Patent Application
20060083826
The present invention is related to a method for the packaging of perishable products, and to a packaging where said method has been applied, by means of the application of a preferably preserving controlled atmosphere. With preference, the perishable products are vegetables and, more preferably, the perishable products consist of fruits.
There is ample knowledge of the variety of methods for packaging and/or packing perishable products, such as food products or others, by using a preserving atmosphere. Among this variety of methods which provide a preserving atmosphere, two large categories may be distinguished, according to their immediate objective: a) methods oriented to providing specific chemical compounds which will release preserving gases or inert gases which displace oxygen; and b) methods which deal with the supply of certain physical conditions in the packaging so that the preserving atmosphere inside it, can maintain the chemical properties expected. The present invention falls within this last category.
Certain types of chemical compounds commonly used to maintain an atmosphere free of specific micro-organisms in fruits, especially table grapes, are those which release sulphurous anhydride (also called sulphur dioxide, whose chemical formula is SO2). These compounds are placed in the so-called “generators”, which are devices made up of paper or semi-permeable plastic sheets, between which an active component is lodged, generally meta-bisulfite or sodium bisulfite. The meta-bisulfite or sodium bisulfite, at the moment of getting in contact with humidity generates sulphurous anhydride.
The microbiostatic and/or microbicidal effect of gaseous sulphurous anhydride is well known, especially its action against fungi which attack and degrade vegetable produces. Additionally, the SO2 generated in the atmosphere which surrounds a fruit, especially in the case of table grapes, has an anti-oxidizing effect, a fact that improves the appearance of the grape bunch stalk, by keeping its green color. In its physiological action, sulphurous anhydride delays the metabolism of the berry up to 80% thus delaying the natural senescence of the fruit.
Even if sulphurous anhydride has a useful fungicide action (particularly suitable to combat fungus Botrytis cinerea Pers frequently found in grapes), it also shows some phytotoxic characteristics. Although grapes may present a good tolerance to this phytotoxicity of SO2, due to the fact that this fruit lacks functional stomas and has a complex cuticular matrix composed of natural waxes, this gas permeates through skin breaks, microscopic wounds and natural openings (lenticels), concentrated around the pedicel, and produces berry whitening or bleaching, due to the destruction of chlorophyll and/or anthocyanic or carotenoid compounds found in the external layers of the berry. This whitening or bleaching affects all cultivations, nevertheless, this symptom is more evident in red and black berries cultivations.
The state of the art does not efficiently address the reduction of the berries' whitening or bleaching when sulphurous anhydride is used in the packaging to control the development of microorganisms. In general terms, the methods of the state of the art consist in placing SO2 generators inside the package of the fruit (kept at refrigeration temperature), in a containing bag, thus permitting a certain accumulation of humidity in the environment and enabling the reaction of the generator compound to produce sulphurous anhydride. Normally, a unit is placed on top of the fruit, preventing the direct contact with the fruit by means of a barrier of absorbent paper. In some cases, and as a complement, a generator in the bottom of the box may be used, but always within the containing bag. The concentration of SO2 is maintained for the time required for the cold storage duration, it suffices that this concentration holds itself between 3 and 7 ppm, for fungistatic control. In these techniques of the state of the art, the containing bags are pierced to avoid an excessive accumulation of SO2.
Commonly, it is expected that the grapes box be maintained at 0° C. with no breakage of the cold chain; however, this is not always accomplished. There is a direct relationship between the temperature and the emission rate of sulphurous anhydride, a fact that may prove critical in regard to levels of tolerance and damage due to the action of sulphurous anhydride, which especially produces the undesirable berries' whitening or bleaching.
The present situation provides a packaging method, and a package as such, which makes use of the generators of preserving gases, preferably—although not limited to—SO2 generators, but without the phytotoxicity inconveniences derived from the current way of using said generators.
Basically, the method of the present invention involves, the same as the previous art, the packaging of fruit in semi-permeable bags, and these bags are placed inside boxes with openings to allow the circulation of cold air, humidity and the eventual preserving gases or those applied for quarantine reasons. In turn, these boxes are piled up, placing these piles, next to one another, in an orthogonal array, to define a block of boxes, which is “arranged” on a transportation platform, better known as pallet. This pallet, with the block of boxes, is wrapped with a cover impervious to gases and with openings, or, with a cover permeable to gases, with or without additional openings. So far, the present invention looks common to the state of the art.
Yet, while said state of the art involves placing preserving gas generators inside each semi-permeable bag (together with the fruit), which is placed in each box of the block formed on the pallet, the present invention—on the contrary—involves placing the gas generating means between the internal face of the cover that wraps the pallet that contains the box block and the surface of said block. This arrangement permits that the gas generated does not act in high concentrations in the vicinity of the fruit, as it occurs when the generators are in each bag of each box, according to the teachings of the previous art.
To better understand the arrangement of the elements and the sequence of operation, according to the method of the present invention, a full description of this will be made, in reference to the drawings of a preferred modality, where:
As it can be seen in
Should they be used, one or more of these semi-permeable bags 2, containing fruit, are placed in shipment boxes 3, which are well known in the art. These shipment boxes are usually made of cardboard, wood or synthetic material and they have slots or openings in their side walls to facilitate the thermal exchange between the cold chambers and the fruit, as well as to allow suitable air circulation, thus enabling to homogenize the temperature, humidity and concentration of the preserving gas.
Several shipment boxes 3 are placed on a transport platform or pallet 4, one next to the other in an arrangement generally orthogonal, in the case that said shipment boxes 3 have a rectangular base, and in such a way that vertical layers of shipment boxes 3 are formed.
In this state of block grouping of shipment boxes 3 on pallet 4, the external surface of the block of boxes is wrapped with a layer of means that generate preserving gas 5, and with a semi-permeable cover layer 6.
The layer of means that generate preserving gas consists, preferably, of a plurality of cells generating sulphurous anhydride, or of a continuous generating element. Said elements, continuous or discrete, are based on the active component, encapsulated or free sodium bisulfite or meta-bisulfite, and retained between two sheets, with at least one of these sheets being permeable to the gases. This, at least one, sheet permeable to the gases from the generators, must be oriented to the surface of the block of shipment boxes 3.
Notwithstanding the former, the present invention is not solely restricted to this specific type of sulphurous anhydride generators, as it can be applied to generators of chlorine, chlorine dioxide, ozone or other preserving gases used in the art of preservation of fresh vegetable produces.
The semi-permeable cover layer 6 may be made up of a sheet impervious to gases and with openings, or of a sheet permeable to gases, with or without additional openings.
Depending on the manner in which the layer of preserving gas generating means 5 is interposed, different modalities are obtained of the method and packaging of the present invention.
In the first modality of the invention, illustrated in
Actually, the preserving gas generator cells which make up each band segment, do not have to be closely contiguous, with a section of “inert” band existing between two cells or group of active cells. Similar consideration is applied in the case of generating means with uniform active components or continuously spread in the band. This particularization is not opposed to what has been formerly stated: “continuous segmented bands, in which each segment defines a generator unit or cells” if it is understood that two contiguous cells must, necessarily, have an area of separating sheet that is the one which, precisely, defines the border between one cell and its neighbor. Likewise, the inert band areas or separation areas may vary in width between one cell and another.
A specific case of a segmented, continuous band, where each segment defines a generator unit and the bordering areas between the cells is constituted by the case illustrated in
In this first modality of the invention, the semi-permeable cover 6 may, simply, consist of a flexible semi-permeable sheet which wraps the set formed by the block of shipment boxes 3 and the layer or layers of continuous segmented bands which define the generating means of preserving gas 5, and where this wrapping is fixed, in its necessary packing folds, by means of ties, staples or adhesives.
A second modality of the invention consists in a different way of associating the sequence box block/generating means/cover, where said generating means of preserving gas 5 are affixed to the semi-permeable cover 6, before this one wraps the transport box block 3 which is already installed on pallet 4.
One way of fastening the generating means of preserving gas 5 to cover 6 may consist in arranging units of said generators 5 in folds formed on said cover 6, like pockets, as illustrated in
Certain generalizations or variants of the invention, must be considered as obvious and, therefore, included in the present description. For instance, the orientation of the segmented bands containing the preserving means, may be different from the vertical; thus, these bands may be installed around the box block according to a horizontal, or slanted orientation, or wrapping them like a wool ball, provided that the main idea of the invention is maintained that is, to place the generating means of preserving gas outside the block of boxes and protected by a semi-permeable cover.
