Note: Descriptions are shown in the official language in which they were submitted.
2~2~7
PR~CESS FOR PREPARING DAIRY PRODVCTS WITH A LOW
CON~ENT OF STEROLS, PARTICULARLY OF ~HOLESTE~OL
The present invention relates to a process for
preparing dairy products with a low content of sterols,
particularly of cholesterol.
The starting materials used in the process
according to the invention are oil in water emulsions
comprising fats of dairy origin like, for example, milk or
cream. Milk is a liquid secreted by mammalian glands of
female mammals. It is composed of five major constituents:
- lipids essentially ~n the form of triglycerides,
- proteins,
_ glucids,
- salts,
- water.
Cream is in fact a milk enriched in fat by sponta-
neous scumming or centrifugingO It contains therefore the
same major elements as milk but in different proportions.
These two products also comprise constituents
present in very minimal amounts like lecithins, vitamins,
enzymes, dissolved gases, the fatty acids present naturally
in the milk and/or arising from the hydrolysis of trigly-
cerides, and sterols. The latter are essentially represen- -
ted by cholesterol to the extent of 98~ and are substances
associated with the fat. The fat of cows' milk contains
about 0.3% of cholesterol namely 0.1 g per liter of milk.
Now it has been established for a long time that
high blood levels of cholesterol (cholesterol LDL) are in
direct correlation with serious cardio-vascular deseases.
The principal o~ these is arteriosclerosis which is
manifested by the alteration o the wall of the arteries
and of which one of the ca~ses is the localized, excessive
and abnormal deposit of cholesterol on the inner surface of
the wall of an artery. The atheroma so formed can have
tragic consequences like myocardial infarctus. By way of
illustration, it may be indicated that a reduc-tion of l~ of
the total blood cholesterol results in a reduction of 2% of
the coronary risk. The excess of cholesterol can also be
the cause of gallstones.
Prevention remains one of the most effective means
for remedying these pathologies. It can consist of reducing
as much as possible the ingestion of oods rich in choles-
terol or indeed also of consuming foodstuffs with a low
cholesterol content.
One of the concerns of industrialists in the food
industry is hence to eliminate the cholesterol from
products of current consumption and particularly dairy
products.
Thus there have already been proposed various
methods of extraction of sterols from fats.
One of them consists of contacting the animal fat
with digitonin which has the property of reacting with the
cholesterol to give a precipitate. The performances and the
results of this method are not satisfactory due to the fact
of the difficulty of separation of the precipitate from the
medium. This method is, in any event, inapplicable
industrially.
The cholesterol can also be extracted from fats by
~5 entrainment by means of a solvent. The major drawback of
this method is that the solvents generally employed are
toxic and that traces of them always remain in the fats
concerned.
There are also known methods of microdistillation,
which are inapplicable at the industrial level, or again
adsorption on columns, as is described, ~or example, in
European patent applications EP n O 174 848 and EP
n O 318 326. These applications teach a method according
to which the fat kept in the liquid state passes through an
adsorbent column, in the event activated charcoal. It is
clear that such a process is very cumbersome to put into
~ ~ 2 ~
practice and, moreover, the ex~raction that it enables is
not very selective.
Another physico-chemical process of extraction of
the cholesterol from fats is disclosed by the Japanese
patent application JP n 59/140299. It consists of
contacting a dry substance charged with cholesterol such as
milk powder, with supercritical C02 at a temperature
comprised between 35 and 45C and at a pressure comprised
between 130 and 200 atm. The production of these physical
conditions necessitates the employment of complex and
expensive equipment. The management of the process is thus
very delicate. Moreover, as is specified in the patent
application, other lipid compounds are entrained by the
supercritical C02. This process is hence not sele~tive.
To remove the sterols from fats, there has also
been contemplated a process of biodegradation of said
sterols disclosed by the patent application n EP 0 278 794
and employing bacteria which, contacted with the fat, are
capable of metabolizing at least one of the sterols that it
contains. Like all methods involving fermentations, this
biodegradation process is very delicate to manage due to
the fact of the inherent variability of living matter. In
addition~ the equipment employed, the relatively long
duration, are, among other things, elements which render
such a process expensive. Finally, the catabolites produced
in these fermentations remain until now totally unknown on
the level of their nature and their toxicity, and are, in
any case, present in the fats so treated.
There is also known, through European patent
application EP n 0 256 911, a process for removing
cholesterol contained in animal fat. It is based on the
property already disclosed of cyclic cyclodextrins-
polyglucoses of frustoconic tubular conformation with 6, 7
or 8 glucose units and denoted respectively by alpha, beta
or gamma- of receiving in their hydrophobic central cavlty
sterol molecules and especially cholesterol, to form water-
'~2~
soluble inclusion complexes. According to this ~rocess, theat kept fluid is contacted with a cyclodex-trin with
stirring for 30 minutes to 10 hours so as to enable the
formation of complexes. The separation of the latter is
then carried out by introduction into the reaction mediu~
of water which solubilizes these complexes. The aqueous
solution thus obtained is then collected after decanta-tion.
The efficiency of extraction of the cholesterol by
this process is not great. In the best of cases, it is in
fact only 41%, and this after 3 successive extractions, as
is indicated in Example 3 of the description of this
European patent application.
It is to be noted that by this process, the fat
must be kept melted under an oxygen-free atmosphere. These
technical characteristics imply recourse to a specific
apparatus for maintaining temperature and supply of neutral
gas. Lastly, the time necessary for the first complexation
phase is a minimum of 30 minutes and actually from 2-3
hours as indicated in the example. This process is hence
necessarily expensive in time, equipment and in energy.
Apart from these scarcely satisfactory performances
this process constitutes a succession of additional steps
in the manufacture of a foodstuff and forms part of an
industrial procedure which is somewhat irrational. In fact
it consists firstly of manufacturing the fat in anhydrous
form, of making it undergo the cumbersome cholesterol
extraction treatment, then of bringing it to a suitable
state in whlch it will be utilizable in a process for
producing foodstuffs. In the case of dairy fat, these
foodstuffs can be reconstituted milks for consumption,
yogurts, cheeses or the like. It is clear that such a
scheme is not acceptable from the point of view of
industrial profitability.
It is apparent from the foregoing that none of
these solutions of the prior art has enabled until now the
production of food fats impoverished in sterols
2~2~
especially in cholesterol, satisfactorily, that is to say,
responding to the industrial conditions of economic
profitability, flexibility of use, and quality of the final
products.
In addition, with regard to this quali~y of the
final products obtained by applying known processes, it is
important to observe that these products, like any dairy
fat, can be oxidized and become rancid, which makes them
unsuitable for consumption. In fact, dairy fat comprises
unsaturated compounds reacting very easily with the oxyyen
of the air. This is the reason why, in the process des-
cribed in patent application EP n 0 256 911 mentioned
above, there is provision for operating under nitrogen. But
it remains nonetheless that the products so treated stay
very strongly subject to becoming rancid, which inevitably
undermines their food value.
One of the essential ob;ects of the present inven-
tion is hence to overcome the drawbacks of the aforemen-
tioned prior art by providing a process for the preparation
of dairy products with a reduced content of sterols and
especially of cholesterol. Consequently, it is no longer a
matter of extracting sterols from intermediate products
which are animal fats, but on the other hand to integrate
the removal of sterols into the production chain for dairy
products
This reformulation of the technical problem, even
if it seems a priori more logical did not establish itself
evidently due to the fact of the existence of a certain
number of obstacles and of technical prejudices which have
never been overcome in spite of the already old knowledge
of the prohlems associated with food cholesterol.
In the first place, it must be realized that dairy
oil-in-water emulsions like milk and cream are hetero-
geneous and complex mediums constituted by colloidal
suspensions of particles (globules of fat and pro-teinic
micellae) in a dispersing aqueous phase~ The cholesterol
~2~a~7
only repres~nts a minor constituent among many other free
substances uch as proteins or fatty acids. In addition, it
is integrated into the membranal structure of the fat
globules. It is hence a priori not directly accessible.
Knowing this, it was reasonable to conclude kherefrom that
cyclodextrin contacted with such a medium would have no
particular affinity ~or the cholesterol due to the fact of
the considerable competition existing between the compounds
of the medium with respect to cyclodextrin, and the situa-
tion of the cholesterol in the membranes of the fatglobules.
In the second place, even on the hypothesis accor-
ding to which the cyclodextrin would complex the choles-
terol, the appearance of an emulsion inversion phenomenon
could be -feared due to the fact of the known role of
cholesterol in the stabilization of the membranal structure
of the fat globules constituting the oil-in-water emulsion.
Now it is evident that a dairy rnedium which has undergone
an emulsion inversion is no longer a suitable basic raw
material for the manufacture of many dairy products. To
exploit it, it would hence be indispensable to reprocess it
by resorting, for example, to exogenic emulsifiers. Here
the failings of known processes would again be encountered.
In the third place, it is indicated in a reference
work ("Science of Milk", Charles ALAIS~ page 102) that
cholesterol has also an role of inhibitor of lipases as the
cause of rancidity development of dairy oil-in-water
emulsions. This constitutes, here again, a brake on the
idea of extraction of the cholesterol from such media.
By going against all these technical prejudices,
Applicant has demonstrated an inventive step by developing
the process according the invention.
Also, it is only after having perfor~ed a whole
series of studies and tests, notably within the Division
Chimie des Corps Gras of IRH0-CIRAD, that Applicant has
demonstrated, quite surprisingly and unexpectedly, the fact
~2~7
according to which lt was possible to prepare dairy
products with a reduced content of sterols, particularly of
cholesterol, by contacting an oil-in-water emulsion
comprising ats of dairy ori~in with cyclodextrin in a
sufficient amount to form inclusion complexes with sterols
so that the latter could be extracted from the fat, and,
simultaneously or not, separating said complexes from the
medium without inversing thQ oil-in-water starting emulsion
into water-in-oil emulsion.
It appeared first of all, under the conditions of
the process, that the cyclodextrin has a remarkable
selective a~finity with respect to the cholesterol present
at the surface of the fat globules contained in an
oil-in-water dairy emulsion.
It was also observed that the starting oil-in-water
emulsion was not inverted into a water-in-oil emulsion, and
this in spite of the xemoval of cholesterol, which is,
however, supposed to be an important agent in the physical
stability of the emulsion by reason of its surface active
role.
In addition, in the process according to the pre-
sent invention the fat is integrated into an oil-in-water
emulsion, which permits its contac~ with the oxygen of the
air to be limited and hence oxidation phenomena.
In addition, and again more unexpectedly and
advantageously, the dairy products derived from the process
according to invention show an increased stability with
respect to oxidation with respect to control products.
Thus, the problems of becoming rancid which cause the
appearance of a redhibitory taste in the dairy products are
at least partly resolved by employing the process according
to the invention. It is all the more astonishing that, as
specified abovs, the cholesterol extracted is known to be
an inhibitor of the action of lipases which play a part in
oxidation phenomena.
Without this being able to constitute a limitation
~J~ ~7
of the present invention i-t may be thought that this
improvement in the resistance to oxidation of the products
prepared according to the invention is due particularly to
the fact that the free fatty acids, naturally present in
the fat o the milk or coming from lipolysis of the try-
glycerides, is also complexed with the cyclodextrin and are
separated at the same time as the cyclodextrin-cholesterol
complexes. Now these free ~atty acids, often unsaturated,
have a stron~ propensity to become oxidlzed and thereby to
induce also the oxidation of other unsaturated compounds of
the fat such as trigl~cerides, vitamins and phospholipids.
This propensity to become oxidized can be appre-
ciated by measuring the acid index whilst the peroxide
index is a significant parameter of the oxida~ion level of
lS the dairy fats as well of products containing them.
According to the present invention the star-ting
oil-in-water emulsion used may be milk or cream of any
animal origin (cows or the like) and of any kind.
The distinction between milk and cream will be made
by considering that the first has a concentration of fat
less than or equal to 10% by weight while that of the
second is higher than 10% by weight.
The milk or cream can especially be raw, heat-
treated (pasteurization, UHT sterilization), enriched in
fat, homogenized or reconstituted for example, from
anhydrous dairy fat and from skimmed milk.
Within the scope of the invention, the term "cyclo-
dextrin" must be understood as encompassing cyclic oligo~
saccharides constituted by 6, 7 or 8 glucopyranose units of
which one at least can be mono- or poly-substituted, the
polymers of which the monomers are constituted by these
cyclic oligo-saccharides, and those products grafted or
immobilized on an inert support.
The cyclodextrin employed, can hence be of the
alpha, beta or gamma type, preferably beta, substituted or
not. The mono- or polysubstituent groups o~ the cyclo-
2~J~
dextrin can be particularly alkyls such as hydroxypro~yl orsaccharides of the glycosyl, maltosyl type or the like.
Cyclodextrin in polymerised form, cross-linked or
not, being usable in the process according to the inven-
tion, ~is for example of the type of that obtained bypolymerisation of monomers of beta-cyclodextrin with
epichlorhydrin.
According to the first embodiment of the process of
the invention the step of contacting consists of adding the
cyclodextrin to the starting oil-in-water emulsion, then
mixing these two compounds by moderate stirring for a time
t s~fficient to permit the formation of cyclodextrin-sterol
(cholesterol) complexes.
The tempera~ure at which this contacting is perfor-
med is preferably higher than or equal to 1C, preferablyat 15C while t is greater than or equal to some seconds,
preferably some minutes.
Moreover, is turns out that the concentration of
cyclode~trin must be comprised between 0.01 and 100% by
weight with respect to the dairy fat, preferably between 1
and 50~ by weight, and, more preferably still, between 2
and 25% by weight.
The cyclodextrin-oil-in-water emulsion starting
mixture is, preferably, subject to at least one physical
separation treatment of the complexes formed occurring in
water-soluble form or not.
To remove the complexes in water-insoluble form,
various treatments can be employed. It may be centrifu-
gation, decantation, filtration on a membrane or any other
technigue known in itself and appropriate.
In order to improve the efficiency of such a
treatment, it is convenient, according to the invention and
preferably when the cyclodextrin is in non-polymerised
form, to reduce the solubility of the complexes formed by
performing it at a temperature, preferably equal or below
20C, for example equal to 4C. In this way, the proportion
2~2~
of insoluble complexes is increased, their separation of
the one or more liquid phas~s thereof is hence facilitated.
In the case of centrifugation, a liquid portion and
a solid portion forming the centrifugation pellet are
obtained. This liquid portion is ~onstituted by a superna-
tant fat phase or cream from which have been extracted at
least in part the sterol complexes (cholesterol)-cyclo-
dextrin because of their weak affinity for the fat, and an
aqueous phase or skimmed milk containing a larger or
smaller amont of soluble complexes according to -the
treatment temperature chosen.
The skimmed milk and the cream so obtained may be
homogenized to form a reconstituted whole milk or be used
separately.
If the physical treatment of separation chosen is a
filtration, the retentate comprises the complexes insoluble
in water whilst the filtrate is an undephased oil-in-water
emulsion. The product obtained has a low content of sterols
and partlcularly of cholesterol and is useful in the dairy
industry as a raw material, as an intermediate product or
as a finished product.
According to an advantageous characteristic of the
invention, the complexes in soluble form are removed by
means of a physical separation treatment of ths ultra-
~5 filtration type, inverse osmosis or the li~e.
Such techniques are perfectly mastered by thetechnician skilled in the art. According to the invention,
they may be applied directly to the mixture starting
emulsion/cyclodextrin, to the aqueous phase (skimmed milk)
obtained from centrifugation or again on the filtrate
derived from passage of the mixture over a membrane. They
consist of concentrating the substrate concerned by passage
through a selective membrane, so as to remove the water as
well as any soluble substances among which figure a portion
of the cyclodextrin-cholesterol complexes.
According to a modification of the first embodiment
of the process according to the invention, applying more
specifically to the manu~ac~ure of cheeses of the type
comprising a coagulation step leading to the formation of a
curd and at least one step of extraction of the whey such
as draining or pressing, the milk is preferably employed as
an oil--in-water startlng emulsion and recourse is had to a
coagulating a~ent.
The latter is added to the milk previously and/or
simultaneously and/or subsequently to the contacting of the
milk with the cyclodextrin.
This enables the obtaining on the one hand, of a
curd adapted to undergo any sort o cheese transformation
and on the other hand, whey or aqueous phase containing all
or part of the complexes formed. This whey is capable of
being at least partly separated from the curd in the course
of at least one extraction step integrating into the
manufacture of cheese.
The coagulation of the casein of the milk occasions
a contraction of the regular network ~ormed by the coagu-
lated proteins and containing fat globules and the serum,
with progressive expulsion of the latter. This phenomenon
is commonly named syneresis. It enables within the scope of
the process of the invention, separation of the water-
soluble cholesterol-cyclodextrin complexes from the curd.
The latter then has the advantage of being notably
impoverished in cholesterol.
The coagulant agent employed is constituted either
by at least one acidogen such as glucono-delta-lactone
and/or by lactic ferments, or by at least one coagulating
enzyme of a suitable nature such as rennet, or by both.
It is self-evident that this modification of the
process according to the invention may be applied to any
cheese manufacture of the type defined above and known by
the technician competent in the field concerned. It does
not necessitate any additional e~uipment and does not
appreciably prolong the manufacturing times.
2~2~6~
In addition, the addition of cyclodextrin does not
result in any troublesome incidence either gualitatively or
quantitativ~ly on the low cholesterol content cheeses
obtained.
According to a second embodiment of the process of
the invention, the contacting of the oil-in-water starting
emulsion comprising dairy fats with cyclodextrin, as well
as the separation of the complexes formed of the starting
emulsion are performed substantially simultaneously and
consists of making said starting emulsion migrate through
an adsorbent or absorbent constituted at least in part by
cyclodextrin.
It is preferably chromatography on a column
eontaining advantageously beta-cyelodextrin in polymerized
form, cross-linked or not, and obtained for example by
polymerization by means of a bifunctional compound such as
epichlorhydrin.
According to a modification, the cyclodextrin can
be immobilized on a support constituted for example of
glass beads. This is more particularly applicable to the
case where the eyclodextrin is in the form of monomers.
According to an advantageous feature of the
invention, the oil-in-water starting emulsion is brought,
before migration, to a temperature comprised between 5 and
60C.
In the case of milk, this temperature is preferably
comprised between 5 and 35C. On the other hand, for
eream, more viscous, it is advantageously comprised between
35 and 60C.
3~ In any case, the invention will be better under-
stood by means of the non-limiting examples which follow,
of the practising of the process of preparation of dairy
products with a low sterol content and especially of
cholesterol, that it concerns.
~,~2~6~
EXAMPLE 1
Preparation of a cr~am impoverished in choles~erol ~y the
~ddition of beta-cyclodextrin to milk.
In this example, the starting material is a raw
cow's milk unpasteurized and unhomogenized. It contains 38
g/l of fat.
Powdered beta-cyclodextrin, marketed by the
ROQUETTE FRERES COMPANY under the registered trade mark
KLEPTOSER and containing 130 6% of water, is added to whole
milk brought to a temperature of about 25C in the propor-
tion of 1~ by weight wi-th respect to the milk, namely 27
by weight with respect to the fat.
The whole milkfbeta-cyclodextrin mixture kept at
this temperature of 25C is stirred intensely manually, for
about 20 seconds. It is then cooled to ~C so as to inso-
lubilize at least in part the complexes formed, then
centrifuged at this temperature and at 8000 rpm for 20
minutes.
A control milk, wi-thout beta-cyclodextrin, is
~ cooled and centrifuged, under the same conditions as those
described above.
Before centrifugation, two distinct phases are
obtained in the case of milk not containing beta-
cyclodextrin. The first, supernatant, is cream. The second,
heavier, is skimmed milk. For the test with beta-
cyclodextrin, a third phase appears in the form of a solid
pellet.
The total cholesterol contained in supernatant
creams and in skimmed milks is assayed by gas phase
chromatography after saponification, extraction of the
unsaponifiable and silylation.
The following results were obtained :
2 ~ ~J) ~ ~ fi ~
14
, .
. Control: T~st with l~ of
without addition ~-cyclodextrin
. ot~-cyclodextrin add~d to the whole milk
l . ~ _
! Cholesterol
i Creams in ~ of the cream O,21 O,10
. supernatant cream.
Skimmed Cholesterol
l in ~ of 3.0 x 10-3 2.1 x 10-3
i milks skimmed mil k
: .. .. , --
The cream of the milk treated with beta-cyclodex-
trin according to the invention is poor in cholesterol. The
reduction ratio with respect to the cream of the control
milk is of the order of 52~.
The skimmed milk obtained by employing the process
according to the invention does not contain more choles-
terol than the control skimmed milk.
The acid index of the creams is maasured by acidi-
metric filtration in milliliters of potassium hydroxide per
100 grams of fat (Method AFNOR T 60204). The control cream
has after preparation an acid index of 0.47, while that of
the test cream is 0. 22.
After 15 days stora~e in the open air and at 4C,
the control cream has an acid index of 1.5 and has a pro-
nounced rancid taste, while the test cream has an acid
index of 0.90 and has the taste of fresh cream. The impro-
vement of the stability of the latter with respect to
oxidation or rancidity formation is hence well demons-
trated.
EXAMPLE 2
Cholesterol ratio of supernatant creams as a function of
the amounts of beta-cyclodextrin employed in the milk.
In this example, the milk used is the same as that
employed in example 1.
Increasing amounts of beta-cyclodextrin are added
to whole milk.
The whole milk beta-cyclodextrin mixtures are
0 ~ 7
stirred slowly mechanically for 15 mlnutes, and at ambient
temperature. They are then cooled to 4C and centrifuged at
this temperature at 8000 rpm for 20 minutes.
The cholesterol determinations are carried out as
described in example 1.
. .Control Tes~s with ~ -cyclcdextrin
without Amounts introduced in ~ of the whole milk
dextrin 0,1 0.3 0.6 0.9 1.2
,
10Cholesterol in
I the supernatant0,21 0,18 0,17 0.14 0.10 O. o8
creams (in ~) ~
When the amounts of beta-cyclodQxtrin introduced
into the whole mil~ increase, the cholesterol present in
the supernatant creams diminishes.
EXAMPLE 3
Preparation of a "whole" milk poor in cholesterol by
recombination of the cr~am and of the skimmed milk derived
from the process o~ preparation accordi~g to the invention
described in example 1
The cream obtained according to the invention,
after treatment of the raw milk, with 1% beta-cyclodextrin,
is recombined with the skimmed milk by homogenization at
8000 rpm for 20 seconds.
The whole milk so prepared has a reduced choles-
terol ratio of 51% with respect to the control whole milk
obtained in the same manner. The two milks have an
identical pH of 6.90.
In addition, the whole milk obtained by employing
the process according to the invention possesses organo-
leptic qualities and a physical stability on storage at
5C, comparable with the control whole milk.
As regards the stability to oxidation, that of the
whole milk obtained by employing the process of the
invention is superior to that o~ the control whole milk.
2~2~7
16
EXAMPLE 4
Pr~paration of a crea~ with low cholesterol content by the
addition of p~l~merized be~ y~lodextrin and filtration ~n
a membrana.
The cream used in this e~ample is a UHT commercial
cream containing 35% of fat and 0.12% of total cholesterol.
It contains 99.98~ of the lipids contained in the initial
milk.
The cyclodextrin used is a beta-cyclodextrin
polymerized with epichlorhydrin.
Cream is heated to 40C. An amount of 2% by weight
of polymerized beta-cyclodextrin, namely 6% by weight with
respect to the fat, is added to the cream. The whole is
stirred for lO minutes at this temperature, then filtered
on a membrane.
The filtered cream has not been destabilized by the
addition of the cyclodextrin. It has a total cholesterol
content of 0.07% by weight namely a reduction of 42~ of the
cholesterol content.
EXAMPLE 5
Preparation of a whole milk poor in cholesterol by passage
over a ~olumn of polymerized beta-cyclodextrin.
In this example, the starting milk is a raw, non-
homogenized and unpasteurized milk, having a fat content of
25 37,5 g/l, a density of 1.0332 and a total cholesterol
content of 21.5 mg per 100 g.
The cyclodextrin employed is a beta-cyclodextrin
polymerized with epichlorhydrin.
Preparation of chromatographic columns with poly-
merized beta-cyclodextrin
The polymerized beta-cyclodextrin is hydrated in 6
to 10 times its weight of water. It is then introduced into
a column, and washed with demineralized water.
Passage of the milk over the column:
The whole milk brought to a temperature of 20C is
chromatographed on two different columns prepared as
17
described above. The eluted volumes of milk correspond at
least to 50 times the amount of cyclode~trin contained in
the column.
The determinations of total cholesterol and of acid
indexes were carried out according to the m~thods described
in example 1.
~__ _
Starting milk ChromAtograph d milks
Ratio of total cholesterol
in mg/100 ~ of fat 21.5 15.0 14.5
.. . _ _
Acid .index in ml
KOH/lQO g af fat 0.45 0.25 0,20
. . _
~ The densities and the contents of fats of the chro-
matographed whole milks are substantially equal to those of
the starting milk namely respectively 1.0332 and 37.3 g/l.
The ratio of cholesterol reduction are of the order
of 30% and those of acid index of the order of 50%.
In this example, whole milk constitutes the star-
ting oil-in-water emulsion. Of course, the latter may also
ba cream. In this case, it is obvious for the man skill~d
in the art to increase the temperature of passage over the
column, taking into account the risk of clogging of the
latter by reason of the higher viscosity of cream at
ambient temperature.
EXAMPLE 6
Preparation of a curd with low cholesterol content by
introduction of beta-cyclodextrin into milk and separation
of the complexes formed during draining.
In this example, the starting emulsion is a pasteu-
rized whole commercial milk containing 36.5 g/l of fa~ and
0.017~ of cholesterol namely 0.46~ of cholesterol with
respect to the fat.
The coagulant used was constituted by lactic fer-
ments and by an enzyme: rennet.
An amount of 1 liter of milk is seeded by means of
2~J~
1~pure lactic bacteria developing a low temperature.
At the end of the fermentation, powdered beta-
cyclodextrin, marketed by the ROQUETTE FRERES Company under
the registered trade mark KLEPTOSER and containing 13.6~ of
water is added to the milk in the proportion of 1.0% by
weight, at a temperature of 18-20~C.
The milk/beta-cyclodextrin mixture is stirred
manually vigorously for about 20 seconds.
The rennetting is then performed at this same
temperature of 18 20C, in the proportion of 0.01 to 0.02
ml of rennet diluted to 1/10,000 per 1 liter of milk. After
24 hours of coagulation, the curd is drained so as to
remove the whey.
A liter of control milk to which beta-cyclodextrin
has not been added was treated under the same conditions to
obtain a curd.
Assays carried out according to the method descri-
bed in example 1 gave the following results:
.
Test with control Test with malk
milk without addition containing 1~ by weigh~
DF ~-cyclodextrin of beta-cyclodextrin
. _
Cholesterol in ~
with respect to the fat 0.40 0.19
in the curd . _
The ratio of cholesterol reduction of the curd
obtained by employing the process according to the
invention is of the order of 52~.
After 15 days of storage of the curds in the open
air at 4C, it was apparent that the curd prepared with the
addition of beta-cyclodextrin to the milk had suffered l~ss
from rancidity formation than that prepared without the
addition of beta-cyclodextrin to the milk.
It was also observed that the addition of beta-
cyclodextrin does not disturb the cheesemaking capacity ofthe milk. ~esides a slight reduction in firmness, the curd
2 ~
19
obtained from the milk treated accordiny to the invention
has substantially ~he same quallties as that obtained from
the control milk.
It is apparent from the examples described above
that the process according to the invention enables dairy
products to be obtained with increased stability to oxi-
dation and with a low content of sterols and particularly
of cholesterol particularly easily and economically.
From starting emulsions such as milk or cream, this
process enables particularly the preparation of whole milk,
cream, of milk especially skim milk, and of cholesterol-
reduced cheese.
It is clear that these products can be intended
directly for consumption, or converted into various
finished or semi-finished dairy products.
Thus the cholesterol-reduced whole milk can serve
as a base for the preparation of yoghurts, of cheeses, of
creams themselves useful for example as a raw material in
the manufacture of butter or in a form converted or not as
a foodstuff ingredient, or the like.
A cream reduced in cholesterol by employing the
process according to the invention can be, either homoge-
nized with a standard skimmed milk to form a reconstituted
whole milk, directly consumable or usable in the manufac-
ture of milk products, or used also as a directly consu-
mable product or as a starting material or intermedia~e
material in the manufacture of milk products.
This enumeration is in no way limiting. It is
intended to give an indication of the multiple outlets of
the dairy products obtained by employing the process
according to the invention.
