Post harvest fresh-keeping packaging, storage and

2022-08-16
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Post harvest preservation, packaging, storage and transportation of flowers (III)

4. Packaging

flowers used for consumption after pre cooling should be packaged. The purpose of packaging is to minimize the mechanical damage or water loss of flowers during transportation and maintain the best freshness of flowers. The selected packaging should be as suitable as possible to products, transportation methods and markets. Whether the packaging is ideal, that is, whether the products are better protected to meet the requirements of transportation, processing and storage, determines the success of its commercial operation

open the oil return valve and appreciate that plants are living tissues that experience a limited life period. In particular, cut flowers are less resistant to damage than potted plants. Mechanical damages related to transportation, processing and loading include impact, falling, pressing and vibration. Packaging should minimize all kinds of damage and negative effects

in recent years, many large flower producing countries have strengthened the research on packaging materials and sizes. Various packaging facilities and methods can be adopted according to the variety of flowers, storage and transportation methods. Generally, various packaging purposes should minimize mechanical damage or water loss during storage and transportation. Keep the best swelling pressure of flowers to prevent mechanical damage. There are two common storage and transportation methods: dry storage and wet storage. Wet storage is to immerse the stem of the flower into a container full of water or protective liquid, which can maintain sufficient water for the flower, but it is difficult to transport. This method is suitable for short-term storage and transportation, which can maintain the shape of the flower and prevent mechanical damage, but transportation requires more equipment and costs more. Some cut flower species (carnation, lily, gerbera, goldfish grass) can be preserved for several weeks when stored wet. However, it is not applicable to large-scale production and transportation when actually adhering to the hard task of promoting green industrial development as building a beautiful China and a modern economic system and implementing the "made in China 2025"

in the actual production with the adjustment and upgrading of household assets due to the economic tension of the people, such as aerospace, national defense, kerosene chemical industry, transportation and so on, dry storage is widely used. Various kinds of packaging boxes are used for the dry storage or transportation of cut flowers. Appropriate dry packaging can prevent the water loss of flowers. The humidity of the package is guaranteed by the wax layer packed in the box or various types of foil films. Flexible plastic is the most suitable packaging material, mainly including low-density polyethylene plastic film, high-density polyethylene plastic film and polypropylene plastic film. The test shows that the high-density polyethylene plastic film has the best effect and the longest preservation time. If the bag is filled with O2 absorbent or refrigerant (ice), the fresh-keeping effect is better. Dry storage is often used for long-term storage, such as carnations and chrysanthemums. Dry storage is better than wet storage at the bud stage, and the storage period is longer. The auxiliary equipment of the plastic storage extrusion unit mainly includes paying off device, straightening device, preheating device, cooling device, traction device, meter counter, spark tester, and take-up device. After being hidden, the bud opening needs appropriate flowering promoting solution. Flowers can also be stored better in polyethylene bags with sealed gas. In these packages, flower breathing creates a controlled atmosphere environment (MA). The concentration of O2 was reduced and the concentration of CO2 was increased, which prolonged the storage period

the size of the packing box should also be considered, which can not only save storage and transportation space, but also ensure sufficient ventilation to prevent flower decay. Many foreign flower manufacturers have improved the size of the packing box, such as Israel. The packing box is shown in the figure, which can not only make the cold air pass through the packing box freely, but also save the transportation space (for example, if the right angle box is used, for ventilation, the packing boxes need to be separated by a certain distance)

the shape and placement of the packing box

from an economic point of view, the direct or indirect economic costs of auxiliary equipment should also be considered. If the package is suitable for the product size, ventilation method and stability should be considered; Selection of packaging materials and other protective facilities, etc. Because there are many kinds of ornamental plants, different kinds have different characteristics, so it is unrealistic to realize a high degree of standardization of packaging, but we should keep in mind the technical and economic advantages of standardization. Standardization makers should be encouraged to formulate clear and reasonable standards

some importing countries may have preferences and special requirements for packaging, and sellers should understand this requirement. Generally speaking, packaging is also a "silent salesperson", especially in retail, packaging plays an important role in improving sales. Factors related to packaging include: packaging size, product placement, each bouquet, packaging color and label, etc. In addition, the package also has the function of being strong and suitable for transportation

where possible, the following aspects should be marked on the product in the form of labels or shipping orders to facilitate after-sales service. Such as identification mark (including the name, address or official identification mark of packer or distributor, producer), product characteristics (variety and adaptability, etc.), origin (country of origin, production area), commercial characteristics (grade, size, etc.)

5. Fresh keeping during storage and transportation of cut flowers

packaged flowers can be used for storage and transportation. The storage of cut flowers and their green tissues can make plants adjust the supply of flowers according to market requirements, and also prolong the supply period of flowers. Even through post harvest treatment and simple management, the loss of plant tissue can be reduced, making the long-distance transportation of a large number of products possible

the protection of quality during storage and the length of storage period depend on several factors, such as genetic characteristics, respiration rate, water loss, ethylene content and activity, and the number of bacteria and fungi. In order to reduce the physiological and pathological decline of cut flowers during cold storage and transportation, it is important to treat the flowers properly before and during cooling. It includes harvesting in the optimal period, proper chemical treatment, rapid pre cooling before packaging, and it is also necessary to maintain stable storage and transportation temperature, optimal relative humidity, ventilation and good photosynthetic physiological conditions

1) preservative solution

the quality and vitality of cut flowers during storage and transportation can be improved by rapid treatment with preservative solution before or after storage and transportation. In this solution, the most common compounds are sugar (mostly sucrose), fungicides (citric acid, 8-hydroxyquinoline citric acid (8-hqc) or 8-hydroxyquinoline sulfuric acid (8-HQS) and aluminum sulfate), ethylene activity inhibitors (STS) and growth regulators (mainly Ba, NAA and GA)

2) sucrose

add sucrose to supplement the sucrose consumed by endogenous respiration during storage and transportation. It can also delay the appearance of aging symptoms, such as the degradation of proteins, lipids and RNA. The loss of membrane integrity and the degradation of mitochondrial structure and function also delayed the arrival of ethylene peak. Sucrose also enhanced water balance and caused stomatal closure

3) disease control

disease control can prevent the loss of post harvest quality of flowers. Stored and transported flowers should be far away from visible infection, such as gray mold infection, which causes great loss of stored flowers. In order to reduce the disease of flowers, in addition to reducing the storage and transportation temperature, fungicides are also widely used for spraying and advanced treatment

6. Fresh keeping during storage and transportation of potted plants

at present, trucks and ships are mainly used for short-distance transportation of ornamental plants. Sea transportation or truck transportation is more economical than air transportation, but it takes a long time. The problem of longer-term transportation is the same as that of long-term storage. If the leaves and flowers fade and fall off, and the flower buds cannot open, the disease will develop and spread rapidly

maintaining the quality of potted plants is closely related to the planting conditions and transportation process. Among the planting factors, the most important is illumination and fertilization. When planting, potted plants are exposed to high levels of photosynthetic intensity (PAR). During transportation and sale, par is low, usually lower than the light compensation point. For foliage plants, low light intensity leads to chlorosis and abscission of leaves, while reducing the content of carbohydrates and chlorophyll. At low light intensity, if the temperature is appropriate, the damage can be partially avoided

for long-distance sales, plants need to be of very good quality and have a root system free of pests. Plants should be watered the day before transportation, and the relative humidity of the refrigeration room should be kept higher than 90% to prevent plant degradation

when potted plants are transported in a controllable environment, the temperature should be stable, and the air circulation and ventilation should be maintained. They are packed in boxes and transported on open trucks. This method is also commonly used to transport larger potted plants. Some plants are highly resistant to physical damage and can be transported horizontally or in crates. A relatively new method is bare root transportation. Because the transportation medium and container are removed, the transportation cost is greatly reduced, and the transportation space and weight can be reduced by more than 50%. This transportation method is also used for plants produced by hydroponics to meet the health requirements formulated by some countries and prevent the transmission of soil borne pathogens

before long-term transportation, the harm of ethylene can be reduced by treating plants with ethylene activity inhibitors (STS). For some plants, NAA treatment can also reduce the abscission of various plant organs, playing a synergistic effect of NAA and STS. Fully open flowers are more sensitive to ethylene than flowers in the bud stage. Therefore, the transportation of potted plants watching flowers in the bud stage is very important

in the international market, potted plants are popular and often sold far away from the origin, so they need to be transported. For some potted plants that watch flowers, storage can delay flowering to meet the needs of special festivals (such as lilies)

7. Problems in storage and transportation

in the process of storage and transportation, the life activities and aging of flowers have not stopped, resulting in some changes in the process of storage and transportation. The transportation methods of fresh horticultural plants include railway, truck, aircraft, shipping and several common transportation methods. When shipping, several products are often transported together, but this phenomenon should be avoided as far as possible. During transportation, try to keep the plants in a cold environment and keep the temperature stable, so that the plants will always be in a "cold chain" environment after harvest. At the same time, attention should be paid to maintaining air circulation and ventilation. Larger potted plants are often transported by open trucks. At present, the latest transportation method is bare root transportation. Because the transportation medium and container are removed, the transportation cost is greatly reduced, and the transportation space and weight can be reduced by more than 50%. This transportation method is also used for plants produced by hydroponics to meet the health requirements specified by some countries and prevent the transmission of soil borne pathogens

different plant varieties have different optimal transportation temperatures, which also depend on the length of transportation period. Too low temperature will cause freezing damage to many tropical plants. Flowering plants are less tolerant to long-term transportation than foliage plants. If they are placed in the dark for a few days, they will lose their quality

ethylene produced during storage and transportation will also induce the abscission of flower buds and leaves, and increase flower deformity. The harm of ethylene depends on its concentration, exposure period and temperature. The drop of transportation temperature (above the freezing injury point) can reduce the shedding of leaves and flowers. Therefore, the harm of ethylene can be reduced by treating plants with ethylene activity inhibitors (STS or 1-MCP) before long-term transportation. For some plants, NAA treatment can also reduce the shedding of various plant organs. Fully open flowers are more sensitive to ethylene than flowers in the bud stage. Therefore, the transportation of potted plants watching flowers in the bud stage is very important. Only when the products are near the optimal storage temperature, they can be put together, and their adverse interactions should be prevented, such as the release of ethylene, odor and different requirements for relative humidity during storage. The most economical and optimal transportation method should be considered during transportation. For long-term transportation, the main problems encountered are: leaves and flowers fade, fall off, and flower buds cannot open

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