People of each grade should put four boxes of special fruit, first-class fruit, second-class fruit and foreign fruit in turn, and each apple should be put into the box of their own grade once. Manual grading usually has no conditions for washing fruits. Graders should have clean wet towels and wipe them off in time when they encounter dust pollution on the fruit surface. According to the actual situation in our country, it is appropriate to manually classify apples before storage, which can not only reduce the number of manual fruit dumping after harvest and avoid mechanical damage caused by repeated picking, but also enable fruit farmers to know their own apples and facilitate classification, stacking, storage and sales.
Both are characteristic fruits, but the fruits are different in size. For example, the transverse diameter of Fuji Teguo is 7.5 cm, 8.0 cm and 8.5 cm, so the fruit should be packaged in several different specifications, which is not only convenient for packaging, but also conducive to pricing according to quality when selling.
The quality inspector shall inspect the grading site and correct the problems found in time. In addition, the apples packed by each grader should be randomly selected to ensure the accuracy and consistency of grading. (2) Apple mechanical grading method In recent years, China has introduced a batch of various types of apple grading assembly lines, which greatly improved the accuracy and speed of apple grading and enhanced the competitiveness of apples in the international market. The flow of Apple's mechanical grading assembly line is as follows:
(1) fruit unloading and cleaning.
The forklift will carry the big wooden box full of apples from the storage room to the fruit discharge conveyor drum at the beginning of the grading assembly line. With the rotation of the drum, the wooden box slowly enters the pool along the slope. Because the specific gravity of apples is smaller than that of water, apples will surface, and empty wooden boxes will be sent out of the pool from the other end along the bottom of the pool. Water contains 50 ~ 200mg/kg chlorine, which can kill mold spores. For varieties susceptible to tiger skin disease, 500 ~ 2000 mg/kg diphenylamine should be added to the water. When it is difficult for clear water to remove the white residual powder with calcium on the surface of fruit, it must be removed by "acid bath". The method is to wash the fruit with 1% hydrochloric acid solution for about 1 min, then neutralize the acid on the fruit surface with 1% sodium carbonate solution, and then rinse it with clear water. Pickling must be proper, otherwise it will do harm to apples. For example, contacting an acidic solution with an apple for 5 minutes is enough to cause the pigment to dissolve and the lenticels to turn black. When the pH value of sodium carbonate solution used to neutralize the remaining acid solution is 10, it will also cause skin hole damage. Therefore, it is necessary to take preventive measures in application. In addition to the above methods, fine soft silk or wet cloth can also be used to wipe the dirt on the fruit surface. The fruit produced by bagging is clean, and there is no need to wash the fruit. ② Rough selection.
The mesh conveyor belt transports the apples out of the pond. In the process of forward transportation, the apples are washed by clean water, absorbed by the roller covered with foam plastic or sponge, and then transported to the next process. Apples with a diameter smaller than the mesh (the smallest diameter of fresh apples) fall on the conveyor belt below, are collected in fruit boxes, and are sent to the juice processing plant. 3 Waxing.
The method of coating a layer of fruit wax on the surface of fruit is called waxing. After waxing, fruits can inhibit respiration and water evaporation, reduce rot, keep fresh and prolong supply time. More importantly, the surface of the fruit has been dressed up in disguise, and the internal quality of the fruit remains unchanged, but the appearance has become clean, beautiful and beautiful. This method has become an important means of modern fruit marketing, especially for high-quality fruits (fine products). It is widely used in Israel, America, Spain, Germany, Britain, Japan and Italy. Although it has not been popularized in China at present, in order to beautify the appearance of fruits and enhance their competitiveness, it will be gradually implemented as a necessary measure in the future.
The types of coatings used for waxing mainly include emulsion wax, shellac wax, fruit wax and other paraffin substances. Natural coating film, such as gum, whey protein, natural wax, gelatin, starch, etc. At present, fruit wax mainly depends on imports. (4) Manual picking.
Waxed fruits are transported by conveyor belts. When passing through the fruit selection platform, workers standing on both sides of the fruit selection platform pick out the fruits with insufficient coloring, deformity, obvious appearance defects and mechanical damage, put them on another conveyor belt above and transport them to the juice. ⑤ grading.
When the apples pass through the computer-controlled optical scanner, the computer will record the coloring degree and size of each apple one by one. Each apple enters a small cup and moves forward. Under the instruction of the computer, the fruits with the same size and color fall from the cup to the horizontally moving conveyor belt at the same position below and enter the packaging process. Some assembly lines also have labeling equipment to label each apple. The label usually indicates the variety name, grade and numerical code of the packer.