FIELD OF THE INVENTION
The present invention relates to a refrigeration system to extend storage life of refrigerated perishable food like fruit and vegetables and in particular to a system for delaying the ripening process for fruit and vegetables susceptible to ethylene gas generation related decay or the like. The present invention delays the ripening process in a refrigerator by decreasing the concentration of ethylene gas in the air adjacent to the fruit and vegetables.
BACKGROUND OF THE INVENTION
While there have existed for years stands and racks inbuilt in the refrigeration system for holding fruit, including vegetables or the like but no system exists for delaying the ripening of fruit and vegetables in a system which is relatively inexpensive and easily implemented by the consumer.
As long as no ethylene gas comes in contact with the fruit, they will stay in the pre-climacteric stage and will not ripen. Most of the prior art deals with keeping fruit and vegetables in this pre-climacteric stage. There are various fruit and vegetables storing systems that keep the atmosphere controlled around the fruit and vegetables in the crisper or other storage area.
One invention for removing the ethylene gas from the ripening rooms is disclosed in U.S. Pat. No.4,506,599. This invention like most for banana ripening is for use in the ripening rooms just after the bananas have entered the post-climacteric stage. Once the bananas are in the post-climacteric stage, they will ripen quickly. As soon as the bananas enter the post-climacteric stage they are sent to the grocers shelf where they have a very short shelf life of less than a week.
The shelf life is so short because once the bananas have crossed over into the postclimacteric stage, the bananas themselves produce a great deal of ethylene gas which increases the ripening rate, so ripening is fast and irreversible.
The biggest problem this causes for the consumer is that the bananas usually turn totally brown in less than a week. There has been very little development in preserving the post-climacteric bananas for the retail establishment or consumer. U.S. Pat. No. 3,459,116 makes post-climacteric bananas last longer for the retail establishment by controlling the temperature of the bananas. By cooling the bananas, this invention slows down the ripening process. However the said invention is not useful for all fruit and vegetables, especially those that need refrigeration as it is meant only for the bananas.
Most of the prior art dealing with fruit and vegetables is concerned with pre-climacteric bananas, fruit and vegetables. When bananas are first picked from the tree, they are in the pre-climacteric stage. While in this stage, the bananas are very green and will last a long period of time without ripening. Bananas in the pre-climacteric stage are in a suspended state in which very little or no ripening occurs. Bananas can be preserved in the pre-climacteric stage long enough to be shipped around the world. The major factor that determines whether bananas stay in the pre-climacteric stage is the presence of ethylene gas. However the present method is an improvement over prior art in this area as it is not limited to bananas and grapes but covers all fruit and vegetables placed in a cooling appliance and freshness lasts for over 10 days.
OBJECTS OF THE INVENTION
It is, therefore, an object of the present invention to provide a refrigeration system for extending shelf life of fruit and vegetables.
It is another object of the present invention to provide a system for delaying the ripening of fruit and vegetables, which is relatively inexpensive to manufacture, easy to use, and effective in operation.
It is another object of the present invention to provide a system for delaying the ripening of bananas, or other fruit, and vegetables which utilizes forced air flow through the fruit and vegetables to be preserved.
It is also an object of the present invention to provide a system for delaying the ripening of vegetables, or other fruit, on a system which may be utilized on a larger, industrial scale, or in supermarkets or the like.
STATEMENT OF INVENTION
According to the present invention there is provided a refrigeration system to extend storage life of refrigerated perishable food like fruit and vegetables, the system comprising:
a freezer compartment provided in the upper portion of the refrigeration system;
a refrigeration compartment located below said freezer compartment and in air
communication with said freezer compartment;
a means for air flow provided in said freezer compartment or said refrigeration
compartment;
a crisper basket provided in said refrigeration compartment for storage of said
perishable food;
a preserving device for delaying the ripening of said perishable food provided in said
freezer compartment or said refrigeration compartment, the device comprising:
a hollow retainer provided with perforations or serrations for allowing flow of air into
and from the retainer;
a first tyvek pouch containing zeolite and/or activated carbon coated with potassium
permanganate fixed inside said retainer; said zeolite and/or activated carbon
additionally being impregnated with a fragrance;
optionally a second tyvek pouch containing activated carbon placed inside said
retainer; and
said retainer provided with a hinged door to securely place said tyvek pouch inside
said retainer or remove said tyvek pouch from said retainer.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 shows the refrigeration system Fig. 2 shows the retainer Fig. 3 shows a pouch
DESCRIPTION
The present invention relates to perishable food storage systems, and in particular to a system for delaying the ripening process for fruit and vegetables or the like in the refrigerator. The present invention delays the ripening process by decreasing the concentration of ethylene gas in the air adjacent to the fruit and vegetables stored in a refrigerator compartment. The present invention accomplishes this by providing a preserving device comprising a filter consisting of a pouch having potassium permanganate adsorbed on activated carbon and/or zeolite along with a lemon oil fragrance, thereby decreasing the ethylene gas concentration of the adjacent air, and thus decreasing the ripening rate. The benefit of this method of removing ethylene gas is that it is inexpensive and easy to implement in conjunction with the specially designed retainer and crisper. The KMn04 coated zeolite is packaged in Tyvek packets that are water resistant, but are highly permeable to ethylene. These pouches are fixed in a retainer and fixed inside the crisper. This retainer may additionally contain a tyvek pouch containing nano carbon (activated carbon) to act as a mal odor absorbing device and hence this device acts as a combination of preserving and removing the common mal odors inside the refrigerator.
As long as no ethylene gas comes in contact with the fruit and vegetables, then they will stay in the pre-climacteric stage and will not ripen. Most of the prior art deals with keeping fruit and vegetables in this pre-climacteric stage. There are various bags and storing systems that keep the atmosphere controlled around the pre-climacteric
fruit and vegetables but all of them have limitations as it can keep them fresh for only few days and not over 10 days.
The present invention provides a relatively inexpensive, easily implemented and effective system for delaying the ripening of fruit and vegetables including, for example, grapes or citrus products, such as oranges, grapefruit, lemons or the like. The invention provides a system for delaying ripening of fruit and vegetables for the consumer or retail establishment and for controlling mal odor while also generating a fresh lemon based fragrance in the refrigeration system.
According to the preferred embodiment the refrigeration system typically comprises a freezer compartment (1) which is located in the upper part of the system. Located below the freezer compartment is a refrigerator compartment (2) which is in air communication through a duct or a opening towards rear of the refrigerator compartment. A fan (7) may be provided in the refrigeration compartment on freezer compartment to effect flow of cool air through a duct (8) to the refrigeration compartment. A crisper basket (3) is provided in the refrigeration compartment (2) for storage of perishable food i.e. fruit and vegetable which are to be stored for extended shelf life. A preserving device (4) is fixed at appropriate place in freezer or refrigeration compartment for delaying the ripening of the stored fruit or vegetables to extend their shelf life. The preserving device comprises a hollow retainer (5) which has a hinged door for facilitating securely putting in said retainer or removing from the said retainer, tyvek pouches (6) containing zeolite and/or activated carbon coated with potassium permanganate, which may additionally be impregnated with a fragrance. The retainer has a number of perforations or serrations to allow air flow in the device.
The present invention provides a system for delaying the ripening of fruit & vegetable in the post-climacteric stage. Post-climacteric fruit and vegetable are known to ripen at a rapid rate thus lasting a very short period of time for the home consumer or retail establishment.
The positive correlation between ripening rates and ethylene gas is well known for bananas and many other fruit. Because bananas produce a large amount of ethylene gas as they ripen, the effect is autocatalytic and thus by ripening, the bananas increase their own ripening rate. It is also the purpose of this invention to make postclimacteric bananas last longer by removing the ethylene gas produced by the bananas and other fruit and vegetables.
The ethylene molecule is very reactive and is readily oxidized into a state that will not do damage to stored fruit and vegetable. There are several ways that may be used to oxidize and remove ethylene from storage areas. One of the simplest and safest methods is to oxidize it with potassium permanganate. This reaction can remove ethylene to very low levels. Potassium permanganate (KMn04) is used as an oxidizing agent in a number of familiar applications, such as in drinking water treatment systems.
In home refrigerator application, natural zeolite is used as a substrate for the oxidizing agent. Zeolite is a pure form of volcanic ash that has a very high surface area, providing an ideal substrate for the ethylene oxidation to occur.
Natural zeolite is often used as an odor absorber and a humidity stabilizer in refrigerators, closets, and automobiles. The very high surface area traps odor molecules and absorbs water when humidity is too high - releasing it back into the atmosphere when it gets too dry. The zeolite used in the preserving device of present invention serves those purposes, but its function as support medium for removing ethylene is its main purpose.
The potassium permanganate is applied to the zeolite which coats the active chemical on the surface uniformly all the way to the center of the zeolite. The resulting product is highly reactive chemically, and yet has high cationic exchange capacity.
The KMnO4 coated zeolite is packaged in Tyvek packets/ pouches that are water resistant, but are highly permeable to ethylene. These pouches are fixed in an air
permeable retainer to constitute a preserving device. The retainer may also contain pouch containing nano carbon (activated carbon) to act as a mal odor absorbing device. These act in combination for preserving the fruit and vegetables and removing the common mal odors inside the refrigerator.
The reaction between the ethylene and potassium permanganate oxidizes the ethylene and, of course, reduces the potassium permanganate, too. The amount of potassium permanganate available in the preserving device may last at least 3 months in most conventional home refrigerators.
In accordance with an embodiment, the preserving device is fixed in a crisper of a refrigeration system, particularly a refrigerator for post-climacteric fruit and vegetables and especially bananas for the purpose of making ripening of fruit like bananas and vegetables slower by removing, or ventilating ethylene gas. This invention is intended for example, for use at the final stage of the banana's life by the consumer or retail establishment.
In accordance with another embodiment, the present invention provides for delaying the ripening of vegetables or fruit, in a refrigeration system comprising support means for supporting a bunch of fruit and/or vegetables inside the crisper. Associated with said support means, is a preserving device comprising filter consisting of potassium permanganate coated zeolite and/or activated carbon, in a tyvek pouch fixed in a retainer. The retainer can be made from a plastic or polymer or metal. The device may additionally also contain a tyvek pouch containing activated carbon or nano carbon to adsorb the mal odors generated in the refrigerator crisper. The zeolite and/or activated carbon filter of the device may also comprise lemon oil fragrance or some suitable fragrance embedded in the filter. Activated carbon is provided to control mal odor generation and remove mal odor in the refrigerator. The device may be put in front of a means for air flow wherein said air flow means may comprise a fan in refrigerator or a freezer compartment.
It is to be understood that the features and concepts of the invention can be adapted to various embodiments by making changes, adaptations, modifications by those skilled in the art. Such variant embodiments are intended to be within the scope of the present invention. The foregoing description illustrates only a particular form of the invention which is only an exemplary embodiment and is not intended to be taken restrictively.

WE CLATM:-
1. A refrigeration system to extend storage life of refrigerated perishable food
like fruit and vegetables, the system comprising:
a freezer compartment provided in the upper portion of the refrigeration system;
a refrigeration compartment located below said freezer compartment and in air
communication with said freezer compartment;
a means for air flow provided in said freezer compartment or said refrigeration
compartment;
a crisper basket provided in said refrigeration compartment for storage of said
perishable food;
a preserving device for delaying the ripening of said perishable food provided in said
freezer compartment or said refrigeration compartment, the device comprising:
a hollow retainer provided with perforations or serrations for allowing flow of air into
and from the retainer;
a first tyvek pouch containing zeolite and/or activated carbon coated with potassium
permanganate fixed inside said retainer; said zeolite and/or activated carbon
additionally being impregnated with a fragrance;
optionally a second tyvek pouch containing activated carbon placed inside said
retainer; and
said retainer provided with a hinged door to securely place said tyvek pouch inside
said retainer or remove said tyvek pouch from said retainer.
2. A refrigeration system as claimed in claim 1, wherein said means for air flow is a fan.
3. A refrigeration system as claimed in claim 1 or 2, wherein said device is provided in front of said means for flow of cool air.
4. A refrigeration system as claimed in claim 1, wherein said device is fixed inside said crisper basket.
5. A refrigeration system as claimed in claim 4, wherein said crisper basket is provided with support means for supporting bunches of fruit and/or vegetables.
6. A refrigeration system as claimed in claim 1, wherein said fragrance is a lemon oil based fragrance.
7. A refrigeration system as claimed in claim 1, wherein said retainer is made of a plastic or a polymer or a metal.
8. A refrigeration system, substantially as hereinbefore described with reference to the accompanying drawings.