Packaging methods and requirements for transporting fruits and vegetables

The selection of packaging materials The earliest packaging containers were mostly made of plant materials, such as leaves, reeds, and grass stalks, and were designed to be easily carried by people. Later, people use livestock transportation, the size of the packaging also increases, the packaging materials used ...

First, the choice of packaging materials

Most of the earliest packaging containers were made of plant materials, such as leaves, reeds, and grass stalks, and were designed to be easily carried by people. Later, people use livestock transportation, the size of the packaging also increases, and the used packaging materials tend to diversify.

At present, there are many outer packaging materials used in fruits in China, which can be divided into the following five types:

Baskets: Baskets made of natural plant materials such as bamboo and Vitex are traditional packaging containers in China. The main advantage of this material is that it is cheap, lightweight, and draws in place, and it can be made into almost any shape and size of container. The disadvantage is that the shape is irregular and often not very solid. Therefore, it is not enough to prevent the occurrence of damage; larger in size, it is easy to fatigue with artificial equipment; the shape is usually large and small, although it can reduce the pressure on the lower layer of fruit, but it is difficult to pile in yards during transportation and storage.

Wooden box: wooden box is better than other natural plant material containers, the advantage is strong, can be made into a uniform shape of various specifications, stronger than other materials to prevent physical damage. However, the wooden box itself is heavier and the operation and transportation are more difficult.

Cardboard boxes: Corrugated cardboard boxes are a product of Western technology. They are lightweight and inexpensive, and as a substitute for wooden boxes, they appear in large quantities in the field of fruit circulation. Another advantage of the carton is that it has a smoother appearance and facilitates the use of printed labels and promotional items. The biggest drawback of the carton is that it cannot be reused. Once it is eroded or processed extensively, it is easily damaged.

Plastic Boxes: Plastic Boxes can be made from a variety of synthetic materials, but are mainly made from the following two materials: the harder HDPE type and the softer low-density Polystyrene type. High-density polyethylene box, strong, high strength, it is easy to withstand the various pressures encountered in circulation under normal circumstances, and can stack a certain height;

At the same time, because this kind of box can be easily manufactured into a unified specification, it can maximize the use of storage space; the strength is large, and there is greater flexibility in design, and it is also possible to add handles and ventilation holes on the wall of the box. It does not impair the mechanical strength of the lice. In addition, easy to clean, smooth appearance, can be made into a variety of bright colors. If the boxes are designed so that they can be nested together, the empty box takes up only about a third of the full box or less.

People think that these plastic boxes have ideal technical characteristics in satisfying the requirements for the circulation of fresh fruits and vegetables and are therefore used as substitutes for traditional packaging containers in any package development project. However, polyethylene is expensive, and it is economically feasible to use such a box only if it can be effectively organized and reused.

Polystyrene is strong, low in density, light in weight and good in heat insulation and can be used to transport pre-cooled goods at normal temperatures. In addition, this material has a good ability to smooth impact. Its main drawback is that if excessive bursts of force are used, it will break or crush. At the same time, due to the inconvenience of cleaning and initial surface deformation, etc., the container made of this material cannot be used for the second time, resulting in excessive use cost.

The above five kinds of packaging materials are mainly made of packaging containers to resist damage from the outside and belong to the outer packaging of goods. In the packaging container, each product may also cause collision or collision of the product and the container. This movement will also bring physical damage to the product. The inner packaging in the packaging container can prevent the damage caused by this collision.

The main materials used for inner packaging are:

Plant material: Plant materials like leaves are the cheapest inner packaging in rural areas. They are mainly used for liners and are very effective in protecting the goods. In many parts of China, leaves are used as internal packaging for baskets. However, the plant material is a biological tissue and therefore it is necessary to breathe. Their breathing can affect the commodity, increase the degree of heat accumulation in the packaging container, and expand the infection of microorganisms. Sometimes, the inner packaging of such plant material also damages the visual appearance of the product.

Paper: Paper is commonly used as an inner packaging material, the oldest being the cheapest. The role of paper and plant leaves is basically the same, but paper liners can also be used to package goods. Compared with plant materials, paper is not necessarily more effective in protecting the product, but it does not have any bad interaction with the product and can significantly improve the visual appearance of the product in the market.

There are many types of inner wrapping paper, including wrapping paper, paper trays, corrugated plugboard, and the like. The wrapping paper can be used to protect a single commodity, and can also be used as a post-harvest chemical processing carrier. Paper trays and inserts can be used to separate the number of rows of products or as additional liners for separate containers, and insert sheets can also be made into a mess or lattice in the packaging container, so that each commodity individual is completely isolated.

Plastics: The method of using plastic inner packaging is the same as paper, and it is of many types. It is more attractive than paper packaging, and it has significant advantages in controlling the loss of water and respiration of goods, but the cost is higher. People also use soft shavings, foam or fiber sheet layers to make inner packagings.

In short, the choice of packaging is limited by the cost of the fruit and vegetable product itself, and the factors such as the value of the product, the cost of the packaging, the effect on the protection of the product quality, and the sales price must be taken into account. The cheapest material for fruit and vegetable packaging is baskets and bags made from locally grown plant material.

However, the actual situation tells people to flash. With this package, the product is subject to a considerable degree of physical damage. For example, bamboo baskets have many limitations. First, they are bulky, and they are difficult to handle with care. Secondly, they are overloaded and put the product under great pressure.

In addition, it is not conducive to stacking during transportation and storage. Therefore, some experts advocate that this material is not suitable for packaging materials and should be abolished step by step to use other packaging materials. According to the actual situation in China, the natural cost accounting for bamboo is low. As long as the packaging containers are made smaller, stamped and appropriately improved, bamboo basket packaging can continue to be used.

Second, the role of packaging on product quality

Packaging is used to protect the product. It protects the product from the following aspects:

1, to prevent mechanical damage

The mechanical damage suffered by the product during distribution can be attributed to four different causes: extrusion, impact (friction) and cutting. The sensitivity of various fruits to the described mechanical damage is different, so these differences should be taken into account in the choice of packaging containers and packaging methods.

The extrusion of the outside of the packaging container first acts on the packaging container, and when the mechanical strength of the packaging container cannot withstand the external pressure, the commodity will be squeezed. It is possible to use trays, honeycomb spacers, etc. in the packaging box to strengthen the mechanical strength of the packaging container, sometimes to cap the packaging container, and to enhance the supporting ability of the packaging container itself to the upper load.

In fact, due to the influence of the external environment, the mechanical strength of the packaging container is weakened, resulting in extrusion such as corrugation in the air in high humidity environment, after condensation occurs, or after being wetted by rain. Fiberboard boxes rapidly lose strength due to moisture absorption.

Therefore, such cardboard boxes are not satisfactory for use in high-humidity refrigeration. In the past few years, the Ministry of Commerce promoted calcium-plastic box packaging for fruit. The low water absorption rate of the packaging box overcomes the shortcomings of moisture absorption in cartons, but the cost is high, and they are brittle under low-humidity conditions and are easily broken.

The cause of the collision is due to a sudden force, such as a brutal operation during loading and unloading, dropping or sudden braking of the package during transportation. Vibration is a common occurrence in transportation. The damage caused by vibration is abrasion. It can cause slight abrasion of the epidermis to wipe off part of the flesh.

All of these wound surfaces due to scratches are browned due to the exposure of tannic acid in the injured tissue to oxygen and similar substances in the air, impairing the quality of the product, especially the appearance, and even more harmfully, these wound surfaces. It is a window of infection and increases the respiration of the fruit, thereby accelerating deterioration.

To prevent the impact of goods and vibrations, pay attention to two aspects: On the one hand, there should be no relative displacement between each commodity and between the product and the packaging container to avoid vibration damage.

On the other hand, the packaging container should be full, but not too full, nor too tight; otherwise, it will increase crushing and bruising.

The products can be wrapped one by one and separated one by one; fruit products can also be packed in separate and layered ways, or covered with cushions that can reduce vibrations, but this will inevitably increase costs and must be considered for use. These packages can reduce the loss and increase the benefits, and then compare them before deciding whether to use such packages. In short, light handling is the best way to reduce physical damage.