Note: Descriptions are shown in the official language in which they were submitted.
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
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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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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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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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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,
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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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(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
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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.
* * *
PREPARAT I ONS 1- 4
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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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-
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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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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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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
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* * *
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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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.
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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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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
: .
2120442
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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