Features Of Vegetable And Fruit Packaging

        Fruits and vegetables are still alive after being picked. They can only be fresh and delicious when kept under a normal metabolism. The metabolic process of fruits and vegetables involves the absorption of oxygen and the breakdown of carbohydrates into water and carbon dioxide. If the supply of oxygen is limited, the chemical reaction will change, producing large amounts of alcohol, resulting in loss of aroma and cell division, which is called "anaerobic spoilage". In this case, the fruits and vegetables will spoil after only a few hours. 

        The moisture content of fruits and vegetables is very high, generally in the range of 75% to 95%. Their average humidity is as high as 98%. Under normal atmospheric conditions, they quickly dehydrate and shrink, causing wilting and shrinking. In general, fruits and vegetables that lose more than 10 percent of their water will wilt and look stale. Therefore, taking appropriate packaging measures can effectively prevent the dehydration and wilting of fruits and vegetables and prolong their storage period.

        Another common form of spoilage of fruits and vegetables is spoilage caused by microorganisms. Microorganisms such as yeast, molds and bacteria can grow and multiply on the surface of fruits and vegetables, especially through scars or cracks on the outside of the product that invade the inside and cause internal spoilage. Many insects also wreak havoc on the surface and interior of products. Therefore, careful handling, surface treatment and protective packaging of fruits and vegetables are essential from the time of harvest.

        As fruits and vegetables ripen normally, their color, texture and aroma also change. Every product has its most suitable and ideal maturity stage. If it is advanced or exceeded this stage, it will cause sales difficulties and be unpopular with customers. Even if it is over-matured, it will cause product corruption, deterioration and scrapping. Although fruits and vegetables are picked and put into circulation prior to maturation, it is obviously difficult to control the product to achieve the proper maturation during the short marketing period.

        The metabolic rate of fruits and vegetables is very sensitive to the influence of temperature and environment. Although the method of refrigeration can delay the metabolism of most fruits and vegetables, different varieties of products have different maturation characteristics and adaptability to temperature, and should be treated strictly differently. 

        In addition, some fruits and vegetables will release volatile gases during the ripening process. If you do not try to remove or absorb these gases, it will also promote early ripening and rapid spoilage of the products.

        It can be seen that in addition to taking refrigerated measures to keep fruits and vegetables fresh, proper packaging can protect the products from the outside world and microorganisms, prevent the products from mechanical damage during handling, and control the wilting of the products due to dehydration and drying. 

        The fundamental purpose of fruit and vegetable packaging is to extend the shelf life of the product, as well as to beautify the product and provide convenience to customers. Through the reasonable selection of packaging materials and container structure design, the damage and spoilage of fruits and vegetables in the process of transportation, handling and exhibition are greatly reduced. 

        Much research has been devoted to climate control methods to delay the spoilage of fruits and vegetables over long distances, even by road, rail and sea. For the storage of apples and pears, for example, the fruit is packed in airtight carton boxes lined with polyethylene film. The packaging is stored at low temperature to inhibit the respiration rate of the fruit, while the oxygen content in the container is gradually reduced, and the amount of carbon dioxide is relatively increased, thus delaying the ripening period of the fruit by more than a few weeks.

        Leafy green vegetables can easily dehydrate and dry out, causing wilting. Therefore, it needs to be packaged with moisture-proof materials. At the same time, it should be noted that such vegetables have a fast respiration rate and are sensitive to anaerobic conditions, therefore, the ventilation of packaging materials is also very important. Such vegetables include cabbage, spinach, Brussels sprouts, lettuce, broccoli, and cauliflower.