When making quick-frozen vegetables, you can proceed as follows:
1. Selection and cleaning of raw materials
Through selection, remove worms, rotten, too old, withered vegetables that are not suitable for making vegetables, and then put them in cold water to wash several times to remove impurities such as mud and sand on them. Since it is a convenient food that can be burned directly, it must be washed.
2. Cutting
Cut off the inedible and roots, and then cut them into various shapes according to the type, customary requirements and product standards.
3. Soak
In order to maintain the crispness of the vegetables, put the washed vegetables in 0.5% to 1.5% salt water for ten to twenty minutes to make the calcium salt react with the pectinase inside it. , Produces calcium pectate, which can increase its hardness and brittleness.
4. Blanching
You can use hot water or boiling water, you can also use steam for blanching, some foreign reports say that the effect of microwave is quite good. If it is carried out with water, its time and temperature should be based on the nature and size of the raw materials, usually tens of seconds to several minutes. During blanching, the temperature increases as quickly as possible. If it rises slowly, its enzymes have not been destroyed, but vitamin C has been lost, which will make it discolored and the surface will be very soft. But not all vegetables need to do this step before freezing, and some vegetables will be of poor quality after blanching. For example, Xihong, etc., direct quick freezing is better.
5. Cool
After the blanching is completed, the vegetables need to be cooled immediately, otherwise the residual heat will add to the change of the soluble components in it, which will darken the color and rot the vegetables. Therefore, it is necessary to use cold water to quickly drop its temperature to 0 degrees.
6. Pre-dehydration
The moisture content in vegetables is usually 90%, so the load in freezing will be high, will consume a lot of electricity, and the cost will become high. Dehydrating vegetables in advance can reduce the volume of frozen products, increase the freezing capacity of quick-freezing equipment, and reduce storage and transportation costs.