Note: Descriptions are shown in the official language in which they were submitted.
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1 BACKGROUND OF THE INVENTION
1. Field of the Invention:
This invention relates to a process for improving the yield of acid
cheese curd in cheesemaking.
2. Description of the Prior Art:
United States Patent 3,039,879 - Vakaleris, describes a process for
increasing the yield of solids from milk during cottage cheese manufacture by
retaining additional protein in the curd. Milk is heat treated at high
temperatures between 127C to about 149C for short periods of time to
denature the milk protein and immediately cooled. Between 40 and 80% of the
protein is denatured. Denaturation in excess of 80% of the protein results in
browning, cooked flavor and adverse conditioning of the protein so care must
be taken during heat treating. The cooled, heat treated milk is converted
into cottage cheese curd by setting the milk with lactic acid starter and
1~ rennin and then cutting the curd.
The prior art also describes various processes for recovery of
soluble protein from milk whey. United States Patent 2,377,624 - Gordon,
issued April 5, 1945, discloses a process which involves acidifying milk
whey to a pH of 1.0 to 4.3 and then adding condensed phosphates to precipitate
the protein from the whey. This process has several disadvantages. For
example, specific gravity of the precipitated protein is not sufficiently
high to permit its separation from the water phase using commercially
available equipment. Protein separation is also complicated by its low
, 25 concentration, i.e., about 0.5 to 0.6 parts by weight of soluble protein per
100 parts by weight of whey.
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Canadian 790,580 - Wingerd, issued July 23, 1968 describes a milk
protein phosphate reaction product obtained by acidifying whey, then
denaturing the protein in the acidified whey by heat treating, thereafter
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adding a solution of potassium polyphosphate and a sodium salt solubilizer
to precipitate the denatured protein from the whey and separating the
precipitated protein reaction product by centrifuging or filtering.
United States Patent 3,864,506 - Grindstaff et al, issued
February 4, 1975 describes treatment of cheese whey with a condensed
phosphate at a pH of 5.5 to 4.0, then adjusting the pH to 6.5 to 8.0 with
base to precipitate the protein and separating the precipitated protein
from whey by filtration.
It will be noted that none of the above processes using condensed
phosphate is concerned with precipitation of protein in the curd during
cheesemaking but in the separation of protein from milk whey after the whey
has been separated from the curd.
SUMMARY OF THE INVENTION
A condensed phosphate salt is added in sufficient amount to increase
the yield of cheese curd by complexing milk protein in milk before or after
acidification, the pH after acidification being from about 4.95 to about 5.3
and the temperature before and after acidification being from about 5C to
about 40C. The condensed phosphate salt forms complexes with whey proteins
I so the proteins remain in the curd and are not removed with the whey. If
1 desired, orthophosphate salts and alkaline earth halides may be added as
, buffers.
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Temperature of the acidified milk and condensed phosphate salt -
mixture is then adjusted to from about 26C to about 40C and maintained at
a temperature of from 26C to about 40C during addition of from about O to
;~ about 0.5 parts by weight of acidogen with the preferred amount being about 0.2 -
to about 0.5 parts by weight of acidogen and from about 0.01 parts to about 0.05parts by weight of proteolytic enzyme per 100 parts by weight of acidified
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milk. This mixture is then allowed to remain quiescent at a temperature of
from about 26C to about 40C for from about 45 minutes to about 2 hours to
form an acid cheese curd suitable for making cottage cheese, baker's cheese,
quark cheese, cream cheese and Neufchatel cheese.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The fluid milk used in this invention may be a reconstituted
powdered milk or fluid milk product such as fresh skim milk, skim milk
having about 1-4 percent by weight or more added NFMS (Grade A, Low Heat,
non-fat-milk-solids), whole milk, milk-cream mixtures, half milk and half
cream, reconstituted condensed milk and the like. The fluid milk may be
obtained by reconstitution of powdered milk with water or a fluid milk. It
is to be understood that fluid milk products may include medium and high
butter fat milk or cream having as much as 20 percent butterfat as well as
milk having butter fat contents of from about 0.01% to about 5% by weight
and a total nonfat solids content of from about 8~ to about 16% by weight.
The condensed phosphates used in this invention include the pyro-,
meta-, poly- and ultraphosphates. Generically, the term encompasses all
phosphates derived from acids containing less water than orthophosphoric
acid (3H20.P205). Pyro-, meta- and polyphosphates are also called "molecularly
dehydrated" phosphates because they can be prepared by a common procedure,
. dehydration of acid orthophosphates. Useful food grade "condensed
i phosphates" include:
(1) Potassium polymetaphosphate also known as potassium meta-
phosphate and potassium Kurrol's Salt has the formula (KP03)x and is a
straight chain polyphosphate having a high degree of polymerization. It
occurs as a white, odorless powder which is insoluble in water but is ~-
soluble in dilute solutions of sodium salts.
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1 (2) Potassium pyrophosphate also known as tetrapotassium
pyrophosphate has the formula K4P207 and a molecular weight of 330.34. It
occurs as colorless crystals or white, granular solid. Potassium
pyrophosphate is hygroscopic and very soluble in water but insoluble in
alcohol. A 1 in 100 solution has a pH of about 10.5.
(3) Potassium tripolyphosphate also known as pentapotassium
triphosphate and potassium triphosphate has the formula K5P301o and a
molecular weight of 448.42. It occurs as white granules or a white
powder. Potassium tripolyphosphate is hygroscopic and is very soluble
in water. A 1 in 100 solution has a pH of between 9.2 and 10.1.
(4) Sodium acid pyrophosphate also known as disodium pyrophosphate
and disodium dihydrogen pyrophosphate has the formula Na2H2P207 and a
molecular wei-ght of 221.94. It occurs as a freely water soluble, white
; fused mass or free-flowing powder. A 1 in 100 solution has a pH of about 4.
(5) Sodium polyphosphate also known as sodium metaphosphate;
glassy sodium phosphate; sodium hexametaphosphate, sodium tetraphosphate;
Graham's Salt; Kurrol's Salt; sodium trimetaphosphate; sodium tetrameta-
phosphate and insoluble sodium metaphosphate. The food grades include
crystalline or amorphous commercial phosphates whose compositions range
( 3)x through NaXH2PX03X+1 to Nax+2Px03x+l. These phosphates
are usually identified by the P205 content or by the Na20/P205 ratio. They
occur as colorless, glassy, transparent platelets, granules or powders.
Except for insoluble sodium ~etaphosphate, they are hygroscopic, water
soluble compositions.
.
The following three classes of sodium metaphosphate are available
¦¦ commercially
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1 Class A. Amorphous sodium polyphosphate, often referred to as
"sodium hexametaphosphate", has an Na20/P205 mole ratio of about 1.1. A 1
in 100 solution has a pH of about 7.
Class B. Amorphous sodium polyphosphate, often referred to as
"sodium tetraphosphate", has an Na20/P205 mole ratio of about 1.3. A 1 in
100 solution has a pH of about 7.8.
Class C. The amorphous and crystalline metaphosphates have an
Na20/P205 mole ratio of 1. A 1 in 100 solution has a pH of about 6Ø
(6) Sodium pyrophosphate also known as tetrasodium diphosphate
and tetrasodium pyrophosphate has the formula Na4P207 and a molecular weight
of 265.90. It is anhydrous or contains 10 molecules of water of hydration
and occurs as a white, crystalline or granular powder. The decahydrate
, ` 15 effloresces slightly in dry air. Sodium pyrophosphate is soluble in water
but insolub1e in alcohol. A 1 in 100 solution has a pH of about 10.
(7) Sodium tripolyphosphate also known as pentasodium triphosphate,
triphosphate and sodium triphosphate has the formula Na5P3010 and a
molecular wetght of 367.86. It is anhydrous or contains 6 molecules of water
of hydration. Sodium tripolyphosphate occurs as white, slightly hygroscopic
granules or as powder. It is freely soluble in water. A 1 in 100 solution
has a pH of about 9.5.
; Orthophosphate salts such as monocalcium phosphate, monosodium
phosphate, monoammonium phosphate, disodium phosphate or the like may be
added as buffers to the fluid milk before or after acidification.
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The fluid milk may be acidified with a 10-90% by weight aqueous
solution of a food grade free acid such as lactic acid, phosphoric acid,
citric acid, acetic acid, malic acid, sulfuric acid, hydrochloric acid,
tartaric acid, adipic acid, glutaric acid, fumaric acid, glutaric anhydride,
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succinic acid or the like. Acidification may be at a temperature
of above 0C to about 30C with the preferred temperature being
about 20C to about 30C to obtain a pH of about 4.95 to about
5.30 with the preferred pH being about 5.00 to about 5.20. The
acid must be added in such a way that the milk is acidified to
the desired pH at the desired temperature without precipitation
of casein or any alteration that will prevent curd formation
in this process. The teachings relate to useful milk acidifica-
tion methods described in U.S. 3,882,250 - Loter et al issued
May 6, 1975 and U.S. 3,620,768 - Corbin issued November 16, 1971.
A primary factor in successful acidification of milk
is the avoidance of casein precipitation (acid coagulation) - -
caused by excessive local acidity. Depending upon the conditions
under which the milk is to be processed, various methods of acid-
ification can be used. For example, acidification can be
successfully carried out in the laboratory using a small amount
of milk under rapid agitation, such as in a blender, with con-
centrated acid such as 85 percent phosphoric being added directly
into the milk container a drop at a time from a pipette. This
is impractical in practice where it has been found that the
best means of acidifying the milk for commercial production is
to introduce diluted acid into a stream of milk recirculating in
a pipe at a uniform rate while constantly reading the milk pH
from a meter inserted in the pipeline beyond the point of intro-
duction or in the vat. Acid can be introduced by any conventional
metering device or can be drawn into the recirculating pipe
using a standard Bernoulli connection, in which case the diameter ~ -
of the connecting tube will determine the acid addition rate.
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1 A change in any of the acidification variables can be easily
compensated for by adjusting other variables. For example, if the milk
temperature is at the low end of the range (slightly above 0C), a more
concentrated acid solution can be introduced, or the acid addition rate
increased, or both of these factors varied. All of these factors may be
varied within the limits of this invention up to the point where casein ~ :begins to precipitate. Taking another example, if the acid is introduced
cold at a lO percent dilution, then it can be introduced into the milk
more rap;dly, or it can be introduced at a higher temperature (approaching
30C), or both of these latter factors can be varied as indicated, but to
a lesser degree.
After acidification, the milk may be maintained at about the same
temperature and from about 0.2 to about 0.5 parts by weight of at least one ~
acidogen based on lO0 parts by weight of acidified milk, and from about -
O.Ol to about 0.05 parts by weight of aqueous proteolytic enzyme solution -
,~ based on lO0 parts by weight of acidified milk are added to the milk. The
resulting mixture is agitated during and after acidogen and enzyme addition
until uniform. The acidified milk is then maintained at about the same
temperature while quiescent until the acid liberated from the acidogen and
the action of the proteolytic enzyme both bring about coagulation of the
milk. It takes from about 45 minutes to about 2 hours after addition of the
acidogen and proteolytic enzyme for a cuttable cheese curd to form.
, ~ An acidogen such as D-glucono-delta-lactone, the low melting
lactide (m.p. 4l-42C) of lactic acid, acetic anhydride, heptonolactone
(the lactone of glucoheptonic acid) or the like can be used. Preparation
of this low melting lactic acid lactide is described in U.S. 2,982,654 -
¦¦ Hanrond and D ne, issued May 2, 1961.
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1 ¦ The proteolytic enzyme can be commercial rennin, Rennet, a diluted
¦ rennet extract, a pepsin-rennin mixture, a vegetable-derived enzyme clotting
¦ agent or the like. Other enzymes such as pepsin, papain and ficin may be
¦ used alone or in combination with rennin, the preferred enzyme. Rennin is
¦ obtained from the stomach of suckling calves. Rennet, a commercial dried
extract containing rennin can also be used. See Merck Index, page 911
(Merck & Co., Inc. - 1968 - 8th Ed). The Rennet of commerce is usually a
solution of the enzyme rennin, stabilized, and with pr.eservatives added and
l standarized in strength to a certain coagulating or clotting power. Useful
¦ commercial aqueous rennin solutions include Hansen's Rennet Extract and
Hansen's Cottage Cheese Coagulator available from Hansen's Laboratory, Inc.,
¦ Milwaukee, Wisconsin. Another enzyme that may be used is produced by pure
; I culture fermentation of the organism Mucor Miehei. This enzyme is available
commercially in units standarized to rennet extract.
The heated, acidified milk containing acidogen and enzyme is then
allowed to remain in a quiescent state at just in excess of 16C to about
41C with the optimum temperature being about 27C to 32C for about 45
minutes to about 120 minutes to obtain a cuttable cheese curd.
The cheese curd is then cut and cooked. It can be cut into large
(3/4-inch, 5/8-inch, 1/2-inch) or small (3/8-inch or 1/4-inch) cubes. The
cooklng rate in the process of this invention is faster than the cooking
rate in the cultured process, that is, about 30 minutes to about 90 minutes
. compared to about 90 minutes to about 150 minutes. Draining and washing of
the cooked curd can be carried out using conventional cheesemaking
procedures.
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To produce cottage cheese, the acid cheese curd is processed with
the additlonal steps of:
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I 1. cutting the curd into cubes,
2. expressing the whey from the curd,
3. cooking and stirring the curd for from about 30
minutes to about 90 minutes at a temperature of
from about 38C to about 65C, and
4. washing and draining the curd. --
To prepare baker's cheese, the acid cheese curd is processed
with the additional steps of:
1. breaking up the curd,
2. bagging the curd and expressing the whey, and
i 3. hanging and draining the bagged curd for about
1 hour, to express further whey.
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To produce Neufchatel cheese or cream cheese, the acid cheese
curd is processed with the additional steps of:
, 1. cutting the curd,
2. cooking and stirring the curd until the
temperature reaches about 55C and then
I continuing cooking for about 15 additional
minutes,
3. cooling the curd to about 15C,
, 20 4. draining the curd overnight at about 3-4C to
obtain a dry, soft curd, -
5. mixing the dry, soft curd with sufficient
lactic acid to reduce the pH of the curd
to 4.60, and
6. blending the curd into a smooth homogeneous
cheese mass.
~` 25
In cream cheese manufacture, the original milk should contain enough cream
O as to have a fat content of about 10.5 to about 11.5 percent. In making
Neufchatel cheese, the original milk should contain enough cream so as to ~-
have a fat content of about 5 to about 6 percent.
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1 For a fuller understanding of the nature and objects of this
invention, reference may be made to the following examples. These
examples are glven merely to illustrate the invention and are not to be
construed in a limiting sense. All parts, proportions and quantities are
by weight unless otherwise indicated. The terms g, ml, C, F and NFMS
are used to indicate grams, milliliters, degrees Centigrade, degrees
Fahrenheit and non-fat-milk-solids respectively in these examples.
EXAMPLE I ~ -
This example demonstrates preparat10n of cottage cheese curd using
sodium polyphosphate.
'' -
Added 256.25 lb pasteurized skim milk to cheese vat. ~ilk
temperature was 3C and pH was 6.77. Total solids in the skim milk was
9.2% by weight. Then added 290 ml of 85% phosphoric acid in increments to
the milk with vigorous stirring to reduce pH of the skim milk to 5.14.
':
Warmed acidified skim milk to 18.3C and added 95 9 monocalcium
phosphate and 368 9 sodium polyphosphate ("Vitrafos" - Stauffer Chemical
Co.). Continued warming skim milk to 38C where the milk pH was 5.10.
Added 408 9 D-glucono-delta-lactone as the acidogen and stirred for
2 min and then 36 ml cottage cheese coagulator (dilute rennet extract,
Hansen's) diluted in 150 ml water to the heated acidified milk. Stirred for
2 min. The heated acidified skim milk had a pH of 4.99.
Allowed milk to stand undisturbed for l hr. At the end of the
hour, the milk formed a very firm, normal, cottage cheese curd. This curd
was cut with 5/8" wire knives. Cut was clean, smooth, normal. The whey had
a pH of 4.73.
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1 ¦ Allowed the cut curd to set to "heal" 15 min, then added 10 ml of
¦ 85% phosphoric acid diluted with 1 pint warm water to the cut curd. Stirred ~-
¦ the cut curd gently and cooked slowly to 41C in 1/2 hr, then to 44C in 45
¦ min, thereafter to 51C in 1 hr and then to a final temperature of 60C in a
¦ total of 75 min. Curds were soft but "meaty" and were uniformly cooked
throughout.
Drained whey, washed the curd 3 times with water, trenched in vat
I and allowed to drain for 30 min. Weight of drained curd was 56.75 lb.
¦ Moisture in curd was 84.2%. Weight of curd calculated to the legal 80%
moisture was 44.8 lb. Curd yield was 17.5% based on weight of skim milk,
or 1.90 lb curd per 1 lb solids in the skim milk. These values were well
above average yields when compared to average yield figures from "Practical
Cheesemaking", G. H. Wilster, O.S.U. Book Stores, Inc. (12th Ed, 1974),
Corvallis, Oregon, which on page V-14, reports that milk having 9% skim
solids gave a good yield of 14-16% based on total weight of skim milk or
1.66 lbs curd per lb NFMS (based on 15% yield, 9% NFMS).
:::
EXAMPLE II
This example demonstrates preparation of cheese curd using poly-
phosphates and a pre-acidified skim milk powder.
Charged 30 gal of water having a pH of 9.3 into a cheese vat. Then
added 144 9 monosodium phosphate, 84 9 monocalcium phosphate, 360 9 sodium
polyphosphate (''Yitrafos" - Stauffer Chemical Co.), and 24 ml of an antifoam
solution to the water. Water pH after this addition was 5.85. Added 15
. .,~
pounds of NFMS (non-fat-milk-solids - powdered skim milk solids) to the
water using a recirculating, powder funnel system, to reconstitute the skim
milk. Reconstituted milk had a pH of 6.3.
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1 ¦ A pre-acidified skim milk powder was prepared by intimately mixing
¦ the following finely ground food-grade acids with a second 15 pound portion
¦ of NFMS: 120 9 tartaric acid, 120 9 citric acid, 72 9 malic acid and 84 9
¦ adipic acid. The pre-acidified skim milk powder was reconstituted using
~ the reconstituted skim milk prepared in the preceding paragraph at 18C and
¦ the powder funnel system, to obtain a skim milk having approximately 10.7%
¦ solids. The reconstituted acidified skim milk pH was 5.11. The skim milk
I was then warmed, with agitation, from l8C to 36C where its pH was 5.09.
¦ The small amount of denatured foam present on the surface of the
l reconstituted acidified skim milk was removed and discarded. A one quart
¦ sample of the acidified skim milk was set aside for 30 min and then carefully
¦ decanted. There was no sediment present in the sampl~e and no specks of
precipitated casein were found in the sample.
Added, with stirring, to the vat of heated acidified milk, 480 g of
¦ acidogen (D-glucono-delta-lactone) and stirred for 2 min. Then added, with
I ¦ stirring, to the vat, 36 ml cottage cheese coagulator (dilute rennet extract,
- ¦ Hansen's) diluted in 200 ml water and stirred for 2 min. Milk pH was 5.05.
¦ Allowed acidified skim milk to set undisturbed for 1 hr. A normal,
firm, cottage cheese type curd formed. The curd was cut with 5t8" wire knives. I
l Cut was very clean, smooth and normal. Whey exuded from curd normally. Whey
¦ pH was 4.85. Curd was allowed to set for 15 minutes to "heal" and 30 ml of
l 85% phosphoric acid diluted with 1 qt warm water was added to the cut curd.
¦ Then stirred the cut curd gently and cooked curd slowly to 52C. The cooked
curd was slightly soft, but was an acceptable large curd type cottage cheese
curd. Whey pH was 4.62. Drained whey, washed curd 3 times with water,
trenched curd and drained for 30 min.
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1 ¦ ~eight of drained curd was 56.75 lbs. Yield, based on 280 lbs
¦ skim milk was 20.27% or 1.89 lbs of curd per each 1 lb of NFMS used. `
Moisture in the curd was 79.4% (80% is legal maximum). Weight of the curd
l calculated to an 80% moisture level was 58.45 lb. Yield of curd was 20.87%
¦ or 1.95 lb of curd per each 1 lb of NFMS (powdered skim milk3 used.
EXAMP E I I I
To two quarts of commercial pasteurized skim milk (1950 g) having a
pH of 6.70 and a temperature of 4C were added with mechanical agitation, 4.7
ml of 85% phosphoric acid (undiluted) drop wise to reduce the milk pH to 5.02.
The milk pH remained unchanged on warming to 13C. Then 4.5 g of sodium
polyphosphate ("Vitrafos", Stauffer Chemical Co.) was added and dissolved in
the milk by stirring for about 1 min to obtain an acidified milk having a
pH of 5.09. The acidified skim milk was warmed to 33C where its pH was
5.22. -`
A solution of 8 9 of D-glucono-delta-lactone dissolved in 20 ml
of water was added to the warm skim milk and mixed by stlrring for 1 min.
Then 0.45 ml standard strength cottage cheese coagulator (dilute rennet
extract, Hansen's) diluted with 5 ml water was added to the warm milk and
mixed by stirring for an additional 1 min.
Agitation of the acidified milk, lactone and coagulator mixture
was then discontinued and the mixture allowed to stand undisturbed at 33C
for 2 hr to form a cottage cheese type curd which was cut into small 3/8"
cubes. The cubes were allowed to settle and "heal" for 30 min while
whey having a pH of 4.53 exuded normally. The cut curd cubes were then
heated externally using a hot water bath while they were stirred and cooked
~ to 54C. No matting of the curd cubes occurred during cooking but there was
; 30 some slight break-up of the cubes with some "fines" being formed.
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1 ¦ Whey having a pH of 4.45 was drained from the cubes. The curd
¦ cubes were then washed 3 times with successively colder water washes,
drained after each wash, transferred to a cheesecloth bag and drained
l for the last time. The drained curd weighed 345 9 and had a moisture
¦ content of 80%. The dry curd yield was 17.7%. The skim milk contained
about 9% solids giving a solids recovery yield of 1.96 lbs dry curd per
pound of skim milk solids.
The yield was above average.
10 1
EXAMPLE IV
¦ A total of 30 gal (260.75 lb) of commercial pasteurized skim milk
I ¦ having a total solids content of 9.2%, a temperature of 3C and a pH of 6.7 1-
1 was charged into a cheese vat. Then 200 ml of undiluted 85~ phosphoric :
acid was slowly poured into skim milk and dispersed rapidly using hand-
l paddle agitation. The pH of the acidified skim milk was 5.44. An ~ -
I I additional 50 ml of 85% phosphoric acid was stirred into acidified milk using
¦ the same procedure. After the second acid addition, the milk pH was 5.29.
I ,. .. ' .-
¦ The acidified skim milk was then warmed with stirring to 27C and
I 70 9 monocalcium phosphate and 420 9 sodium polyphosphate ("Vitrafos",
¦ Stauffer Chemical Co.) were added with stirring. Continued stirring and
warmed the milk to 41C where the milk had a stable, rich, creamy ¦~
¦ appearance and a pH of 5.30.
I Added 408 9 D-glucono-delta-lactone to the warmed, acidified
milk and stirred for 2 min. Then added 45 ml cottage cheese coagulator
(rennet extract, Hansen's) diluted with 200 ml water to the milk in the vat
¦ and stirred for 2 min. At this point, the skim milk pH was 5.21.
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1 ¦I The milk was then allowed to stand undisturbed for 1 hr at 40C
¦¦ and formed a medium firm, typical cottage cheese type curd. The curd was
I cut with S/8" wire cheese knives. Allowed the cut curd cubes to set and
¦ "heal" for 1/2 hr. Whey having a pH of 4.92 exuded rapidly from the cubes.
¦ Circulated hot water through vat jacket while the curd cubes were cooked
and stirred in the vat in usual manner while heating to 57C over 1 hr.
The cooked cubes were slightly soft.
Drained whey having a pH of 4.70 from the cubes. The cubes were
then washed with 3 successively colder water washes; first wash was with
28C water, second wash was with 14C water and third was with 3C water.
After the third wash, drained, trenched and then drained the trenched cubes
for 30 min. --
, The drained curd cubes were slightly soft, but "meaty". There was
no free whey inside the cubes. Weight of drained curd was 54.25 lb and the
moisture content was 83.3%. Weight of curd cubes calculated to 80% moisture,
was ~5.3 lbs. Yield was 17.37% or 1.89 lb dry curd per pound of skim milk
solids.
,11
, 20 Yield was above average.
..
; EXAMPLE V ;
A total of 30 gal (261.25 lb) of commercial pasteurized skim milk
having a total solids of 9.25% by weight, a temperature of 3C and a pH of
6.72, was charged into a cheese vat. Then added, with good agitation, 950 9
instant non-fat-milk-solids (powdered skim milk). Total solids in the skim
milk after the powdered milk addition was 10.4%. Using good hand-paddle
agitation, 200 ml of undiluted 85% phosphoric acid were slowly poured into
skim milk to reduce the pH to 5.25.
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1 The acidified skim milk was warmed by circulating warm water
through the jacket of the cheese vat. When the milk temperature reached 19C,
10 9 monocalcium phosphate and 475 9 sodium polyphosphate ("Vitrafos",
Stauffer Chemical Co.) were added with stirring. The stirred skim milk was
warmed to 41C. Appearance of milk at 41C was rich, creamy, clean with no
specks or foam and the pH was 5.25.
Then 408 9 of D-glucono-delta-lactone was added with stirring to
the warm milk and the milk was stirred for 2 min. Diluted 36 ml cottage
cheese coagulator (dilute rennet extract, Hansen's) with 150 ml water and
poured the diluted cheese coagulator into the milk and stirred for 2 min.
At this point, the milk pH was 5.13. Then allowed skim milk to stand
undisturbed for 1 hr at 41C to form a firm cottage cheese type curd. i
Curd cut was very clean, and easy with 5/8" knives. Allowed cut curd cubes
to "heal" for 15 minutes. Whey pH was 4.88. Added 10 ml of 85%
phosphoric acid to 1 pt warm water and distributed the diluted acid over
cut curd cubes. Then gently stirred the diluted acid into curd cubes and
whey and allowed curd cubes to set another 10 min.
; Circulated warm water through vat jacket. The curd cubes were
stirred and cooked to 43C over 20 min. Very little matting of curd and
minimum shattering occurred during stirring and cooking. The cubes were
cooked another 30 min to 52C. They firmed slowly, were cooked another ~ ;
10 min to 54C and then drained. The whey pH was 4.67. The curd cubes -
were washed three times: first wash at 28C, second wash at 10C, third
wash at 0.6C. Trenched the curd cubes and then drained the cubes for 50
min.
Moisture in curd was 83.0%. Weight of curd calculated to 80%
, moisture was 51.21 lb. Yield based on 283.85 lb skim milk (261.25 lb
starting skim plus 22.6 lb skim milk from the 950 9 added skim milk powder)
;~ ~ ~
,
., , __ . . _, . _ , , _.. . ,, , , ,.. ,, . . , ~ , ~ . . .. , . . , . _ .. , _ , _, , ., , . .,, ., .. , . ~ _ ,, ,, . . ,, .
- - : --:
108Z042
was 18.04%. Yield on total skim milk solids present (26.25 lb total non-fat
milk solids) was 1.95 lb curd per pound of non-fat milk solids.
l Yield was above average.
5 j
EXAMPLE VI
Two quarts of commercial skim milk having 9.2% total solids were -~
warmed to 27C. Then 2.4 9 monoammonium phosphate, 2.4 g disodium
phosphate~.2 g monocalcium phosphate, and 4.8 9 sodium polyphosphate
("Vitrafo , Stauffer Chemical Co.) were added to the stirred warm milk.
After the phosphate additions, the milk pH was 6.55. Then using vigorous
mechanical agitation, 6 ml undiluted 85% phosphoric acid was added in 1 ml
increments to the warm milk at 27C. Skim milk pH after each 1 ml increment
addition was: 6.23, 5.95, 5.68, 5.41, 5.16 and 4.94 respectively. There
were no specks of precipitated protein present in the milk and the milk was
normal in appearance.
.
The acidified skim milk was then warmed to 32C. Milk pH at 32C
was 4.96. Then 6 g of D-glucono-delta-lactone was added with mechanical
ag;tation and the mixture stirred for 1 min. Diluted 0.35 ml cottage
cheese coagulator (dilute rennet extract, Hansen's) with 20 ml water,
added the diluted coagulator to the skim milk and stirred the mixture for
1 min. After this addition, pH of the milk was 4.92.
' . .
The milk was then allowed to stand undisturbed for 65 min and
I ~ formed cottage cheese type curd, which was slightly softer than normal, but
acceptable. Curd was cut into 3/8" cubes which were allowed to "heal" 15
min, then cooked and stirred in usual manner to 49C. Curd cubes shrunk and
firmed satisfactorily. Drained whey from curd cubes, washed cubes 3 times
with successively colder water and drained washed curds in a cheesecloth bag.
-18-
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.. . .. ' ' '. : :: . - ' -
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~ . . . - . .
108;~)4Z ~:
Weight of drained curd, adjusted to 80% moisture, was 373.7 9.
Yield was 19.17~ or 2.08 lbs of curd per pound of skim milk solids.
Yield was above normal.
EXAMPLE VII
Pasteurized skim milk (1850 gal having a total solids of 9.2%) was
acidified in-line, at 8C, by metering undiluted 85% phosphoric acid into
the milk line leading to the cheese vat to obtain an acidified milk having a
pH of 4.95. -
The acidified skim milk was mechanically agitated and heated to
32C by circulating warm water through the vat jacket~During heating,
three 16 lb portions of sodium polyphosphate ("Vitraf ', Stauffer Chemical
Co.) were added between 10C and 16C to the milk. On heating to 32C, the -skim milk had a pH of 5.2. A solutton of 80 pounds of D-glucono-delta-
lactone in 15 gal of water was prepared, poured into the acidified milk at
32C and the mixture stirred for 4 min. Cottage cheese coagulator (dilute
rennin solution) was prepared by diluting 23.5 fl oz of standard strength
cottage cheese coagulator (dilute rennet extract, Hansen's), in 2 gal of
water, poured into the acidified milk mixture and stirred for 3 min.
..
The skim milk was then allowed to set undisturbed at 32C for 105
min and formed a normal cottage cheese curd. The curd was cut with 1/4"
wire knives and allowed to "heal'' for 15 min. The whey had a pH of 4.65.
Diluted 54 fl oz of 85% phosphoric acid with 2 gal of warm water and poured
the diluted acid over the cut curd cubes which were then cooked and stirred
in the usual manner to 49C in 90 min.
Drained whey having a pH of 4.42 from the curd cubes. Then washed
cubes with 3 successively colder water washes. Last wash was ice water
_19_
. .
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. . :. . . ...... - . .. . .. . ,:... . -........ . . . . . .
.. . .- . ~ - .. ,.. .-: . .. ... ~ . . .
.. . . .. - . , , ~ . - ~: -
: . . . .
. . . . ............ . . . . . .. .
108204Z
containing 32 fl oz of a 50% citric acid solution. The curd cubes were
set overnight in the acidified ice water wash and wash water was drained
the next morning. The curd cubes were then piled, allowed to drain and
~ shoveled into bulk containers where they were mixed with a pre-weighed
¦ amount of cream dressing.
l Weight of dry curd obtained was 2790 lb having a moisture content of¦ 77.19%. Calculated to an 80% moisture content, the dry curd weight would be
l 3182 lb. Dry curd yield was 20%, or on a solids basis, 2.17 lb curd per
10 ~ pound skim milk solids.
An equal volume of skim milk, from the same bulk tank, was made
into cottage cheese by culturing with a bacterial starter, and no phosphate
¦ was added to the skim milk. Cheese curd obtained from this vat was 2403 lb
I after adjustment to an 80% moisture content. Yield of cultured curd was
1 15.1%, or on a solids basis, 1.64 lb curd per pound skim milk solids.
I .-.
EXAMPLE VIII
This example demonstrates preparatlon of a polyphosphate baker's
cheese product.
A 2 qt sample of commercial, pasteurized skim milk (1945 9), total
solids of 8.4% was heated slowly to 59C and then cooled to 5 C. The
,l purpose of this second heat treatment was to modify the milk proteins to
produce a softer curd which is desirable in baker's cheese.
l~ Then 4.5 ml of undiluted 85% phosphoric acid was added with
mechani cal agi tation to the 5C milk. After acidification, the milk
had a pH of 4.88 and no curdiness or precipitation~casein was observed.
A total of 5.6 9 of sodium polyphosphate ("Vitrafos~, Stauffer Chemical Co.)
was added to the acidified milk. After the polyphosphate addition, the pH
-20- -
~ . ~'.
. ~ . . .... . ....... .. . . . ... .. .. .. .. ... ... . . . . .
~ ,
~18'~4'~
1 was 4.98.
The acidified skim ~ilk was warmed to 32C and 5.6 g D-glucono-
delta-lactone (acidogen) added. The milk was then stirred for one min
and then 0.3 ml cottage cheese coagulator (dilute rennet extract,
Hansen's) diluted with 5 ml water was added to the skim milk. The milk
was then stirred for 1 min and allowed to set undisturbed for 1 hr at 32C.
A very soft, smooth curd formed.
The curd was cuttable, but not a firm cut. The curd was broken up
using a spatula and gentle mechanical stirring. The curd-whey mixture had
a pH of 4.9. Then 0.75 ml 85% phosphoric acid was added and the curd stirred
for 1 min. Whey pH was 4.65. The curd-whey mixture was filtered through
coarse filter paper, then drained further in a cheesecloth bag, with slight
; pressure on bag to obtain an acceptable baker's cheese. Moisture in thecurd was 73.0% and pH was 4.6. Weight of curd was 243 9. When ca1culated to
an 80% moisture level, weight of curd was 328 9. A percentage yield of
16.8% did not appear to be high until the low solids content (8.4%) of the
starting skim was considered. On a solids basis, the yield was 2.0 lbs
curd per lb of so-lids, which is well above normal.
.
EXAMPLE IX
.' . . "
To 2 qt (1950 9) of commercial pasteurized skim milk having a
total solids of 11.3% and a pH of 6.64 were added at 6C:
2.4 9 monoammonium phosphate
1.2 9 monocalcium phosphate
2~4 g disodium phosphate
4.8 9 sodium polyphosphate ("Vitrafos", Stauffer
Chemical Co.).
~ 30
`~ -21-
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. . . . , ... . : . : ~- . . . . :
. . . ,. . . , . . . ~ : . .-
~ 108Z~)~Z
1 After these additions, pH of milk was 6.42.
To 190 g of 85% phosphoric acid was added 30 9 of potassium
polymetaphosphate. The acid was warmed until the phosphate dissolved,
then was cooled to room temperature to obtain a clear, syrupy, phosphoric
acid-phosphate solution.
To the above 2 qt of skim milk was added at 11C, 5.5 ml of the
phosphoric acid-phosphate solution, slowly with vigorous mechanical
agitation. The pH of the ~cidified skim milk was 5Ø No instability
of the acidified milk was observed and no specks of precipitated casein
were noted.
The acidified skim milk was then warmed to 33C, with stirring,
in a 41C water bath. The pH of the warm milk was 5.13. Then added 0.9 ml
cottage cheese coagulator (dilute rennet extract, Hansen's) diluted in 10 ml
water and stirred for 2 min. The milk was allowed to set undisturbed for 1
hr at 33C. A rather firm, cottage cheese type curd formed.
The curd was cut into 3/8" cubes, allowed to set and "heal" for
40 min. Whey pH was 5.15. Diluted 1 ml 85% phosphoric acid with 20 ml hot
water and distributed the diluted acid over top of the cut curds. Whey pH
was 4.82. The cut curds were cooked and stirred in usual manner to 52C in
1 hr. Curds were "meaty" with no free-whey inside curd particles. Drained
whey from curds and washed drained curds with successively colder water,
drained last water, then drained further in a cheesecloth bag. Weight of
drained curds was 367 g representing a yield of 18.8%. Moisture in curds
was 71.3%. Calculated to an 80% moisture basis, weight of curds was
~¦ 526.6 g. ield was 27% or 2.39 lbs curd per lb NFMS.
~ 22-
,
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108;~0~2
I ~ ~XAMPLE X
This example is a control experiment to determine cheese curd yield
~ when a polyphosphate is not added.
¦ A mixture of 1.2 g fumaric acid, 1.2 g citric acid and 0.8 g
¦ succinic anhydride was ground in a mortar to a fine powder. This powder -
¦ was intimately mixed into 100 g of low heat, non-fat-milk-solids (skim milk
¦ powder).
To 1 qt of water at 24C were added: .-
¦ 1.1 9 monoammonium phosphate
1.1 g disodium phosphate
1.1 g monocalcium phosphate
0.5 g magnesium chloride.
15 1
The resulting water solution had a pH of 6.17. To the water solution, at
24C, was added the pre-acidified non-fat-milk-solids mixture prepared above
using vigorous mechanical agitation to obtain an acidified reconstituted
¦ skim milk having a pH of 5Ø
¦ Warmed the milk to 32C where it had a pH of 4.9. To the warm milk
¦ at 32C added, with stirring, 4 g D-glucono-delta-lactone (acidogen) which
had heen dissolved in 20 ml of water. Then mixed 0.24 ml cottage cheese
coagulator (dilute rennet extract, Hansen's) with 5 ml water and added this
¦ mixture to the warm skim milk. Stirred the mixture for 2 min to obtain a
1 milk having a pH of 4.89. Allowed milk to set undisturbed for 1 hr at 32C.
I A smooth, medium firm, normal cottage cheese curd formed.
}, I Cut curd into 3/8" cubes. Whey exuded in a normal manner and had
I a pH of 4.7. Heated the cut curds, cooked and stirred for 25 min to a
I ~. .
,~ I :
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)4Z
¦ temperature of 53C. Curds cooked and shrunk in a normal manner. Drained
¦ whey having a pH of 4.55. Washed curds 3 times with successively colder
¦ water; let drain. Weight of drained curds was 142 g representing a yield
¦ of 14.56% or 1.42 lbs curd per lb of NFMS. Moisture in curds was 79.2~.
I Calculated to 80% moisture, weight of curds was 147.7. Yield of 80%
moisture cheese curd was 15.15% or 1.47 lbs curd per lb NFMS.
l EXAMPLE XI.
10 ¦ This example shows cheese curd yield is improved when a poly-
phosphate is added.
A mixture of 1.6 g fumaric acid and 1.6 g citric acid was ground in
a mortar to a fine powder. This powder was intimately mixed into 57 9 of non-
l fat-milk-solids (skim milk powder).
15 I
To 1 qt of water at 22C were added:
¦ 1.2 9 monoammonium phosphate
0.5 9 monocalcium phosphate
l 0.6 g disodi um phosphate
I 1.1 g sodium polyphosphate ("Vitrafos", Stauffer
Chemical Co.).
¦ The resulting water solution had a pH of 6.3.
I :-
To the water solution added, with stirring, 57 9 of regular,
25 ¦ unacidified, non-fat-milk-solids to obtain a reconstituted skim milk having a pH of 6.4.
I To the reconsti tuted milk at 22C added wi th vigorous mechanical
; ~ agitation, the 57 9 of pre-acidified non-fat-milk-solids prepared above to
obtain an acidified,reconstituted skim milk having a pH of 5.13. Warmed the
3o -
: r 2 4~
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108Z04Z
milk, with stirring, to 33C where its pH was 5.15.
Dissolved 4 9 acidogen ~D-glucono-delta-lactone) in 20 ml water,
added and stirred into the warmed skim milk. Then diluted 0.25 ml cottage
cheese coagulator (dilute rennet extract, Hansen's) with 5 ml water, added
to skim milk and stirred for 1 min. Allowed the milk to set undisturbed
for 70 min. A firm, normal, cottage cheese curd formed.
Cut curd into 3/8" cubes. Whey exuded slightly slower than normal.
The whey pH was 4.85. Warmed the cut curds, cooked and stirred to a
temperature of 52C. Curds firmed well, were heavy, settled easily and
had no tendency to mat or stick together. Drained whey having a pH of 4.7.
Washed curds 3 times with successively colder water and drained. Weight of
; drained curds was 190 9 representing a yield of 17.9% or 1.66 lbs curd per 1
, lb NFMS. Moisture in curd was 77.2%. Calculated to an 80% moisture basis,
weight of curds was 216 9 representing a yield of 20.3% or 1.89 lbs curd per
1 lb of NFMS.
'. . ' . "~
. EXAMPLE XII
This example shows cheese curd yield is further improved when
additional polyphosphate is added.
:
A mixture of 1.6 9 tartaric acid, 1.0 9 citric acid and 0.6 9 malic
acid was ground in a mortar to a fine powder. This powder was intimately ~ ~-
mixed with 57 g non-fat-milk-solids (skim milk powder).
-
, To 1 qt of water at 18C were added:
i~ 1.2 9 monosodium phosphate
0.7 9 monocalcium phosphate
0.5 ml of an anti-foam solution (food grade) and
-25-
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.. . ..... _.... , .. .... ~
, . . .. . . . . .
~ . ,
~8Z~4Z
l ~ l
1 1 2.1 9 sodium polyphosphate t"Vitrafos", Stauffer
Chemical Co.).
l The resulting water solution had a pH of 5.65.
¦ To the water solution was added, with stirring, 57 g of regular,
unacidified, non-fat-milk-solids to obtain a reconstituted milk having a
pH of 6.25.
l Then added, with vigorous mechanical agitation, the 57 9 of pre-
1 acidified NFMS to the milk at 18C to obtain an acidified, reconstituted
skim milk having a pH of 5.12. Warmed the milk, with stirring, to 38C
I where its pH was 5.17. Milk was rich in appearance, shiny, smooth, with
; ¦ no specks of precipitated casein. ~-
. - .
l Added 5 9 of D-glucono-delta-lactone (acidogen) to the milk at
¦ 37C and stirred for 1 min. Diluted 0.25 ml cottage cheese coagulator
(dilute rennet extract, Hansen's) with 10 ml water, added to the milk and
stirred for 1 min to obtain a skim milk having a pH of 5.1. Allowed the
milk to set undisturbed at 37C for 1 hr. A firm, smooth, cottage cheese
curd formed.
. 20 Cut curd into 3/8" cubes. Whey hav;ng a pH of 4.84 exuded
easily. Warmed, cooked and stirred curds to a final temperature of 54C.
Drained whey having a pH of 4.54. Washed curds 3 times with successivelY
colder water, then drained. Weight of drained curds was 237 g representing
a yield of 22.36% or 2.08 lbs curd per lb NFMS. Moisture in curd was 81.2%.
Calculated to an 80% moisture basis, weight of curd was 222.8 g
representing a yield of 21% or 1.95 lbs curd per lb of NFMS.
. .~ '.
The foregoing yield values are well above an average calculated
yield of 15.36% obtained by averaging yield figures for 15 vats of cultured
cottage cheese and an average c lculated yield of 1.66 lbs curd per lb of NFMS
.
.
_ _. , . , . , .. ,. . -- . . . . . . . .. . . .... .. . . , ,, . _ ___ _
.
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1(~ 04Z
¦ obtained by dividing lbs of cheese per 100 lbs of milk by the lbs of solids
¦ in 100 lbs of milk using the data in Table 2 on page 717 of the article
entitled "Relation Between Certain Skimmilk Constituents and th~e Yield of
l Cottage Cheese" by Bender and Tuckey in J. Dairy Science, Volume 40,
713-721 (1957).
I EXAMPLE XIII
I
This example shows that yield is increased, if polyphosphate is
added to a vat of cheese milk, the milk is then acidified by adding a -
lactic-acid producing bacterial culture and making cottage cheese by the
usual culturing method.
Into a cheese vat was pumped 86 gals of pasteurized skim milk at
27C. Milk pH was 6.65, titratable acidity was 0.14% and total solids content
was 8.65%.
Added, with stirring, 804 9 of sodium polyphosphate ("Vitrafo~),
Stauffer Chemical Co.). Skim milk takes on a watery, pale appearance due
to the polyphosphate altering the colloidal state of the calcium. (The
normal white appearance returns as acid is produced and the calcium returns
to its original colloidal state). Skim milk was warmed, with stirring, to
32C. At 32C, 5 gals of an actively growing, lactic-acid producing,
bacterial starter was added and stirred in thoroughly. Milk was allowed to
set for 1 hr to ripen, titratable acidity increased to 0.20% indicating the
culture to be growing and unaffected by the added polyphosphate.
` At this point, 20.5 ml of cottage cheese coagulator (dilute rennet
extract, Hansen's), was diluted with 90 ml clean, cool water, added to the
at and stirred in thoroughly. Stirring was stopped and skim milk allowed to
culture undisturbed.
-27-
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108Z04Z
1 ¦ In 5-1/2 hrs (from time of adding starter) the milk returned to
its original white appearance, a medium soft cottage cheese type curd formed
and the pH of some expressed whey was 4.75.
¦ Curd was cut into 1/4" cubes, using wire knives. Cut was clean,
¦ easy, slightly soft but curds did not break-up.
Curd was allowed to settle and "heal" for 15 min.
¦ Warm water was pumped through the cheese vat jacket and the cut
¦ curds were stirred gently and cooked in the usual manner to a temperature of
51C.
Curds were firm, "meaty", of good texture and fine taste. ; -
¦ Whey, with a pH of 4.7, was drained from the curds.
¦ Curds were washed with two water washes, first wash at 27C and
second, final, wash at 8C.
¦ Wash water was drained.
¦Curds were trenched in vat and allowed to drain.
1 .
Weight of drained curds was 118 lbs. Moisture in drained curds was
¦ 80.81%. Calculated to an 80% moisture basis the weight of curd was 113.22
¦ lbs. Yield, based on 788 lbs total skim milk, was 14.37%, Qr on a solids
¦ basis, 1.66 lbs. curd per lb of NFMS.
25 1 A control vat of cultured cottage cheese was made, using the same ; ¦ herd milk, in the same equ1pment and by the same cheese maker.
Total solids in the control skim milk was 8.91%. From 828.7 lbs --
¦ of this skim milk, with no polyphosphate added, 111.6 lbs of curd (corrected
¦ to 80% moisture~ was obtained. Control yield was 13.5%, or on a solids basis,
-28-
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108;~042
1 1.51 lbs curd per lb of NFMS.
On a solids basis the increase in yield of the phosphate cheese
~ curd compared to the control cheese curd was 9.9%.
I While the invention has been described with reference to certain
specific embodiments thereof, it is understood that it is not to be so
limited since alterations and changes may be made therein which are within
the full intended scope of the appended claims.
10 ~ . . ~
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