Note: Descriptions are shown in the official language in which they were submitted.
1045446
The present invention is directed to a method
for preserving high moisture content agricultural grains
which become subjeet to bacterial degradation due to
the high moisture content present. More particularly,
the present invention is directed to a method for
preserving high moisture content agricultural grains by
treating said grains with a specific acid/alkali or
alkaline earth metal sulfate salt/surfactant a~mixture.
In our co-pending application of identical title,
there is described a means for preserving high moisture
content grains employing a mixtur'e of a food-grade organic
acid or phosphoric acid and a surfactant. The present
invention is an improvement over that invention.
United States Patent 3,682,653 employs a surfactant
and propionic acid, in combination, as a grain conditioner
lubricant for softening a mass of whole kernel grains.
Essentially, the patentee employs a mixture of liquid
lecithin, propionic acid, and water. The propionic acid
serves to reduce the pH of the lecithin and permits the
lecithin to become water dispersible.
The invention of the patentee is quite different
from that disclosed and claimed herein for a number of
reasons. Firstly, the patentee is not at all concerned
with the preservation of high moisture content grains.
Secondly, the patentee requires the presence of a natural
amphoteric surfactant (lecithin), whereas, as will be seen
from the discussion which follows, a synthetic organic
cationic or anionic surfactant is required for this invention
toenhance the spreading factor of the acid contained in
applicants' composition required to preserve the high
-- 2 --
1~45446
moisture content grains. Non-ionic or amphoteric sur-
factant will not suffice for applicants' purposes.
Finally, one observes upon a reading of this
patent, that the patentee requires propionic acid for the
purpose of dispersing the lecithin, whereas in the instant
invention, the surfactant is employed for the sole purpose
of dispersing the acid of applicants' composition in the
high moisture content grain for preservation purposes.
Aside from the foregoing, according to the
patentee, 1/4 lb. of acid per ton of grain would be
required, whereas with the present invention, appreciably
more acid per ton would be required, and as such, the
patentee's acid content would be so minimal that preservation
of a high moisture content grain could not be achieved.
United States Patent 2,890,120 discloses a
method for preserving edible plant materials, i.e., fruits
and vegetables which become deteriorated via enzyme
deterioration. Specifically, the method includes applying
to said plant materials, a composition containing at least
an acid, a volatile oxygenated organic solvent and a
wetting ~surface active) agent. The invention of this
patentee is distinguished from the invention disclosed
and claimed herein on at least three bases. Firstly, the
plant materials of the patentee are deteriorated via
enzymes whereas the grain materials disclosed in the instant
invention is deteriorated through bacteria as a result of
the high moisture content present. Secondly, an alkali or
alkaline earth metal sulfate salt is an absolute require-
ment for the instant invention whereas for the patentee,
it is not taught or suggested. Finally, the patentee
- 3 -
1~)45446
requires the presence of a volatile oxygenated organic
solvent for two reasons: 1) to facilitate the penetration
of the patentee's acid through the cell walls and membranes
of his plant materials, and 2) for acting synergistically
with the other c~mponents of the patentee's solution to
promote enzyme inactivation. In the instant invention, no
volatile oxygenated organic solvent is at all required.
In fact, to employ such would be detrimental to the purposes
intended to be achieved by the applicants.
It is the primary object of the present invention
to provide a method for preserving high moisture content
agricultural grains.
Accordingly, to this end, it is intended for the
purpose of this invention to employ a high moisture content
agricultural grain preserving composition, which consists
essentially of: 1) a food-grade organic acid or phosphoric
acid, 2) an alkali or alkaline earth metal sulfate salt,
any one of which is characterized as being water soluble,
non-corrosive and non-toxic to the grain treated, and 3)
a synthetic organic cationic or anionic surfactant for
enhancing the penetration of the acid employed in this
composition into the high moisture content grain for
effecting preservation of the same. Non-ionic or amphoteric
surfactants will not serve applicants' purposes here.
In terms of definition, the term "food-grade organic
acid" refers to conventional organic acids approved for use
with food products and with respect to the expression "non-
corrosive" respective of the alkali or alkaline earth metal
sulfate salt, this expression simply indicates that the salt
must be non-corrosive to the high moisture content grains
1~45446
treated, as well as being non-corrosive and non-toxic
to animals who might consume such grains.
The term "high moisture" as it pertains to
agricultural grains means any agricultural grain whose
moisture content is 18% or more.
With respect to the food-grade organic acids
suitable for the purpose of this invention, these acids
which are preferred, are those of formic acid, acetic acid,
propionic acid, and lactic acid. Of these, propionic acid
is the acid of choice because it not only serves the
function required of an acid for the purpose of this
invention, but, in addition, this particular acid is an
effective fungicide and as such, enhances the preservation
power of the composition employed. However, any other
food-grade organic acid approved for use by the Food and
Drug Administration's "GR~S" list is acceptable also.
Respective of the inorganic sulfate salts,
suitable for applicants' purposes, sodium sulfate is
preferred. However, potassium, calcium, magnesium or any
other alkali or alkaline earth metal sulfate will equally
suffice.
With respect to the concentration parameters for
the acids, alkali or alkaline earth metal sulfates and
surfactants employed in applicants' composition, naturally,
the concentration of same will vary over wide limits,
depending upon the moisture content of the grain treated.
However, generally the following guidelines are suggested.
For one ton of grain containing 25% moisture content,
the following active ingredient concentrations are suitable
for applicants' purposes:
1~4544~
(1) Acid - 10 lbs.
(2) Alkali or alkaline earth metal
sulfate salt - 1/2 lb.
(3) Surfactant - 1 lb.
Similarly, for one ton of grain having a moisture
content of 15%, the following active ingredient con-
centrations are suitable.
(1) Acid - 2-1/2 lbs.
(2) Alkali or alkaline earth metal
sulfate salt - 1/8 lb.
(3) Surfactant - 1/4 lb.
Referring to the above examples, with respect to
the grain having a moisture content of 25%, 12% of that
moisture is inactive. Consequently, the amount of active
water in the 25% moisture grain is actually 13% (25-12%).
Similarly, with respect to the grain having a
15% moisture content, the amount of active moisture contained
in said grain would be 3%, (15-12%).
Accordingly, 15% moisture grain requires 3/13 times
the formula or roughly 1/4 of the formula used for
application to a 25% moisture grain. This is based on
perfect mixing conditions. For practical purposes it may
be necessary to use an inert diluent. Based on the
foregoing guidelines, it is believed that the skilled artisan
can easily calculate the amount of acid, alkali or alkaline
earth metal sulfate, and surfactant required for
applicants' purposes simply by determining the amount of
moisture content contained in a particular grain and
calculating the amount of each active ingredient required
on a proportional basis in light of the above guidelines.
With respect to the surfactants suitable for
1~45~46
applicants' purposes, applicants do not limit themselves
to any particular cationic or anionic surfactant. That
is, virtually any of these will suffice for applicants'
purposes. However, without limitation, the following
commercially available surfactants have been found to
be quite suitable. Any sodium alkylsulfonethanolamine;
any ammonium or sodium alkylarylpolyethersulfonate
(Triton); any long alkyl chain sulfonate; any alkyl
aryl sulfonate; any sulfonated fatty acid; or any sodium
sulfosuccinate. Specific illustrative examples of the
following aforementioned types of surfactants are: sodium
dodecylsulfonethanolamine, ammnoium dodecylbenzene-
polyethersulfonate, sodium dodecylbenzenepolyether-
sulfonate, dodecylsulfonate, sodium dodecylbenzenesulfonate,
sulfonated myristic acid, sulfonated palmitic acid,
sulfonated stearic acid and di-(2-ethylhexyl) sodium
sulfosuccinate. These and other cationic and anionic
surfactants useful in the instant invention can be found
in the text entitled "ENCYCLOPEDIA OF SURFACE ACTIVE
AGENTS", by Sisley and Wood, published by Chemical
Publishing Company, New York, New York (1964).
Naturally, for the purpose of this invention,
more than one food-grade acid can be employed, that is,
mixtures of conventionally acceptable food-grade acids are
equally as suitable for the purposes of this invention.
With the foregoing in mind, the following brief
explanation will provide the skilled artisan with a basis
to fully understand the uniqueness and novelty of the
present invention.
-- 7 --
~ra~ ~qar~
1~45446
Firstly, the basis of this invention is the
realization that food-grade acids can be used to preserve
high moisture content grain, such as corn grain or any
other agricultural grain which tend to deteriorated via
bacteria as a result of the high moisture content
present. However, a problem arises when using such an
acid and mainly, the acid alone cannot normally penetrate
or permeate through the high moisture content grain
sufficiently to impart this preservative effect.
Consequently, the uniqueness of the instant
invention is the realization that when an alkali or
alkaline earth metal sulfate salt, as heretofore described,
is combined with a conventional food-grade acid and a
synthetic organic cationic or anionic surfactant capable
of enhancing penetration of that acid through high moisture
content grains, the alkali or alkaline earth metal sulfate
salt, somehow combines with the surfactant to enable the
food-grade acid to fully penetrate throughout the high
moisture content grain so as to permit an overall
substantial preservative effect to be achieved.
It is interesting to note that when the alkali or
alkaline earth metal sulfate salt is deleted from applicants'
composition, or in the alternative, when the surfactant is
omitted, inferior acid penetration and hence, little or no
preservation effect is observed. Consequently, for the
purpose of this invention, the combination of acid hereto-
fore described, the alkali or alkaline earth metal sulfate
salt heretofore described, and the surfactant is absolutely
essential to achieve applicants' goal.
In application, one simply determines the amount
- 8 -
- 1~45446
of high moisture content grain to be treated as well as
the amount of moisture contained in that grain. The amount
of moisture contained in a particular grain can be easily
determined by means well known to the skilled artisan
concerned with the subject matter of this invention.
Subsequently, based upon these estimations, the basic
formulation of the present invention is prepared by
simply mixing together the essential ingredients. Then,
the prepared formulation is applied to the high moisture
content grain by any suitable means, for example, spraying
the same onto the grain mass, until the high moisture
content is saturated with the formulation.
A better understanding of the present invention
will be gained from the following examples, which are
simply illustrative and non-limitative thereof.
EXAMPLE I
This example, set out in two parts (part A and
part B) illustrates the "spreading factor" discussed in
connection with the formulation of this invention.
PART A
RATE OF PENETRATION OF THE ACID THROUGH THE GRAIN MASS,
THE SPREADING FACTOR
Formulation Inches per Hour
50% - Propionic acid 5.0
50% - Mixture of Propionic acid (60~)
and Acetic acid (40%)5.1
50% - Propionic acid and 1/4% sodium
sulfate 16.4
50% - Mixture of Propionic acid/Acetic
acid and 1/4% sodium sulfate 17.0
50% - Propionic acid and l/ln% sodium
alkylsulfonethanolamine* 7.5
50% - Propionic acid and 1/10% sodium
alkylsulfonethanolamine* and 1/4%
sodium sulfate 19.8
*sodium dodecylsulfonethanolamine
_ g _
1~45446 _lo _
Each of the above formulations were diluted with
distilled water to be required percent. 35mm Pyrex tube~
(specially prepared) were employed. High moisture corn
(25%) was packed in the tubes at 5 lbs. per square inch at
each inch level. All experiments were conducted at 70F.
These values hold only for the particular batch of corn used
and are not absolute, and vary with the degree of attrition
if ground.
PART B
(RATE OF PENETRATION OF THE ACID THROUGH THE GRAIN
KERNEL, THE ABSORPTION FACTOR)
Formulation Percent Absorption in Hours
1/2 1 2 4 12 24
50% - Propionic acid 20 24 28 28 30 37
50~ - Propionic acid/Acetic
acid 60/40 mixture 19 23 26 29 32 35
50% - Propionic acid and 1/4%
sodium sulfate 27 29 31 32 38 49
50% - Propionic acid/Acetic
acid mixture and 1/4%
sodium sulfate 19 24 26 27 35 44
50% - Propionic acid and 1'/10%
sodium alkylsul-
fonethanolamine* 30 38 35 56 64 75
50% - Propionic acid/Acetic
acid mixture and 1/4%
sodium sulfate and
sodium alkylsul-
fonethanolamine* (1/10%) 63 67 79 90 91 90
50% - Propionic acid, 1/4%
sodium sulfate
and 1/10% sodium
alkylsulfonethanolamine* 51 60 71 80 92 93
In the above comparative studies, 100 gram portions
of the 25% moisture corn were employed. The various test
liquids were mixed at the rate of 1% with the grain mass.
The preparation was allowed to stand for the varying time
periods noted at 50F. The test liquids were then eluted
- * Tr~d~ ~Rk
*sodium dodecylsulfonethanolamine
~45446
from the grain with three successive washes of distilled
water. Aliquots were titrated for acid not absorbed
an~-calculations were noted for the percent of acid
ab~orbed. These values are not absolute and hold only
for the particular batch of corn used, and vary with the
degree of attrition, if ground.
EXAMPLE II
GROWTH OF MOLD IN 30% HIGH MOISTURE CORN AT 70F
Formulation Days
4 14 2880
1/2% - Propionic acid 0 1 2 3
1/4% - Propionic acid 1 2 4 4
1/2% - Propionic acid and 1~4%
sodium sulfate 0 0 4 4
1/4% - Propionic acid and 1/4%
sodium sulfate 0 4 4 4
1% - Propionic acid, 1/4% sodium
sulfate and 1/10% sodium
alkylsulfonethanolamine* 0 0 0 0
1/2% - Propionic acid, 1/4% sodium
sulfate and 1/10% sodium
alkylsulfonethanolamine* 0 0 0 0
1/4% - Propionic acid, 1/4% sodium
sulfate and 1/10% sodium
alkylsulfonethanolamine* 0 0 1 4
In the above comparisons, 200 gram samples in wide
mouth jars with loose lids were allowed to stand over water
in a loose-lidded container at 70F. The growth of mold
in the high moisture corn employed was then determined.
The degree of mold growth ranged from 0 to no growth to 4
or maximum growth.
EXAMPLE III
With respect to the surfactants illustrated previous-
ly and used for applicants' purposes, the following data, set
.
*sodium dodecylsulfonethanolamine
~4S446
out in Table I below is pertinent from the standpoint of
demonstrating the ability of the surfactants to enhance
acid penetration.
~ABLE I
Surfactant Percent
Absorption
Sodium alkylsulfonethanolamine*+
Propionic acid (50%) 75
Ammonium alkylarylpolyethersulfonate+
propionic acid (50%) 79
Sodium alkylarylpolyethersulfonate+
propionic acid (50%) 77
Sulfonated fatty acid+propionic acid
(50%) 68
Propionic acid by itself (50%) 33
Conditions same as in Example I, part B.
These values are not absolute and serve only as
examples as they vary with the particular batch of corn
used, and degree of attrition, if ground. These are
weighted values based on the surfactant employed and
propionic acid.
It should be emphasized that while the foregoing
examples have been directed to high moisture content corn,
it is obvious that other high moisture content grains are
susceptible to the same treatment.
Although the present invention has been adequately
described in the foregoing specification and examples
included therein, it is obviously apparent that various
changes and/or modifications can be made thereto without
departing from the spirit and scope thereof.
*sodium dodecylsulfonethanolamine
l.ammonium dodecylbenzenepolyethersulfonate
2.sodium dodecylbenzenepolyethersulfonate
3.sulfonated palmitic acid
