U.S. patent number RE28,995 [Application Number 05/345,182] was granted by the patent office on 1976-10-05 for method for storing fruit.
This patent grant is currently assigned to Grumman Allied Industries, Inc.. Invention is credited to Stanley P. Burg.
United States Patent |
RE28,995 |
Burg |
October 5, 1976 |
**Please see images for:
( Certificate of Correction ) ** |
Method for storing fruit
Abstract
1. The method of preserving mature, but less than fully ripe,
fruit .Iadd.which produces ethylene and is ripened thereby,
.Iaddend.comprising enhancing the rate of diffusion of ethylene
from the fruit by storing the fruit at a subatmospheric pressure in
the range of 100-400 mm. Hg-.Iadd.absolute .Iaddend.in a
continuously moving stream of water saturated air having a normal
21% O.sub.2 content, said stream continuously flushing ethylene, as
it is diffused, away from the vicinity of the fruit.
Inventors: |
Burg; Stanley P. (Miami,
FL) |
Assignee: |
Grumman Allied Industries, Inc.
(Garden City, NY)
|
Family
ID: |
26978095 |
Appl.
No.: |
05/345,182 |
Filed: |
March 26, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
311828 |
Sep 26, 1963 |
03333967 |
Aug 1, 1967 |
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Current U.S.
Class: |
426/419;
426/486 |
Current CPC
Class: |
A23B
7/148 (20130101); A23B 7/152 (20130101) |
Current International
Class: |
A23B
7/144 (20060101); A23B 7/152 (20060101); A23B
7/148 (20060101); A23K 003/02 () |
Field of
Search: |
;426/418,419,486,506,487,488,262,263,267,268,269,270,312,316,321,333,335,395,404 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wyse; Thomas G.
Assistant Examiner: Therkorn; Ernest G.
Attorney, Agent or Firm: Bosworth, Sessions & McCoy
Claims
What is claimed is:
1. The method of preserving mature, but less than fully ripe, fruit
.Iadd.which produces ethylene and is ripened thereby,
.Iaddend.comprising enhancing the rate of diffusion of ethylene
from the fruit by storing the fruit at a subatmospheric pressure in
the range of 100-400 mm. Hg .Iadd.-absolute .Iaddend.in a
continuously moving stream of water saturated air having a normal
21% O.sub.2 content, said stream continuously flushing ethylene, as
it is diffused, away from the vicinity of the fruit.
2. The method as claimed in claim 1 wherein the fruit .Iadd.is
bananas and .Iaddend.is maintained at a temperature of about
15.degree.C. .Iadd. 3. The method of claim 1 wherein the fruit is
bananas and the pressure is maintained at about 150mm. Hg absolute.
.Iaddend..Iadd. 4. The method of claim 1 wherein the fruit is green
tomatoes and the pressure is maintained at about 130mm. Hg
absolute. .Iaddend.
Description
This invention relates to retarding the ripening of edible picked
fruits, such as bananas, tomatoes, apples, pears, cherries.[.,.].
.Iadd.and .Iaddend.limes, .[.and other citrus fruits.]. .Iadd.which
produce ethylene and are ripened thereby, .Iaddend.and to apparatus
useful in storing such fruits in a manner to retard their ripening
without adverse effects.
As is well known, distances and time involved in transportation of
tropical fruit produce renders it necessary to pick the fruit in
unripe condition with the hope that the ripening process can be
controlled until the fruit is ready for display or delivery at the
consumer point of acceptance. Heretofore, aeration or refrigeration
has been relied on almost exclusively in the attempt to control the
ripening process in the transportation and marketing of fresh
bananas. Such procedures often do not delay the ripening long
enough--resulting in loss of merchantable fruit, especially when
unforeseen transportation delays are encountered.
It is an object of this invention to improve methods for
controlling fresh fruit ripening and, in particular, to deal more
effectively with the concentration build-up within the fruit of
volatile products--specifically ethylene in the case of
bananas--which are in part at least responsible for the ripening
process--so that the ripening is retarded for longer periods than
heretofore thought possible. This is done in accordance with the
method of this invention by storing the bananas in a moving gaseous
stream, as of air, at subatmospheric pressures, with the result
that the moving gaseous stream tends to flush away undesirable
gases generated during storage after their more ready release under
the conditions of reduced pressure. Undue increase in their
concentration within the fruit is thus prevented. However, such
storage without more tends to desiccate and shrink the fruit and
render it unfit for normal ripening when removed from storage
conditions.
Accordingly, in addition to maintaining the bananas in the moving
gaseous stream at subatmospheric pressure, such harmful desiccation
is avoided by saturating the moving gaseous stream with water at
the subatmospheric pressure with the result that ripening has been
retarded for periods as long as 50 to 60 days under storage
conditions without encountering harmful desiccation, thus
permitting normal ripening to resume when the fruit is removed from
the controlled storage conditions.
A further object of the invention is to provide apparatus suitable
for carrying out the methods of this invention. Such apparatus is
diagrammatically shown in the accompanying drawing wherein 10
represents a suitable storage chamber which is formed by a
conventional insulated housing 12 (broken away to indicate extent)
adapted to be vacuumized, and having an inlet conduit 24 and an
outlet conduit 26. The outlet 26 is connected with a suitable
vented oil seal vacuum pump 27 through a needle valve 28.
The inlet 24 communicates with chamber 10 through a vessel 30
within the housing 12 which contains a body of water 32 into which
inlet pipe 24 extends. Conduit 24 leads from a vacuum valve 36
having an attached vacuum gauge 38 and from a flow meter 40, the
inlet to which is open to the atmosphere. Vessel 30 communicates
with chamber 10 through a pipe or aperture 41.
Also indicated in the drawing is a water reservoir .[.40.].
.Iadd.39 .Iaddend.with a valve 42 and sealed inlet 44 into the
vessel 30.
With this apparatus, when the vacuum pump exhausts the chamber 10
to a reduced pressure for which the vacuum valve 36 is set, the
vacuum valve will thereafter open slightly to permit flow of air
through the body of water 32 at the subatmospheric pressure and
thereby becomes saturated with water at the subatmospheric pressure
before passing through pipe 41 into the storage chamber 10 where
the bananas or other fruit are stored.
The rate of flow of air through the chamber 10 is read from the
flowmeter 40.
A suitable pressure for example for bananas is about 150 mm. Hg
.Iadd.absolute, .Iaddend.as shown on the vacuum gauge, and in
practice a suitable rate of air flow may be about one fruit chamber
volume of air per hour, although the rate of air flow is not
critical within wide margins.
While the apparatus may be operated at room temperatures, even
better results are obtained if the chamber is cooled to for example
15.degree. C., as by a refrigerator system indicated by coils 50.
The temperature of the body of water 32 is thus maintained
substantially as low as that of the chamber 10 in order to prevent
excess condensation of water in the chamber 10. 52 indicates a
temperature gauge to control the temperature in the chamber 10.
At pressures of about 150 mm. Hg and a temperature of 15.degree. C.
bananas can be kept for a period of in excess of two months and
upon removal from the chamber will continue to further ripen in a
normal manner. In general, the ripening period, compared to that
taking place with control bananas ripening at atmospheric pressure
and under normal humidity conditions, is easily doubled or tripled,
the length of successful storage in the apparatus of this invention
being governed more by the development of fungal infection than by
any over-ripening. Thus, for example, in one instance the original
mature green banana control sample commenced to turn yellow after
14 days, while comparative samples stored in the chamber of the
apparatus under 150 mm. Hg and at 15.degree. C. with slow air flow
were still completely green when removed after 24 days.
In the case of green tomatoes utilizing 130 mm. Hg pressure at
16.degree. C. there was no ripe fruit peel in 40 days as compared
with a control where 100% were ripe in 27 days. Samples of tomatoes
removed after 40 days, and thereafter stored at 24.degree. C. in
air, ripened well within a week with excellent taste. In the case
of tomatoes and fruits other than bananas, storage at even lower
temperatures, for example 6.degree. C., should permit the storage
of the fruit for a period exceeding two months. For bananas,
temperatures lower than about 15.degree. C. unfortunately tend to
discolor the peel.Iadd., and green tomatoes also experienced
chilling damage.Iaddend..
Similarly in the case of avocados, at 150 mm. Hg .Iadd.-absolute
.Iaddend.pressure, 15.degree. C., ripening was definitely
perceptible in the control after 6 days as compared with 12 days
for the samples stored in the apparatus in accordance with this
invention.
Similar results were secured with Florida sweet cherries and guavas
picked green. Green limes remained green for 80 days as against a
control where 98% of the control samples ripened in 28 days.
As previously stated, the desired results are explainable on the
ground that reduced pressure in the range of 100-400 mm. .Iadd.Hg
absolute .Iaddend.enhances the rate of diffusion of ethylene from
the fruit while the moving stream flushes the ethylene away from
the fruit surfaces. Respiration and ripening of the fruit appears
also to be retarded due to the reduced oxygen tension.
The apparatus can be incorporated into, or installed on the chassis
of mobile units, such as trucks, railroad cars, or in ships' holds,
as well as in warehouses. Normally the fruit will be boxed and
stored in chamber 10 in boxes so that large quantities can be
stored without crushing damage to the bottom layers of fruit.
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