Recently, a netizen posted a comparison of the transparency of lychee flesh after just being picked and stored for a few days, summarizing the "tips" for judging whether lychee is fresh, which has aroused people's attention to the freshness of fruits. Under related topics, many people have left comments: Whether it's lychee, cherry, loquat, or bayberry, it's easy to achieve "fresh fruit freedom". How can fruits stay fresh from the branches to the tip of the tongue? How can consumers store fruits to maintain their freshness after purchasing them? The reporter interviewed relevant experts and practitioners regarding the freshness of fruits. In recent years, consumers have generally felt that they can still purchase fresh seasonal fruits even if they are far away from their place of origin. What are the reasons for this? Li Xian, a professor at the School of Agriculture and Biotechnology and director of the Institute of Fruit Science at Zhejiang University, said that behind this lies the improvement of technologies such as fruit breeding, planting, storage, preservation, and logistics. Taking Zhejiang Yangmei as an example, researchers are committed to studying early maturing, late maturing, and different flavored Yangmei varieties. In the past, Yangmei matured during the rainy season, but continuous rainfall caused Yangmei to easily drop fruit, resulting in reduced yield and weakened fruit flavor, making it difficult to store. Early maturing or late maturing varieties can avoid the rainy season, extend the supply period of fresh Yangmei fruit, and continue to supply the market from May to July, which is conducive to industrial development. Yangmei is a perennial woody fruit tree with a long breeding cycle. Relatively speaking, the improvement effect of cultivation techniques is more significant. Some fruit farmers adopt the "Luoman" cultivation method, using a device similar to a mosquito net to cover the Yangmei tree. The top can provide shelter from rain, the sides can be ventilated, and it can also prevent insects and flies. In recent years, facility cultivation has made great progress in improving the quality of Yangmei fruit, and many fruit farmers choose to build connected greenhouses. In practice, the Yangmei greenhouse has also been upgraded to multiple versions. For example, changing from a flat top greenhouse to a pointed or arched dome greenhouse to facilitate rainwater runoff; The film on the edge of the greenhouse can be opened regularly to regulate the temperature and humidity inside the greenhouse; Various sensors are installed inside the greenhouse to dynamically monitor and adjust environmental parameters... These measures help to advance or delay the ripening time of Yangmei, prolong the supply period of Yangmei fresh fruit, improve its quality, and enhance its storage resistance. The widespread application of facility agriculture has significantly improved fruit quality and extended the supply period of fruits. Recently, with the development of intelligent control technology, the emergence of preservation techniques in the market has extended the post harvest preservation period of Yangmei from the original 1-2 days to 2 weeks. With the development of infrastructure construction and logistics information management at home and abroad, convenient and fast logistics services worldwide have enabled fruits from both the northern and southern hemispheres to be listed on the market at different times, which is also an important reason why consumers can purchase a large amount of fresh fruits at any time. Express delivery transportation is an important part of fruit circulation. How can the prosperity of e-commerce and the construction of logistics systems shorten the time for fruits to travel from the branches to the tip of the tongue? Tan Jinghua, Vice President and General Manager of Special Economic Projects Department of SF Group: From fresh fruits on the branches to delicious food in the hands of consumers, this process cannot be separated from the precise cooperation and technological innovation of various links in express delivery transportation. Starting from picking in the orchard, we enter the "countdown guard" of umami. We determine the optimal picking time based on indicators such as maturity and sugar content, and adopt a refined layered sorting strategy according to the time requirements of different agricultural products. For agricultural specialty products such as Jiaodong fruits, Jinnan fruits, and western Guangdong fruits and vegetables, a pre-processing center has been established to achieve full standardization of sorting, refrigeration, packaging, and shipping. In the transportation sector, we integrate all cargo planes, high-speed trains, cold transportation, warehousing resources, and other transportation resources to create a multi-dimensional collaborative transportation system of "air rail land". We actively promote the application of new technologies such as logistics drones, unmanned vehicles, automated equipment, and smart cloud warehouses, and have also opened green channels for priority transit and delivery of various fruits. Many fruits require cold chain transportation, and the related infrastructure is gradually improving. Like our cold transport temperature control cage car, it has an intelligent temperature control system that can accurately adjust the temperature, achieving the function of "multiple categories and multiple temperature zones". At the "last mile" of final delivery, through multi-level capacity stratification and flexible scheduling of flexible resources, SF Express can provide delivery services such as "half day delivery" and "hourly delivery", allowing fresh packages to be efficiently delivered to consumers. At present, more and more fruits are being delivered and ordered through live streaming e-commerce, which puts higher demands on the response speed, delivery quality, and after-sales customer service of the logistics supply chain. The smart logistics platform we have built applies IoT technology to various links such as receiving, forwarding, and transportation, and introduces functions such as intelligent dispatching, vehicle visualization tracking, and big data analysis to help merchants improve their abilities in shipping, stocking, and sending goods. What factors can cause a decrease in freshness of fruits after they leave the branches? Does freshness affect the nutrition of fruits? How should consumers store fruits to lock in freshness? Professor Cao Jiankang from the School of Food Science and Nutritional Engineering, China Agricultural University: After fruit harvesting, the moisture in the skin is easily lost, and the fruit is prone to ripening, softening, and aging, resulting in a decrease in freshness over time. There is some truth to online posts about the freshness of lychee, which can be judged from the condition of the flesh. However, the color of lychee flesh is also related to the variety and maturity period. To measure the freshness of fruits, it is generally judged through sensory and other comprehensive evaluations. Fresh fruits and vegetables have high nutritional content, especially vitamin C. After long-term storage, nutrients will definitely decrease. Consumers can consider the taste, flavor, and nutrition of fruits comprehensively when making choices. To preserve the harvested fruits, temperature is the main influencing factor. At low temperatures, the physiological metabolism and aging of fruits are slow, and they can maintain a fresh state as much as possible. In addition, it should be stored at a higher relative humidity to prevent the loss of moisture from the fruit skin. Fruits can be wrapped in packaging such as plastic film to create a microenvironment. Maintain relatively stable humidity and gas composition in this microenvironment to prevent moisture loss. Nowadays, fresh fruit supply is very abundant, and consumers do not need to stock up too much fruit every time. Fruits bought at home, such as strawberries, blueberries, apples, pears, etc., can be stored in the refrigerator. After cooling down for 2 to 4 hours in the refrigerator, put it in a fresh-keeping bag and continue to store it in the refrigerator. During the process, prevent squeezing and collision to prevent condensation in the bag. But bananas, mangoes, citrus fruits, etc. generally do not need to be stored in the refrigerator, they can be stored in a cool place. Fruits such as kiwi, banana, avocado, etc. are climacteric fruits that undergo a sudden increase in respiration rate and release ethylene gas after harvesting, and then quickly ripen. This type of fruit can only become soft, juicy, rich in flavor, and sweet and palatable after natural ripening or artificial ripening. (New Society)