Ripening chamber and method for ripening adstring fruits

Description

[0001] The invention relates to a ripening chamber and a method for ripening astringent fruits. The invention relates in particular to a ripening chamber and a method for reducing the tannin concentration in persimmons. Technological background

[0002] The persimmon, also known as kaki plum, is the sweet, orange fruit of the persimmon tree (Diospyros kaki), resembling a large tomato in appearance. Most persimmon varieties have a high tannin content. Tannins give the persimmon a bitter, astringent taste, leaving a furry feeling on the tongue. Consuming large quantities of tannins can also lead to the formation of harmful phytobezoars (stomach stones). Therefore, persimmons must be ripened (bletting) to reduce the taste-impairing tannins. The astringency of the tannins is eliminated in various ways. Examples include ripening through several days of light exposure and wrapping the persimmons in paper (likely because this increases the ethylene concentration in the surrounding air).Ethylene ripening can be used to increase the reliability and uniformity of ripening, and the process can be considerably accelerated by adding ethylene gas to the atmosphere in which the fruit is stored. It is common practice to store ripening persimmons in a clean, dry container with other fruits that release particularly large amounts of ethylene during ripening; apples and related fruits such as pears are effective, as are bananas and several others. Other chemicals are used commercially to artificially ripen or delay the ripening of persimmons. Examples include alcohol and carbon dioxide, which convert the tannin into its insoluble form. Such deaeration processes are sometimes initiated by subjecting the fruit to cold or frost. The resulting cell damage stimulates the release of ethylene, which promotes cell wall degradation.When persimmons are fumigated with carbon dioxide, the tannins are rapidly broken down. Various studies exist regarding CO2 concentration and fumigation duration, e.g., Salvador et al., 2008. In practice, a fixed temperature of approximately 20°C and a CO2 concentration between 50% and 100% are used for 24 hours. Fumigating the fruit with a constant CO2 concentration for 24 hours can lead to excessive or insufficient ripening, depending on the fruit's ripeness and tannin content. This impairs the flavor and damages the persimmons. Therefore, the fruit is currently often fumigated with a lower CO2 concentration or for shorter periods, and the remaining tannins are then broken down through conventional storage. However, this significantly reduces the shelf life of the resulting ready-to-eat persimmons.

[0003] Most detannation methods aim to promote the accumulation of acetaldehyde in the fruit pulp, which causes the polymerization of the astringent soluble tannin molecules, transforming them into a gel-like compound that is insoluble and therefore non-astringent. The most commonly used methods include: the application of ethyl alcohol vapor, which activates the enzyme alcohol dehydrogenase with subsequent accumulation of acetaldehyde, and the promotion of anaerobiosis, which induces the conversion of pyruvate to acetaldehyde in a reaction catalyzed by the enzyme pyruvate decarboxylase.

[0004] The main characteristic of astringent persimmon varieties is their high content of soluble tannins, which are responsible for the fruit's astringency. In the mouth, tannins precipitate proteins present in saliva, particularly amylase, which, once bound to taste receptors, create a sensation of dryness on the palate characteristic of astringent foods.

[0005] Acetaldehyde is the compound responsible for the polymerization of tannin molecules. The accumulation of acetaldehyde in the pulp of persimmons is observed days before they become non-astringent. Acetaldehyde is formed under normal conditions during fruit ripening and is one of the compounds responsible for aroma development.

[0006] Another way to increase acetaldehyde production is to expose the fruit to an anaerobic condition.

[0007] Both the dosage and the duration of fruit exposure to detannation treatments vary depending on the effectiveness of one variety over another. Detannation depends on several factors, which vary from variety to variety, as well as climatic factors, harvest time, size, and soil type. Mistakes during the process can lead to softening and / or blackening of the flesh, loss of shelf life, altered flavor, and even fruit failure.

[0008] Conventional methods for the degradation of tannin are known from CN 204393263 U, KR 10 - 241152 B1 and KR 10-1865658 B1.

[0009] Conventional storage systems are known from US 2015 / 257401 A1, US 2012 / 097050 A1, US 5 063 753 A, CN 204 393 263 U, JP S56 68348 A, KR 1999 0040367 A and JP S59 66836 A. In light of these factors, the process of post-ripening, preservation and increasing shelf life was developed without altering the fruit properties through the inventive method and the associated post-ripening chamber. Summary of the invention

[0010] The object of the present invention is therefore to provide an improved ripening process for astringent fruits and a corresponding ripening chamber. In particular, a gentler ripening process for persimmons is to be achieved by controlled CO2 gassing.

[0011] The method according to the invention relates to a method for ripening astringent fruits, wherein the fruits to be ripened are arranged in a gas-tight ripening chamber and their respiration activity is measured during ripening, characterized in that the method comprises controlled gassing of the fruits with carbon dioxide.

[0012] The ripening chamber according to the invention relates to a post-ripening chamber for the post-ripening of astringent fruits, wherein the chamber comprises: a) a gas-tight ripening chamber for arranging fruit to ripen, b) a means for monitoring a carbon dioxide and an oxygen concentration, c) a carbon dioxide gas source, d) a temperature control system, e) a carbon dioxide adsorber, f) a nitrogen generator, g) a heat exchanger, h) a lung, i) a pressure valve, and j) an oxygen supply; wherein the maturation chamber is configured to carry out the method according to one of the preceding claims.

[0013] These tasks are solved by a post-ripening process and a post-ripening chamber with the features of the independent claims.

[0014] The present invention relates to an object defined in the appended claims. The following description is subject to this limitation. Any disclosure outside the scope of the claims serves only for illustration and comparison purposes.

[0015] Thus, a first aspect of the invention relates to a method for ripening astringent fruits, in which the fruits to be ripened are arranged in a gas-tight chamber and respiration of the fruits is measured during ripening, the method comprising controlled gassing of the fruits with carbon dioxide.

[0016] The inventive method and the associated ripening chamber analyze the respiration of the fruit within a specific timeframe and determine the key characteristics, i.e., the optimal time to detoxify the fruit without damaging it. By measuring its respiration, the fruit transmits information to the ripening chamber according to the invention, which it requires for detoxification. This information includes temperature, O2, CO2, and ethylene (C2H4) values. Using these values, the inventive method adapts the ripening chamber to the specific needs of the fruit. Different variables apply to different quantities of persimmons.

[0017] In contrast to standard ripening in conventional ripening chambers, where a temperature and a fixed carbon dioxide concentration are set once over a fixed period during the ripening process, the ripening method according to the invention, particularly for use in a ripening chamber according to the invention, involves not only controlled temperature control but also measuring the respiration of the product and, in particular, dynamically controlling a gas concentration (CO2 / O2 / ethylene) in a ripening chamber of the chamber depending on this respiration.

[0018] Bletting here means that the astringent fruits are processed after harvesting in such a way that the bothersome astringents in them are broken down; preferably the tannin responsible for the astringent effect of the fruits is converted into a harmless form; preferably water-soluble tannin is converted into a water-insoluble form.

[0019] The ripening chamber and method according to the invention are not limited to use on persimmons. They can be used to ripen all fruits in which a high tannin concentration is reduced by carbon dioxide gassing. Examples include medlars, quinces, rowan berries, and other fruits with astringent tannins.

[0020] The key advantage of the present invention is that the tannin concentration in the astringent fruits can be reduced in a controlled manner within a few days. For example, the tannin concentration can be reduced to 1 to 1.8% within 42 to 96 hours. In particular, this eliminates the need for subsequent conventional storage of the fruits to break down any remaining tannins, which would negatively affect the fruit's shelf life. After the inventive ripening process, the fruits are immediately ready for consumption, and their shelf life is maximized. Furthermore, better and more uniform ripening of all fruits throughout the entire ripening chamber is achieved. The quality of the fruits ripened according to the invention is reproducible and therefore consistently good.Furthermore, the necessary ripening time (depending on the initial product quality and condition) can be automatically determined and calculated by the ripening program (and can therefore vary accordingly). By taking fruit respiration into account during the ripening process, carbon dioxide consumption can be precisely controlled to meet the fruit's needs and thus reduced to a minimum compared to the prior art. The shortened ripening time also allows for increased ripening chamber throughput and energy savings in process control. In particular, the product can be more easily stopped or maintained at its current ripening stage. This is especially advantageous for long delivery routes to the end customer, as a predetermined ripening state (soluble tannin concentration in the fruit) can be varied and controlled by the inventive method.Furthermore, the process allows for flexible adjustments to changing sales volumes in the retail sector, significantly reducing the risk of complaints and product loss (spoilage). Fruits ripened using this inventive post-ripening method have a higher Brix value, meaning they contain more sugar and the flesh is firmer than fruit ripened using conventional methods.

[0021] In a preferred embodiment of the invention, the ripening process is therefore controlled and / or regulated by means of CO₂ concentration, O₂ concentration, ethylene concentration and / or temperature in the chamber, particularly in a ripening chamber. During the ripening process, a gas exchange takes place between the fruit and the environment, which is referred to as respiration.

[0022] As the fruit absorbs oxygen, it ripens, forming and storing low-molecular-weight carbohydrates, especially sugars. Carbon dioxide is produced in this process and escapes as a respiration gas. This process is triggered by the presence of ethylene (C₂H₄), which, in the presence of oxygen, is converted into the relevant carbohydrates. Therefore, the respiration parameters (CO₂, C₂H₄, and O₂) of the fruit indicate the tannin concentration (degree of ripening). Respiration determines the ideal CO₂ concentration, i.e., the measurement of oxygen uptake per unit of time and / or CO₂ emission from the fruit per unit of time. Based on these measurements and values, the optimal CO₂ concentration is set between 10 and 90 vol.% at the fruit and in the chamber. Once the optimal CO₂ concentration in the chamber is reached, it is regulated to this value, and the fruit's respiration continues to be measured and monitored.Once the respiration rate no longer changes measurably, for example, due to the fruit's oxygen uptake or CO2 release, the CO2 content is significantly reduced. Simultaneously, the temperature is lowered to between +18°C and +25°C. In this stage, the fruit's respiration becomes homogenized, meaning the persimmon should respire evenly again and thus become stress-free. As soon as this occurs, the astringency is eliminated, the ripening process is complete, and the fruit is ready to eat.

[0023] The fruit can then be stored further in the chamber at a temperature between +0°C and +12°C.

[0024] Preferably, the oxygen concentration in the chamber is maintained within an optimal range of 15.0 to 20.9 vol.% throughout the entire ripening process. This is achieved by supplying fresh air to the chamber when the O₂ concentration deviates from the optimal range. Gas concentration measurements are only taken when no fresh air or carbon dioxide is actively supplied or removed, in order to measure solely the influence of the fruit on the gas atmosphere in the chamber.

[0025] The present invention is therefore distinguished from conventional ripening methods in particular by the fact that the fruit respiration during the ripening process, especially in a ripening chamber according to the invention, is controlled and monitored by suitable means for measuring respiration and a means for evaluating the measured values ​​obtained.

[0026] It has been shown that excessive carbon dioxide gassing of fruit can lead to an over-regulation of the ripening process, which is difficult to stop and control. This results in uncontrolled ripening of the fruit, damage to the fruit, and a deterioration of its flavor. The respiration measurement according to the invention now enables targeted gassing of the fruit with carbon dioxide, which does not exceed the necessary level of carbon dioxide, thus achieving a particularly gentle ripening of the fruit.

[0027] In a preferred embodiment of the invention, a predetermined carbon dioxide concentration is set in a ripening chamber of the ripening chamber, which is varied over the duration of the ripening process. This has the advantage that the carbon dioxide concentration does not exceed a necessary level and, in particular, can be adjusted to the progress of the ripening process during the process, which in turn leads to gently ripened fruit with a consistently low tannin concentration.

[0028] In a particularly preferred embodiment of the invention, it is further provided that, during gassing with carbon dioxide, the carbon dioxide concentration is in the range of 10 to 90 vol.%, preferably in the range of 65 to 85 vol.%, and even more preferably in the range of 70 to 80 vol.%, and in particular, that it does not exceed 90 vol.% at any time during the process according to the invention. It has been found that gassing of more than 90 vol.% in the ripening chamber leads to an over-control of the ripening process, which is avoided by the specified preferred concentrations.

[0029] The specified values ​​refer specifically to ripening chambers filled to at least 60% capacity and must be adjusted accordingly if the ripening chambers are less fully utilized. For example, the carbon dioxide value should be considered as a regulated absolute gas value supplied in vol.%.

[0030] Preferably, the carbon dioxide concentration within the ripening chamber is reduced after a predetermined period and maintained at the reduced level, in particular at no more than 1 vol.%, preferably no more than 0.3 vol.%, and even more preferably no more than 0.06 vol.%. This embodiment of the inventive method further optimizes the uniformity of the ripening process and the shelf life of the ripened fruit, as the ripening is carried out even more gently. An initially higher concentration is necessary to initiate the ripening process, but is then reduced to a minimum level of carbon dioxide to achieve a progressive, very gentle ripening process down to a predetermined target value. Furthermore, this design has the advantage of reducing carbon dioxide consumption, which results in cost savings.

[0031] With particular advantage, the post-ripening process of the method according to the invention comprises several phases, which are characterized in particular by the gas concentrations and / or the temperatures in the post-ripening chamber.

[0032] The first phase, or start-up phase, of the inventive process initially enables all ripening fruits arranged in the ripening chamber to reach a similar ripening state, so that all fruits have essentially the same initial ripening conditions and thus achieve a comparable ripening result under the subsequent identical ripening conditions. A measure of this is the fruit's O2 uptake and CO2 release before ripening. The temperature in the chamber is set to +15 to +20 °C, preferably +16 to +19 °C. Its respiration rate is measured over a period of 2 to 6 hours. The phase ends when the respiration is uniform, i.e., when the change in CO2 production per unit time (increase in CO2 concentration Δ[CO2]) and / or the change in O2 concentration Δ[O2] per unit time (decrease in O2 concentration Δ[O2]) remains constant.

[0033] A particular advantage is that in the second phase, only the O2 concentration is measured as a function of time, and CO2 gassing begins within the chamber. The temperature is increased to between +20 and +30°C. At this point, the persimmon fruit's metabolism increases intermittently, meaning the fruit is intentionally encouraged to respire more. The system then searches for the ideal temperature for the fruit's metabolism. This process lasts 2 to 6 hours. Once the fruit's respiration becomes regular again, CO2 gassing begins. At this point, the persimmon fruit begins to senescent. A distinction is made between oxygen uptake and CO2 release, resulting in the formation of a large amount of acetaldehyde in the pulp. Acetaldehyde begins to dilute the tannins, consequently reducing the astringency of the persimmon fruit. The correct and optimal CO2 concentration is reached when oxygen consumption remains constant at altitude and does not fluctuate.The CO2 concentration in the chamber increases over time due to the continuous CO2 aeration. Once the oxygen consumption per unit of time has reached a certain value and remains constant, the optimal CO2 concentration for the fruit has been found.

[0034] In the third phase, the CO2 concentration within the chamber is kept constant by dynamically changing the CO2 gas supply, preferably at a value of about 50 to 90 vol.%, more preferably 60 to 85 vol.%, and even more preferably 70 to 80 vol.%. If no change in the O2 concentration is measured and it falls below a predetermined value, the final phase is started.

[0035] In the final phase, the temperature is set to +10 to +35°C, preferably +18 to +25°C. CO2 gassing is stopped, the chamber is purged with fresh air, and the fruit is left to rest for 20 to 52 hours. Preferably, the carbon dioxide concentration in this phase is a maximum of 1%. During this phase of the cycle, the fruit's respiration becomes homogenized, meaning the persimmon should respire evenly again and thus become stress-free. Once this occurs, the astringency is eliminated, and the ripening process is complete. Preferably, the ethylene concentration in the ripening chamber is also monitored during this phase.

[0036] After the final stage, the ripened fruits can be taken for consumption or stored further under conventional storage conditions.

[0037] This embodiment allows for active intervention in the ripening process and thus an intensification or reduction of the ripening process in the fruits, triggered by adjustable parameters.

[0038] As the fruit ripens, its respiration rate changes in a predictable manner. By measuring the respiration gases, the ripening process according to the invention enables the precise determination and control of the ripening progress.

[0039] Optionally, the active manipulation of the ripening process is also enabled by other atmospheric parameters in the ripening chamber. In a further preferred embodiment of the invention, the temperature in the ripening chamber, and in particular the temperature of the fruit, is controlled and / or regulated.

[0040] A particular advantage is that the measurement and / or control of the aforementioned parameters is constant or performed at predetermined intervals. This means, in particular, that the measured values ​​are monitored continuously or at short intervals, and that a check is only performed if the critical limit (critical concentration change) is exceeded or fallen below. Alternatively or additionally, control is carried out after setting or resetting individual parameters at predefined intervals or at predetermined times, which are stored in a defined process cycle. In this embodiment, the inventive method, depending on an initial state of the fruit and / or the quantity of fruit, comprises, in particular, several cycles contained in the four phases described above, specifically time intervals, temperature and gassing parameters, as well as limit values ​​for gas concentrations within the ripening chamber.This embodiment makes it possible, in the broadest sense, to carry out an automatable implementation of the method according to the invention.

[0041] Accordingly, one aspect of the invention relates to a method for ripening astringent fruits, in which the fruits to be ripened are arranged in a gas-tight ripening chamber and their ripening state during the ripening process is measured by means of respiration of the fruits, wherein the method comprises controlled gassing of the fruits with carbon dioxide.

[0042] Another aspect of the invention relates to a ripening chamber for ripening and storing fruit, comprising a gas-tight ripening chamber, wherein the ripening chamber is configured to carry out the inventive method of one of the aforementioned embodiments. The ripening chamber according to the invention comprises a gas-tight ripening chamber for arranging fruit to be ripened, a means for monitoring carbon dioxide and oxygen concentrations, a carbon dioxide gas source, a temperature control system, a carbon dioxide adsorber, a nitrogen generator, a heat exchanger, a lung, a pressure valve, and an oxygen supply.

[0043] Another aspect of the invention relates to the use of a gas-tight ripening chamber for ripening astringent fruits, wherein the astringent fruits to be ripened are arranged in the ripening chamber and their respiration activity is measured during the ripening process.

[0044] In a preferred embodiment, the ripening chamber comprises means for measuring temperature (air and fruit temperature) and / or C2H4 concentration within the ripening chamber and corresponding means for evaluating the measured values. This embodiment makes it possible to monitor the respiration necessary for the inventive process and to actively control the ripening process by means of atmospheric parameters within the ripening chamber. According to the invention, the chamber consists of a ripening chamber that is gas-tight according to the criteria of so-called CA storage technology and thus sealed gas-tight to the outside.The gas tightness requirement is met when, after generating a negative or positive pressure of 15 mm WS (water column = 150 Pa) in the ripening chamber, this pressure decreases or increases by a maximum of 5, preferably 4, preferably 3, and even more preferably 2 mm WS (20 Pa) within 0.5 hours, with a smaller value corresponding to increased tightness. The ripening chamber comprises a gas-tight CA door and preferably a means for regulating the supply air, the exhaust air, and / or the positive / negative pressure of the ripening chamber. Additionally, a means for generating nitrogen, a means for adsorbing CO2, and corresponding measuring equipment are preferably provided and fluidically connected to the ripening chamber.

[0045] In a preferred embodiment, the chamber includes means that enable continuous air circulation, for example, air fans. This circulation is enhanced by an air barrier system on the fruit carton (carton with pallet) to create pressure differentials across the carton, as this promotes air and gas exchange through the cartons. This is particularly useful for the ripening of persimmons. For uniform ripening, preferably only one air circulation direction control function is installed.

[0046] In conventional ripening systems, a fan rotation direction reversal function was necessary to improve the uniformity of the ripening result, which is no longer required in the system according to the invention.

[0047] In the inventive system of ripening chamber and method, nitrogen can be flushed into the chamber as needed, and excess CO2 can be removed from the chamber atmosphere. If the oxygen content is too low, oxygen is supplied to the ripening chamber in a controlled manner, for example, via a gas-tight ventilation system. Furthermore, the air circulation rate (air volume flow and fan speed) in the ripening chamber dynamically adjusts to the ripening process and the airflow permeability of the fruit cartons, preferably automatically. Advantageously, this requires only one direction of rotation / airflow direction for the fans over the fruit cartons, while still ensuring uniform ripening of the fruit throughout the entire ripening chamber.

[0048] With particular advantage, the ripening chamber according to the invention is arranged in a container or a refrigerated case, so that the method according to the invention is not limited to a stationary implementation.

[0049] Thus, another aspect of the invention relates to a container / refrigerated case for ripening, storing and / or transporting fruit, wherein the container comprises or consists of a gas-tight ripening chamber in which the fruit to be ripened is arranged, as well as a unit for monitoring and controlling respiration gases inside the ripening chamber, so that the respiration activity of the fruit can be measured and controlled during transport, ripening and / or storage.

[0050] The maturing chamber has, in particular, the features of a maturing chamber described above for carrying out the method according to the invention.

[0051] Designing the ripening chamber as a container offers the advantage that the ripening process according to the invention can be combined with the transport of the fruit. This provides enormous time and energy savings and is therefore particularly attractive from an economic standpoint. Furthermore, storage times are reduced during which the fruit must be kept at a specific ripening stage or during which uncontrolled ripening occurs. For the reasons already described, this results in high-quality fruit with a well-balanced flavor. Separate ripening at the destination is no longer necessary, thus eliminating the need for costly storage space and ripening equipment.

[0052] The external shape and size of the container preferably correspond to a conventional container used for transporting fruit. Thus, the container is defined as a basic body, particularly a regular one, with a base, a bottom, and four sides. Preferably, in addition to the usual door, the container has a gas-tight partition wall with a special sealing mechanism. This is preferably a pressure-tube sealing frame wall module, which is inflated and maintained under pressure by means of gas pressure, e.g., compressed air or nitrogen. The increase in volume of the sealing tube caused by the introduction of air results in a gas-tight seal of the transitions between the partition wall and the container body. Alternatively, the partition wall is sealed using a film technique, whereby the wall is, for example, sealed gas-tight with a disposable film for the duration of transport or storage.

[0053] The container is preferably stackable and reversibly lockable.

[0054] In a preferred embodiment, the monitoring and control unit comprises a means for measuring ethylene concentration and / or temperature within the ripening chamber, as well as corresponding means for evaluating the measured values, and optionally a means connected to at least one evaluation means for controlling and regulating the atmosphere within the container's ripening chamber. Furthermore, a system for continuous air circulation and compartmentalization around the transported goods is provided. This is comparable to a conventional ripening chamber or one described above, where a forced airflow is achieved via a pressure differential across the container.

[0055] A further advantage of this container is its ability to regulate the temperature within the ripening chamber. The air is cooled and heated as needed. With conventional containers and ripening technology, the increased heat generated by biological respiration during traditional ripening, combined with limited space and insufficient airflow, often leads to overheating of the fruit. This results in uncontrolled and uneven ripening, ultimately leading to spoilage. However, this system, which regulates temperature, ethylene levels, and gas concentrations, particularly CO2 and O2, prevents both overheating and freezing of the fruit.

[0056] Another advantage of this design is that the fruit can be kept in a defined state of post-ripening. In other words, post-ripening is interrupted. The fruit remains in a controlled, or controllable, state of post-ripening.

[0057] In a preferred embodiment of the invention, it is additionally provided that a means for monitoring the ripening state, in particular a camera / sensor for determining the ripening state, is arranged inside the ripening chamber. This is particularly advantageous during the transport of the fruit, since monitoring by visual inspection is impossible during this period. It is especially advantageous if the monitoring means is connected to a monitoring center and / or the control unit for controlling the process in order to compare a determined ripening state with a target value and to adjust the process and / or the temperature in case of deviation. The process enables a controllable and reproducible consistent ripening quality, so that ripening profiles and ripening states can be assumed based on respiration data and empirical values ​​even without a camera / sensor system.For example, using radio and satellite technology and a planned arrival time at the recipient, the ripening process can be initiated during transport. The goal is for the fruit to reach the desired state of ripeness upon arrival at the destination. The collected respiration data also provides information and insights into the current ripening status of the specific fruit varieties being transported.

[0058] The container according to the invention is preferably not equipped with a carbon dioxide adsorber. This would take up a lot of space, which would be lost as fill volume. The function of the carbon dioxide adsorber is then preferably taken over by regulating the inlet of nitrogen, ethylene, and oxygen. The CO2 concentration is thus reduced relatively by increasing the oxygen, ethylene, and / or nitrogen. In other words, excess CO2 is regulated with the help of the N2 generator by purging the ripening chamber in the container with nitrogen to limit the CO2 content in the container.

[0059] The desired carbon dioxide and oxygen concentrations are controlled or changed as needed. Therefore, in the control process, these parameters (O2 and CO2 concentrations) are preferably readjusted and supplied accordingly in a timely manner, especially simultaneously.

[0060] For the ripening of fruit during transport, a source or storage facility should also be available where carbon dioxide is stored to achieve the desired enrichment in the container. This is preferably achieved using fluid-carrying pressurized cylinders containing the relevant gases.

[0061] A further advantage of the ripening chamber in the container is the provision of a means for regulating pressure, in particular a pressure relief valve, through which excess container air can escape into the environment.

[0062] In a particularly preferred embodiment, the container is designed as a reversibly lockable container. This allows the container to be used as a transport container on a ship, a truck, or a freight train.

[0063] Due to their universal applicability, ISO containers are particularly suitable for various uses. ISO containers are standardized large-capacity containers (sea freight containers) made of steel, enabling the simple and quick loading, transport, storage, and unloading of goods. The relevant standards (e.g., dimensions, fittings, stackability) were coordinated by the International Maritime Organization (IMO) and are defined in ISO standard 668.

[0064] When used on a truck, insulated box bodies for trucks, as defined by the container according to the invention, are preferably used. An insulated box body, due to its typically double-walled GRP cladding with an insulating core of polyurethane foam and wooden or aluminum bracing, is significantly heavier than a comparable closed tarpaulin body. This reduces the usual maximum payload from 25 to 24 tons.

[0065] To ensure that the standardized internal width of 2.40 m, which is practical for standardized transport equipment such as Euro pallets and wire mesh containers, is maintained, temperature-controlled bodies are permitted to have a total width of 2.60 m, thus exceeding the otherwise maximum permitted overall width of 2.55 m without a special permit. However, since the maximum vehicle length cannot be increased, standard refrigerated semi-trailers can only transport 33 Euro pallets instead of 34.

[0066] Alternatively or additionally, the container according to the invention is designed as a prefabricated component for a post-ripening chamber.

[0067] In this context, the term "container" also includes refrigerated truck trailers, such as those used in the truck transport industry for perishable foodstuffs. The described technology can also be applied here.

[0068] Another aspect of the invention relates to the use of the container according to the invention for post-ripening, storage and / or transport on a ship, a truck or a freight train.

[0069] The container preferably has an access point for a power supply that can be connected to an external power source or to the power supply of the ship, truck, or freight train. Furthermore, it is advantageous if the container has a means for external data exchange.

[0070] When used on a truck, a non-lockable arrangement of the container on the loading platform of the truck and / or a trailer is particularly preferred. In summary, the container according to the invention offers the advantages of controlled, uniform, and optimal ripening of fruit during transport, such as by sea or land. Ripening can be initiated and monitored in a targeted manner using modern communication methods. In each individual container, a modern tracking system allows for data exchange regarding origin, contents, destination, and arrival date via remote monitoring, enabling ripening to be started at the ideal time, ensuring that the desired degree of ripeness is reliably achieved upon arrival.The recipient and distributor can immediately pick and deliver the goods to the delivery and consumption points without having to initiate any further targeted ripening process.

[0071] Using the ripening process according to the invention, significantly less cooling and heating energy is required for ripening. This makes it technically possible to successfully carry out controlled and uniform ripening within the spatially limited and highly restricted confines of containers. The complete control over the ripening process and the significantly lower cooling energy requirement make this possible and are due to the ripening process according to the invention.

[0072] Further preferred embodiments of the invention result from the other features mentioned in the dependent claims.

[0073] The various embodiments and aspects of the invention mentioned in this application can be advantageously combined with one another, unless otherwise specified in individual cases. In particular, representations and descriptions of preferred configurations and embodiments of the method are always transferable to the ripening chamber and the container, and vice versa. Brief description of the characters

[0074] The invention is explained in more detail below with reference to an exemplary embodiment and accompanying drawings. The figures show: Fig. 1 shows a schematic representation of a ripening chamber according to the invention in a preferred embodiment of the invention. Detailed description of the invention

[0075] Figure 1This represents a ripening chamber 1 according to the invention, which includes a ripening area 2 for receiving fruit for ripening or storage. The ripening area 2 is designed to be gas-tight in accordance with so-called CA (controlled atmosphere CA) quality, so that only very minimal gas exchange takes place between the interior of the ripening area 2 and the exterior of the chamber 1. This is ensured by loading the ripening area 2 with the fruit 3 via a CA door 13. Only an optimal ripening process and the storage of fruit with absolutely uniform and reproducible gas concentrations guarantee uniform ripening of the fruit. This is ensured by a CA door 13, which closes, for example, according to the principle of static contact force. The fruit 3 is arranged, for example, on pallets. The volume of a preferred ripening area 2 is typically between 177 m³ and 266 m³, depending on the chamber type.However, the dimensions can be adapted to the desired quantity of fruit 3 and the structural conditions.

[0076] The pallet size, pallet quantity, and quantity of ripening fruit may vary.

[0077] It was found that when the ripening chamber 2 is utilized to 60%, i.e., 14 filled pallets in relation to the preceding example, the concentration values ​​in the inventive method do not need to be adjusted. At lower occupancy levels, and optionally at any occupancy level of ripening chamber 2 that deviates from 100%, the monitoring and control parameters of the method can be adjusted, e.g., using a control program.

[0078] The ripening chamber 2 has at least one measuring device 4, for example for temperature measurement, or is connected to a device 5 + 6 that allows the removal of gas from the ripening chamber 2 for the measurement of atmospheric parameters. These atmospheric parameters are, for example, a carbon dioxide concentration, an ethylene concentration, and / or an oxygen concentration. Furthermore, the ripening chamber 2 is preferably fluidically connected to a CO2 supply 16, an oxygen supply 15, for example as a fresh air supply, and a nitrogen generator 8. These can be released into the ripening chamber 2 by a control device for regulating the gas atmosphere within the chamber. In addition, the ripening chamber 2 is fluidically connected to a carbon dioxide adsorber 7, which allows the removal of carbon dioxide.

[0079] When used in the container according to the invention, the function of the carbon dioxide adsorber 7 is preferably taken over by the inlet of nitrogen and oxygen. The CO₂ concentration is thus reduced relatively by increasing the oxygen and / or nitrogen. To prevent a pressure increase in the ripening chamber 2 when gas is supplied, e.g., when fresh air is supplied via the adjustment means 15, when nitrogen is required, or by CO₂ gassing, the ripening chamber 2 additionally has a pressure relief valve 12, which is designed to equalize overpressure or underpressure. Alternatively or additionally, the ripening chamber 2 is fluidically connected to a so-called lung 11, in which excess gas can be released or from which gas can flow back. This allows certain pressure fluctuations in the ripening chamber to be compensated for.

[0080] In addition to the oxygen and carbon dioxide gases, the ripening process can be influenced by other parameters in the ripening chamber 2, particularly the temperature. To provide a means of intervention, the ripening chamber 2 preferably has a heat exchanger 10 in combination with fans 17, which is fluidically connected to a temperature control system 9, for example, a cooling and / or heating system.

[0081] The adjusting means and devices 4, 5, 6, 7, 8, 9, 15, suitable for influencing the atmosphere within the ripening chamber 1 and the CO2 supply 16, are preferably connected to a control unit 6 in which, for example, an algorithm for controlling a process is stored that enables automatic control of the atmosphere within the ripening chamber 1 depending on measured values ​​and time parameters. In particular, the method according to the invention is carried out here, which can be controlled automatically and / or at least partially manually.

[0082] This can preferably be achieved by setting the temperature in ripening chamber 1 to approximately +16°C to +20°C and measuring the increase in carbon dioxide concentration or the decrease in oxygen concentration within approximately 0.5 to 2 hours in ripening chamber 2 due to the ripening processes. If this concentration change Δ[O2] or Δ[CO2] is greater than a predetermined value, the second phase can be started. In the second ripening phase, the temperature is further increased to between +20°C and +30°C. The fruit begins to respire more intensely. The carbon dioxide concentration in the chamber is gradually increased over time. Subsequently, after the change in oxygen concentration has increased and remains constant, the carbon dioxide concentration in the chamber is kept constant by dynamic control of the carbon dioxide aeration.In the third phase, when no further change in oxygen concentration can be detected, the CO2 gassing is stopped, the chamber is purged with fresh air and the temperature is set to a lower value, preferably +18 to +25°C.

[0083] A method according to the invention, which can be carried out with the ripening chamber described above, is described in detail in a preferred embodiment. In this embodiment, the method comprises a plurality of phases.

[0084] In the first phase, a comparable state of the individual fruits, based on their ripeness and post-ripening stage (ripeness and astringency of the fruits at the beginning of post-ripening), is achieved by setting the temperature to +15 to +20°C and measuring the respiration gases CO2 and O2. The actual post-ripening process then takes place in the subsequent phases. First phase:

[0085] The first phase lasts approximately 2 to 6 hours and involves setting a temperature within a range of +15 to +20 °C and regularly, especially hourly, measuring the CO2 production / O2 uptake by the fruit. If the respiration rate, i.e., the change in CO2 production (increase in CO2 concentration Δ[CO2]) and / or the change in O2 concentration Δ[O2] (decrease in O2 concentration Δ[O2]), remains constant at a predetermined value, the next phase is started. Second phase:

[0086] The temperature is raised to a value between +20 and +30°C and maintained at a stable level. At this point, the persimmon's metabolism increases intermittently / unevenly, meaning the fruit is intentionally encouraged to respire more. The system thus seeks the ideal temperature for the fruit's metabolism. This second phase lasts approximately 2-6 hours. During this time, the O2 and CO2 concentrations are measured at regular intervals, for example, every 0.5-2.5 hours, to determine how much O2 is absorbed and how much CO2 is released by the fruit, as this provides insights into the ripening process. Once the fruit is stress-free and respiration is regular, carbon dioxide is introduced in a controlled manner to achieve a concentration between 50% and 90% by volume in the chamber. The fumigation of the fruit begins with a slowly increasing CO2 concentration.This means that the CO2 supply is constant and leads to an increasing CO2 concentration in the ripening chamber / room. The correct and optimal CO2 concentration is reached when the oxygen consumption remains constant at altitude and does not fluctuate. Third phase:

[0087] The third phase lasts approximately 18 to 32 hours, during which the temperature is kept stable between +20°C and +30°C. The O₂ concentration is measured at regular intervals, e.g., every 0.5 to 2.5 hours, to determine how much O₂ is absorbed by the fruit, as this provides information about the ripening process. CO₂ injection is dynamically controlled around a target CO₂ concentration within the ripening chamber. This target CO₂ concentration is set to the level reached at the end of the second phase, preferably between 50 and 90% by volume. If the O₂ measurements do not detect any further changes in O₂ concentration, the final phase is initiated. Final phase:

[0088] In the final phase, the temperature, starting from the temperature of the intermediate phase, is slowly reduced, particularly over several hours, especially 20 to 52 hours, to a value of +18°C to +25°C. Furthermore, the CO2 gassing is stopped and the ripening chamber is purged with fresh air. A CO2 concentration of no more than 1% by volume is preferably established.

[0089] Preferably, the oxygen concentration in chamber 1 is maintained at an optimal level of 15.0 to 20.9 vol.% throughout the entire ripening process during all four phases described above. This is preferably achieved by supplying fresh air to the chamber via the fresh air supply 15 when the O2 concentration in the chamber deviates from the optimal range. Gas concentration measurements using the gas analyzer 6 are only taken when no active fresh air supply is in place, in order to measure solely the influence of the fruit contained in the chamber on the atmosphere within the chamber.

[0090] Once the final phase is complete, the actual ripening process is finished. The ripening chamber can be opened and no longer needs to be sealed airtight. The fruit is ready to eat immediately, but can also be stored further if desired. The ripening process according to the invention produces firm and astringent fruit. Reference symbol list

[0091] 1. Ripening chamber with equipment 2. Ripening room 3. Transport device with fruit 4. Temperature sensors 5. Actuator gas measuring pump 6. Control device and gas analyzer 7. CO₂ adsorber 8. N₂ generator 9. Temperature control system 10. Heat exchanger and gas / liquid medium for temperature control (cooling / heating) 11. Lung 12. Pressure damper 13. CA gate 14. Flexible air separation system 15. Oxygen ventilation system with fan / fresh air supply 16. Carbon dioxide gas cylinder 17. Fan

Claims

1. A method for post-ripening astringent fruits, wherein the to-be-post-ripened fruits are placed in a gas-tight post-ripening chamber (2), and their respiration activity is measured during the post-ripening, characterized in that the method comprises controlled fumigation of the fruits with carbon dioxide.

2. The method according to claim 1, wherein the fruits are persimmons.

3. The method according to any one of the preceding claims, wherein a carbon dioxide concentration in the post-ripening chamber (2) is varied continuously or at regular intervals.

4. The method according to claim 3, wherein the carbon dioxide concentration is varied within a range of 40 to 90 vol.%.

5. The method according to any one of claims 3-4, wherein the carbon dioxide concentration is varied as a function of an oxygen concentration.

6. The method according to claim 1, wherein in a second phase, the fumigation with carbon dioxide takes place as soon as a predetermined increase in a carbon dioxide concentration and / or a predetermined decrease in an oxygen concentration is measured within a defined time unit in a first phase.

7. The method according to any one of the preceding claims, wherein temperatures of the fruits and gases inside the ripening chamber (2) are measured and regulated continuously or at regular intervals.

8. A post-ripening chamber for post-ripening astringent fruits, comprising: a) a gas-tight post-ripening chamber (2) for arranging to-be-post-ripened fruits (3), b) a means for monitoring carbon dioxide and oxygen concentrations (6), c) a carbon dioxide gas source (16), d) a temperature control system (9), e) a carbon dioxide absorber (7), f) a nitrogen generator (8), g) a heat exchanger (10), h) a gas reservoir (11), i) a pressure valve (12), and j) an oxygen supply (15); wherein the post-ripening chamber is configured to carry out the method according to any one of the preceding claims.

9. The post-ripening chamber according to claim 8, wherein the oxygen supply (15) is designed as a fresh air supply and the carbon dioxide gas source (16) is designed as a carbon dioxide gas cylinder.

10. The post-ripening chamber according to any one of claims 8-9, wherein the post-ripening chamber is designed as a reversibly lockable container.

11. Use of the container according to claim 10 for post-ripening, storage, and transport on a ship, a truck, or a freight train.

12. A motor vehicle comprising the container according to claim 10.

13. Use of a gas-tight post-ripening chamber (2) for post-ripening astringent fruits, wherein the to-be-post-ripened astringent fruits are placed in the post-ripening chamber, and their respiration activity is measured during post-ripening of these fruits.