Note: Descriptions are shown in the official language in which they were submitted.
~`~ c~731
S~
The invention relates to ice cream and to a st~biliser
*yst~lu iol llse, l`or ins-tancc, ~ ic~ cream.
The way in which ice cream beha~e~ on ex~oPure to nor~al
room temperature is important for -the consumer. I~ ~ product
behaves too atypically, for instance if a product melts too
rapidly or separates into a ~atty phase and a clear aqueous
phase on melting, -then the product will be unacceptable. In
the ice crea~ industry methods have been developed ior
measuring suoh properties, ~or instanee melt-down &nd stand-
up. These are described later.
It is known that such properties can be afieeted by
the use of stab~lisers, o~ten called thickeners. A problem
that arises is that the stabiliser~ deleteriously af~ect
the feel of the ice cream in the mouth; a eloying, ~ummy
or even greasy ~eel can oocur. ~his problem is acute in
ice creams that require more than usual stabilisation.
~hat is desired is a stabiliser system that is good or at
least adequate with respect to all aspects of stability. This
is difficult to achieve ~or normaliee creams and particularly
so for ice creams that require more than usual stabilisation.
A stabiliser ~ystem has now been ~ound that is surprisingly
e~ective in stabilising ice cream without gi~ing
an unacceptable mouth-feel. The stabiliser system i9
microcry~talline cellulose in combination with one or more
o~ carboxymethylcellulose and galaoto~annan gums. PreYerably
the stabiliser system oonslst~ o~ microcrystalline cellulose,
~ carboxymethylcelluloqe and a galactomannan gum. Example3
; ~of galactomannan gums are guar gum, locu~t bean gu~ and tara
gum.
The lnvention there~ore~ provides an ice cream ~ontaining
a stabilising~amount o~ microcrystalline cellulose and one
2 - ~
cQ731
5~ ~3 ~
or luole of c~lrbo.~ymeltlylcclllllose and galactoman~tc~ uu~s,
~alactom~lltlan gum is p~fer.lbl~r pres~ntO
Tho nluoullt of microcrystalline cellulose IS preferably
at least O.Olp, particularly preferably at least O.l~oO
Prefer~bly not more -than 0.8~o will be used~ particularly
prcferably not more than Oo~S/7cost is a factor.
pre~erred range is 0015qo to 004~0, par-ticularly to 0,~/0.
The amolmt o~ total car~o~Yymethyl-cellulose (cQlclllated as
sodium carbo~ymethylcellulose) and galactomannan gums is
pre~erably not more than 15~, particu~arly preferably not
more than 0.5~0 and preferably is in the range OolS~/O to
0035/0. The lo~er limit for carbo~Yyme-thylcellulose is
preferably 0.01%9 The lolrer limit for galactomannQn gu~s,
in particular for locust bean gum, is preferably O.OS,0~
Of course not more than one compone~t should be at or near
their lol~er limits, in any one stabiliser sys-tem.
- The weight ratio of microcrystalli~e cellulose to total
carboxymethylcellulose (calculated as sodium carbox~mæthyl-
cellulose) alld galactomannan gume is pre~erably ill the~ -
range 4:1 to 1:~1, particularly preferabl~ in the ranga 2:1
to 1:3. Total stabliser is preferably in the range 0015
to 1-0~ particularly pre~erably 0.30 to O~S~O The weight
ratio of microcrystalline cellulose to carbo~Ymethylcellulose
is preferably no-t more than 3:1 alld preferably is not less
than 1:2.
As emphasised above the stabilisei- system is particularly
use~ul in ice creams that require more than usual stabilisation
A proble~l~with con~ention~l ice creams is tha-t at deep
,
Xree~e temperatures, eg. -20C, they cannot be served or
eaten as readily as when they are a-t normal eating temp-
eratures, eg. -10 C. The consumer canIIot treat them ~ven
aRpro~imately ln -the normal ma~lner im~ediately whell t~l;en
from the deep ~roeze. In some cases cnnventional icc crea~s
¢annot even be scooped out with a spoon at -20C, i.e. are
::
not, spoon~lble. Re~ormulatibn to ensure that such
~ o~731
~S~73L~
properties, eg. spoonability at deep freeze temperatures
are approxima-tely those expected at normal eating temp-
eratures is comparatively simple. Methods are outlined
later. The dif~iculty is that such reformulation leads
to products that do not have acceptable properties, in
particular stability, a$ normal eating temperature~. It
has 3esmed impussible to get an ice cream that ha~ at both
deep freeze and normal eating temperatures even approxi~ately
the serving and eating properties conventionally e~pected
at normal eating temperatures and that is sufficiently
stable. The present inve~tion provides a stabiliser ~ystem
with which this can be achieved.
It will be appreciated that the product-characteristics
required ~or a conventional ice cream will depend on the
personal tastes oi the consumer and ice creams are formulated
to meet a variety o~ such ta~te~; the ~or~ulation o~ any one
conventional ice cream will depend on the taste~ oi the
consu~er~ concerned. In thi~ context a conventional ice
cream is one prepared by a process involving ~reezing and
hardening to tem-peratures in the order of -20C to -40C.
One important characteristic oi ice cream particularly in
relation to scoopability is the log C, as de~ined later,
o~ the ice crea~. In the UK ~or instance, an ioe crea~
can normally only be called a conventional ice cream i~
its log C at -20C aiter hardening i3 in the range 2.9 to
3.7; usually -the log C oi a UX non dairy ice crea~ at
_20C ai~ter hardening will be in the range 3.3 to 3.7; ~or
a dairy ice cream the range is 2.9 to 3.3. In other
countries values for log C wlll be comparable but can be
different, often higher, a~d indeed even within a country
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~Q731
~ 5~
various conventional ice creams will vary in -th~ir log C
values (A technique for measuring C~ the penetrometer value,
and hence log C is described la-ter in the speciiication).
Whatever the conventional ice cream used, its properties
at deep-freeze temperatures can be approximated to those
expected at normal ea-ting templerature by adding ~reezing-
poin-t depressants such as monosiaccharides and low molecular-
weight alcohols, preierably polyalcohols and in particular
glyoerol and sorbitol. It has been found that nor~ally
sufiicient oi such freezing-point depressants should be
added to the iormulation oi a co~ventional ice cream, eg.
at expense o~ wa$er, to lower the log C at -20C by between
0.25 and 1, pre~erably by 0.4 to 0.75. ~he notional replace-
men$g eg. o~ ~reezing-point depressant ~or sugar~water, should
be such that the product has the desired (by the consumer)
sweetness as well as the desired log C, or spoonability,
at -2QC.
As indicated above, a problem ~acing ice crea~ manu-
facturers is that in general ice creams ~ormulated to have
the conventional eating temperature properties at -20C, in
particular to be spoonable at -20C, have unacceptably poor
properties, eg. stand-up and meltdown, at nor~al eating
temperatures~ For the ice cream to be spoonable at -20C
it has been found that its log C should preierably be less
than 2.8, particularly pre~erably less tha~ 2.5; a corre-
lation has bee~ iou~d to exist between spoo~ability and
log C.
An e~pecially important aspect oi the present invention
is an improvement in an ice cream whose log C (C being it5
penetrometer value) at -20C has been lowered by between
0.?5 and 1 by use o~ ~reezi~g-point depressants, the improve-
~ent oonsisting o~ the use o~ the stabiliser system o~ ithe
. . - . . . . . .
cQ731
~I:)S~iL7~
present invention.
Microcrystalline cellulose is a well-known industrial product.
Its use at comparatively high levels in low calorie products,
including low-calorie ice creams, is described in sritish patent
specification 961~398. Processes for its preparation are well-
known and are for instance described in US 3,157,518. One
problem with microcrystalline cellulose is its dispersability.
Methods for overcoming this are well-known; a particular technique
involves the use of carboxymethylcellulose. Microcrystalline
cellulose is sold under the trade mark Avicel by FMC Corporation
and a readily dispersible form containing sodium carboxymethyl-
cellulose is sold as Avicel RC-591. It is stated to be a colloi-
dal form of microcrystalline cellulose which has been blended
with sodium carboxymethylcellulose and dried. The amount of
sodium carboxymethylcellulose lS ~ , by weight of micro-
crystalline cellulose. Microcrystalline cellulose is fully
characterised in for instance GB 961,398 and US 3,157,518 but
briefly can be stated to be cellulose crystallite aggregates with
a level-off D.P. Level-off DP is the average level-off degree of
polymerisation measured in accordance with the paper by O.A.
Battista entitled "Hydrolysis and Crystallisation of Cellulose"
Vol. 42 (1950), Industrial and Engineering Chemistry, pages 502
to 507. As stat d in GB 961j398 suitable microcrystalline
celluloses have average level-off DP's in the range 125 to 375,
particularly 200 ~o 300; the particle siæe of the aggregates of
microcrystalline cellulose will usually be in the range 1 to
300 microns.
Galactomannan gums are well-known material and are
~ 6 --
cQ7~'l
~CI 5~7~
- describecl for instance hy 1~l. Glick~tan in "Gum Techno'lo~y
in the Food Industry", ~cademic Press, 1969. Pre~erred
galactomannan gu~s ~or use in -the in~ention are locust bean
gtllU and tara gum. Carboxymethylcelluloses are standa1tl
S industrial products.
In this specification, including the claims, percen-
tages are by weight and in particular are by l~eight o~ ice
cream e~cept l~here the conte~t reqnires otherwiseO
Other than in the use of s~ icie~t ~reezing point
' \ ' ' :
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cQ731
~LC35~7~L
depressant for the preferred aspect of the invention and in
the use o~ a thickening agent compri~ing particular components
no especial insight is required in the formulation or
processing o~ ice creams accord:ing to the invention. Details
o~ conventional ~ormulations and processing conditions for
ice cream can be ~ound in the usual trade publications and
text books. Particularly useful in this respect is
Arbuckle, "Ioe Cream", 1972 ~2nd Edition), AVI Publishing
Corp., Westpoint, Conn.
The invention will now be illustrated further by the
~ollowing examples.
The properties of the stabili~er system are most
surprising when compared with the properties of the separate
componentsO This is illustrated in the examples but it will
be appreciated that the stabiliser system is also useful in
products other than ice cream.
EXAMPLE 1
.
An ice cream was prepared by conventional proces~ing
techniques to the following ~ormulation:
In~redient
Made~up skimmed ~ilk (32.5% solids) 27
Sucrose ~3
~lucose syrup 2
Liquid oil blend 9.5
Monoglyceride emul~i~ier 0.45
Colour and flavour 0.03
( Locust bean gum 0.15
Thick-
ening Avicel RC 591~* 0.2
agents
SQdium carboxymethyl cellulose* 0.15
Salt 0 05
Glycerol 3.0
Water to 100
*Supplied by ICI as powder B600 **trade mark
~ cQ731
~35~
* Supplied by FMC and believed to contain by weight il%
sodium carboxymethyl cellulose.
The presence of the thickening agents can be detected
analytically in such a product. The product itself is an
excellent ice cream resembling conventional UK ice cream in
eating properties but being spoonable at -20C.
E~AMPLE 2
An ice cream mix was prepared frDm the Yollowing
ingredients, in parts by weight:
Palm oil 505
Stearic monoglyoeride 0.15
Spray-dried milk powder 10.0
Sucrose 14.0
Microcry~talline cellulose 0.4
(containing 11~ of sodiam
carboxymeth~lcellulose)
Sodium carboxymeth~loellulose* 0.2
Locust bean gum 0.22
Trisodium citrate 0.3
Water 64
The stearic monoglyceride was di~persed in the p~lm
oil to give a fat pha~e. The ~ilk powder was di3persed in
the water and to the dispersicn waæ added the remaining
ingredients, giving an aqueous pha~e. ~he ~at and aqueous
phase at 65 were mixed, homogenised at a pressure of 2000
psi and the emul~ion ~ormed was pasteurised at 70 ~or 20
minutes and cooled at 5 at which it ~ad pH 605. Aiter
ageing for 2 hour~ at 5C 6 part~ of a concentrated orange
~uice, 0.04 parts of coloaring a~ent, and 3 parts o~ a 33~0 by
weight aqueous solution of citric acid were mi~ed with the
emulsion. The re~ulting emulsion o~ pH 3.5 w~s converted to
~ 5~
*Supplied by ICI as/powder B600
.
_ 9 _
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cQ731
" .~
~ L~S~t~
an ice cream by cooling and whipping at -4, and the ice cream
was blast frozen to -20 and stored.
This example shows the use of the stabiliser system in
stabilising an acid ice cream, a type of ice cream that requires
more stabili~ation than an average ice cream.
The stabiliser system is particularly useful in an acid ice
cream, i.e. an ice cream with a pH in the range 3.0 to 5.2. The
pH should, as well as being within this range, preferably be
sufficiently below the isoelectric point of any acid-precipi-
table protein present in substantial amount for that protein tobe present substantially uncoagulated. Alternatively whey
protein preferably purified by reverse 05mosis, can be used;
whey protein is not acid precipitable. Such ice creams axe
described and claimed in our co-pending German OS 2361658, open
for public inspection before June 4, 1975.
EXAMPLES 3~ to 14 and COMPARISONS A TO F
Ice cream mixes were prepared conventionally to the
following formulation. Further details are given in Table 1
immediateIy before claims which also shows results obtained with
ice cream prepared conventionally from the mixtures. A standard
U.K. non-dairy ice cream differs from this formulation in
containing no glycerol and 1.4~ by weight more sugar. 3%
glycerol is roughly equivalent in sweetness to 1.5% sugar.
~Spray dried milk powder 9.5
Sugar 13.5
Maltodextrin 40 DE* (Glucose syrup) 1.7
Palm oil ~ 9.5
Monoglycerdie from palm oil Q.5
Glycerol 3.Q
-- 10 --
'
~ cQ731
~S~
Salt 0~05
Flavour and colour O.1
S-tabiliser~ Table l**
~ater to 100
* DE = dextrose equivalent
** ~he SCMC used was powder B600 supplied by ICI ~imited.
The log C values at -20C o~ Examples 3 to 14 and
Comparisons A to F were in the range 2.S and 2.9 and averaged
2~7. The log C of the standard ice cream mentioned above was
in the ra~ge 3.2 to 3.3.
Test methods
. _ .
Melt-Down Test and Shape Retention
A rectangular block o~ ice cream o~ length 13.6 cm,
height 400 cm and width about 8.8 cm which has been stored
at -20C i9 placed on a wire gauze (10 ~ires per inch) in
a~ atmosphere maintained at 15C. ~rrangements are made
ior collection o~ the liquid drained fro~ the gauze. The
time ~or the collection o~ the iirst 10 ml o~ liquid is
noted. The volume o~ liquid collected i~ each subsequent
10 ~inute period is measured and the slope o~ the ~raph
obtained by plotting volume collected against time i~ taken
as the melt-down ~mls/hr). A~ter 4 hours thawi~g photo-
graphs o~ the residue o~ the brick are take~, and the degree
oi shape retention assessed as bad~ poor~ -fair, good or very
good.
~tability to Temperature ~y~
This was carried out o~ a~ appro~i~ately cuboid ~ gallon
block oi ice cream in a plastic container. A~ter storage in
a deep-~reeze it ~as tra~s~erred to ambient (20C~ ~or 12 hours
and then to~a re~ridgerator at -10~ Next day the block was
subjected to ~urther temperature shock cycling by being taken
,
11
.
c~731
3~5~7~L~
out o~ the re~rigerator and le~t at ambient ~or 1 hour.
~his (each day 1 hour at ambient) was repeated to a total
of six times and then the block was returned to the deep-
~reeze for assessment the next day. ~he total test -took,
allowing ~or a weekend, not more than ten days~ Product
stability was assessed as ~ollows:
Bad : total breakdown
Poor : ~20~o~ product converted to serum
Fair : 5 - 20% of product converted to serum
Good : C 5% 0~ product converted to serum
C and Lo~ C
To determine C and hence log C the iollowing method
is used:
Principle
The hardness o~ ice cream is measure~ by allowing a
standard cone to penetrate a sample ior 15 seconds using a
cone penetrometer. ~he C-value can be calculated ~ro~ the
penetration depth.
~ 7
- 12 -
- . : .~ ,. . .. .
cQ.73~
~53L~
Appara$us:
Ebonite cone
With an apex angle of 40 +10 and the tip blunted by
a few strokes on fine abrasive paper to give a flat
0-3 _0.03 mm in diameter. '~otal weight of cone and
sliding penetrometer shaft 80 +0.3 g.; also additional
weights of 8V +0.3g.
Penetrometer
With a scale calibrated in 0.1 mm., and.
fitted with a lens. The penetrometer made by Sommer
and Runge, Berlin, is reco~mended, parti¢ularly for
static use. The Hutchinson instrumènt c~n al~o be
used; it requires ~o electricity SUpply3 bu$ mu~t be
modi~ied for sati~factory operation. The accuracy o~
pene~rometer timing mechanisms must be checked regularly.
The use of a x3 magni~ication lens o~ about 6 - 8 cm.
diameter fitted to the penetrome$er facilitates the
- setting of the cone tip on the sample surface9 and an
unfocused light limited to the equivalent of a l-watt
2Q bulb at a distance of about 5 cm. (to aYoid heating t~e
sample surface) is also advantageous.
Temperature probe
Reading to within 0,lC. The temperature probe should
have a ste~ about 1 ~m. in dia~eter and about 4 cm.
long. Its accuracy should be checked regularly in
baths of know~ temperaturas.
::
- 13
.
~ c~.73l
1~5~7~:~
Temper~n~ f~cili-les
(a) Room controlled at required temperature ~ 1C;
(b) Gonstant_temperature cabinets, tolerance + 0.2~C.
The forced-draught constant~temperature cabinets
supplied by Zero N~Vo Rotterdam are satisfactory.
Process:
Samplin~
Samples should be convenient size and p~efera~ly with
smooth surface~ to incre~se accuracy.
iO Tempering
2 Days at whatever temperature is required e.g.
- -20C. Measure te~perature aocurately before penetration.
Mea~urement
Where possible, penetrations are made in the
temperature-controlled room, and should be completed
- within two minutes o~ removing -the sample ~rom the constant-
temperature cabinet~
1. Insert ~the temperature probe as near horizoDtally a~
~20 possible ~at a few ~m. below the sa~ple surface; read and
~: note the sa~ple temperature a~ter 30 ~econds. (Reject any
: ~amples di~fering by ~ore than 0.5C fro~ the nominal te~t
- . ~
~: ~ temperature~) -
~ ,
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.- .. . . .. , . . . .. ~ ... .
~-~ c~7~1
~L63 5~71~
2. Place the samples on the levelled penetrometer table~
3.~ Set the cone tip accurately on the sample surface~
using a lens and, i~ necessary, oblique lighting.
4. Releaise the arresting device and allow the cone to
penetra-te the sample for 15 seconds.
5 Read and note the penetration depth.
6. Should the penetration depth be less than 72 x 0.1 mm.
(equivalent to a C_value of more than 500 g./cm.2) the
measurement should be repeated with the cone weight
increased by 80 g.
Further 80 g. weights
may be added as necessary to ensure adequate penetration
of the sample and the C-value scale reading corrected--
accordingly.
7. Penetration measurements should not be made within
2 cm. of the sample edge nor within 2.5 cm. o~ each othcr.
Determinations in which air bubbleis~ cracks, etc. inter~ere
should be rejected. -
Calculation of C_va~lues
20 ~ ~he C-value can be calcalated~frbm the penetration
depth using the formu~a: -
~ x F
C~ 6
where C = Yield value or C_value (g.~cm.2)
P =~To~tal welght of cone and sliding stem (gO~ -
; P = Penetration depth (0.1 mm.)
`~ ~ = Factor dependlng on cone angle:
.: . . .
, . . , . , -. i -
',~: . . ,, ' ~ ' ' '
~5~7~ cQ731
Cone an~le K valwe
9670
5840
6~ 281
1~40
* Depending on the likely so~tne~s o~ the product, the cone
weight should be adjusted, e.g.
at -10C use 80 gm
at -15C use 1~0 gm
at -20C ase 240 gm
i.e. it depend~ on temper~ture o~ measure~ent.
C valaes will usually be taken a~ter hardening
conventionally, a9 for inst,ance described on page 4,
lines 18 to 209 and in the standard text-books~ -
It should be noted that an ice cream according to ~he
invention preierably has a mslt-down, determined as described
above, o~ less thMn 25 ~lJhr and particularly pre~erably o~
between S and 20 ml/hr..
It should ~urther be noted that the log C at -20C oi
an ice cream according to the invention should pre~erably
not be less than 2,3.
Further details of suitable ~ircrocrystalline celluloses
a~e available i~ pa~phlets ob$ainable iro~ FMC Corporation,
A~icel Department~ Marcus Hook, Pe~nsyl~a~ia 19061 ~or i~stance
1n Bulletin ~C-16 and pamphlets RC-30 and ~C-34. RC-30
describes use o~ microcrystalline cellulose i~ ~ro~en desserts
and states, inter alia9 that i'It is co~patible with all stabil-
islng systems except:those containing Guary Loc~st Bean, and
Na Alginate",
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