Technological process

Material harvesting → inspection → bracts filaments removal → inspection → dressing → rinsing → threshing → cleaning → blanching → cooling → selection → ice water precooling → drainage → quick freezing → selection → vacuum packaging → refrigeration → inspection

Material harvesting

The harvest time of sweet corn is milk ripening period, that is, 20-22 days after pollination. Generally, the pollination time is calculated when the silks of corn ear spit out about 1 inch (3.3 cm). The moisture content of corn kernels should be 70% ~ 73% at harvest time, the taste flavor of sweet corn at this time. The harvested corn should stay in the field for a long time be exposed to the sun. During transportation transfer, do knead too much to avoid the damage of corn kernels.

Clearing threshing

Because the quick-frozen corn grains are no longer thawed cleaned before eating, they must be cleaned with mobile water. Threshing is carried out on a special corn thresher. The depth of the thresher should be cut according to the grade to avoid cutting the corn grain too deep too shallow. If the corncobs are cut too deep, the appearance taste of Jingxiang products may be cut; if the corncobs are cut too shallow, the yield is low the materials are wasted.

Blanching 

Blanching is the key process in the process of tender corn processing. It is necessary to strictly control the blanching temperature time. The effects of blanching are as follows: it can inactivate enzymes in corn arrangement, because low temperature cold storage will make enzymes lose activity, slow physiological chemical reactions are still carried out, so that the nutrient components of grains are damaged; Blanching can also kill some microorganisms insect eggs to ensure the hygiene food safety of the products. The air in the blanched corn kernels is squeezed out, which reduces the swelling pressure when ice crystals are frozen, increases the resistance to swelling pressure, correspondingly reduces the oxygenation degree of materials, adheres to the color nutrients of the products.

Cooling

The blanched corn kernels should be cooled immediately, otherwise the residual heat will seriously affect the quality, such as darkening color, increasing dry consumption, prolonging quick freezing time wasting energy, which also provides conditions for microbial reproduction. Therefore, cooling must be timely thorough to ensure the color quality of products.

Drip dry

Drainage can remove the moisture on the surface of corn kernels, prevent the formation of ice due to excessive surface moisture during freezing adhesion between corn kernels, affect the appearance net weight, reduce the power consumption. The drainage can be carried out on the vibrating screen, but with cold air drying, one is that the drainage is complete, the other is that it can be further cooled.

Quick-frozen

Quick freezing is the decisive factor to ensure the quality of products. The faster the freezing speed is, the better the product quality is; otherwise, the longer the freezing time, the worse the quality. The suppliers of quick-frozen sweet corn will use fluidized-bed quick freezing tunnel for quick freezing treatment. Corn kernels are laid flat on the conveyor belt, there are many typhoons under the conveyor belt. At the speed of 6 ~ 8 m / s, the cold air is blown down to up to make the corn grain in suspension, the temperature in the center of corn kernel can reach - 18C. The frozen corn kernels should adhere to each other the surface should be free of frost. If the evaporation temperature of the machine is - 34 ~ - 40C, the cold air temperature is - 26 ~ - 30C, the thickness of corn kernels is 80 ~ 38mm, freezing for 8 ~ - 5 minutes can meet the requirements.