Everything about storing fruits and vegetables in a controlled atmosphere -

Everything about storing fruits and vegetables in a controlled atmosphere

Storing food before marketing is very important. During storage the quality of food can deteriorate depending on the storage conditions, due to the action of external agents: air, water, heat, bacteria, pests.

The effects are very noticeable in the case of vegetables and fruits.

Food degradation can not be prevented, but it can be greatly slowed down by changing storage conditions: temperature, humidity, composition of the atmosphere in the warehouse.

Food storage under modified environmental conditions is known as controlled atmosphere storage. Storage in a controlled atmosphere can slow the loss of quality after harvesting. It is a well-known technique and an important alternative to chemical preservatives and pesticides.

It has great potential to reduce post-harvest losses and to maintain both nutritional and market values.

As in any application in the food area, the reason for using nitrogen is always the same: preventing food degradation. Nitrogen replaces the oxygen to which food is exposed and slows down the oxidation process.

Controlled atmosphere storage systems with Parker technology-Smartstock system

Reducing the oxygen content in a cold store slows down the process of degradation of stored food. Creating such an atmosphere is done by introducing high concentration nitrogen produced by a Parker nitrogen generator into the chamber.

Oxygen concentration, room temperature, humidity and RH are monitored and controlled by an automatic system. The system ensures the maintenance of the favorable atmosphere throughout the storage period.

Advantages Of SmartStock:

– Increase the shelf life of food (especially fruits and vegetables)

– Continuous monitoring of storage parameters

– Automatic control of the storage atmosphere

– The possibility of expanding the system with the growth of the warehouse

Controlled atmosphere systems maintain the organoleptic characteristics of the products and reduce losses due to pathogens. Fruits and vegetables stored in warehouses with controlled atmosphere can withstand several months without damage.

The Controlled Atmosphere systems offered by Frigother group SRL are able to meet any requirement of our customers. Their management is completely computerized, and integrated with the cooling system, allowing a total automation of the activity in the warehouse.

Controlled atmosphere cells have a number of particular characteristics that differentiate them from simple refrigerated cells. The design, construction and installation of controlled atmosphere cells requires a lot of attention and extensive experience in the field.

Panel joints

The joining of the panels must be absolutely tight, to guarantee complete sealing of the interior of the cell with controlled atmosphere, compared to the outside.

Access doors

Doors used in cold stores must be adapted for use in a controlled atmosphere warehouse. They are equipped with 4 additional locking systems and glass for inspection.

CO2 absorption systems

Carbon dioxide absorption systems can be used either as independent units that can manage one or two cells, or as centralized units that can manage a larger group of cells.

The absorption systems use special filters with Activated carbon, and aim to keep the concentration of CO2 constant inside the cells, even under the conditions of a very low percentage of oxygen. The systems are managed by a computer and an automatic cell monitoring system. It consists of CO2 and O2 analyzers that continuously monitor the interior of the cells, automatically analyzing the air and maintaining its characteristics between preset values.

CO2 absorption systems are provided with pneumatic valves that do not require any intervention and maintenance. Optionally, a nitrogen regeneration system NRS (Nitrogen Regeneration System) can be added which improves conservation in conditions of minimal presence of Hyper Low Oxygen (HLO).

Ethylene absorption systems

The use of ethylene absorption systems allows to maintain a low level of ethylene in the refrigerated cells, eliminating the negative effects that it has during the conservation of fruits and legumelor.Cu using this system can absorb other harmful gases, such as hydrocarbons and sulfur dioxide.

This absorption system is mainly used in the preservation of fruits, vegetables and flowers (especially kiwi) and in general of all products that during the preservation produce small amounts of ethylene, but which are also sensitive to the presence of this gas.

Nitrogen generation systems

They produce nitrogen with purity from 95% to 99% using the technology of separating compressed atmospheric air by means of a screw compressor. The introduction of nitrogen is done very quickly so that carbon dioxide is not formed at the same time.

Nitrogen generators are used in sectors where “ecological” nitrogen is required, without combustion residues (CO2, CO, NOx, SO2, C2H2, etc.). They are available in fixed or mobile versions. The models proposed by us can also be used for the production of enriched oxygen, for maturation cells.

Computerized control systems

Managing all systems is a complex task that requires the presence of a multitude of sensors connected to a control panel. The entire system allows the sampling and storage of all conservation parameters, such as: percentages of CO2, O2, ethylene, humidity, pressure, but also provides automatic controls to the necessary equipment, to keep these parameters within the required limits.

The effects are very noticeable in the case of vegetables and fruits.

Food degradation can not be prevented, but it can be greatly slowed down by changing storage conditions: temperature, humidity, composition of the atmosphere in the warehouse.

It has great potential to reduce post-harvest losses and to maintain both nutritional and market values.

Controlled atmosphere storage systems with Parker technology-Smartstock system

Advantages Of SmartStock:

– Increase the shelf life of food (especially fruits and vegetables)

– Continuous monitoring of storage parameters

– Automatic control of the storage atmosphere

– The possibility of expanding the system with the growth of the warehouse

Panel joints

The joining of the panels must be absolutely tight, to guarantee complete sealing of the interior of the cell with controlled atmosphere, compared to the outside.

Access doors

Doors used in cold stores must be adapted for use in a controlled atmosphere warehouse. They are equipped with 4 additional locking systems and glass for inspection.

CO2 absorption systems

Carbon dioxide absorption systems can be used either as independent units that can manage one or two cells, or as centralized units that can manage a larger group of cells.

Ethylene absorption systems

Nitrogen generation systems

Computerized control systems

Refrigerated storage systems with controlled atmosphere are mainly aimed at long-term storage of vegetables and fruits, storage carried out immediately after their harvest. Refrigerated storage with controlled atmosphere is carried out within the field of industrial and commercial cold, with the modification of storage conditions, controlling the temperature, humidity and composition of the atmosphere in the refrigerated warehouse (refrigerated warehouses, production areas, storage, packaging areas, airlock areas).

Controlled atmosphere storage of fruits is a method by which their quality is preserved by maintaining an optimal level of the ratio between oxygen concentration and carbon dioxide concentration, regulating ethylene concentrations, temperature and humidity.

The fruits breathe; they absorb oxygen and remove carbon dioxide, thus continuing their natural process of ripening and ripening. Long-term fruit storage involves slowing down these ripening and ripening processes, thus preserving the flavor and quality of the products. In fact, is baking delayed by changing the atmospheric conditions in the warehouse so as to reduce the breathing process?fruits and vegetables.

By changing the atmospheric conditions and reducing the temperature, the organoleptic characteristics of the products are maintained unaltered and the losses due to pathogens are reduced.

The quality and freshness of the fruits stored in controlled atmosphere warehouses are maintained without the use of chemicals, the products can be stored up to four times more than usual.

Controlled atmosphere warehouses have a number of characteristics that differentiate them from the usual cold stores:

– the joining of the panels must be absolutely watertight to guarantee complete sealing of the interior of the cell with controlled atmosphere compared to the outside.

– the access doors must be adapted for use in a warehouse with controlled atmosphere, being equipped with 4 additional closing systems and glass for inspection.

– specific technological equipment: atmosphere control station, nitrogen generator, CO2 scrubber, ethylene converter, humidity control station.

The effects are very noticeable in the case of vegetables and fruits.

Food degradation can not be prevented, but it can be greatly slowed down by changing storage conditions: temperature, humidity, composition of the atmosphere in the warehouse.

It has great potential to reduce post-harvest losses and to maintain both nutritional and market values.

Controlled atmosphere storage systems with Parker technology-Smartstock system

Advantages Of SmartStock:

– Increase the shelf life of food (especially fruits and vegetables)

– Continuous monitoring of storage parameters

– Automatic control of the storage atmosphere

– The possibility of expanding the system with the growth of the warehouse

Panel joints

The joining of the panels must be absolutely tight, to guarantee complete sealing of the interior of the cell with controlled atmosphere, compared to the outside.

Access doors

Doors used in cold stores must be adapted for use in a controlled atmosphere warehouse. They are equipped with 4 additional locking systems and glass for inspection.

CO2 absorption systems

Carbon dioxide absorption systems can be used either as independent units that can manage one or two cells, or as centralized units that can manage a larger group of cells.

Ethylene absorption systems

Nitrogen generation systems

Computerized control systems

By changing the atmospheric conditions and reducing the temperature, the organoleptic characteristics of the products are maintained unaltered and the losses due to pathogens are reduced.

The quality and freshness of the fruits stored in controlled atmosphere warehouses are maintained without the use of chemicals, the products can be stored up to four times more than usual.

Controlled atmosphere warehouses have a number of characteristics that differentiate them from the usual cold stores:

– the joining of the panels must be absolutely watertight to guarantee complete sealing of the interior of the cell with controlled atmosphere compared to the outside.

– the access doors must be adapted for use in a warehouse with controlled atmosphere, being equipped with 4 additional closing systems and glass for inspection.

– specific technological equipment: atmosphere control station, nitrogen generator, CO2 scrubber, ethylene converter, humidity control station.

Construction for storing vegetables and fruits:

To ensure the consumption of vegetables and fruits throughout the year, they must be stored, canned and conditioned. Horticultural products continue during the preservation of a number of metabolic processes namely:

– respiration, maturation, cornering, etc. the storage conditions vary from one product to another and the warehouses are designed with these needs in mind.

Classification of deposits for vegetables and fruits:

Deposits for vegetables and fruits are classified according to several criteria, namely:

– according to the nature of the production stored are: specialized warehouses for a single product, universal warehouses for several products and recovery complexes with TI activity of storage and storage of products;

– dupa modul de realizare a conditiilor de pastrare is deosebesc depozite fara posibilitati de reglare to conditiilor de depozitare, depozite cu enables you to reglare to conditiilor de depozitare, cu atmosfera controlata, prevazute cu instalatii de ventilatie mechanics if frigorifice;

– according to the type of construction adopted, the warehouses can be: pavilions and merged;

– after the temperature limits for storage, the deposits are: with positive temperatures

(0 °C – 5 °C), with negative temperatures up to -24 °C for frozen products and with temperatures close to those of the external environment, which are determinants in the realization of the indoor microclimate;

– according to the degree of equipment of the warehouse, there can be: special warehouses with mechanized installations for sorting and realization of the indoor climate, simple warehouses, without installations, intended for short-term storage;

– by capacity there are warehouses of small capacity (50 – 100 tons) and high capacity (20,000 tons).

Constructive features for vegetable and fruit warehouses:

The warehouses for vegetables and fruits are diversified in a multitude of types, according to the constructive-functional characteristics, from simple ditches and trenches to constructions with large capacity equipped with technological utility and performance. Traditional solutions use local and less demanding materials and new solutions use modern materials and technologies of execution.

Small capacity warehouses:

Small capacity warehouses are used for small quantities of vegetables and for short periods of time, generally used to serve individual households and production units in rural areas.

Large capacity warehouses:

They are warehouses with structures generally made of prefabricated reinforced concrete, consisting of:

glass foundations, pillars and beams, prefabricated panels for walls, roof elements, straight or curved, lightweight heat-insulating panels for exterior closures. Large capacity warehouses are ground floor or multi-level type.

Elements of the design of vegetable and fruit warehouses:

The necessary spaces for storing vegetables and fruits are determined by the species of products and storage technology.

The microclimate necessary to be created in warehouses is especially important becauseit directly influences production. The temperature required to be achieved is important because at low temperatures the metabolic processes are reduced; the duration until the appearance of aging is prolonged; water losses are reduced (thus avoiding wilting) and the qualitative impairments due to the attacks of fungi and bacteria occur in a much smaller proportion.

Relative humidity varies between 70-90%; lower humidity causes the products to wrinkle due to water loss and high humidity favors the development of fungi (mold)and bacteria. To achieve optimal microclimate conditions, the closing elements of the vegetable and fruit stores are designed to ensure efficient thermal insulation.

Plants and machinery used in vegetable and fruit warehouses:

The installations and machines provided in the vegetable and fruit warehouses are determined by the technological process adopted and allow indoor air conditioning, artificial lighting, transportation and handling of stored products and their conditioning. The indoor air conditioning systems ensure the microclimate in the refrigerated cells by maintaining the optimum temperature, humidity and air composition. Installed cooling devices are used for storage for longer periods of time and maintain optimum temperature, humidity, pressure and gas content. Aaer humidification installations have the role of maintaining the necessary humidity in the storage cells. The Controlled Atmosphere installation is designed to maintain all climate factors specific to each type of storage, namely:

– temperature

– humidity

– oxygen and carbon dioxide concentration

– etc.

Lighting installations (generally fluorescent), provided in vegetable and fruit warehouses are differentiated:

– in the sorting hall the lighting is done so that it is as close to the natural tea as possible;

– in storage cells, light is not required because it would stimulate or intensify some unwanted processes (vegetation, wilting, etc.).);

– in the alleys and outbuildings, ordinary lighting.

The transport and stacking machines are necessary for handling the mass to be stored in good conditions and with a low cost price. These machines are:

– mobile conveyors with rubber band

– grips

– mechanical shovels

– electrocare with lifting arm

– manually or mechanically operated trolleys

– forklifts, electric forklifts, etc.

Machines and conditioning systems are used to prepare vegetables and fruits for storage and then delivery.

Storage of blueberries in a controlled atmosphere for a long time:

Maturity: for long-term storage, blueberries must be picked at the right time. The timing of harvesting depends on several factors:

– the color of the fruit at the time of harvesting.

– the content of sugar or antioxidant acids. Blueberry berries are harvested when they are almost ripe, because the quality of the fruits quickly decreases after harvesting.

– Step 4 storage: starts when the potatoes have reached the final storage temperature. Temperature / humidity conditions may vary depending on the final destination of the potatoes, namely: potatoes for chips will store at +..+ 12°C / 90% rH , potatoes for frying will store at + 5… + 6°C / 90% rH , potatoes for consumption will store at +4++7°C / 90% rH, potatoes for seed will store at+3.5…+5°C / 90% rH, potatoes for starch will store at+4. + 5°C / 90% rH.

Process: mechanical ventilation with cooled air, maintaining constant temperature + humidity.

Duration: 90-180 days.

– stage 5 heating: this stage begins about 10 – 15 days before the delivery of potatoes and represents the reverse process of cooling potatoes.

This heating stage is performed with two purposes: time is given to the reducing sugars produced during cooling to turn into starch( avoid the Maillard reaction), condensation is avoided on the surface of the potatoes at the time of delivery.

Process: increase the storage temperature to a level of + 8..+ 10°C.

Duration: 10-15 days.

For storing potatoes you can choose one of the following systems:

– simple wooden boxes with the possibility of good ventilation (ventilation) stored in mechanically ventilated spaces and equipped with refrigeration / humidification systems.

– wooden boxes provided with a suction side and a pressure side stored in ventilated / refrigerated spaces provided with a logical process unit.

– bulk storage in warehouses provided with ventilation through the floor / ventilation channels and equipment for temperature / humidity control.

Long-term storage of onions in controlled atmosphere:

Onion storage

And onions can be stored both in warehouses with mechanized ventilation and in cold stores.

In warehouses with mechanical ventilation The Onion is kept in bulk with a height of 3-3. 5 m.and in this case certain storage periods are observed, the ventilation having different duration depending on the stage.

Thus, the first stage is drying, it lasts 8-10 days, the ventilation time is 18-20 hours a day. It is ventilated with dry air from the outside with a temperature of 6°C higher than onions and the actual humidity of 60-70%.

The cooling stage lasts from the moment of filling the cell, until the moment when the onion has reached the storage temperature. Ventilate at night for 8-12 hours out of 24.

The storage stage itself lasts between 3 and 6 months, the storage temperature being maintained around 0°c and the relative humidity of 75%.

Storing onions in cold stores can be done in bulk (in warehouses with floor ventilation) or in bins. The same technological stages of ventilation as in the case of mechanical ventilation storage are observed.

Onion Forum

Medium-ripening Golden onions are ideal for long-term storage (6-8 months. Growth period of 110-120 days. The leaves are dark green in color, covered with a layer of wax, which allows plants to withstand diseases. It has a rounded shape, Brown and tan outer color, weighing 100-170 g, 1/3 of the onions are located above the soil surface. Onions dry strongly, it is airtight and is well protected during storage. The internal appearance is thick, juicy and crispy. It has a pronounced spicy taste, suitable for drying and universal use. The average sowing rate is 4-5 kg / ha. The number of plants per hectare should be about 800,000 – 1,200,000. If large onions are desired, drilling is done rarely, with results of 600,000-800,000 plants per hectare. Harvest is better carried out, 80-90%, with drip irrigation. It is recommended to sow in rows of 6 and 8 (the distance between rows 27 cm). Proper planting is essential for a high yield. With an even row of plants, mechanical treatment in the field, harvesting and drying are facilitated. This allows you to get a high-quality product. Great attention should be paid to watering, the onions are very demanding to moisture. The largest amount of water is consumed by onions during the period of intensive growth. The yield is 45-70 t / ha.

Onion Fachir

Fachir-medium early golden onion. Vegetation-85-100 days. Variety grown annually. Green leaves with a wax coating. Onions are round, thick, large, weighing 130-170 g, leaves from the outside attractive yellow-golden color, inside – White, juicy, fatty and crispy, medium-spicy taste. Recommended for sowing directly in the soil, or by cuttings (cassette technology). Sowing rate of 4-5 kg / ha. The number of plants per hectare should be about 800,000 – 1,200,000. It is recommended to sow with a spacing of 30-45cm, and the distance between plants of 2.5 – 4.0 cm or 8.0-12.0 cm ( depending on what kind of products we want to get). With drip irrigation is recommended 8 and 6 in line (per meter should be 20-25 plants at a distance of 27 cm between rows). Proper sowing-it is essential for a high yield. With an even row of plants is facilitated mechanical treatment in the field, harvesting and drying. This allows to obtain a high-quality and uniform product. Particular attention should be paid to watering, the lack of moisture can be detrimental to the future harvest. Humidity during germination and early bulb formation should be at least 75-80%, and in the period of formation -70% of HB. The largest amount of water is consumed by onions in the intensive growth stage. Yields of Golden onions Fachir – 50-65 t / ha.

Onion Emir

Emir – medium early white onion. The growth period of 110-120 days allows harvesting and drying before the rains begin. Annual crop. Emir onions are strong and have economic growth potential. Onions of spherical shapes, compact, large in size, weighing 120-200 g, on the outside perfectly white. Inside – white, thick, juicy and crispy. Suitable for storage (up to 4-6 months). Recommended Emir for all regions, sown directly in the field, or by cuttings. The average sowing rate – 4-5 kg / ha. The number of plants per hectare should be about 600.000 -800.000 . Harvest is better carried out, 80-90%, with drip irrigation. It is recommended to sow in rows of 6 and 8 (the distance between rows 27 cm). Proper planting is essential for a high yield. With an even row of plants, mechanical treatment in the field, harvesting and drying are facilitated. This allows to obtain a high-quality product. Great attention should be paid to watering, the onions are very demanding to moisture. The largest amount of water is consumed by onions during the period of intensive growth. The yield is-50-80 t / ha.

Onion Pharaoh

Pharaoh-medium white onion variety. The growth period of 110-120 days after germination. Bulbs of medium quality Pharaoh grow in a year. Plants with leaves of dark green color, covered with a layer of wax. Onions are rounded, large in size, weighing 160-220 g perfectly white external color. with the inside – white, thick and juicy. Arw a strong taste, suitable for drying, and universal use. Productivity is 60-70 t / ha. Suitable for long-term storage (up to 6 months). Varieties of onions that can be grown in all regions from seeds directly in the field or by cuttings. Sowing rate of 4-5 kg / ha. The number of plants per hectare should be about 800,000-1,200,000. If large bulbs are desired, rare drilling is used, with 600,000-800,000 plants per hectare. Recommended sowing with row spacing of 30-45 cm and a distance of 2.5 – 4.0 cm, between plants, or 8.0-12.0 cm (depending on the type of products to be obtained). With drip irrigation is recommended 8 and 6 seeds per line (the distance between rows – 27 cm). Proper planting is essential for the success of the crop. With an even row of plants is facilitated mechanical treatment in the field, harvesting and drying. This allows you to get a high-quality product. Onions –it is moisture-loving, so it should be watered regularly. The largest amount of water consumed by onions is at the stage of intensive growth.

Onion Timur

Timur-early middle class, red onion. Growth period of 80-100 days. Plants with leaves of dark green color, covered with a layer of wax. Onions have an elongated rounded shape, large in size, weighing 140-200 g, with purple-red sheets in color. Interior of purple-pink color, juicy with medium-spicy taste. Recommended growth in all regions, with sowing directly in the field or by cuttings.For seedlings it is best to be sown in boxes, or in the drawer. These seedlings can tolerate transplantation and easily settle. Optimal sowing is done with an average of 4-5 kg / ha. The number of plants per hectare should be about 800,000 – 1,200,000, if large onions are desired, drilling is done rarely, with results of 600,000 – 800,000 plants per hectare. Harvest is better carried out, 80-90%, with drip irrigation. It is recommended to sow in rows of 6 and 8 (the distance between rows 27 cm). Correct planting is essential for a high yield. With an even row of plants, mechanical treatment in the field, harvesting and drying are facilitated. This allows to obtain a high-quality product. Great attention should be paid to watering, the onions are very demanding to moisture. The largest amount of water is consumed by onions during the period of intensive growth. The yield is – 50-70 t / ha. Shelf life of onions is 6-7 months.

Storage of onions for a shorter period of time in an artificial space

The storage of apples begins as soon as possible after harvesting and is stored in batches of the same variety.

The apples are stored in boxes that are stacked on 8-9 levels, up to 5-7 m high, the space between the ceiling and the last box is 80 cm. Also leave spaces of about 20-30 cm between the walls and the rows of stacks so that the air can circulate.

Filling a cell should not take more than 2 weeks, during this period ventilation is provided.

The storage temperature depends on the variety. Thus the apples of the Golden and Red delicious variety are stored at temperatures between 0 and +1°C. The Apples of the Ionathan and the Ioared variety, which are more sensitive to cold, are stored at temperatures between +3 and +4°C. the relative humidity of the air is 90-95%.

In refrigerated warehouses with controlled atmosphere (2-3% O2 and 1-3% CO2) the storage temperatures will be higher by 0.5-1°C, depending on the variety.

The shelf life also differs depending on the Variety, the apples of the Golden and Red delicious groups can be kept 5-6 months in refrigerated warehouses with normal atmosphere and 7-8 months in refrigerated warehouses with controlled atmosphere.

Root storage in controlled atmosphere:

Root crops (carrot, parsley, parsnip, celery, beetroot, radish) are stored in cold stores. Within a maximum of two days after harvesting, storage must be done.

Before Storage, The Roots will go through the conditioning stage, which consists in the qualitative sorting and shaping of the roots (cleaning them of leaves).

Storage of Roots is done in wooden or plastic jars. Vegetables are not washed and must be stored in warehouses without a light source. The optimum storage temperature is around 0°c and relative humidity 90-95%. The shelf life is between 5 and 6 months.

Long-term controlled atmosphere storage of grapes:

Almost all these fruits are pre-dried and many of them are stored for different periods of time before consumption. On the other hand, for fresh consumption, the fruits of Vitis species are largely limited to distribution on the local market.

The grapes grow hard and must be at full maturity at the time of picking because the entire ripening period must be on the stump. “Mature” here has psychological significance, that is, it is the state in which the fruit looks pleasant to the eye and can be eaten with satisfaction. However, the grapes should not be passed from the ripening, as this predisposes them to serious problems after harvesting: the weakening of the stem / tail of the bunch for some varieties , such as the seedless Thompson variety, which causes the detachment of the berries and the increased probability of being attacked by decomposition microorganisms. The danger of fruit decomposition increases in case of exposure to rain or excessive wet weather before harvesting (favorable conditions for infecting in the field with Botrytis cinerea.

Cooling and storage:

Grapes are vulnerable to the drying effect of air due to the relatively high ratio between surface and volume, especially those with tails. The condition of the coditis is an important quality factor and an excellent indicator of the treatment that has been applied to the fruit. The tail should be kept fresh , green, not only in appearance , but also because it becomes brittle by drying and can break. The tail of a bunch of grapes, unlike other fruits, is the part that is held when handling; if this breaks the fruit is lost for any practical purpose, even if the berries are in excellent condition. Therefore, special attention should be paid to operations that minimize moisture loss.

The rate of water loss is high especially before and during pre-ripening, because the grapes are normally harvested in conditions of high temperature and dry air. The heat in the field must be quickly removed after harvesting to minimize the exposure of the grapes to low vapor pressure conditions. The volume and temperature of the pre-drying air, the speed with which it passes over / among the containers and the accessibility of the fruit to this air are significant factors in the heat elimination rate. These factors are drastically influenced by the location and ventilation of containers, their alignment (air channels) and packaging materials.

Table grapes are initially cooled with a forced air cooling system. A pressure gradient is so given that a positive flow of cold air between the fruits is created from one ventilated end of the container to the other end . The containers are arranged so that air must pass through the container before returning to the cooling surface. The pre-hardening time is usually 3-6 h, depending on the packaging system and air flow.

The recommended storage temperature for Vitis vinifera grapes (European or Californian type) is -1°C. relative humidity should be 90-95 %. Although temperatures of – 1.7 °C did not affect the well – ripened fruits of some varieties, other varieties of grapes with a lower sugar content were damaged by exposure to-0.5 °C. grape deposits must ensure uniform air circulation in containers. The fruits must be forcibly cooled by Air jet to less than 4°C before storage. During the initial storage, a well-destroyed air flow rate of 52 l/s per ton of grapes is required for the completion of cooling. After the fruits have been pre-dried, the air velocity must be reduced to a value that allows uniform temperature maintenance throughout the room (no more than 0.05 to 0.1 m/s in the channels between the legs of the stack).

The biggest change in stored grapes is the loss of moisture. The first notable effect is the drying and browning of the tail and the stem of the bunch. This becomes evident even at a loss of only 1 to 2% of the fruit mass. When the loss is 3% to 5 % the fruits lose turgor and velvety.

Maintaining a humidity of 90 to 95% in grape warehouses is often a problem , especially at the beginning of the storage season when the packages are dry. Each package absorbs 0.15 to 0.3 kg of water in a month and the less moisture is introduced into the room the more is extracted from the fruit. Spray humidification is effective for minimizing shrinkage. With an adequate balance of water and air pressure, the right nozzle type, a fine spray can be obtained even at -0.5 °C.

Smoking / fumigation:

Vinifera grapes should be fumigated with sulfur dioxide after packaging to prevent or delay the spread of decomposition microorganisms. The surface treatment sterilizes the fruit, and in particular the lesions produced during handling.

Fumigation with SO2 in the warehouse prevents new infections but does not control those that have been contacted in the field. Most of the time they are not developed long enough to be identified at harvest and as a result are the primary cause of decomposition in the warehouse. Harvey describes a method of measuring infection in the field to predict decomposition during storage ; the forecast indicates batches that are safe and can be safely stored and those that have a higher probability of decomposition and should be marketed earlier.

The common practice at initial cooling is to fumigate the fruits in the evening. In this way the preraciation is not delayed and fumigation can be done after the departure of the staff. This initial treatment is the responsibility of the frigotechnical staff.

Everything about storing fruits and vegetables in a controlled atmosphere

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