Note: Descriptions are shown in the official language in which they were submitted.
Z~
PRODUCTION OF SPONGE CAKE
The present invention relates to a continuous
procedure for the manufacture of sponge cake.
Sponge cake is traditionally made by forming
a batter containing flour, sugar, eggs and water, along
with baking powder to provide leavening and any desired
flavouring agents, and baking the batter in an infra-
red radiation oven, Such procedures require time to
effect leavening. Further, the proportions of ingredients
are critical to achieving the required texture. In addition,
the baking procedure often forms a hard crust on the
cake, which can lead to undesirably hard particles and
crust coloration in a comminuted mixture, when the cake
is to be used in crumb form.
The present invention overcomes the prior art
problems and enables sponge cake with characteristics
comparable to sponge cake made by conventional methods
to be formed continuously without the necessity for a
long leavening time, without the development of crust
and with considerable flexibility of the proportion of
ingredients. The present invention involves the utiliza-
tion of a unique batter mixing procedure and microwave
baking of the batter under controlled conditions.
In accordance with the present invention, there
is provided a continuous process for forming a sponge
cake, which comprises: intimately mixing cake~forming
components including flour, sugar, egg and water with
each other in a continuous mixing zone, extruding a sponge
cake-forming batter from the continuous mixing zone,
and substantially immediately after the extrusion, heating
the batter by microwave energy to cause moisture in the
batter to form steam to expand the batter and cook the
same to a sponge cake.
The sponge cake which is produced by the process
of this invention has characteristics comparable to those
of conventional sponge cake, except that no crust is
formed on the surface thereof. The absence of such crust
avoids the presence of hard particles and crust coloration
in the particulate form which results from comminution
of the sponge cake, and this is quite desirable in many
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applications of the comminuted cake.
The comminuted cake crumbs may have any desired
particle size) depending on the end use. The density~
resulting in part from the porosity of the cake and in
5 part from the size of the individual particles, ranges
from about 0 2 to about 0.4 g/cc (12.5 to 25 lb/cu.ft.)
and the shear value ranges from about 8 to about 25 kg.
In accordance with a specific embodiment of
the invention, there is provided a continuous process
for manufacture of sponge cake, which comprises: feeding
cake-forming components including flour, sugar, egg and
water to a continuous mixing zone in quantities such
that the total quantity of moisture in the cake-forming
components is about 20 to about 45% by weight, advancing
the cake-forming components in plug flow manner through
the mixing zone in about 20 to about 180 seconds, subjecting
the cake-forming components to conditions of shear within
the mixing zone such that the work done on the mater als
within the mixing zone varies from about 4 to about 7
watt/hr/lb of cake-forming components to cause mixing
of the components, subjecting the cake-forming components
to a back pressure within the mixing zone of about 10
to about 75 psig, extruding from the mixing zone a cake-
forming batter mix of density from about 0.65 to about
0.95 g/ccj substantially immediately after the extrusion,
baking the extruded batter mix in a microwave baking
zone using microwave radiation at an input of about 3
to about 12 kw min/lb. of batter while passing air through
the zone to remove generated steam, and maintaining
the batter in the zone for a time sufficient to result
in a baked sponge cake having an internal temperature
of about 180 to about 230F and to effect a loss of
moisture of about 10 to about 23 wt.%.
The initial cake-forming ingredients used in
this invention include those conventionally used in cake
making- including water, flour, eggs and sugar. The
term "flour" as used herein usually refers to a soft
wheat flourv but includes any combination of wheat flours,
including those known as cake or high ratio cake flours,
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2a
Varying quantities of cake forming components
may be used and the procedure of the invention enables
less critical proportions of ingredientst to be utilized
than is the case in conventional cake-making procedures,
particularly additive components, such as, emulsifying
agents and surfactants which are conventionally employed
to improve the functional properties of the major components
and to effect cost reductions with improvements in keeping
quality from a staling or onset of undue firmness standpoint.
In addition to the basic cake-forming components,
salt, flavouring agents, such as, vanilla and cocoa,
and colouring agents usually are used. Baking powder,
which is conventionally used along with entrained gas
to provide the total leavening of the cake, is not required,
since leavening is achieved by the generation of steam
in the microwave baking step along with gas expansion.
Some baking powder may be used, however, to enhance the
steam leavening.
The cake-forming components may be provided
in the form of a dry mix containing sugar and flour and
a wet mix containing egg and water. One suitable dry
mix comprises:
Sugar about 40 to about 60 parts by weight
Flour about 40 to about 60 parts by weight
Sugar and Flour 100 parts by weight
.
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In addition, one or more of the following optional
components may be added:
Bakin~ powder 0 to about 2.0 parts by weight
Salt 0 to about 1.5 parts by weight,
typically about 0.5 to about
1.5 parts by weight
Cocoa 0 to about 15 parts by weight,
typically about ~.5 to about
15 parts ~y weight
One suitable wet mix comprises:
Llquid egg 100 parts by weight.
Liquid egg has a high moisture content typically about
74 wt.%, and this moisture provides part of the moisture
requirement for the batter.
An optional component which may be present in the
wet mix is:
Vanilla extract 0 to about 2% by weight of the egg
In the process of the invention, the cake-forming
components are fed to inlets at one end of a continuous
mixing zone capable of plug flow therethrough. The mixing
zone mav take the form of an elongate, screw-type mixer-
extruder, suitably modified to provide the required
processing conditions therein.
The dry mix~ wet mix and additional water are separ-
ately metered to one end of the mixing zone in proportionssuitable to provide an overall moisture content of inter-
mixed components of about 20 to about 45% by weight,
preferably about 28 to about 38% by weight.
Within the mixing zone, the cake-forming components
are continuously intermixed while they are conveyed from one
end of the mixing zone to the other, over a time period of
a~out 20 to about 180 seconds, preferably about 30 to
60 seconds.
A plurality of spaced gaseous inlets may be provided along
the length of the mixing zone and a gaseous material, or
mixture of gaseous materials, is injected into the mix
through the openings. The gaseous material usually is
carbon dioxide, often in admixture with nitrogen, although
other materials, including air and oxygen, mav ~e used
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When utilized, the total gas fed to the mixing zone is in
the range of about 1.3 to about 18 SC~H, preferably about
4.4 to about 7 SCF~, per 100 lb. of cake-forming components.
The addition of gas in this way generally decreas2s
the density and increases the shear value of the product
obtained. In the a~sence of gas deliberately added in this
way, there is always some entrained gas in the batter.
The cake-forming components and the entrained gas,
together with any injected gas, are subjected to shear forces
within the mixing zone, sufficient to cause simultaneous
uniform mixing of the components and dispersion of the
gas throughout the mix. The work done on the fiatter within
the mixing zone yaries from about 4 to about 7 watt hr/lb.
of batter, preferably about 5 to 6 watt hr~lb.
The temperature within the mixing zone is controlled
at a desired value, but the value is not critical to the
process and heat generally is not used. The temperature
generally corresponds to the inlet ambient temperature
of the water and liquid egg, which may vary widely, depending
2Q on the time of the year, typically from about 5 to about
25C ~about 40~F to about 80~L. The batter which results
from the operations ln the mixing zone is extruded therefrom
under a low back pressure of about 10 to about 75 psig,
preferably about 20 to about 50 psig.
The operations which are effected in the mixing zone
result in the continuous extrusion of a uniformly-mixed
gas-infused foaming batter having a density from about 0.65
to about 0.~5 g~cc and a moisture content corresponding to
that fed to the m~xing zone.
The sugar which may be used in the cake-forming
components in this invention lncludes crystalline sugar and
liquid sugar, including those syrups derived from corn or
other starches, or a combination of such sweeteners. In
conventional cake batter-making operations, the crystalline
form of sugar is required, since t~e abrasive nature of the
sugar crystals fireaks up the egg and enables it to be
evenly distri~uted throughout tfie batter, and mixing is
effected to dissolve the sugar.
In this invention, the action of crystalline sugar
113~;9;~1
is not relied on to distri~ute the egg and it ~as been
found that the mixing which occurs in the mixing zone in
this invention results in solid phase sugar bein~ present
in ~e batter, when crystalline sugar is used as the source
of sugar. Liquid sugars normally cannot ~e used, for the
above reason, but may ~e used in this invention to pro~ide
texture improvements not readily achieved by conventional
mixers, and improvements in keeping times by delaying the
onset of staling or firming and provide the option to use
the most economical sweetener blend.
The ~atter, extruded from the mixing zone then enters
a microwa~e baking oven, usually in the form of a long
tunnel through which the ~atter is conveyed in a continuous
fashion. The microwave energy causes the water in the
batter to be rapidly heated to produce steam which expands
and cooks the cake. The dissolved gaseous material also
expands, and any leavening a~ent present, is activated.
The microwave baking is effected at an energy input
of from about 3 to about 12 kw min/l~. of batter, preferably
about 4 to about 8 kw min~lb. of batter, for a time
sufficient to raise the temperature to about 180 to 2300F,
preferably about 200 to a~out 212F, and to result in a
moisture loss of a~out 10 to a~out 23 wt.~. An air stream,
which may ~e of am~ient temperature or higher, is passed
through the microwave oven to remove generated steam.
The sponge cake which results from the microwave
~aking step is fully cooked but relatively moist at a
moisture level of about 12 to a~out 33 wt.%. The cake may
be dried to a desired moisture level, usually about 3 to
akout 8 wt~% in any convenient manner, including continued
application of microwave energy, and, if to be used in a
comminuted form, such as, in pudding mixes, then comminuted
to sponge cake crumbs of any desired particle size. The
cake crumbs have a density from a~out 0.2 to about 0.4 g/cc
and a shear Yalue of about 8 to about 25 kg.
The continuous procedure of the invention, therefore,
comprises essentially two steps, namely ~atter mixing
and microwave ~aking. The result is a sponge cake of
properties corresponding to those formed ~y conventional
4Q baking, ~ut produced in a continuous manner.
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The invention is illustrated by the following
Examples:
Example 1:
This Example illustrates the formation of d
vanilla sponge cake by two separate procedures, one involving
the addition of gas and the other wherein gas addition
is omitted.
An initial dry mix containing the following
ingredients was prepared:
ComponentParts by Weight
Flour 46.7
Salt 1.0
Baking powder 1.1
Sugar 50.5
Myvaplex 600* 0.7
100 . O
*Monoglyceride emulsifier sold by Eastman Chemical
Products Inc. (Trademark).
An initial wet mix was also prepared, containing
the following ingredients:
Liquid whole egg (74% moisture) 98.9
Colour 0.2
Vanilla o.g
100 . O
The dry mix, wet mix and water were fed into
one end of an extruder at the following flow rates:
Dry mix 8.75 parts/min
Wet mix 4.46 parts/min
Water 0.68 parts/min
These flow rates correspond to a moisture content of
32%,
The components were continuously intermixed
during passage from one end of the extruder to the other
in about 35 seconds. In one run, carbon dioxide was
fed into the extruder at six different locations along
the length of the extruder at a rate of 5.75 SCF/100
lb. of batter whereas in another run no gas feed was
employed, Work of 5 watt hr/lb. of batter was applied
to the batter during formation thereof and passage through
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6a
the extrusion and a back pressure of 35 psig exited at
the extruder outlet orifice.
A gas-infused evenly-mixed batter of temperature
54.5F was extruded from the extruder and fed directly
into a
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continuous microwave oven where~n the batter was su~jected
to microwave energy at an energy input of 4.75 kw min~lb.
of ~atter as it passed t~rough the o~en in 150 seconds.
A ~low of air at am~ient temperature was passed through
the oven to remove moisture. The microwave ~aking was
effected to result in a moisture loss of 14~5% by weight
(to 20,4 wt.%l and an internal temperature of 212F.
The resulting sponge cake was dried to a moisture
level of S wt,% and cut into convenient lengths. The
lQ samples ~rom the two runs exhi~ited the following
properties:
With gas No gas
add`itlon addition
Density ~g/cc)Q.29 0~35
Shear (kg) 21 11
It will be seen from these results that the addition of the
gas decreases the density of the product while increasing
the shear value thereof.
Example 2
-
This ~xample illustrates the formation of a chocolate
sponge cake.
The procedure of Example 1 was generally repeated
using the following components to form the batter.
Dry mix
Sugar 50.22
Flour 36.31
Salt O.qg
Baking powder1.34
Sodium bicar~onate 0.32
Cocoa 10.82
100. 00
Wet mix
Liquid whole egg ~q.16
Vanilla 0.84
lOO.OQ
Feed rates
Dry mix 8.848 parts~min
Wet mix 4.350 parts/min
Water 0.68 parts/min
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The batter had a moisture content of 33 wt.% and a
temperature of 56F. Microwave baking was effected as
follows:
Energy used 5.88 kw min/lb. of batter
Temperature rise to 212F
Moisture loss 21.7 wt.% ~to 14.4 wt.%)
After drying to 5 wt.% moisture, the sponge cake had a
density of 0.2~ g/cc and a shear value of 13 kg.
Example 3
This Example illustrates the formation of a vanilla
sponge cake wherein baking powder is completely a~sent.
The proced~re of Example 1 was again repeated using
the following components to form the batter:
Drv mix
-
Sugar 51.233
Flour 57.759
Salt 1.008
lao. ooo
Wet mix
.
Liquid whole egg 9~.0
Vanilla 0.~1
100. 00
Feed rates
~ =.
Dry mix 8.75 kg~min
Wet mix 4.375 kg/min
Water 1.04 kg/min
The batter had a moisture content of 34 wt.% and a
temperature of 57F. The batter was subjected to microwave
baking under the following conditions:
Energy used 7.45 kw min/lb.
Temperature rise to 219F
Moisture loss 21 wt.%~to 16.4 wt.%2
After drying to 5% moisture content, the sponge cake had a
density of 0.28 g~cc and a shear value of 12 kg.
SUMMARY OF DISCLOSURE
In summary of this disclosure, the present invention
provides a unique procedure for the baking of sponge cake,
by using steam generation ~or leavening, microwave energy
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for cooking and continuous operation. Modifications are
possi~le within the scope of the invention.
