting essentially of solid phosphate particles of less than 38 microns in size on their largest dimension, wherein the phosphate is selected from orthophosphate, metaphosphate, polyphosphate, and pyrophosphate, and mixtures thereof, suspended in a lipid medium in which they are insoluble.

A composition of Claim 1 wherein the solid phosphate particles are less than 10 microns on their largest dimen-sion.

A suspension of Claim 1, wherein the medium is an edible medium.

A suspension of Claim 2, wherein the medium is an edible medium.

A product of Claim 3, wherein the phosphate is a non-toxic edible phosphate.

A product of Claim 4, wherein the phosphate is a non-toxic edible phosphate.

A product of Claim 5 in combination with a tocopherol, a Labiatae extract, or solid ascorbic acid or tea catechin particles of less than 38 micron size on their largest dimension, or a synthetic antioxidant.

A product of Claim 6 in combination with a tocopherol, a Labiatae extract, or solid ascorbic acid or tea catechin particles of less than 38 micron size on their largest dimension, or a synthetic antioxidant.

A product of any of Claims 1 through 8, comprising a non-ionic surface-active agent.

A product of Claim 9, wherein the non-ionic surface-active agent is selected from the group consisting of leci-thin, mono- and di-glycerides, acylated mono- and di-glycerides, tartaric acid esters of mono- and di-glycerides, and caproic-caprylic acid polyglycerides.

A fat, oil, fatty food or food ingredient substrate stabilized against oxidation with solid phosphate particles of less than 38 microns in size on their largest dimension, wherein the phosphate is selected from orthophosphate, metaphosphate, polyphosphate, and pyrophosphate, and mixtures thereof, or a composition of any of Claims 1 through 10.

A stabilized substrate of Claim 11 wherein the solid phosphate particles are less than 10 microns on their largest dimension.

A stabilized substrate of Claim 11 wherein the sub-strate includes a carotenoid.

A method of stabilizing a fat, oil, food, or food ingredient substrate which includes the step of combining the substrate with solid phosphate particles of less than 38 microns in size on their largest dimension, wherein the phosphate is selected from orthophosphate, metaphosphate, polyphosphate, and pyrophosphate, and mixtures thereof, or a composition of any of Claims 1 through 10.

A method of Claim 14 wherein the solid phosphate particles are less than 10 microns on their largest dimen-sion.

A method of Claim 14 wherein the substrate includes a carotenoid.

A method of making an antioxidant composition consist-ing essentially of phosphate particles of less than 38 microns in size on their largest dimension, comprising the step of milling commercial phosphate particles in a lipid medium until the size of the individual particles thereof is reduced to less than 38 microns on their largest dimen-sion, and then suspending the phosphate particles in a lipid medium in which they are insoluble.

The method of Claim 17, wherein the size of the particles is reduced to less than about 10 microns on their largest dimension.