FAST REHYDRATING PULSES

LEGUMINEUSES A GRAINES COMESTIBLES SE REHYDRATANT RAPIDEMENT

English Abstract

Fast rehydrating pulses obtained by a process in which the pulses are cooked with steam under pressure, cooled by placing them
under vacuum and dried.

French Abstract

On obtient des légumineuses à graines comestibles se réhydratant rapidement, à l'aide d'un procédé dans lequel on cuit celles-ci à la vapeur sous pression, on les refroidit en les plaçant sous vide et on les sèche.

Claims

- 7 -
Claims
1. A process for preparing fast rehydrating
pulses, in which the pulses are cooked with steam under
pressure, cooled by placing them under vacuum and
dried.
2. A process according to Claim 1, in which the
starting material is pulses having a water content of
40-80%, which are cooked at a temperature of 105-140°C
for 3-40 min and cooled to a temperature of 20-80°C
while placing them under vacuum by drawing off steam
and/or condensed vapour to a residual pressure below
300 mbar and maintaining this vacuum for 2-10 min.
3. A process according to Claim 1, in which the
pulses are dried to a residual water content of 3-10%.
4. A process according to Claim 3, in which the
pulses are dried under vacuum at 40-60°C, at a pressure
of 20-40 mbar for 5-20 h.
5. Fast rehydrating pulses obtained by the process
according to one of Claims 1 to 4.

Description

~ 2 1 7 9 ~S 3 8
Wos6/ls~ ~ P~ ,S/04200
Fast rehydrating pulses
Field of the in~ention
The present invention relates to a process for
preparing fast rehydratins pulses.
Background of the Invention
Various processes fo- preparing fast cooking or
instant pulses, comprising 2 precooking and a drying of
the pulses, are known. One of the problems encountered
when carrying out these processes is the bursting
and/or parti2i disintegration of the pulses. During
this burstir.s, due to differences in surface tensions
between the skin and tne cotyledon, the pulse may split
into two halves which separate and cause it to resemble
wings of an insect. This phenomenon is known to a
person skilied in the art by the term butterflying.
To avoid this disintegration, the suggestion
has been made to carry out a controlled drying of the
cooked pulses.
In the case where cooking takes place under
pressure, 2 person skilled in the art may also
contemplate a controlled relaxation of the steam
pressure, followed by a controlled cooling of the
pulses, in other words contemplate ca-rying out the
steps of relaxing the steam pressure and cooling the
pulses carefully and above all slowly, for example.
US 4,273,795 desc-ibes a process for preparing
fast rehydrating pulses which do not burst during the
drying which follows cooking, in which the pulses are
cooked, at atmospheric pressure or unde- pressure, in a
5-7~ sugar solution, and dried using ar.y ~nown drying
process such as lyophiiization or drying unaer vacuum,
with hot a r, using infrared or using ~.iclowaves, for
example.

53~ _~
WO ~/1~ P~ I i~r9S/~2
Summary of the Invention
The object of the present inver.tion is to
propose a process for preparing fast rehydrating pulses
which comprises a step of cooking under pressure but
which avoids the bursting of the pulses, without it
being necessary to cook them in a sugar solution or to
provide for a controlle~ relaxation of the pressure
and/or a controlled cooling of the pulses.
To this end, in tAe process according to the
presen- invention, the pulses are cooked with steam
under ?ressure, cooled by piacing them under vacuum and
dried.
It was found, in effec~, sur?rislngiy, that, in
order tO avoid the bursting of pulses cooked wilh steam
in ~ vessel under p_essure, the pulses can be cooled
directly by placing them under vacuum, thal is to say
by drawing off steam and/or condensed vapour (flash
coolins), without taking special precautions, to a
residual pressure in the vessel which is significantly
below atmospheri_ pressure.
In other words, the present process makes it
possible no~ oniy to p_eserve the integrity of the
pulses, which Aardly burs. at all, but also to cool the
pulses significantiy more quickly than if, for
comparison, the steam pressure ls relaxed carefully in
order to reestablish atmospheric pressure in the
vessel, and the pulses, which are still at a
temperature o 100C after this pressure relaxation,
are then cooled slowly.
Detailed description of the Invention
~o carry ou the present process, the starting
material ca-. be co~mercial fresh or dry pulses, in
particular drv soya, bea-., pea or lentil seeds, for
example.
It is preferable for the starting material to
be pulses having a water content of 40-80~, this water

~ WO ~/IS~ P~ ,5/~200
content being that of the fresh pulses or that of the
dry pulses rehydrated by soaking.
In the latter case, namely in order to
rehydrate dry pulses, they may be soaked beforehand for
3-30 h at 15-30C in pure water or in water with the
addition of 0-0.5% of NaHSO3 and/or of 0-1% of C~H5Na3O7
as agent for stabilizing the colour, for example.
The pulses may be cooked at 105-140C for 3-40
min in a vessel in which a pressure equal to the
saturation vapour pressure at the chosen temperature
can be established, for example. The steam atmosphere
may be created in the vessel either by vaporization of
an approprlate amount or water, or by direct injection
of steam, the air initially present in the vessel being
driven out of the latter at the beginning of the
process, for example.
The pulses may be cooled to a temperature of
20-80C while placing them under vacuum by drawing off
steam and/or condensed vapour to a residual pressure
below 300 mbar and maintainins this vacuum for 2-10
min, for example.
It is important, and can be most especially
recommended, not to allow the pulses to come into
contact with cold air before the end of this cooling
step.
After the cooking and cooling, the pulses may
be dried to a residual water content of 3-10%, for
example. This drying may be carried out under vacuum at
40-60C, at a pressure of 20-40 mbar and for 5-20 h,
for example.
The pulses thereby obtained have a very similar
appearance to that of corresponding dry but uncooked
pulses. The proportion of burst pulses is, in
particular, exceptionally low.
These pulses may be rehydrated generally ~n
5-10 min in boiling water, or even in 3-4 min in water
at 70-80C for small-sized pulses such as lentils, for
example. They may be used as they are or as an

WO 96/lSC84 s ~ ~r9~i/04200
~ 4
ingredient in a dehydrated mixture for fast cooking
soup, for example.
The examples below illustrate various
embodiments of the process for preparing fast
rehydrating pulses according to the present invention.
The percentages are expressed therein by weight.
Example 1
Commercial dry navy beans are soaked for 6 h in
water at room temperature containing 0.25% of NaHSO3 and
0.5% of C6HsNa3O7, after which they have a water content
of 54.0~. The soaked pulses are rinsed for 5 min in
running water.
The pulses are piaced in an autoclave. Steam is
injected directly into the autoclave while first
driving out the air contained in the latter. The
temperature of the pulses is brought to 120C in 2 min.
The temperature is maintained at 120C for 12 min. The
pulses are then placed under vacuum by drawing off the
steam to a residual pressure of 250 mbar. This vacuum
is maintained for 3 min, after which the autoclave is
opened.
The cooked pulses have a water content of
50.6~. Burst pulses amount to only a few per cent.
The pulses are dried at 50C at 30 mbar for
14 h.
The pulses thereby obtained have a residual
water content of 6.2~. They have the appearance of the
original dry navy beans and rehydrate in 6 min in
boiling water.
Examples 2-4
Dehydrated dwarf kidney bean, red kidney bean
and Borlotti bean seeds are prepared in a manner
similar to that described in Example 1 for navy beans.
The values of the different working parameters
during the different steps, 2S well as the water

~~ WO ~/l~W 21795~8 PcTn~S/W200
5 - :~
contents of the pulses, are coIlated in Table 1 below,
in which the corresponding values presented in Example
1 have also been recorded.
.
5 Ta~le 1
Steps andEx. l Ex. 2 Ex. 3 Ex. 4
respective navy beans dwarf red kidney Borlotti
conditions kidney beans beans
beans
C~ki ng at room t~"~r~rature
time (h) 6 16 16 16
additive0.~5% NaHSO3 0.25~ NaHSO3 - -
additive0.s4
C~HsNa307
water 54.0 58.2 55.9 54.7
concent (9~)
Rinsing in rl~nni ng water
time (min) ¦ 5 ¦ 5 ¦ 5 ¦ 5
Steam cooking
temperature 120 125 125 130
( C)
time (min) 12 30 30 35
Cooling
pressure 250 250 250 250
(mbar)
time (min) 3 3 3 3
temperature 70 70 70 70
( C)
water 49.4 50.8 S0.0 51.4
content (~)
Drying
temperature S0 50 50 50
( C)
pressure 30 30 30 30
(mbar)
time (h) 14 15 15 15
water 6.2 5.5 7.0 5.3
content (~)

Wog6/lS~ 2~ 9S3a 6 - PCT~Pss/04200
The pulses thereby obtained have the appearance
of the respective original pulses. Very few have burst.
Their colour has remained excellent. They rehydrate in
5-10 min in boiling water.