Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a process for the production of a
pasteurised cheese in powder form which, after reconstitu-
tion, has the properties of Mozzarella.
5 It is known that Mozzarella is a cheese with stretching and
stringing properties which is used in large quantities in
the production of pizzas. The often artisanal processes for
producing Mozzarella generally result in the formation of a
curd which is very difficult to handle. The individual opera-
tions involved are numerous and laborious and involve relati-
vely high production costs. In addition, major problems are
involved in the distribution and keeping of this-cheese, in
addition to which there are no absolute guarantees from the
bacteriological point of view. In addition, the fact that it
is virtually impossible to find any stable commercial product
containing all the ingredients required for the production of
a plzæa, including cheese, shows how difficult it is to provl-
de for public consumptlon a powder-form cheese of which the
taste, appearance and properties after reconstitution are the
same as those of Mozzarella.
There is already a known process for producing Mozzarella in
powder form, although the cheese obtained in this known pro-
cess, by the nature of its individual operations, is not a
pasteurised cheese. Although the bacteriological risks may
readily be controlled in a modern distribution circuit, there
is a risk that non-pasteurised Mozzarella in powder-form will
be left for too long on the shelves of a rural grocery store
or will not be properly stored or used by the consumer.
The invention specifically provides a solution to these bac-
teriological problems because it enables a pasteurised cheese
to be produced in powder form. The invention relates to a
production process in which
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- a colloidal lactic starting solution having protein/lactose
and protein/calcium ratios at least about twice as high as
those of natural mllk and a pH-value in the range from 5.0
to 5.5 is prepared,
S - this solution is adjusted to a pH-value of from 6.3 to 6.4
and pasteurised,
- the pH is returned to a value of from 5.0 to 5.5,
- and finally the solution is dried to give said cheese in
powder form.
In the context of the invention, the expression "colloidal
lactic solution" is understood to mean an aqueous solution
which essentially consists of the constituents encountered
in animal milk and which has the principal properties thereof.
Accordlngly, the irst step of the process according to the
lnvention comprises preparing this colloidal lactic solution.
In a first embodiment, this solution is obtained by reconsti-
tution in water using for example concentrates or powdersof casein, lactalbumin (if desired), lactose, mineral salts...
The proportions are such that the solution obtained has pro-
tein/lactose and protein/calcium ratios at least about twice
as high as those in natural milk. The pH is adjusted by chemi-
cal acidification, for example using hydrochloric acid. In apreferred variant, the pH-value is adjusted by biological
acidification, in particular using the normal acidifying
ferments of milk.
In another embodiment, the colloidal lactic solution is pre-
pared by ultrafiltration. In this way, it is possible direct-
ly to obtain as retentates products having protein/lactose
and protein/calcium ratios at least about twice as high as
those of the milk used. If desired, particularly for adjusting
the protein/lactose ratio and the demineralisation level, it
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is possible to apply diafiltration, i.e. to dilute the reten-
tate during the ultrafiltration step. In the same way as
I before, the pH-value is adjusted chemically or biologically,
acidification being possible with the dilution solution used
ln the event of diafiltration which may consist of a cheese
whey for example. Ultrafiltration may even be carried out at
elevated temperature if it is desired to increase the yield
of treated product. In this particular case, the proteins may
be denatured beforehand by heating, in particular by the in-
jection of steam.
In a preferred variant, a whole milk or skimmed milk is bio-
logically acidified to a pH value of only from 5.8 to 6Ø
This acidified milk is then subjected to ultrafiltration and
biological acidification is allowed to continue during the
ultrafiltration step so that the retentate obtained is the
starting colloidal lactic solution which has both the above-
mentioned ratios higher than those of natural milk and the
desired pH-value in the range from 5.0 to 5.5.
It should be pointed out that the use of ultrafiltration has
the advantage o a better yield because the serum proteins or
lactalbumin are retained and end up in the powder-form cheese.
In addition, a higher acceptable lactose content is not only
possible, but also readily controllable.
The next step of the process comprises raising the pH of the
solution to a value of from 6.3 to 6.4 which may readily be
achieved by the addition of an alkali, such as sodium hydro-
xide for example. Pasteurisation becomes possible at a pH-
value of this order whereas, at a pH-value in the range from
5.0 to 5.5, it would have given rise to precipitation of the
product. Pasteurisation may be carried out by the injection
of steam, for example at a temperature in the range from 70
to 140C.
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When the pH-value of the solution is in the range from 6.3
to 6.4, a fat, such as butter oil, peanut oil or soya oil
or even a high-melting fat, such as hydrogenated palm oil
for example, may be added, especially with heating, for
example to a temperature of approximately 55 to 65C. The
object of adding a fat is to standardise the powder-form
cheese or to form a cheese having normal fat content where
the starting colloidal solution is a skimmed milk solution.
If it is desired to obtain alow-fat cheese, it is of course
possible to start with an at least partly skimmed-milk solu-
tion and not to add any fat. The solution obtained after
the addition of fat is preferably homogenised before pasteu-
risation, for example using a homogenizer or directly by the
injection of steam.
The subsequent step, re-acidification of the solution to a
pH-value of from 5.0 to 5.5, may be carrled out chemically
or blologically in the same way as for the starting solution.
It ls preferably carried out chemically by the addition of
hydrochloric acid. Under these conditions, the salt formed
through neutralisation and chemical acidification replaces
at least a large part of the salt which would otherwise have
to be added to the product before drying. Reacidification is
again preferably carried out after cooling to between 5 and 10C.
Finally, the solution is dried to form a powder. Drying may
be carried out in any way, for example in a spray-drier or
by freeze-drying.
It should be pointed out here that the process according to
the invention differs radically from the traditional proces-
ses for producing Mozzarella because, in these traditional
processes, the starting milk is coagulated which involves a
physico-chemical modification of the proteins and a fundamen-
tal change in their properties. By contrast, in the process
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according to the invention, the proteins do not have to under-
go any modification and may remain in their native state.
There is no coagulation.
The powder-form cheese obtained is a pasteurised cheese which
is thus characterised by bacteriological stability. After
reconstitution in water, it forms a paste which has the
stretching properties and the behaviour of Mozzarella. Accor-
dingly, this cheese may readily be used as a substitute for
the traditional cheese, particularly in the production of
pizzas.
The process according to the invention is illustrated by the
following Examples in which the percentages quoted represent
percentages by weight.
Example 1
A standardised milk is pasteurised for 15 s at 72C. After
cooling to 37C, the milk thus pasteurised is inoculated with
a thermophilic lactic starter, acidification being left to
continue to a pH equal to 5.9. After cooling to 20C, ultra-
filtration is carried out in an apparatus of the plate type
equipped with cellulose acetate membranes having a cut-off
of 6000. Ultrafiltration is carried out at a temperature of
20C to a reduction in volume of 3 to l which means that the
volume of the retentate is one third of the volume of the
starting milk. During ultrafiltration, acidification continues
and the retentate has a pH equal to 5.2.
This pH is raised to 6.3 by the addition of a solution of
sodium hydro~ide, followed by pasteurisation by the injection
of steam for 15 s at 80C.
The pasteurised product is then cooled in a plate-type heat
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exchanger to a temperature of the order of 8C and then re-
acidified to pH 5.2 by the addition of hydrochloric acid.
I
This product, which has the stretching and stringing proper-
s ties, is lntroduced into a drying tower from which a powderis collected.
When reconstituted in water, this powder gives a stringy
paste which so resembles as to be mistaken for Mozzarella.
It may be used in the production of pizzas.
Example 2
A skimmed milk is pasteurised for 15 s at 75C. The milk thus
pasteurised is cooled to 37C and inoculated with a culture
of lactic ferments. Biological acidification is left to con-
tinue to pH 5.8. After cooling to 20C, ultrafiltration is
carried out in an apparatus of the tubular type equipped
wlth cellulose acetate membranes having a cut-off of 20'000.
Ultrafiltration is continued at ambient temperature to a re-
duction in the volume of the retentate to one third of the
initial volume. During ultrafiltration, acidification is
continued and the retentate has a pH equal to 5.3. The reten-
tate is neutralised to pH 6.3 by the addition of sodium hydro-
xide and then heated to 50C. Hydrogenated palm oil having atemperature of 60C is then added in such a quantity that the
end product contains 45 % of fats based on dry matter. The
concentrate thus standardised is homogenised under a pressure
of 200 bars. It is heated for 20 s to 82C by the injection
of steam and then cooled to 10C in a plate-type heat exchan-
ger. Its pH is adjusted to 5.2 by the addition of hydrochloric
acid, followed by spray drying. A powder is obtained which,
after reconstitution, has the same properties as Mozzarella,
particularly its stretching and stringing properties.
If this powder is rehydrated with different quantities of
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water ranging from 40 to 60 ~ by weight of dry powder and
then heated to different temperatures ranging from 5G to 80C,
a pasty mass is obtained in each case, so resembling as to be
mistaken for Mozzarella.
If the powder is rehydrated without heating and if a pizza
is made with the mass obtained, the product removed from the
oven has the appearance, texture and taste of a pizza made
from traditional Mozzarella.
Example 3
A powder is prepared in the same way as described in Example
2 except that melted butter is used instead of the hydroge-
nated palm oil. A product having the properties describedin Example 2 is obtained.
Example 4
A reconstltuted skimmed milk having a dry matter content of
15 % is prepared from skimmed milk powder. It is then steri-
lised for 10 s at 120C by the injection of steam. After
cooling to 10C, the product thus sterilised is acidified
to pH 5.2 by the addition of hydrochloric acid. It is then
subjected to ultrafiltration and to diafiltration on a conti-
nuous production line equipped with modules of the tubular
type fitted with membranes having a cut-off of 20'000. This
operation is continued until the retentate has a lactose con-
tent of 20 % based on dry matter. Its pH is then adjusted to
pH ~.3 by the addition of sodium hydroxide, followed by
heating to 55C. Soya oil heated to 60C is then added to the
retentate which thereafter is treated at a temperature of
120C by the injection of steam for lO s. After cooling to
10Ç, it is adjusted to a pH of 5.2 by the addition of HCl
and dried by spray-drying. A powder is obtained in which the
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particles of fat are attached particularly firmly to the
proteins and which, after reconstitution, has the properties
of a particularly creamy Mozzarella.
Example 5
A fresh skimmed milk is subjected to heat treatment at 120C
for 30 s by the injection of steam. It is then subjected
to hot ultrafiltration at a temperature of 55C in an appara-
tus of the plate type equipped with cellulose acetate membra-
nes having a cut-off of 20'000 which enables a better output
to be obtained. A retentate having a dry matter content of
15 % is collected. It is cooled to 38C, inoculated with 2 ~
of a culture of thermophilic lactic ferments containing acidi-
fic~tion activators and acidification left to continue to pH5.3. The product is now subjected to diafiltration to adjust
the proteln/lactose ratio and to obtain the required demine-
ralisation level. The pH is increased to 6.2 by the addition
of NaOH and hydrogenated palm oil is added in a quantity cal-
culated to give a fat content of 45 % based on dry matter. Themixture is homogenised, pasteurised at 85C, cooled to 10C,
acidified to pH 5.2 with lactic acid and dried by spray drying.
A powder i- obtained which, after reconstitution, has the pro-
perties of Mozzarella.
Example 6
A skimmed milk having a dry matter content of 20 % is prepa-
red by reconstitution and then pasteurised for 15 s at 75C,
followed by cooling to 20C. The product is then subjected
to ultrafiltration and to diafiltration with an overacidified
lactoserum emanating from the production of a soft cheese.
Diafiltration is continued to a pH-va}ue of 5.2. The further
procedure is then as described in Example 5, giving a powder
which, after reconstitution, has the properties of Mozzarella.
