METHOD AND APPARATUS FOR PREVENTING VIOLET COLOURATION OF WHITE ASPARAGUS AFTER HARVEST

Abstract: A biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting and a mechanism for its realization. The invention pertains to a biological-technological method which prevents the appearance of a violet colouration on white asparagus shoots after harvesting, as well as to the mechanism for the realization of this method, with which it constitutes a single invention unit and comprises the exposure of white asparagus shoots to carbon dioxide in gas form, for 10-24 hours and temperature conditions of 0-20 degrees Celsius, immediately after their harvest and within 10 hours of it, placed inside a refrigerated airtight chamber, or inside a refrigerated chamber with a selective respiratory gas permeability (a). This invention, on the one hand as a method can be applied in asparagus canning factories, asparagus packing-sorting places, research laboratories, etc. (fig. 1), on the other hand as a mechanism can constitute a container (fig. 2) for the transportation of asparagus to the processing or consumption places, regardless of the transportation time and distance from the place of harvest, without there appearing any longer the problem of the violet colouration on the surface of the white asparagus shoots.

Description: METHOD AND APPARATUS FOR PREVENTING VIOLET COLOURAΗON OF WHITE ASPARA¬ GUS AFTER HARVEST The invention pertains to a biological-technological method which prevents the appearance of a violet colouration on white asparagus shoots after harvesting, through their exposure to carbon dioxide in gas form inside a refrigerated airtight chamber or inside a refrigerated chamber in which a selective permeability to respiratory gases is ensured, where the white asparagus shoots are placed, as well as to the mechanism for the realization of this method, with which it constitutes a single invention unit. As known, Greece exports 95% of its annual white asparagus harvest, that is, about 27,000 tons of white asparagus per year, thus covering 35% of the white asparagus imports of the Federal Republic of Germany, plus certain percentages in the imports of other countries such as France, The Netherlands, etc. One of the most serious problems the producers, transporters, retailers and consumers face with regard to the quality of the white asparagus shoots is the appearence of a violet colouration, a few hours after they are harvested. This colouration, due to the formation of anthocyanin, results in the deterioration of the quality and, by extention, in a fall in the price, which may be as much as 50% below the price of what is today considered to be 'white' asparagus according to the quality tolerance allowed by the quality specifications, with serious economic losses not only for the producer but for the local and national economy as well. In addition, the fact that large quantities are canned and distributed internationally with the violet colouration flaw, lowers the quality of the product, leading to a restriction of its marketability, which is internationally high. Scientific research and its applications have not been able to solve this problem to this day. Until now, carbon dioxide in gas form has been used in high concentration (20% - 100%) to solve various other problems regarding fruit and vegetables such as the breaking down of chlorophyl and the loss of the green colour, browning, softening, bacterial rot, insect control, etc. However, neither in the applications of these researches nor in the international bibliography has there appeared any ascertainment or a simple mention or even any speculation as to the effect of carbon dioxide on the prevention of the appearance of a violet colouration created on white asparagus shoots after harvesting. Moreover, the particular problem of the appearance of a violet colouration on white asparagus shoots has, to this day, never been dealt with by any other method or product. This is precisely the problem the present invention solves. The advantanges of this invention lie on the fact that, on one hand, this method prevents the appearance of a violet colouration, thus removing this particular flaw from the asparagus as well as all the above-mentioned unfavourable consequences on the marketability of the product and the economy and, on the other hand, the mechanism for the realization of this method, with which it constitutes a single invention unit, can be manufactured in dimensions which allow its autonomy and, therefore, make possible its independent transportation by any transport means for short or long distances (be it by container lorries, trailing containers or portable crates), an advantage which eliminates completely the time interval between harvesting and processing and, therefore, any danger due to possible delays in transportation are neutralized. The biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting, according to the present invention, is characterized by the fact that immediately after the asparagus shoots have been harvested and within 10 hours after that, the shoots are exposed to carbon dioxide in gas form, inside a refrigerated airtight chamber or a chamber in which a selective permeability to respiratory gases is ensured, equipped with a carbon dioxide supply conductor and a system controlling its flow, a gas sampling conductor, a carbon dioxide analyser, an oxygen analyser, and in which chamber there is a temperature of 0-20 degrees Celsius, for a period of 10-24 hours,effecting the prevention of the appearance of a violet colouration on the white asparagus shoots. Now, the mechanism for the realization of this method, with which it constitutes a single invention unit, according to the present invention, is characterized by the fact that it can constitute a permanently established or an autonomous, portable, transportable system for the prevention of a violet colouration on white asparagus shoots after harvesting, in view of the fact that the supply sources for the carbon dioxide in gas form as well as those for refrigeration can be situated either inside or outside the chamber. The chamber is equipped with a carbon dioxide supply conductor and a system controlling its flow, a carbon dioxide analyser and an oxygen analyser, a gas sampling conductor through which the refrigerated chamber's gases are channelled to the oxygen and carbon dioxide analysers. The dimensions and the shape of the refrigerated airtight chamber, or the chamber in which a selective respiratory gas permeability is ensured, where the shoots are exposed to carbon dioxide in gas form and which constitutes part of the realization mechanism of this method, with which it constitutes a single invention unit, can vary, while the chamber walls can be manufactured from all kinds of material (e.g., metal, plastic, glass, etc.) provided the airtightness or the selective respiratory gas permeability of the chamber is ensured. The carbon dioxide in gas form channelled to the asparagus shoots can be stored either inside or outside the refrigerated airtight chamber and be channelled into it through any kind of conductor (e.g., pipe, hole, etc.) made of any kind of material (plastic, metal, etc.). The exposure of the asparagus shoots to carbon dioxide in gas form can be ensured either through the accumulation of the carbon dioxide produced by the respiration of the shoots or through the supply of carbon dioxide in gas form channelled from an artificial source inside or outside the chamber. Figure 1 depicts an application of the biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting. The white asparagus shoots, packed in crates, are placed in a chamber (figure 1 , a), cooled by a refrigerated source located, alternatively, inside or outside it (figure 1 , b, c) and equipped with a C0 2 analyser (figure 1 , h) and an O 2 analyser (figure 1 , i) towards which 0 2 and C0 2 accumulated inside the chamber (figure 1, a) are channelled through a conductor (figure 1, g) for measurement. From a supply source of C0 located alternatively inside or outside the refrigerated chamber (figure 1, d, e), C0 2 is channelled through a conductor (figure 1, f) into the chamber, controlled during its flow by the C0 2 flow control system (figure 1, j). Figure 2 depicts an application of the mechanism of the biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting, with which this method constitutes a signle invention unit. The white asparagus shoots, packed in crates, are placed inside a chamber (figure 2, a), cooled by a refrigerated source located alternatively inside or outside it (figure 2, b, c) and equipped with a C0 2 analyser (figure 2, h) and an 0 2 analyser (figure 2, i), towards which are channelled for measurement through a conductor (figure 2, g) the 0 2 and the C0 2 accumulated inside the chamber (figure 2, a). From a C0 2 supply source located alternatively inside or outside the refrigerated chamber (figure 2, d, e), CO 2 is channelled through a conductor (figure 2, f) into the chamber, controlled during its flow by the C0 2 flow control system (figure 2, j). The mechanism, as seen in figure 2, can also be an autonomous, portable, wheel- or vehicle- transportable system preventing the appearance of a violet colouration on white asparagus shoots after harvesting. One way of how the invention works is described with reference to the figures. The biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting and the mechanism of the realization of this method, with which it constitutes a single invention unit, consists of the exposure for 10-24 hours of the asparagus shoots to carbon dioxide in gas form inside a refrigerated airtight chamber or inside a chamber (figure 1, a) in which a selective respiratory gas permeability is ensured, and in which chamber there is a temperature of 0-20 degrees Celsius and inside which have been placed the white asparagus shoots within 10 hours of their harvest, thus preventing the appearance of a violet colouration on them. The chamber is equipped with a carbon dioxide supply conductor (figure 1, f) and a flow control system (figure 1, j) with a carbon dioxide analyser (figure 1, h) and an oxygen analyser (figure 1, i), a gas sampling conductor through which the gases of the refrigerated chamber are channelled towards the oxygen and carbon dioxide analysers (figure 1, g.) The carbon dioxide in gas form can be accumulated either through the respiration of the shoots or be stored within or without the refrigerated airtight chamber or the chamber in which a selective respiratory gas permeability is ensured (figure 1, d, e) and be channelled into it tlirough any kind of conductor (e.g., pipe, hole) (figure 1, f) made of any kind of material (plastic, metal, etc.), effecting the same desired results. The dimensions and the shape of the chamber (figure 1 , a) inside which the shoots are exposed to carbon dioxide in gas form, which forms part of the realization mechanism of this method and with which it constitutes a single invention unit, can vary, while the chamber walls can be manufactured from any kind of material (e.g., metal, plastic, glass, etc.), provided the airtightness or the selective respiratory gas permeability of the chamber is ensured.The refrigerated source can be either inside or outside the chamber (figure 1 , b, c.) Therefore, the present invention on the one hand as a method for preventing the appearance of a violet colouration on white asparagus shoots has the distinct advantage of being able to be applied either in packing-sorting places or in research-experimental laboratories or in specially designed containers transporting the white asparagus shoots from the place of harvest to the canning factories or to the packing, sorting or distribution places, on the other hand, as a realization mechanism of this method with which it constitutes a single invention unit, it can be a permanently established (figure 1) or an autonomous, portable, transportable (figure 2) system preventing the appearance of a violet colouration on white asparagus shoots after harvesting. According to the invention, the exposure of the asparagus shoots to carbon dioxide in gas form can be achieved either through carbon dioxide accumulation produced by the respiration of the shoots or through the supply of carbon dioxide in gas form channelled from an artificial source which can be located inside or outside the airtight chamber (figure 1, d, e).

Claims: CLAIMS 1. A biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting, tlirough their exposure to carbon dioxide in gas form, coming from an artificial source (d, e) or from the respiration of the shoots, inside a refrigerated chamber (a), which is characterized by the fact that the shoots are exposed to carbon dioxide in gas form for 10-24 hours, within 10 hours after they have been harvested, inside a refrigerated airtight chamber, or a chamber in which a selective respiratory gas permeability is ensured (a) and which has a temperature of 0-20 degrees Celsius. 2. A mechanism for the realization of this method, with which the method of claim 1 constitutes a single invention unit, which consists of a refrigerated airtight chamber or a chamber in which a selective respiratory gas permeability is ensured (a) equipped with a conductor supplying it with carbon dioxide (f) and a flow control system (j), with a carbon dioxide analyser (h) and an oxygen analyser (i), with a gas sampling conductor through which the gases of the refrigerated chamber are channelled towards the oxygen and carbon dioxide analysers (g) and has the characteristic of being either solidly and permanently established (figure 1) or able to move (figure 2) as an autonomous, portable, transportable system for the prevention of the appearance of a violet colouration on white asparagus shoots after harvesting. 3. The biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting, in accordance with claims 1 and 2, is characterized by the fact that the time the white asparagus shoots are exposed to carbon dioxide in gas form inside a refrigerated airtight chamber (a) is from 10 to 24 hours. 4. A biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting and a mechanism for the realization of this method, with which the method of claim 1 constitutes a single invention unit, according to claims 1, 2 and 3 which is characterized by the fact that the walls of the refrigerated chamber (a) can be made from any kind of material (e.g., metal, plastic, glass, etc.), provided the airtightness of the chamber or the selective respiratory gas permeability is ensured. 5. A biological-technological method for the prevention of the appearance of a violet colouration in white asparagus shoots after harvesting and a mechanism for the realization of this method, with which the method of claim 1 constitutes a single invention unit, according to claims 1, 2, 3 and 4 which is characterized by the fact that the dimensions and the shape of the refrigerated chamber (a), inside which the white asparagus shoots are exposed to carbon dioxide in gas form, can vary, provided they accommodate an instalation of a refrigerating source (b, c) and a carbon dioxide in gas o form supply source (d, e.) 6. A biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting and a mechanism for the realization of this method, with which the method of claim 1 constitutes a single invention unit, according to claims 1, 2, 3, 4 and 5 which is characterized by the fact that the carbon dioxide in gas form can be accumulated through the respiration of the shoots, or is stored outside or inside the refrigerated airtight chamber (d, e) and be channelled into it through any kind of conductor (f) (e.g., pipe, hole, etc.) made from any kind of material (plastic, metal, etc.) 0 7. A biological-technological method for preventing the appearance of a violet colouration on white asparagus shoots after harvesting and a mechanism for the realization of this method, with which the method of claim 1 constitutes a single invention unit, according to claims 1, 2, 3, 4 and 5, which is characterized by the fact 5 that the refrigerating mechanism of the refrigerated chamber (a) can be located either inside or outside the chamber (b, c), while the supply and the regulation of the refrigeration can be ensured in any kind of way.

Inventors: DOGRAS KONSTANTINOS, SFAKIOTAKIS EVANGELOS, SIOMOS ANASTASIOS, DOGRAS, KONSTANTINOS, SFAKIOTAKIS, EVANGELOS, SIOMOS, ANASTASIOS
Applicants: ARISTOTLE UNIVERSITY OF THESSA, ARISTOTLE UNIVERSITY OF THESSALONIKI
Application year: 1996
Main classification: A23B7
IPC codes: A23B7