Storage of sweet corn ears
The production of sweet corn ears has strong seasonality, is not resistant to storage, and has a short shelf life. It is difficult to meet the frequent needs of the masses. For the storage and preservation of sweet corn ears, the following aspects should be noted. 1. Harvest at the right time. Different varieties of sweet corn, different climatic conditions and different cultivation techniques, the harvesting period of sweet corn ears is not the same. The taste evaluation and the determination of the sugar content are generally carried out about 18-24 days after the filament is taken out. Experience has shown that sweet corn ears are harvested too early, yield is low, sugar is insufficient, and the aroma is not strong; when harvested too late, most of the sugar in the sweet corn ear is converted into starch, the grain is aging, the skin is hardened, and the flavor is not good. Generally, when the sweet corn kernels are full and full, when the skin is broken by hand, when the white milk is outflowed, the harvest is suitable. 2. Harvest time and technology. Morning and evening are good times to harvest sweet corn ears. Take advantage of the lower temperature of the outside world to reduce the heat in the field to facilitate faster pre-cooling. When it is hot at noon, it is not suitable for harvesting. When collecting sweet corn ears, it should be smashed from the plants together with the leaves. Because of the significant difference in the rate of sugar loss between the leaves and the leaves without leaves after harvesting. After the ear of the eucalyptus leaves was placed for 1 hour, the sugar content began to decrease, and the rate of decline increased after 4 hours. The sugar content of the leaves with eucalyptus leaves was relatively stable, and there was almost no change after 4 hours of harvest. During the picking process, it prevents the crushing and damage of sweet corn kernels in the leaves. After harvesting sweet corn ears, they should not be stacked for a long time under high temperature to avoid sun and rain. They should be transported back to the cold storage in time for pre-cooling. 3. Pre-cooling. Sweet corn is a fruit and vegetable with high sensitivity to freezing damage, which is slightly frozen to reduce quality. The sweet corn ears shipped back to the cold storage should be pre-cooled as soon as possible to near 0 °C, otherwise the sugar will be quickly converted into starch. This rate of change is 6 times that of 0 °C at 10 °C and 10 times that of 0 °C at 21 °C. 20 times at 0 ° C at 32 ° C. The main pre-cooling method for production applications is cooling in a cold storage. The cold storage temperature is 0-5 ° C, the relative humidity is 85%-90%, and the air flow rate is about 5 meters per second. The pre-cooling process is completed when the center temperature of the sweet corn ears stacked in the cold storage is below 5 °C. Another method is to pre-cool the sweet corn ear in cold water at 0 ° C, and the corn ear can be cooled to about 1 ° C in a short time. This method is economical. It is best to add some preservatives to the cold water to prevent microbial contamination. There is also a vacuum gasification cooling method abroad, but the cost is high. 4, packaging. The sweet corn ears are usually packed in polyethylene film bags or other plastic bags. It can be peeled off the leaves, removed, and then packaged after selection. It can also retain all the leaves or leave 2-4 leaves, repackage, coat the crate, and store it in the cold storage. The packaging operation was carried out at low temperature (5 ° C) pre-cooling. Chitosan obtained from chitin can prevent spoilage without causing hypoxic respiration due to its good film forming and biochemical properties. Chitosan also has the advantages of non-toxic, odorless, easy to decompose, etc. It will not cause environmental pollution. It has become a good coating material for fresh-keeping of fruits and vegetables, which can reduce the loss of nutrients and prolong storage time of sweet corn to some extent. . Low temperature is an important basis for the preservation of sweet corn, and the combination of chitosan coating and low temperature environment is an ideal measure for sweet corn storage. The sweet corn coated with chitosan had significantly lower respiration rate and ethylene yield than the non-film, while 1.0% chitosan coating was better. 5, storage and preservation. The pre-cooled sweet corn ears are sent to a low temperature freezing room for quick freezing. The temperature between the low temperature is -25--30 ° C, the freezing time is more than 10 hours, and when the central temperature reaches -18 ° C, it can be stored in the low temperature storage at -18 ° C for a long time. In this way, the original color, aroma, taste and nutritional value of sweet corn can be retained after 7-8 months of storage. Another method is to store sweet corn ears at a temperature of 0 °C. However, the 0°C cold storage method cannot store sweet corn for a long time, and the mold may be metamorphosed for a long time. Wenzhou Celecare Medical Instruments Co.,Ltd , https://www.celecaremed.com