Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF T~E INVENTION
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This invention relates generally to food or feed
products and processes. More particularly, this inven-
tion relates to a process for enhancing the protein content
` 5 of food or feed products. Additionally the invention relates
to food and eed products having an increased protein con-
tent as produced by the subject process.
` One of the most serious problems which the world- faces is supplying nutritionally adequate protein to meet
` 10 the demands of a population which is expanding by approximately
55 million people annually. If the average protein require-
ment for an individual is about 52 pounds per year, this
means that there must be produced an additional 2.g billion
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`~ pounds of protein each year just to keep pace with the popula-
15 tion increase. This does not take into account the fact
- that much of the present world population does not have suf-
ficlent pro-tein in their diet to be healthy enough to lead
meaningful lives. Thus, there is a very pressing need for
ways of increasing the total protein production of the world.
A problem associated with the need to supply adequate
protein for the world population is the fact that cereal grains
and cereal grain products make up a high percentage of the
diet of most of the developing nations. Unfortunately,
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these grains and grain products usually contain 10% or less
protein which is very often deficient in some of the essential
amino acids. Since the average person requires at least 65
grams of high quality protein per day for good health, this
means that an intake of 650 grams of cereal grains would ~e
required to supply this quantity of protein. Ingesting this
much cereal grain would supply too much carbohydrate relative
to the amount of protein. Furthermore, the protein contained
within these cereal grains is generally of relatively poor
quality.
The present invention is directed to a solution to the
above-described problems by increasing the ratio of protein to
carbohydrate in cereal grains and products thereof while con-
cominantly improving the overall amino acid ba~lance for the
treated grain.
Much of the grain grown in the world is fed to mono-
gastric animals (swine, chickens, etc.) who have roughly the
same nutritional requirements as man. Accordingly, the present
invention would lead to economy in feeding these animals since
it would not be necessary to add protein supplements to these
grains (soy bean meal, cotton seed meal, fish meal, etc.) if
the animals were fed grains treated by the process of the
present invention.
Studies have been made in the past to developprocesses
for treating various foods containing carbohydrates with lower
fungi so as to increase their protein content. The process
suggested in such studies, however, are less desirable than
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the process of the present invention because these other
processes either require "fixed" inorganic nitrogen, produce
nutritionally deficient proteinr or require separation of
the protein to produce an accep-table food or feedstuff.
On the other hand, the present process suffers from
none of these drawbacks. A(food or foodstuff such as a
cereal grain twheat, corn, and the like) treated by the
instant process may be dried to the customary moisture levels
and processed by conventional methods to provide food and
feed products such as bread, dry cereal products, dog and
cat foods and the like which contain enough high ~uality protein
to be nutritionally well balanced and have a flavor which
is highly acceptable.
Another aspect of the present invention is the fact
that agricultural waste products such as peanut hulls, corn
residue, grain straws and the like may be mixed with cereal
grains and treated by this process to give products which
are particularly well suited for animal feedstuff. Materials
such as corn silage could also be treated by the present
process.
Additionally concePts have previously been disclosed
relating to the art of cultivating mushrooms from a mycelium
of the genus Pleurotus including Pleurotus ostreatus, Pleurotus
ulmariums, Pleurot_ sapidus, Pleurotus corinicopiae, and
Pleurotus florida.
At least one publication suggests that mushrooms may
be cultivated in a culture medium comprising, for example,
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corn fibers and rice bran (or corn bran) and subsequently
the cultivation medium may be used as feedstuff.
At least one other previously known publication dis-
closes that a nutrient substance which comprises one or more
cellulose-containing agricultural waste products may be
crushed, mixed wi-th water and placed into a ventilated con-
tainer which is sterilized. The sterilization is carried
out either by heating to 70 to 80C for 5 hours or by intro-
ducing propylene oxide. After the mixture is placed inside
the sterilized container, it is injected with a mycelium of
the fungus P _ rotus ostreatus. The nutrient substance is
preferably wheat, barley, rye, peas, rice shells, sun flower
stalks and seeds.
The container is kept at a constant temperature between
16 and 20C after seeding. When the nutrient is permeated
with~the mycelium, the temperature is lowered to between 5
and 16C. After the onset of the crop of mushrooms, the
container is opened and illuminated with light.
Still another theorist suggests that a substrate such as
seed oil residues (e.g., cottonseed meal, coconut meal,
peanut meal, etc.) which are advantageously mixed with a
cereal material such as wheat or the like may be innoculated
with a mycelium of mushrooms including, among others,
Pleurotus ostreatus. The substrate (e.g., peanut meal) is
first acid hydrolyzed by treating it with mineral acid. The
calcium carbonate is added and the pH is adjusted to between
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5 and 8. This mixture is then innoculated with the mycelium
of mushrooms te-g-, Pleurotus ostreatus) which has been grown
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on a medium of the same composition.
Although the above noted disclosures have at least a
; 5 degree of conceptual appeal in the art of growing mushrooms,
little if any attention has been directed to developing a
protein enriched food or food stuff using a spawn culture of
the genus Pleurotus. In none of these publications has any
mention been made of the fact that Pleurotus will grow in the
presence of materials already containing protein (cereàl grain
and the like) without substantially altering the protein
already present, and at the same time produce additional protein
by fixing nitrogen which is in the air and using the grain as
a source of carbon.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, a general object of the present invention
is to provide a novel process for preparlng a food or feed
product which has an enhanced protein content.
A more specific object of the present invention is to
provide a novel process for increasing the protein content
of food or feed products.
Another object of the invention is to provide a novel
process for increasing the protein content of a food or food-
stuff utilizing nitrogen from the atmosphere.
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A further object of the invention is to provide a
novel process for increasing the protein content of cereal
grains while concomitantly improving the overall amino acid
balance for the treated grain.
; 5 A still further object of the invention is to provide
a novel process for increasing the protein content of agri-
cultural waste products to,produce a product particularly
; suited for animal feedstuff.
Still anotiler object of the present invention is to
provide a protein enriched food or feed product produced by
this process.
Other objects and advantages of the invention will
; 10 become apparent from the following summary and description
of the preferred embodiments of the present invention.
Summary
In one aspect, the present invention provides a process
for increasing the protein content and improving
the overall amino acid balance of a food product which contains
carbohydrates, without substantially altering the protein
present in the food product by fixing nitrogen from a gaseous
mixture of molecular nitrogen comprising:
a) forming a mlxture of from about 20% to about 80~ by
weight food product and from about 20% to about 80$
by weight water;
b) sterilizins said mixture in order to substantially
eliminate the growth of substances which might
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compete with the growth of a spawn culture of the
genus Pleurotus;
c) inoculating said mixture with from about 0.5~ to
about 20% by weight of at least one member selected
from the group consisting of Pleurotus ostreatus,
Pleurotus ulmarius, Pleurotus sapidus, Pleurotus
corninicopiae, and _leurotus florida;
d) maintaining the inoculated mixture in the presence of
a gaseous mixture of molecular nitrogen and oxygen at
a temperature of from about 5C to about 46C and for
a period of time sufficient to enable the mycelium of
said spawn culture of the qenus Pleurotus to
reproduce; and
e) recovering from the inoculated mixture a food product
which has an increased protein content and improved
; amino acid balance wit~out substantially altering the
protein initially present.
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In another aspect, the present invention comprises the
product produced by the above des~ribed proçess.
DESCRIPTION OF PREFERRED EMBODIMENTS
The process of the present invention involves treating
a food or feed product with a spawn culture of the genus
Pleurotus. The food products useful in this process include
any carbohydrate containing food product on which Pleurotus
mycelium will grow in the presence of air. Such products include,
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for example, cereal grains such as corn, rye, oats, milo, rice,
barley, soybeans, manioc, yams, and sweet potatoes; products
of the milling industry that contain carbohydrates such as
wheat bran and rice bran; other carbohydrate containing food
products such as lima beans, pinto beans, and pulses including
white acre peas, black-eyed peas, and the like, and agri-
cultural wastes such as peanut hulls, corn residue, grain
straws, cottonseed hulls, bigasse, corn silage. Mixtures of
two or more food or feed products may also be used.
The first step in the subject process comprises mixing
the food or feed product with water. Water is needed so that
when the food or feed product is innoculated with Pleurotus it
will have a sufficiently moist environment in which to grow.
The mixture should contain generally from about 20%
to about 80~, typically from about 30% to about 70% and
preferably from about 40% to about 60~ by weight food or feed
product, and correspondingly generally from about 20~ to
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from about 40% to about 60% by weight water. These per-
centages are based upon the total weight of the mixture.
In a preferred embodiment of the present invention,
calcium carbonate may be added to the mixture of the food
S product and the water. The purpose of the calcium carbonate
- is to increase the pH of the mixture to a value in the range
of from about 6 to about 8 for the purpose of providing the
preferred pH for the growth of Pleurotus. The calcium carbonate
is also added for the purpose of supplying nutrient to the
mixture.
Although calcium carbonate is preferred, any compound
which is non-toxic and which will supply required nutrients
is useful in the growth of the Pleurotus mycelium. Such
compounds include calcium hydroxide, calcium sulfate, dicalcium
phosphate, organic calcium salts such as calcium citrate,
and the like, and other mineral nutrient materials such as
nutrient compounds of potassium, magnesium, iron, phosphor~ls,
zinc, copper, boron, sulfur, and the like. Mixtures of two
or more nutrient compounds may also be used.
These nutrient compounds must be in a form such that
they are not toxic to the mycelium. Harvested grains usually
contain sufficient quantities of these nutrients and their
addition is not required for efficient growth when harvested
grains are employed.
The second step of the present process comprises steri-
lizing the mixture so as to substantially eliminate the growth
of substances which might compete with the Pleurotus.
The mixture may be sterilized by any means known to
those skilled in this art. For example, the mixture may be
~'~ 30 sterilized by heating or by pretreating the substrate with
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chemical compounds such as propylene oxide -or anhydrous
ammonia.
If the mixture is s-teriliæed by means of heat, it
should be heated to temperatures in excess of 120C for a
sufficiently long period of time to allow the entire mixture
to attain a minimum temperature of 120C.
The sterilized mixture is next innoculated with a spawn
culture of the genus Pleurotus at temperatures which are
generally from about 5C to about 46C typically from 10C
10to about 30C and preferably from about 20C to about 30C.
Mixtures of two or more members of this genus may also be
used.
As used herein, the term "spawn culture" refers to a
living culture of the mycelium growing on any substrate which
will support its growth.
- The mixture may be innoculated with the spawn culture
by adding a small amount of the culture as finely divided as
possible and mixing this culture into the new substrate as
thoroughly as possible. The amount of Pleurotus used to
innoculate the food product mixture may be generally from
about 0.5~ to about 20%; typically from about 1% to about 5%,
and preferably from about 1% to about 3% by weight based upon
the total weight of the innoculated mixture.
The innoculated mixture is then maintained in the
presence of a mixture of nitrogen and oxygen at a tèmperature
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of generally from about 5C to about ~6C, typically from
about 10C to about 35C, and preferably from about 20C
to about 30C. These temperature ranges are important in that
they represent those temperatures at which Pleurotus will
grow. At temperatures substantially below about 5C or sub-
stantially above about 46C Pleurotus does not experience
substantial growth.
The innoculated mixture must be maintained in the
presence of a mixture of nitrogen and oxygen in order to
produce an increase in protein content of the food product.
Any ratio of nitrogen to oxygen may be employed
in the process of the present invention although the mixture
shall preferably contain more than 10% by welght oxygen and
more than 10~ by weight nitrogen. The amount of gas mixture
which is employed is important only in that substantial
protein increase may not occur if there is insufficient
nitrogen and/or oxygen present during the growth period.
Other gases may also be included in this mixture. Air which
is at or near the surface of the earth is a preferred gas
mixture since it contains oxygen and also contains approxi-
mately 78~ molecular ni-trogen by volume.
The innoculated mixture should be maintained in
contact with the gas mixture for a period of time long
enough to effect sufficient growth of the mycelium but not
for too long a period of time since there is no advantage in
doing so and since contamination with other fungi or bacteria
may occur.
The innoculated mixture should be kept in contact
with the gas mixture for generally from about 2 days to about
80 days, typically from about 14 days to about 56 days, and
preferably from about 21 days to about 35 days.
If the innoculated mixture is kept in contact with
the gas mixture for a tlme period substantially less than
about 2 days, then the protein increase is comparatively in-
! significant. On the other hand, if the innoculated mixture is
kept in contact with the gas mixture for a time period sub-
stantially in excess of 80 days, the amount of protein increase
over and above that attained up until that time is also
comparatively lnsignificant.
After sufficient mycelium growth has taken place,
the growth of the mycelium is terminated. Growth may be
terminated, for example,~ by dehydrating the mixture to a
molsture content of generally less than about 20%,typically
less than about 18g~,and preferably less than about 12%
by weight based upon the total weight of the innoculated
mixture. Growth may also be terminated by chemical steriliza-
tion or heating.
Prior to treatment according to the process of thepresent invention, the food product has a protein content of
generally less than about 25 percent, by weight, based upon
the weight of the food product as determined by nitrogen
analysis.
After treatment according to the process of the
present invention, the food product has a protein content
which is generally at least about 30 percent to 65 percent
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by weight higher; based upon the weight of the food
product.
The following Examples are given as specific illustra-
tions of the claimed invention. It should be understood,
however, that the invention is not limited to the specific
details set forth in the Examples. All parts and percentages
in the Examples as well as in the remainder of the specifica-
tion are by weight unless otherwise specified.
Examples 1 - 7
These Examples illustrate the preparation of the
enriched protein food product of the present invention. The
following general procedure applies to each of these Examples.
One hundred twenty five (125) grams of the food
product, one hundred (100) grams of water, and two point five
(2.5) grams of finely divided calcium carbonate are mixed
in a glass container. The container is closed with a cotton
pluy and the mixture is sterili~ed by heating in a steam
autoclave. The mixture is then cooled to room temperature
and innoculated with a Pleurotus ostreatus spawn culture. The
innoculated mixture is then maintained in the presence of
atmospheric air at 21C. The specific details of each
Example are given in Table I below.
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TABLE I
EXA~lPLES l 2 3 4 S 6 7
Wheat 50~ White
Food Product Corn Rye Oats Rice Wheat Corn 50% Acre
By Weight Peas
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Amount P.O.
(grams) 2.02.0 2.02.0 2.0 2.0 2.0
Initial Pro-
tein Content11.3 14.314.0 8.015.5 12.8 22.5
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Protein Con-15.7 17.7418.8 8.7 -- -- --
tent After
3 weeks
Protein
` Content -- -- -- -- 19.2 18.9 32.5
: . After
4 Weeks
Protein
Content
After -- 23.9 --10.8 -- -- --
5 Weeks
The protein content of each e~ample was determined by
; 20 the well known technique of nitrogen analysis.
The above examples illustrate that the present invention
provides a process whereby protein content of a food product is
substantially increased by innoculating the food produc-t with
mycelium of the genus Pleurotus. By means of this process, the
ratio of protein to carbohydrate in cereal grains and other ~ood
products may be increased, thus alleviating to some degree the
problems associated with the lack of protein in the diet of
much of the world population.
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Comparative Example
Example 2 was repeated except that Agaricus bisporus
mycelium was used instead of Pleurotus ostreatus. Sub-
stantially no increase in protein content was measured.
The above-described Examples illustrate that when the
process of the present invention is employed, there is pro-
duced a food product having an increasedprotein content. On
the other hand, when the same process is carried out using
Agaricus Bisporius rather than Pleurotus, there results sub-
stantially no protein increase.
The principles, preferred embodiments, and modes of
operation of the present invention have been d.escribed in the
foregoing specification. The invention which is intended to
be protected herein, however, is not to be construed as
limited to the particular forms disclosed, since these are to
be regarded as illustrative rather than restrictive. Varia-
: tions and changes may be made by those skilled in this art
without departing from the spirit of the invention.
WHAT IS CLAIMED IS:
