Technological process

Corn cobs quality inspection- Peeling and stigma removal – trimming, cleaning, grading – blanching – cooling – vacuum packaging – high temperature sterilization – cooling, pack drying – Final package inspection – storage – finished products for sale.

Operating Points:

Fresh corn cobs reception:

When fresh  cobs are  picked according to the harvesting standards, they can not be thrown on the ground at will, nor can serious bumps and squeezes occur during loading, unloading and transportation. They should be handled lightly to reduce losses and improve the yield. It is required that ears be free of worms, grains are arranged evenly and neatly, rich and full, and the color is pale yellow or yellow, and there are no impurities. It can still be used as raw material for fruits with moth whose length meets the requirement after pruning.

2. Peeling and stigma removal:

When removing bracts and stigmas, it is necessary to handle them lightly and remove mildew, lack of grains, water grains, clusters of grains with too high or too low maturity.

3. Trimming, cleaning and grading:

Artificial pruning of corn cobs, trim to remove  tips and worm destroyed parts, to ensure that the cut surface is smooth. The cutter should be cut quickly during manual cutting, otherwise the corn grains will be crushed, the influence rate will be guaranteed, and the cutting surface will be perpendicular to the axis. Otherwise, it will affect beauty. If the knife is not fast, it must be grinded, the rest of the knife holder should be loose and the blade should be thin and thicker. After cutting, clean the ears with flowing water, and wash the silk and dirt of the corn. The cleaning process should be rapid and the ears should not be immersed in water for a long time to avoid loss of nutrients. Grading after washing and grading in the process of putting in the turnover basket. According to the panicle length, it can be divided into four grades: 12-14, 14-16, 16-18 and 18-20 cm.

4. blanching:

0.1% citric acid and 1% salt were added to the blanching water. The blanching time was 10-12 minutes, and the temperature was 95-100 degrees Celsius. Steam can also be used for blanching. Blanching in hot water is preferable. Blanching can release gases from maize and destroy the activity of enzymes in Maize tissues, kill toxic organisms on the surface of ears, reduce the number of pathogenic bacteria, and lay a foundation for improving germicidal efficacy.

5. Cooling and bagging:

After blanching, the ears must be cooled in time, otherwise, because the temperature is too high, the corn grains will lose water and wrinkle, which will affect the appearance and quality. Generally, spraying or soaking in cold water for 3-5 minutes can decrease the surface temperature of the ear to ensure that the temperature of the ear is about 50 C during bagging. On the contrary, when the temperature is too high, the water vaporizes and produces steam during vacuum bagging, which has a negative impact on the sealing quality. Bag after cooling, cool the ears and use them for other purposes. When bagging, the ear should be pushed down to the bottom of the packing bag quickly, and the impurities such as corn syrup should not be left at the sealing place, so as to avoid affecting the sealing quality.

6. Corn cobs vacuum packaging:

After bagging, the corn can be vacuum sealed. The vacuum of the seal is 0.08-0.09 MPa. The sealing area must be smoothed by hand to check whether there are foreign bodies and folds. If there are, the sealing quality will be seriously affected. Therefore, the sealing quality should be strictly improved. Generally, the vacuum time is 12-20 seconds, and the sealing heating time is 3-5 seconds. If the production is large, it can be packed in thermoforming packaging machines. Fully automatic stretching film packaging machine can save manual bagging link. Only one person is responsible for putting corn beside the equipment. While putting it in place, it can check the surface of corn again for foreign bodies, filaments, insects and so on. The corn packed by fully automatic stretching film packaging machine is more upgraded.

corn cobs vacuum packaging machine
7. High temperature sterilization:

Before sterilizing at high temperature, it is necessary to check whether the seal meets the standard requirement. There is a gap between the ear and the packing bag. It is easy to move the ear by hand, which indicates that the quality of vacuum operation is not enough. They should be used for other purposes. Then the qualified person is sent to sterilizing tank for high temperature sterilization. The sterilization formula is 15-20-20/121 C, that is, 15 minutes to make the temperature in the sterilization tank reach.

121 for 20 minutes at constant temperature. In the meantime, the pressure in the sterilizer should be kept stable, otherwise the bag will be broken. Because the moisture in the bag expands when heated. In order to prevent bags from breaking, reverse pressure cooling should be adopted, and the pressure should be higher than the sterilization pressure of 0.2-0.03 Pa. Cooling time is 20 minutes, so that the temperature is reduced to 40 C.

8. wipe the bag:

Use clean cotton cloth to wipe off the moisture and stains on the surface of the bag, and carry out the third quality inspection of the product. The unqualified products should be eliminated. If the amount of processing is large, we can directly use the bag dryer to remove the moisture on the surface of the bag.

9. Insulation and inspection:

Corn bags were stored in a 37 C thermal storage for 7 days and nights. It has to be flipped twice during the period. After heat preservation, the corn bags are taken out of the warehouse and the products with bulging bags are picked out. The other qualified products can be packed, stored and sold.