Note: Descriptions are shown in the official language in which they were submitted.
1047831
The present invention relates to a manufacturing pro-
cess for producing ready-to-eat rice which can be restored to its
original shape in a very short time by the simple expedient of
pouring boiling water on the ready-to-ea-t rice.
The study and development of so-called ready-to-eat
rice, such as pre-cooked boiled rice, rice gruel, porridge of
rice and vegetables and so on, is and has been in process, and
foodstuffs, produced by processes developed are on -the market.
However, presently available foodstuffs have many defects in
cooking and quality, and no satisfac-tory product has so far
been developed. The conventional manufacturing process of ready-
to-eat rice is divided broadly into three categories as follows:
(1) Fresh rice is boiled and then dried.
(2) Fresh rice is boiled and then fried in oil.
(3) Fresh rice is boiled, flattened and then dried.
However, ready-to-eat rice prepared by the first
process requires a longer time to restore to the original
shape, and it lacks the stickness peculiar to boiled rice and
the pleasant texture to a tongue when it is restored.
The second process requires that the temperature of
the oil in which it is fried be raised. Therefore, it is rather
difficult to maintain a good quality of the boiled rice. The
ready-to-eat rice made by this process have the defect that
they are not easily restored to their original shape by only
pouring boiling water on them.
The ones made by the third process are not restored
to their original shape peculiar to rice but remain in the
flattened state, and are far from boiled rice in both flavor
and feeling when eating.
After examining these defects in the conventional pro-
cesses, the invention has been completed for a manufacturing
process for new pre-cooked or processed rice foodstuffs which
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restore to the original shape, and have as good a flavor and
taste as boiled rice, in a very short time, e.g. a few minutes
only after pouring boiling water on them.
Specifically, this invention relates to a process for
manufacturing ready-to-eat rice wherein the grains of rice are
soaked in water, the soaked grains are gelatinized and pressed,
and then fried in edible oil at temperatures between 130C and
200C. Preferably, the oil is removed from the rice processed
in this wayO
More specifically, the invention relates to a process
for preparing ready-to-eat rice which can be reconstituted into
a foodstuff essentially in the form of original rice grains when
mixed with hot water, said process comprising'
(1) soaking rice grains in water or liquid seasoning,
(2) gelatinizing the soaked rice,
(3) reducing the moisture content of the gelatinized
rice to 18 - 70% by weight,
(4) pressing the resultant rice between rolls spaced
0.1 to 1.0 mm apart from each other to cause slides in but not to
completely decompose the rice grain,
(5) reducing the moisture content of the grains
to 8 - 25% by weight, and
(6) frying the thus obtained rice grains at a temper-
ature of 130 - 200C.
The manufacturing process in this invention is de-
scribed in detail below.
A variety of types of rice irrespective of their kind
and quality, including rice grown in Japan or elsewhere can be
used as raw material for this invention.
The grains of rice are first washed with water and
soaked in water or liquid seasoning~ Then, surfactants such as
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glycerine, fatty acid esters, sugar esters, etc. or edible oil -~
or talc are mixed with the grains. After that, they are gela-
tinized by boiling.
Since the surfactants or edible oil is added only in
order to prevent boiled rice grains from joininy with one another
and from sticking to the surface of a roll used in pressing,
only a small quantity is required.
Steamed rice should be gelatinized to the heart by
proper means, such as usual steam cooking or pressure steam
cooking.
Next, the gelatinized rice is exposed to the air at
temperatures of 20 - 100C for instance, wherein the moisture
content is adjusted to 18 - 70%. The rice is then pressed.
In addition to ventilation by exposure to air as
mentioned above, cereal flour such as dry wheat flour, rice
flour, starch, etc., cellulose powder and talc may be applied
.
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l~
1~)478;~1
to absorb moisture from the rice.
As for the pressing method, boiled rice may be for-
cibly passed through a slit between rolls or pressed by metal
plates. However, from a productivity and economical viewpoint,
the pressing method by rolls is desirable.
In case of pressing by rolls, if boiled rice is for-
cibly passed through between metal rolls as it is, the gralns
join with one another and stick to the rolls. Therefore, it is
desirable to dry the boiled rice beforehand so that the moisture
content is reduced to less than 35%. If it is over 35%, it is
necessary to lower the temperature of the grain surface to some
extent. If it is dried so that the moisture content is less
than 18%, it becomes stiff and is broken when pressed. There-
; fore, in general, a moisture content of 18 - 35% is the most
suitable.
The degree of pressing may be adjusted by changing
the distance between the rolls through which the boiled rice
is forcibly passed. If too strong a pressure is used, the rice
is cracked and loses its force of restitition to restore it to
~20 its original shape. However, if the pressing is too weak it
has no effect. In such cases, it is necessary to adjust the
slit between the rolls.
Generally speaking, when the moisture content is high,
it is necessary to make the slit between the rolls wider, and
vice versa.
As a result of experiment, it was found desirable
that the slit between the rolls is adjusted to be 0.1 - 1.0 mm
as shown in ~able 1 under the conditions therein.
Japanese Patent Publication No. 46-21770 mentioning
the process of flattening boiled rice to a width of 1.5 - 2.0
mm says that flattening to less than 1.5 mm brings flaking of
boiled rice.
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This is because free water in boiled rice is evaporated
and boiled rice loses elasticity in the said patented process as
it is flattened by heat rolls where free water is evaporated.
In the present process, however, it is desirable that
the slit between the rolls should be considerably narrower
compared with that in the said patented process as puffing of
the boiled rice by the frying step will take place later.
Besides, the present process differs in the pressing
method from the patented process. Pressing in the patented
process does not cause evaporation of free water. It aims at
partial destruction or slipping of the internal construction of
boiled rice so that puffing by frying is easily made.
P~essed rice is dried so that the moisture content
becomes 8 - 25% in order to make puffing of flattened boiled
rice easier, and then the frying process is carried out in the
previously heated edible oil. As shown in Table 2, flattened
boiled rice can be processed at a lower temperature within a
shorter time compared with non-pressed boiled rice.
The effective oil temperature in the invention ranges
from approximately 130C to 200C while non-pressed boiled rice
requires 170 - 220C. Thus flattened boiled rice can be pro-
cessed at a comparatively lower temperature and this prevents
oil rancidification and the quality of the products from being
lowered by scorch or some other causes.
It is remarkable that the rice having an excellent
force of restitution is obtained in accordance with this inven-
tion even by processing at temperatures as low as 130 - 170C.
The function of adequate pressing can be considered as
follows.
The gelatinized rice with its adjusted moisture con-
tent, adequate plasticity and elasticity, is forcibly passed
between the rolls so that the grains are pressed and flattened.
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.
.
104~
However, in the case where it is pressed through an adequate
size of slit between the rolls, it can be restored to almost
the same shape as the original one.
When boiled rice is pressed, the internal construction
of the rice is partly broken or slipped to make a number of
particles inside the boiled rice.
In other words, it turns into a great number of par-
ticles which can be easily puffed by frying.
As a result, all the construction of boiled rice can
be heated uniformly and simultaneously yet promptly in the
frying process.
Therefore, it can be fried in oil at a lower tempera-
ture in a shorter time compared with non-pressed boiled rice,
and the whole grain is also easily puffed.
Boiling water soaks into the interior of this puffed
boiled rice completely as soon as it is poured, and the boiled
rice restores to the original shape uniformly without the hard
core.
Since the construction is not completely destroyed,
but only compressed and slipped, boiling water will permeate
- the fried boiled rice sufficiently and promptly to restore it
to a complete granular shape.
Puffed boiled rice applied in this invention is far
superior to conventional non-pressed boiled rice in time re-
quired for restoration, and in flavor and taste after restora-
tion as shown in Table 1.
Pre-cooked rice foodstuffs having as good a taste as
boiled rice may be obtained by merely pouring boiling water in
the bowl containing this puffed rice mixed with powdered soup
and a mixture of desiccated vegetables, eggs, meat and the like
suitable for the object, for instance, pilaf, frizzled rice,
chicken and rice, rice cooked together with various vegetables,
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meat, shrimps, etc., stew and so on.
As shown in Table 3, puffed boiled rice fried in oil
after adequately pressed has a better effect on removing oil and
has more uses than non-pressed puffed rice.
Rice gruel, baby food, a relish, a cake, etc. can be
also made by adjusting the degree of pressing and the temperature
of the oil at w'nich the rice is fried.
TABLE 1
Pressinq deqree for boiled rice and quality_after restoration
Pressing degree Apparent Time required Quality after
(Distance between specific for restoration restora-tion
rolls)gravity after pouring
(mm)boiling water
(min)
Contrasted with
non-pressed one 0.34 7 Undercooked.
Poor taste.
(*) 0.20 5 No elasticity.
Poor taste.
1.8 0.34 7 Undercooked. -
Poor taste.
1.6 0.33 6 Undercooked.
Poor taste.
1.4 0.32 5 Partly undercooked.
Inferior taste.
1.2 0.28 4 Partly undercooked.
Inferior taste.
0.8 0.26 3 As good a taste
as boiled rice.
0.4 0.28 3 As good a taste
as boiled rice.
0.2 0.24 1.5 As good a taste
as boiled rice.
.
0.05 0.22 1.0 Not restored to
the original
granular shape.
No elasticity.
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REMP~S:
1) Japanese grown rice made into gelatinized starch
and dried before-hand until moisture content
became 26% was passed through the fixed slit
between the rolls.
2) Apparent specific gravlty was for puffed boiled
rice fried in palm oil at a temperature of 160C
after adjusting the moisture content of the press-
ed boiled rice to be 13%.
3) Diameter of the rolls was approximately 200 mm
and the revolving speed of the rolls was 10 r.p.m.
(*) Conventional non-flattened puffed boiled rice
fried in oil at a temperature of 200C for 15
seconds was used.
TABLE 2
Frying oil The oil content Time required Quality after
temperature after deoiling for restoration restoration
(C) process (sec)
(%)
a. 19 100 Some scorched
220
b. 17 5 Scorched
a. 16 180 No elasticity
200
b. 15 15 Good, but insuf-
ficient elasticity
- a. 14 240 Insufficient
elasticity
190
b. 13 25 Good
., :
a. 12 360 Undercooked
170
b. 8 30 Good
a. 10 - Undercooked, No good
150
b. 4 120 Good
-
(con't)
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TABLE 2 (con't)
a. - Impossible to fry in oil
130
b. 3 180 Good, but slightly
undercooked
_
120 Impossible to fry in oil
_
REMARKS:
a. = Non-pressed boiled rice
b. = Pressed boiled rice
Dried rice ...... Moisture content .. ~.......... 13.5%
Distance between the rolls ... O.lmm
TABLE 3
Pressinq deqree, amountofoil removedandqualitvafterrestoration
(Fried at a temperature of 165 C)
Distance between The oil content before The oil content after
the rolls deoiling process the deoiling process
(mm) (~O) (%)
Contrasted with 25.0 * 12.1
non-pressed one 21.3 ( ) 14.3
0.8 23.0 7.3
0.4 21.2 5.1
0.1 23.1 7.1
(*) In case of d~éep frying at a temperature of 200 C
for 15 seconds.
As puffed boiled rice processed by frying usually has
an oil content of 20 - 30% as shown above, it suits the food-
stuffs such as frizzled rice, pilaf, etc.
However, by removing oil from this puffed boiled rice
by a physical method applying centrifugal force or a blast of
hot air or by a chemical method applying a solvent like ethyl
alcohol as mentioned in Japanese Patent Application Nos. 48-68410,
48-68411 and 48-68412, pre-cooked rice foodstuffs suitable for
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sushi (vinegared fish and rice), boiled rice with tea, white-
polished boiled rice, etc. can be obtained.
EXAMPLE 1
The grains of 2.0 Kg of rice were washed with water
and soaked in water for 15 hours.
After draining off the water, 20 grams of nonoglyceride
was uniformly mixed with the grains of rice soaked in water.
Then the grains were put into a pot and boiled for 25 minutes at
a steam pressure of 1 Kg/cm .
The boiled rice was exposed to a hot blast at 60 - 80C
so that the moisture content of the boiled rice became 26%, and
such dried boiled rice was forcibly passed through a 1.0 mm
slit between rolls to get the ready-to-eat rice.
This ready-to-eat rice was exposed to hot air at
60 - 80C to reduce the moisture content to 13%. After that, it
was processed in palm oil heated to a temperature of 190C for
10 seconds to get the product.
Furthermore, the following were put in a polystyrene
bowl:
Powdered soup 6.0 gm
Freeze-dried mushroom 0.5 gm
" shrimp 1.0 gm
" egg 1.0 gm
" parsley 0.3 gm
" green peas 1.0 gm
Then 100 gms of the above-mentioned product was added
and mixed with them. 150cc of boiling water was poured into
the bowl, the lid was put on and kept on for three minutes.
Thus pilaf having good flavor and taste was prepared.
EXAMPLE 2
The gralns of 2 0 Kg of rice were washed with water
and soaked in water for 15 hours.
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After draining off the water, 20 gms of monoglyceride
was uniformly mixed with the grains of rice soaked in water.
Then the grains were put in a pot and boiled for 25 minutes at
a steam pressure of 1 Kg/cm .
The boiled rice was exposed to a hot blast at 60 - 80C
so that the moisture content of the boiled rice became 30%, and
such dried boiled rice was forcibly passed through a l.Omm slit
between the rolls to get pressed rice.
This pressed rice was exposed to hot air at 60 - 80 C
to reduce the moisture content to 24%. After that, it was pro-
cessed by palm oil, previously heated to a temperature of 140C,
for 10 seconds to get the product.
This puffed boiled rice was placed in a basket-type
centrifuge with a diameter of 230mm and processed for 30 seconds
at 1,200 r.p.m., maintaining a temperature of 60C. Thus puffed
boiled rice having a moisture content of 5% was obtained.
80 grams of this puffed and deoiled rice was put in a
polystyrene bowl. Then, the following were put in the bowl and
mixed with the rice:
Powdered soup 5.0 gm
Laver 0.5 gm
Rice-cake cubes 2.0 gm
After that, 300 cc of bolling water was poured into
the bowl, the lid was put on and kept on for three minutes. Thus
the product for boiled rice with tea having as good a taste as
boiled rice was obtained.
EXAMPLE 3
Puffed boiled rice obtained with the process applied
in Example 1 was processed to remove the oil in such a way as
mentioned in the Example 2, and the ready-to-eat rice suitable
for sushi (vinegared fish and rice), which is restored to the
original shape by boiling water in three minutes, was obtained.
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EXAMPLE 4
By changing the temperature of previously heated palm
oil to 180C instead of 190C in the same process as mentioned in
Example 2, rice gruel, which can be restored to the original
shape in 30 seconds by pouring boiling water, was obtained.
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