Note: Descriptions are shown in the official language in which they were submitted.
CA 02409358 2008-03-04
PACKAGING OF BANANAS
This invention relates to the packaging of bananas.
Respiring biological materials consume oxygen (02) and produce carbon dioxide
(COz) at
rates which depend upon temperature and the stage of their development.
Ideally, a respiring
material should be stored in a container whose permeability to 02 and COZ is
correlated with (i)
the atmosphere outside the package, (ii) the rates at which the material
consumes 02 and
produces CO2, and (iii) the temperature, to produce the desired atmosphere
within the container.
This is the principle behind the technology of controlled atmosphere packaging
(CAP) and
io modified atmosphere packaging (MAP), as discussed, for example, in US
Patent Nos. 3,450,542
(Badran), 3,450,544 (Badran et al.), 3,798,333 (Cummin et al. 4,734,324
(Hill), 4;830,863
(Jones), 4,842,875 (Anderson), 4,879,078 (Antoon), 4,910,032 (Antoon),
4,923,703 (Antoon),
5,045,331 (Antoon), 5,160,768 (Antoon), 5,254;354 (Stewart) and 6,013,293 (De
Moor),
lnternationaC Publication Numbers WO 94112040 (Fresh
Western), WO 96/38495 (Landec) and WO 00/04787 (Landec), and European Patent
Applications Nos. 0,351,115 and 0,351,116 (Courtaulds).
Bananas are respiring biological materials whose storage and ripening present
the most
serious problems because
(i) bananas are grown in locations far distant from the locations at which
they are
consumed;
(ii) they are damaged by storage at temperatures below about 14.4 C, with the
extent of the damage depending upon the time spent below that temperature and
how far
the temperature is below 14.4 C (58 F);
(iii) they go through a climacteric when they ripen, thus producing a very
large
increase in respiration rate and the generation of heat;
-(iv) they generate ethylene as they ripen, and they ripen at a rate which
increases
with the concentration of ethylene around them -- as a result, a single
prematurely ripe
3o banana can trigger premature ripening of many others; and
(iv) once they have ripened, and have been exposed to air, they rapidly become
over-
ripe.
These problems have not yet been solved. The conventional procedure is to
harvest the
bananas when they are, hard, green and unripe; to transport the green bananas,
at 13-14 C, to
the location where they will be consumed; to ripen the green bananas by
exposing them to
ethylene in a ripening room at that location; and to place the ripened bananas
on sale. The time
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at which the bananas are harvested depends on the time needed to transport
them to the point-
of-sale. Thus bananas are typically harvested at week 11 (i.e. 11 weeks after
the flower
emerges from the plant) or week 12. The green bananas- are shipped in bags
made of
polyethylene about 0.04 to 0.06 mm (1.5-2.5 mil) thick, with each bag
containing about 18 kg (40
s Ib) of bananas and being supported by a cardboard box. In many cases, after
the bananas have
been placed in the bag, most of the air is exhausted from the bag, and the bag
is then sealed;
this is the procedure generally described in US Patent No. 3,450,542 (Badran).
In other cases,
the bag contains vent holes.
A serious disadvantage of the conventional procedure is the need to harvest
the bananas
a good while before they are fully grown. It would be desirable to harvest the
bananas at a later
time, when they are larger. However, the later the bananas are picked, the
greater the
propensity for their climacteric to be triggered by small concentrations of
ethylene, and
experience has shown that if the bananas are harvested later than the
'presently established
timetables, this results in prematurely ripe bananas when the bananas are
shipped in vented
bags, and in so-called "green-ripe" bananas when the bananas are shipped in
sealed bags.
Green-ripe bananas soften, but remain green, and have an unpleasant flavor.
Another serious disadvantage of the conventional procedure is that, in order
to ripen the
green bananas by exposing them to ethylene, it is necessary to open each of
the shipping bags
if, as in most cases, the bags have been sealed during shipping.
Another serious disadvantage of the conventional procedure is that the
bananas, once
ripened, must be sold within a few days, or scrapped.
Another serious disadvantage of the conventional procedure is that the heat
generated
by the ripening of the bananas is generated over a relatively short period of
time, which heats
the bananas to an extent that causes dehydration of the bananas and/or
increases the demand
on the refrigeration equipment used to keep the bananas cool.
The present invention mitigates or overcomes one or more of these
disadvantages by
packaging bananas in a bag (or other container) having designed permeabilities
to oxygen (02)
and carbon dioxide (COZ), and in many aspects of the invention, also to
ethylene. Some
embodiments of the invention make it possible to maintain bananas, before
and/or after their
climacteric in a packaging atmosphere which enables storage and/or ripening of
green bananas
in a controlled fashion. Other embodiment of the invention make it possible to
store bananas,
after their climacteric, within a desired range of color stages (e.g. within
the range most attractive
for retail sale) for a longer period than is possible under conventional
practice.
The containers used in the present invention preferably, but not necessarily,
include at
least one atmosphere control member which provides a pathway for 02 and C02,
and which
comprises a gas-permeable membrane comprising
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CA 02409358 2008-03-04
(1) a microporous film, and
(2) a polymeric coating on the microporous film.
The atmosphere control member is preferably a control member as described in
one or
both of WO 96/38495 and WO 00/04787.
Different aspects of the
invention make it possible to ripen bananas in a sealed container, for example
in a conventional
ripening room or while the bananas are being transported; and/or to harvest
bananas at a later
time than is now possible; and/or to preserve bananas in a satisfactory
ripened state for longer
than is now possible.
In a first aspect, this invention provides a container which is suitable for
packaging bananas and which has at least one, and preferably both, of the
following
characteristics
(1) the container can be sealed around a quantity of bananas, said quantity
being at
least 4 kg, preferably at least 15 kg, especially 16 to 22 kg, and, when
sealed around the
bananas, has an 02 permeability at 13 C, per kg of bananas in the container
(OP13/kg),
of at least 700, preferably at least 1000, particularly at least 1500,
ml/atm.24 hrs and an
R ratio at 13 C of at least 2, preferably at least 3, and preferably has an
ethylene
permeability at 13 C, per kg of bananas in the container (EtOP13/kg) which is
at least 3
times, preferably at least 4 times, the OP1 3/kg of the container; and
(2) the container includes at least one permeable control member which (i)
provides a
pathway for 02, CO2 and ethylene to enter or leave the packaging atmosphere
and (ii)
comprises a gas-permeable membrane comprising
(a) a microporous polymeric film, and
(b) a polymeric coating on the microporous film.
In a second aspect, this invention provides a package which comprises
(a) a sealed container, and
(b) within the sealed container, bananas and a packaging atmosphere around the
.bananas;
the sealed container having an 02 permeability at 13 C, per kg of bananas in
the container
(OP1 3/kg), of at least 700, preferably at least 1000, particularly at least
1500, ml/atm.24 hrs and
an R ratio at 13 C of at least 2, preferably at least 3.
In a third aspect, this invention provides a method of ripening green bananas
which
comprises
(A) providing a sealed package which comprises
(a) a sealed container, and
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(b) within the sealed container, green bananas and a packaging atmosphere
around the green bananas;
the sealed container having an 02 permeability at 13 C, per kg of bananas in
the
container (OP1 3/kg), of at least 700, preferably at least 1000, particularly
at least 1500,
ml/atm.24 hrs, an R ratio at 13 C of at least 2, preferably at least 3, and
an ethylene
permeability at 13 C, per kg of bananas in the container (EtOP1 3/kg) which
is at least 3
times, preferably at least 4 times, the OP13/kg of the container; and
(B) placing the sealed package in an atmosphere containing ethylene.
In a fourth aspect, this invention provides a method of ripening green bananas
which
comprises
(A) placing, in a sealable container,
(a) the green bananas, and
(b) a source of ethylene;
(B) sealing the container around the green bananas and the source of
ethylene, thus providing a sealed package which comprises
(a) a sealed container, and
(b) within the sealed container, the green bananas, the source of ethylene,
and a packaging atmosphere around the green bananas;
the sealed container having an 02 permeability at 13 C, per kg of bananas in
the
container (OP13/kg), of at least 700, preferably at least 1000, particularly
at least 1500,
ml/atm.24 hrs, an R ratio at 13 C of at least 2, preferably at least 3, and
an ethylene
permeability at 13 C, per kg of bananas in the container (EtOP1 3/kg) which
is at least 3
times, preferably at least 4 times, the OP13/kg of the container; and
(C) exposing the bananas in the sealed package to ethylene from the source of
ethylene in the sealed container.
In a fifth aspect, this invention provides a method of storing green bananas
which
comprises
(A) placing the green bananas in a container which comprises an atmosphere
control member which comprises
(1) a microporous film, and
(2) a polymeric coating on the microporous film;
(B) sealing the container, thus providing a sealed package which comprises
(a) a sealed container, and
(a) within the sealed container, the green bananas, and a packaging
atmosphere around the green bananas; and -
(C) maintaining the sealed bag at the temperature of 13-18 C.
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In a sixth aspect, this invention provides a package which is stored in air
and which
comprises
(a) a sealed container, and
(b) within the sealed container, 1 to 2.5 kg (2 to 5 Ib) of bananas which have
passed their climacteric and which are at a color stage less than 5, and a
packaging
atmosphere around the bananas;
the sealed container including at least one permeable control member which
provides a pathway
for 0 2 and CO2 to enter or leave the packaging atmosphere and which comprises
a gas-
permeable membrane comprising
(1) a microporous film, and
(2) a polymeric coating on the microporous film; and
the packaging atmosphere containing at least 0.8%, preferably 1.5 to 6%,
especially 1.5 to 3%,
of 02, and less than 15%, preferably less than 7%, of C02 , with the total
quantity of 02 and CO2
being less than 16%, preferably Iess than 10 %.
In a seventh aspect, this invention provides a package which comprises
(a) a sealed container, and
(b) within the sealed container, bananas and a packaging atmosphere around the
bananas;
the sealed container including at least one permeable control member which
provides a pathway
for 02 ,C02 and ethylene to enter or leave the packaging atmosphere and which
comprises a
gas-permeable membrane comprising
(a) a microporous polymeric film, and
(b) a polymeric coating on the microporous film.
In an eighth aspect, this invention provides a method of ripening green
bananas which
comprises
(A) providing a sealed package which comprises
(a) a sealed container, and
(b) within the sealed container, green bananas and a packaging atmosphere
around the green bananas;
the sealed container including at least one permeable control member which
provides a
pathway for 02 CO2 and ethylene to enter or leave the packaging atmosphere and
which
comprises a gas-permeable membrane comprising
(a) a microporous polymeric film, and
(b) a polymeric coating on the microporous film; and
(B) placing the sealed package in an atmosphere containing ethylene.
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In a ninth aspect, this invention provides a method of ripening green bananas
which
comprises
(A) placing, in a sealable container,
(a) the green bananas, and
(b) a source of ethylene;
(B) sealing the container around the green bananas and the source of
ethylene, thus providing a sealed package which comprises
(a) a sealed container, and
(b) within the sealed container, the green bananas, the source of ethylene,
and a packaging atmosphere around the green bananas;
the sealed container including at least one permeable control member which
provides a
pathway for 02 ,C02 and ethylene to enter or leave the packaging atmosphere
and which
comprises a gas-permeable membrane comprising
(a) a microporous polymeric film, and.
(b) a polymeric coating on the microporous film; and
(C) exposing the bananas in the sealed package to ethylene from the source of
ethylene in the sealed container.
In a tenth aspect, this invention provides a method of storing green bananas
which
comprises
(A) placing the green bananas in a container which comprises an atmosphere
control
member which comprises
(1) a microporous film, and
(2) a polymeric coating on the microporous film;
(B) sealing the container, thus providing a sealed package which comprises
(a) a sealed container, and
(b) within the sealed container, the green bananas, and a packaging
atmosphere around the green bananas; and
(C) maintaining the sealed bag at the temperature of 13-18 C.
In an eleventh aspect, this invention relates to the use, in packaging
bananas, of a
container including at least one permeable control member which provides a
pathway for 02 and
C02, and which comprises a gas-permeable membrane comprising
(1) a microporous film, and
(2) a polymeric coating on the microporous film.
In this specification, including the Examples and the Claims below, reference
is made to
particular features of the invention. It is to be understood that the
disclosure of the invention in
this specification includes all appropriate combinations of such particular
features. For example,
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where a particular feature is disclosed in the context of a particular aspect
or embodiment of the
invention, or a particular claim, that feature can also'be used, to the extent
appropriate, in the
context of other particular aspects and embodiments of the invention, and in
the invention
generally.
In describing and claiming the invention below, the following abbreviations,
definitions,
and methods of measurement are used. OTR is 02 permeability. COTR is CO2
permeability.
EtTR is ethylene transmission rate. OTR, COTR and EtTR values are given in
mI/m2.atm.24
hrs; in some cases, the equivalent in cc/100 inch2.atm.24 hrs is given in
parentheses. OTR and
COTR values referred to herein can be measured using a permeability cell
(supplied by
io Millipore) in which a mixture of 02, CO2 and helium is applied to the
sample, using a pressure of
0.7 kg/cmZ (10 psi) except where otherwise noted, and the gases passing
through the sample
were analyzed for 02 and CO2 by a gas chromatograph. The cell could be placed
in a water
bath to control the temperature. The abbreviation Pio is used to denote the
ratio of the oxygen
permeability at a first temperature T1 C to the oxygen permeability at a
second temperature T2,
where T2 is (T1-10) C, Ti being 10 C and T2 being 09C unless otherwise noted.
The abbreviation
R or R ratio is used to denote the ratio of C02 permeability to 02
permeability, both permeabilities
being measured at 20 C unless otherwise noted. Pore sizes given in this
specification are
measured by mercury porosimetry or an equivalent procedure. Parts and
percentages are by
weight, except for percentages of gases, which are by volume; temperatures are
in degrees
Centigrade, and molecular weights are weight average molecular weights
expressed in Daltons.
For crystalline polymers, the abbreviation To is used to denote the onset of
melting, the
abbreviation TP is used to denote the crystalline melting point, and the
abbreviation AH is used to
denote the heat of fusion. T, Tp and AH are measured by means of a
differential scanning
calorimeter (DSC) at a rate of 10 C/minute and on the second heating cycle. To
and Tp are
measured in the conventional way well known to those skilled in the art. Thus
TP is the
temperature at the peak of the DSC curve, and To is the temperature at the
intersection of the
baseline of the DSC peak and the onset line, the onset line being defined as
the tangent to the
steepest part of the DSC curve below Tp.
Where reference is made herein to sealing bags containing bananas, it is to be
understood that the sealing can be, but generally is not, hermetic sealing.
Conventional
methods for sealing bags of bananas can conveniently be used in this
invention. Such
conventional methods include, for example, the use of a cable tie to seal the
neck of the bag. A
moon seal made by conventional methods is not a hermetic seal, and has the
advantage that it
permits equilibration of the pressures inside and outside the bag. If the bag
is sealed
hermetically, it will generally be desirable to include one or more pinholes
in the bag, to achieve
such equilibration.
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Control Members
As noted above, this invention preferably makes use of an atmosphere control
member
comprising (a) a microporous polymeric film, and (b) a polymeric coating on
the microporous
film. The microporous polymeric film preferably comprises a network of
interconnected pores
having an average pore size of less than 0.24 micron, with at least 70% of the
pores having a
pore size of less than 0.24 micron. Preferably the pores in the microporous
film constitute 35 to
80% by volume of the microporous film. Preferred microporous films comprise a
polymeric matrix
comprising (i) an essentially linear ultrahigh molecular weight polyethylene
having an intrinsic
viscosity of at least 18 deciliters/g, or (ii) an essentially linear ultrahigh
molecular weight
polypropylene having an intrinsic viscosity of at least 6 deciliters/g, or
(iii) a mixture of (i) and (ii).
The microporous film may contain 30 to 90% by weight, based on the weight of
the film, of a
finely divided particulate substantially insoluble filler which is distributed
throughout the film. A
preferred process for preparing suitable microporous films comprises
1s (A) preparing a uniform mixture comprising the polymeric matrix material
in the form of a powder, the.filler, and a processing oil;
(B) extruding the mixture as a continuous sheet;
(C) forwarding the continuous sheet, without drawing, to a pair of heated
calender rolls;
(D) passing the continuous sheet through the calender rolls to form a
sheet of lesser thickness;
(E) passing the sheet from step (D) to a first extraction zone in which the
processing oil is substantially removed by extraction with an organic
extraction liquid
which is a good solvent for the processing oil, a poor solvent for the
polymeric matrix
material, and more volatile than the processing oil;
(F) passing the sheet from step (E) to a second extraction zone in which
the organic extraction liquid is substantially removed by steam or water or
both; and
(G) passing the sheet from step (F) through a forced air dryer to remove
residual water and organic extraction liquid.
The polymeric coating on the control member preferably comprises a
crystalline polymer having a peak melting temperature Tp of -5 to 40 C, e.g.
0 to
15 C, or 10 to 20 C, an onset of melting temperature T such that ( TP- T )
is less
than 10 C, and a heat of fusion of at least 5 J/g. The polymer preferably
comprises
a side chain crystalline polymer moiety comprising, and optionally consisting
of, units
derived from (i) at least one n-alkyl acrylate or methacrylate (or equivalent
monomer,
for example an amide) in which the n-alkyl group contains at least 12,
preferably at
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least 14, for example 16-50, preferably 16-22, carbon atoms, for example in
amount
35-100%, preferably 50-100%, often 80-100%, and (ii) one or more comonomers
selected from acrylic acid, methacrylic acid, and esters of acrylic or
methacrylic acid
in which the esterifying group contains less than 10 carbon atoms. The polymer
can
be a block copolymer in which one of blocks is a crystalline polymer as
defined and
the other block(s) is crystalline or amorphous. Preferred block copolymers
comprise
polysiloxane polymeric blocks, and (ii) crystalline, polymeric blocks having a
Tp of -5 to 40 C. Such a polymer can be prepared by copolymerizing a mixture
of reactants
which comprises (i) at least one n-alkyl acrylate or methacrylate in which the
n-alkyl group
contains at least 12 carbon atoms and (ii) a polysiloxane having a
copolymerizable group at one
end thereof.
Other polymers which can be used to the coat the microporous film include cis-
polybutadiene, poly (4-methylpentene), polydimethyl siloxane, and ethylene-
propylene rubber.
The gas-permeable membrane preferably has one or more of the following
is properties
(i) a Pio ratio, over at least one 102C range between -5 and 15 C or between
10 and
C, of at least 2.0 to 2.8;
(ii) an oxygen permeability at all temperatures between 202 and 252C of
2,480,000 to
7,000,000 mI/m2.atm.24 hr. (160,000 to 450,000 cc/100 in2.atm.24hr); and
20 (iii) an R ratio of at least 2.0, preferably at least 3.0, particularly at
least 3.5. -
In one embodiment, the control member comprises
(a) the gas-permeable membrane; and
(b) an apertured cover member which lies between the gas-permeable
membrane and the air surrounding the package;
the gas permeable membrane having, in the absence of the apertured cover
member,
(i) an 02 permeability, OTRperm, of at least 155,000 ml/m2 = atm =24 hr
(10,000 cc/100 in2 = atm = 24 hr), and
(ii) a permeability ratio, RPerm, of at least 2, and
the apertured cover member being composed of
(i) a barrier portion having an 02 permeability, OTRbar, which is less than
0.5
times, preferably less than 0.01 times, OTRperm, and
(ii) an aperture portion which comprises at least one aperture having an area
of
at least 0.015 in2 and through which the gas-permeable membrane is exposed to
the air surrounding the package, the aperture portion being such that the
control
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member has apermeability ratio, Rc ntr I, which is at most 0.9, preferably at
most
0.8, times Rperm, and which is preferably greater than 1.00.
The aperture portion of the cover member may have an area A pen which is at
most 0.04 times
Aperm, where Aperm is the area of the gas-permeable membrane. The aperture
portion can consist
of one or more apertures, each aperture having an area, Aaperture, less than
0.155 in2. For further
details of such atmosphere for control members, reference should be made to
U.S. Patent No.
6,013,293.
The permeability of the container, whether or not it includes an atmosphere
control
member, can be influenced by perforating the container in order to make a
plurality of pinholes
io therein.
Ripening bananas in an ethylene atmosphere
In the third and eight aspects of the invention, green bananas are ripened
while in a
sealed container. This method can be carried out in a conventional ripening
room containing
ethylene, typically but not necessarily at a concentration of 500 to 1000 ppm.
It was surprising to
discover that, when using suitable containers, it was unnecessary to follow
the conventional
practice of opening the bags, and that the bananas would ripen satisfactorily
in this way. An
important advantage of this method of ripening bananas is that the ripening
takes place in a
more controlled fashion, resulting in lower peak temperatures in the bananas,
which in turn
results in reduced dehydration of the bananas and reduced demand upon the
refrigeration
equipment when the ripening is carried out at temperatures below room
temperature.
The temperature at which ripening is carried out and the concentration of
ethylene in the '
atmosphere influence the rate at which ripening takes place. In general,
slower ripening results
in bananas which remain in a desired range of color stage for a longer period.
On the other
hand, this must be balanced against delivery dates required by retail outlets
and inventory
constraints. Generally the ethylene-containing atmosphere will be maintained
at the temperature
less than 22 C, preferably less than 20 C, for example 16-21 C.
The atmosphere within the bags will change substantially during the ripening
process, as
the bananas consume 02 and generates CO2 . Preferably, the packaging
atmosphere, for at
least part of the period before the bananas reach their climacteric, contains
at least 10%
preferably at least 12%, particularly 14 to 19%, of 02, and less than 10%,
preferably less than
4%, of C02, with the total quantity of 02 and CO2 being less than 20 %,
preferably less than 17
%. For at least part of the period after the bananas have passed their
climacteric, the packaging
atmosphere preferably contains at least 0.8%, preferably 1.5 to 6%, especially
1.5 to 3%, of 02,
and less than 15%, preferably less than 7%, of CO2 , with the total quantity
of 02 and C02 being
less than 16%, preferably less than 10 %.
Ripening bananas using a source of ethylene within the container
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In the third and ninth aspects of the invention, green bananas are ripened by
means of a
source of ethylene placed with the bananas in the sealed container. This
aspect of the invention
is particularly useful for ripening bananas while they are being transported,
for example on a
ship. The ripening process can be controlled so that the bananas are at a
desired color stage
when the bananas reach their destination. During the ripening process, there
is no need to alter
the normal atmosphere in which the bags of bananas are being transported
(though the
invention does not exclude the possibility that a controlled atmosphere is
used). The source of
ethylene can make ethylene available immediately after packaging the bananas,
or after a
desired delay.
In these aspects of the invention, relatively slow ripening of the bananas is
generally
desired, and in consequence the temperature around the bags of bananas is
generally
controlled, during at least part of the ripening process, at a temperature
less than 18 C,
preferably less than 16 C, for example at 14-15 C.
Any convenient source of ethylene can be used. I have obtained good results
using 2-
chloroethyl phosphonic acid, which is often referred to herein as 2CPA. 2CPA
can be used in
the form of an aqueous solution, for example of concentration 3-4%. The rate
at which 2CPA
generates ethylene increases with increasing pH of the aqueous solution, which
can be
adjusted, for example to more than 4, particularly more than 7, by the
addition of suitable
materials, for example buffer solutions and/or sodium bicarbonate solutions.
In one
embodiment, a 2CPA solution and any pH adjuster are adsorbed on the same or
different
absorbent pads, e.g. paper pads, and the pad(s) placed in the bottom of the
bag and covered
with a polymeric sheet before the bananas are placed in the bag. In another
embodiment, a
solution of 2CPA is applied to the green bananas, for example by dipping 6r
spraying, before the
bananas are placed in the bag.
As in the aspects of the invention which involve ripening in an ethylene-
containing
atmosphere, the atmosphere within the sealed bags containing the source of
ethylene will
change during the ripening process. The atmospheres in the bag, for at least
part of the periods
before and after the climacteric, are preferably as stated above when the
bananas are ripened in
an ethylene-containing atmosphere.
Quantities of bananas
The invention can in principle be used for any quantity of bananas. However,
when the
invention is used for ripening bananas, or for storing green bananas, it is
particularly valuable
when relatively large quantities are involved. Thus it is generally preferred
that the sealed
container contains at least 4 kg, preferably least 15 kg, especially 16 to 22
kg of bananas.
However, in the sixth aspect of the invention, much smaller quantities (1 to
2.5 kg (2 to 5 lb.) are
used in order to increase-the shelf life of the bananas at 'a desired color
stage.
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CA 02409358 2008-03-04
EXAMPLES
The-invention is illustrated in the foliowing Examples, a number of which are
comparative
Examples, designated by the letter C before the number of the example. The
bananas, bags and
control members used in the Examples were as follows.
Bananas The bananas were Cavendish bananas, from Ecuador in Examples 1 A-B,
C11-12, 2, C2,
4A-B and C41-42, from Costa Rica in Examples 5 A-C and C5, and from Colombia
In the other
Examples.
Bags
io The large bags were about 0.96 m (38 in.) wide and about 1.2 m (50 in.)
long, and were
made from polyethylene film about 0.056 mm (2.2 mil) thick (available from
Roplast lndustries
under the tradename RA 3030). The polyethylene film had an OTR at 13 C of
about 2915 (188)
and at 22 C of about 4,650 (300), and EtTR at 13 C of about 11,400 (735) and
at 22 C of
about 18,100 (1,170), an R ratio of about 4.5, and a Pi0 ratio (between 0 and
10 C.) of about
is 1.76. The small bags=were about 0.3 m (12 in.) wide and about 0.46 m (18
in.) long, and were
made from the same polyethylene film.
Control Members
The Type S control members were as described in
corresponding Intematlonal Publication No. WO 00/04787
20 and comprised a microporous polyethylene film coated with a
polysiloxane/SCC block
copolymer. The Type S members had an OTR at 13 C of about 3,803,850 (245,410)
and at 22
C of about 5,000,000 (324,000), an EtTR at 13 C of about 16,280,000
(1,050,300) and at 22 C
of about 19,500,000 (1,260,000), an R ratio of about 3.8, and a P10 ratio
(between 0 and 10 C.)
of about 1.8. The microporous polyethylene fiim contained 50-60% silica, had a
thickness of
25 about 0.18 mm (0.007 inch), a tear strength of about 90g, a porosity of
about 65%, an average
pore size of about 0.1 micron and a largest pore size of 4-10 microns
(available from PPG
Industries under the tradename Teslin SP 7). The block copolymer was prepared
by the reaction
of a polydimethyi siioxane terminated one end only by a methacryloxypropyl
group (available
from Gelest under the tradename MCR M17), 40 parts, dodecyl acrylate, 26.8
parts and
30 tetradecyl acrylate, 33.2 parts, as described in Example A7 of
corresponding International Publication No. WO 00/04787.
The Type A control members were as described in
corresponding lnternational Publication No. WO
96/38495, and comprised the same microporous polyethylene film coated with an
SCC polymer
35 of dodecyl acrylate, 42 parts, tetradecyl acrylate, 53 parts, and acrylic
acid, 5 parts. The Type A
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members had an OTR at 22 C of about 1,705,000 (110,000), an R ratio of about
4, and a P10
ratio (between 0 and 10 C.) of about 1.4.
In each Example, the control member was secured to a portion of the bag in
which one or
more round holes had been cut. The effective area of the control member is
about equal to the
area of the hole or holes in the portion of the bag to which the control
member is attached:
However, in Examples 1A-B, C11-12, 2, C2, 3A-D and C31-33, the periphery of
the control
member was heat sealed to the interior of the bag, thus creating a control
member of the kind
described in United States Patent No. 6,013,293. In the other Examples, the
control member
was secured to the exterior of the bag by means of a layer of a pressure
sensitive adhesive on
the peripheral margin of the control member.
The color stages referred to in the Examples are those accepted by the
industry and as
shown below.
Color stage Description
1 95% green
2 80% green, 20% slightly yellow
3 50% yellow, 50% green
4 80% yellow, 20% light green
5 95% yellow, with slight green color at stem and blossom end
6 100% yellow
7 100% yellow with brown sugar spots
Bananas are preferably at color stage 3.5 to 5 when put on retail sale.
Many of the Examples are summarized in Tables 1-8 below. In the Tables, when
more
than one result is given for a particular Example, this reflects the fact that
more than one test
was carried out under the same conditions.
Examples 1 A-B, C11-12. 2 and C2
Each of these Examples uses a large bag. In Examples C 11,1A-B and 2, each bag
has
one S-type control member placed under two or more holes in the bag. In
Example C11, the
control member had an area of 1935 mm2 (3 in2) and was placed under two holes,
each of
diameter 20.6 mm (0.81 in.). In Example 1A, the control member had an area of
6450 mm2 (10
in2) and was placed under 6 holes, each of diameter 20.6 mm (0.81 in.). In
Examples -1 B and 2,
the control memberhad an area of 12,900 mm2 (20 in2) and was placed under 6
holes, each of
diameter 28.7 mm (1.13 in). Each bag was packed with about 20 kg (44 Ib) of
green bananas.
The bananas had been harvested at week 11 and maintained at 13-14 C for about
11 days after
harvest before being packed. Except in Examples C12 and C2, excess air was
extracted from
the bags using a vacuum pump, and the bags were then sealed using tie wraps.
In Examples
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C12 and C2, the bags were left open. The bags were maintained at 13 C. for an
extended time,
Examples 1 A, 1 B, C11 and C12 being terminated at day 62, and Examples 2 and
C2 being
terminated at day 40. The results are given in Table 1 below. In Example 2,
traces of ethylene
(generated by the ripening of the bananas) remained in the test chamber from
Example 1 and
s caused the bananas to ripen more rapidly than in the otherwise substantially
identical Example
1 B. This demonstrates the desirability of excluding ethylene when long
storage periods are
needed (and conversely, the ability to accelerate ripening when desired).
Table 1
Example No.
C11 1A 1B C12 2 C 2
Control member yes yes yes no yes no
Total area of holes in bag under 670 2000 3880 - 3880. -
control members (mm2)
Color stages
first change at day > 62 44 44 12 26 15
days to change from 3.5 to 4.5 - - - - 4.5 *
days to change from 3.5 to 5 - ** 11 7 # *
Weight loss (%) on day 26 - - - - 0.35 3.7
on day 41 0.38 0.45 0.60 4.73 - -
Taste and texture on day 40 - - - - Exct =
on day 62 UGH Exct Exct Overripe -
% 02 (approximate)
at day 7 5.1 11.9 13.8 atm - atm
at day 8 - - - atm 14.35 atm
at day 47 (after climacteric) 5.0 0.96 2.2 atm 2.15 atm
% C02 (approximate)
at day 7 5.3 3.6 3.05 atm - atmta
at day 8 - - - atm 3.05 tm
at day 29 (after climacteric) - - - atm 8.0 atm
at day 47 (after climacteric 5.3 7.9 8.4 atm - atm
UGH unripe, green and hard.
* the bananas had a color of 4.5 when the test was terminated at day 62
Exct excellent taste and texture
# test terminated at this point; extrapolation indicates that time to change
from color 3.5 to
5 would be 5.9 days.
Bananas removed on day 26 because they were over-ripe.
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Examples 3 and C31-33
Each of these Examples uses a large bag. In Examples C31-33 and 3, each bag
has one S-tjrpe control member placed under one or more holes in the bag. In
Example
C31, the control member had an area of 967 mm2 (1.5 in2) and was placed under
a
single hole of diameter 20.6 mm (0.81 in.). In Example C32, the control member
had an
area of 1935 mm2 (3 in) and was placed under 2 holes, each of diameter 20.6 mm
(0.81
in.). In Example C33, the control member had an area of 3225 mm2 (5 in2) and
was
placed under 4 holes, each of diameter 19 mm (0.75 in.). In Example 3, the
control
member had an area of 12,900 mm2 (20 in2) and was placed under 6 holes, each
of
diameter 25 mm (1 in.). In Example C34, the bag did not have a control member.
Each
bag was packed with about 18.1 kg (40 lb) of green bananas. The bananas had
been
harvested at week 13, and maintained at 13-14 C for about 11 days after
harvest before
being packed. Except in Example C34, excess air was extracted from the bags
using a
vacuum pump, and then securely tied (the bags were not, however, as completely
sealed as in Examples 1 and 2). In Example C34, the bags were left.open. The
sealed
bags were cooled to about 13 C and shipped to Gulfport, Mississippi, and then
to San
Francisco, California, maintaining the temperature at about 13 C. In San
Francisco, 36
days after packing, half the bags in each Example were opened, and the other
half left
intact. All the bags were then exposed to ethylene (500-1000 ppm) in a
commercial
ripening room for about 24 hours. The bananas in the opened bags ripened
rapidly in
the expected way; thus by day 43, their color was 6, by day 46 their color was
greater
than 7, and by day 49, they were overripe. The bags which were still sealed
were
opened on day 49. The results for the bags opened on day 49 are shown in Table
2
below. These Examples demonstrate that bananas harvested at 13 weeks can be
transported in a suitably designed bag, and can be ripened into an excellent
product by
exposure to ethylene, either through the bag or after opening the bag.
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TABLE 2
Example No.
C31 C32 C33 3 C 34
Control member yes yes yes yes no
Total area of hole(s) in bag under control 335 670 1140 3040 -
member (mm2 )
Days to change from color stage 3.5 to color > 8 > 8 > 8 5.5 DDU
stage 5
Taste and texture on day 49 SGU SGU SGU Exct DDU
lo 02 (approximate) at day 23 8.6 9.8 12.7 15.5
at day 46 2.9 0.6 1.8 2.2
% CO2 (approximate) at day 23 4.45 3.65 3.3 2.85
at day 46 13.8 11.4 5.0 9.0
SGU soft; green and unpalatable
DDU dehydrated, decayed and unpalatable by day 47 (day 11 after exposure to
ethylene)
Exct excellent taste and texture
Examples 4A, 4B, C41 and C42
Each of these Examples uses a.small bag. In Examples 4A-B, each bag has one A-
type
control member placed over four or five holes in the bag. In Example 4A, the
control member
had an area of 145 mm2 (5.7 in2) and was placed over four holes each of
diameter 19 mm (0.75
in.). In Example 4B, the control member had an area of 4516 mm2 (7 in2) and
was placed over 5
holes, each of diameter 19 mm (0.75 in.). In Example C41, the control member
and the holes
under it were as in Example 4A, except that the control member was an uncoated
microporous
film. In Example C42, the bag was intact except for 200 pinholes each about
0.5 mm (26 gauge)
in diameter. Each bag was packed with about 1.35 kg (3 Ib) of green bananas
which had been
maintained at 13-14 C for about 11 days after harvest. Except in Example C42,
excess air was
extracted from the bags using a vacuum pump, and the bags were then securely
tied. In
Example C42, the bags were left open. After three days, to allow the packaging
atmosphere to
equilibrate, the bags were exposed to ethylene (500-1000 ppm) in a ripening
room. The results
are shown in Table 3 below. These Examples demonstrate that small quantities
of bananas can
be ripened in a suitably designed bag, and can remain in the bag in excellent
condition for
several days longer than bananas exposed to the air.
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Table 3
Example No.
4A 4B C41 C42
Control member yes yes 4 no
Total area of holes in bag over control member (mm ) 1140 1425 1140 -
Color stage on day 10 after ethylene treatment 4.0 4.4 7.0 6.8
Weight loss (%) on day 10 after ethylene treatment 0.57 0.72 1.05 0.61
Taste & texture on day 10 after ethylene treatment Exct Exct Over- Over-
ripe ripe
uncoated microporous film
Exct excellent taste and texture
Examples 5A, 5B, 5C and C5
These Examples show that the bananas generate heat more evenly when ripened in
a
container including an atmosphere control member. In each Example, a large bag
was packed
io with about 18.1 kg (40 lb.) of green bananas. The green bananas had been
harvested 13 days
previously and had been stored at 13-14 C since harvest. A temperature sensor
(available from
Sensitech, Beverly, Massachusetts, under the tradename Temptale P) was
inserted into one
banana in each bag. In each of Examples 5A, 5B and 5C, the bag had two S-type
control
members, each having an area of 11,300 mm2 (17.5 in2). Each control member was
placed over
a single hole in the bag, the hole having an diameter of 70 mm (2.75 in.) in
Example 5A, 74.4
mm (2.93 in.) in Example 5B, and 78.7 mm (31 in.) in Example 5C. In Example
C5, the bag was
perforated so that the bananas were surrounded by air. The bags were then
sealed with rubber
bands. The sealed bags were placed in a refrigerated room at about 13 C.
After about 84
hours, the temperature of the room was raised to about 16.7 C and after about
12 hours, an
ethylene generator was used to provide an initial ethylene concentration in
the room of 500-1000
ppm. About 24 hours after the generation of ethylene had begun, the room was
vented. The
temperature of the bananas was monitored for about 15 days, and reached a peak
at about 60
hours after the generation of ethylene had begun. At that time, the
concentration of 02 and CO2
was measured. The results are shown in Table 4 below. It will be seen that the
peak temperature
was substantially lower in the bags containing control members than in the
perforated bag.
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Table 4
Example No.
5A 5B 5C C5
Control member yes yes yes no
Total area of holes in bag under control members (mm ) 7700 8700 9700 -
Temperature ( C) of bananas 12 hrs after temperature of room 16.3 15.9 15.7
16.6
was set to 16.7 C
Peak Temperature C 21.2 21.1 20.9 23.9
Difference between peak temperature and 16.6 C 4.9 5.3 5.2 7.3
% 02 60 hours after injection of ethylene 2.2 1.75 1.9 20.95
% CO2 60 hours after injection of ethylene 7.95 6.1 7.4 0.03
Examples 6 A-E
Each of these Examples uses a large bag having two S-type control members,
each
control member having an area of 11,300 mm2 (17.5 in). Each control member was
placed over
seven holes in the bag, each hole of diameter 25.4 mm (1 in). A paper pad
about 300 x 400 mm
(12 x 16 in.) impregnated with an aqueous solution of 2CPA (3.9%) was placed
in the bottom of
each bag and covered with a sheet of polyethylene. The amount of the solution
varied from
Example to Example, and is shown in Table 5 below. About 18.1 kg (40 lb.) of
green bananas
were then placed in each bag, and the bags were sealed with rubber bands. The
green bananas
had been maintained at 13-14 C for about 11 days after harvest. The sealed
bags were left in a
cold room at 13-14 C. The color stage of the bananas was monitored, and Table
5 below shows
the time in days taken to reach color stages 4 and 5.5.
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Table 5
Example No.
6 A 6B 6C 6D 6E
Control member yes yes yes yes yes
Total area of holes in bag under control 7100 7100 7100 7100. 7100
members (mm2)
mL of 3.9% 2CPA solution on paper pad 30 50 100 200 500
Days to color stage 4 11 10.8 10.6 11 9.6
* 20.4 20.1 12 12
* 10.5 11 11 11
Days to color stage 5.5 17.5 * 17.4 16 16.1
* * 24.2 16 16.9
* 17.5 17.4 16 16.3
Days from color stage 4 to color stage 5.5 6.5 - 6.8 5 6.5
- 3.1 4 4.9
- 7 6.4 5 5.3
* this color stage had not been reached when the experiment was terminated
after 27 days.
Examples 7 A-D and C71-74
The procedure of Example 6 was followed except for the changes noted below.
1. In Examples 7A-D, there was a single hole, diameter 82.5 mm (3.25 in.),
under
each of the two control members. The total area of the holes was 10,700 mm2.
2. In Examples 7A, 7B and 7C and in comparative Examples C72 and C73, a paper
io pad impregnated with 0.1 N NaHCO3 solution was placed adjacent to the paper
pad
impregnated with 2CPA solution, thus increasing the pH of the 2CPA solution
and
increasing the rate at which ethylene was generated. The amount of the NaHCO3
solution varied from Example to Example as shown in Table 6 below.
3. In Examples 7D and C74, 2CPA was not used, but three days after
packing, the bags were exposed to ethylene for 24 hours in a conventional
ripening room
at 16.7 C and containing 500-1000 ppm of ethylene.
4. Comparative Examples C71-74 were carried out in which no ethylene was used
(C71), or the bag was sealed but did not have a control member (C 72-73), or
the bag
was not sealed (C74).
5. The ethylene concentration in the bags was measured at various times after
packing.
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The results obtained are shown in Table 6 below.
Table 6
Example No. 7A 7B 7C 7D C71 C72 C73 C74
Control member yes yes yes yes yes no no no
mL 3.9% 2CPA solution 30 30 30 no no 30 30 no
mL 0.1 N NaHCO3 15 30 60 no no 13 30 no
Exposed to ethylene in no no no. yes no no no yes
ripening room
Days to color stage 4 12 10.2 6.2 6.5 4.2
12.5 1 0.2 9.4 6.5 4.5
15 8.4 9.8 7.1 4.5
Days to color stage 5.5 * * 9.5 11.5 6.6
* * 12.5 12 7
* * 12.9 12.3 7.2
Days from color stage 4 to - - 3.3 5 2.4
color stage 5.5 - - 3.1 5.5 2.5
- - 3.1 5.2 2.7
Color after 15 days 2 2 2
ppm ethylene after
0 hrs 0.47 4.11 8.65 5.72 10.7
7 hrs 0.58 2.36 10.04 7.81 13.35
72 hrs 0.68 1.94 6.66 10.8 20.51
79 hrs - 3.28 4.7 5 16.65
9.43
%02 after 15 days 3.73 3.97 3.72 0.21 0.34
%C02 after 15 days 6.23 6.2 4.67 27.3 25.5
*this color stage had not been reached when the experiment was terminated.
Examples 8A-J and C81-83
Examples 8A-J and C 81-83 followed the same procedure as Examples 7A-C and C71-
74 except for the changes noted below.
1. The ethylene, 02 and C02 concentrations were determined at different times.
2. In some of the examples, the second paper pad was impregnated with 30 mL of
an aqueous buffer solution (i) containing potassium phthalate and having a pH
of 4, (ii)
io containing dibasic sodium phosphate, monobasic potassium phosphate, sodium
chromate and potassium dichromate, and having a pH of 7, or (iii) containing
sodium
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carbonate and sodium bicarbonate and having a pH of 10. These buffer solutions
are
available from Orion Research lnc.,Beverley, Massachusetts USA
3. In Examples 8H and C83, the bag was taken to the ripening room 3 days after
packing.
4. In Example 8G, the sealed bags were left in a room at about 21 C (in the
other
Examples, the room was at 13-14 C).
5. In Example C83, the bag was not sealed.
The results are shown in Table 7 below.
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Table 7
8A 8B 8C 8D 8E 8F 8G 8H C81 C82 083
Control member yes yes yes yes yes yes yes yes yes no no
mL 3.9% 2CPA 30 30 30 30 30 30 30 no no 30 no
solution
mL 0.1 N NaHCO3 no no no 45 60 75 60 no no 60 no
30 mL of buffer pH 4 pH 7 pH no no no no no no no no
having 10
Exposed to ethylene no no no no no no no yes no no yes
in ripening room
Days to color stage 4 11.9 15.4 13.1 9.4 8.5 9.0 8.2 7.7 * * 3.7
13.0 11.3 11.5 9.0 9.3 8.1 7.6 - - - 3.9
14.3 10:1 10.8 10. 8.0 8.1 6.7 10. - - 3.9
1 6
Days to color stage - - - 15. 13. 12. 14. 14 * * 5
5.5 - 15.3 - 7 8 4 8 - - * 6
- - 16.6 12. 13. 11. 12. * - - 6
3 1 4 2
15 11. 11. 9.0
9 4
Days from color * ~ - 6.3 5.3 3.4 6.2 6.3 - - 1.3
stage 4 to color stage * 4 - 3.3 3.8 3.3 4.6 - - - 2.1
5.5 * 5.8 4.9 3.9 3.3 2.3 - - - 2.1
ppm ethylene after 24 0.88 1.67 1.37 3.2 4.3 5.5 10. 0.4 0.3 39. 0
hrs 5 9 8 9 9 9 5
%02 after 8 days 3.72 5.58 2.93 3.2 2.3 2.5 1.9 2.9 17 0.3 -
9 2 5 7
%C02 after 8 days 4.73 4.7 5.3 4.9 5.1 5.4 7.9 4.7 1 17. -
7 3 7 7 3 6
* this color stage had not been reached when the experiment was terminated
after 17 days.
Examples 9A-C and C91-92
The procedure of Example 6 was followed, except for the changes noted below.
1. There was a single hole, diameter 82.5 mm (3.25 in.), under each control
member. The total area of the hole was 5350 mm2.
2. No 2CPA-impregnated paper pad was placed in the bag.
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3. The bananas, before being packed into the bag, were dipped into a dilute
aqueous solution of 2CPA. The concentration of the 2CPA varied from Example to
Example as shown in Table 8 below.
4. Comparative Examples C91 and C92 were carried out in which the bag did not
have a control member (C91) or the bananas were not treated with 2CPA solution
(C92).
Comparative Example C91 is the same as the comparative Example C71.
The results obtained are shown in Table 8 below.
Table 8
Example No.
9A 9B C91 C92
Control Member yes yes no yes
Concentration of 2CPA (ppm) 1116 128 1116 0
Days to color stage 4 11.9 14.6 * *
* * *
11.9 11
Days to color stage 5.5
* * *. *
10 * this color stage had not been reached when the experiment was terminated
after 27 days
Table 9 below shows, for each of the bags in Examples 5A-C, 6A-E and 7A-E, the
permeability of the bag to 02 and to ethylene ("Et" in Table 9), and the
respective contributions
of the control member and the remainder of the bag. For this calculation, the
size of the bag,
after sealing, was assumed to be 0.96 x 1.04 m (38 in. x 41 in.), i.e. to have
a total area of 2 m2
(3115 in2).
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Table 9
Exampie Perm. of bag Perm. of bag Hole area Perm. Of Perm. of rest
No. (mUatm.24hr) at at 13 C /kg of (m2 ) ACM at 13 C of bag at
13 C bananas 13 C
C11 02 8,450 02 470 0.000670 02 2,550 02 5,900
Et 36,000 Et 2,000 Et 10,900 Et 25,100
1A 02 13,500 02 745 0.002000 02 7,600 02 5,900
Et 57,650 Et 3,185 Et 32,550 Et 25,100
1 B 02 20,650 02 1,140 0.003880 02 14,750 02 5,900
Et 88,250 Et 4,875 Et 63,130 Et 25,100
2 02 20,650 02 1,140 0.003880 02 14,750 02 5,900.
Et 88,250 Et 4,875 Et 63,130 Et 25,100
C31 02 7,200 02 395 0.000335 02 1,300 02 5,900
Et 30,650 Et 1,695 Et 5,500 Et 25,100
C32 02 8,500 02 470 0.000670 02 2,550 02 5,900
Et 36,000 Et 2,000 Et 10,900 Et 25,100
C33 02 10,250 02 565 0.001140 02 4,350 02 5,900
Et 43,650 Et 2,400 Et 18,550 Et 25,100
3 02 17,450 02 965 0.003040 02 11,550 02 5,900
Et 74,600 Et 4,120 Et 49,500 Et 25,100
A 02 35,000 02 1,935 0.007700 02 29,100 02 5,900
Et 149,800 Et 8,280 Et 124,700 Et 25,100
5B 02 39,000 02 2,155 0.008700 02 33,100 02 5,900
Et 166,650 Et 9,200 Et 141,550 Et 25,100
5C 02 42,900 02 2,370 0.009700 02 37,000 02.5,900
Et 183,550 Et 10,150 Et 158,450 Et 25,100
6 A-E 02 32,840 02 1,815 0.007100 02. 26,940 02 5,900
Et 140,500 Et 7,750 Et 115,400 Et 25,100
7 A-E 02 46,500 02 2,570 0.010700 02 40,600 02 5,900
Et 199,200 Et 11,000 Et 174,100 Et 25,100
24
