Analysis of Vegetable Freezing Temperature

With the acceleration of the pace of modern life, frozen food is becoming more and more popular among consumers due to its convenience and good nutrition retention. In particular, frozen vegetables are loved by many families because they do not need to be washed and can be used at any time. Frozen vegetables can not only save cooking time, but also retain the color, aroma and nutritional components of vegetables to a large extent. However, to achieve these advantages, the key lies in controlling the vegetable freezing temperature.

Vegetable freezing temperature:

The reason why frozen vegetables can maintain bright color and crisp taste for a long time is closely related to the strict freezing temperature control. The freezing process of frozen vegetables must meet the following key temperature requirements:

Temperature of quick freezing zone: During quick freezing, the ambient temperature should be controlled between -30℃ and -40℃ to ensure that vegetables quickly pass through the maximum ice crystal formation zone (-1℃ to -5℃) in a short time.

Central temperature requirement: After quick freezing, the core temperature of vegetables should not be higher than -18℃. This can effectively inhibit enzyme activity and microbial growth and prevent vegetable deterioration.

Storage temperature: frozen vegetables must be stored at -18°C or below to ensure that the freezing chain is not interrupted and thus maintain product quality.

Vegetable Freezing Equipment

Quick freezers are core equipment for rapidly cooling vegetables and locking in their moisture and nutrients. According to different needs, quick freezers are divided into many types, such as fluidized quick freezers, spiral quick freezers, tunnel quick freezers, etc. The function of quick freezers is to quickly reduce the core temperature of vegetables to below -18°C in a very short time, thereby inhibiting microbial activity and preventing quality degradation.

Precautions during the processing of frozen vegetables:

To produce high-quality quick-frozen vegetables, in addition to temperature control, the entire processing process also needs to be strictly controlled:

• Raw material selection and pre-treatment: Select fresh vegetables as raw materials, and perform pre-treatment such as washing and cutting. If necessary, blanch them to inactivate enzyme activity.
• Blanching and cooling: Many green leafy or bean vegetables need to be blanched for a short time before freezing to stabilize their color and taste. After blanching, they should be cooled quickly to prevent continued heating from causing overcooking.
• Draining and pre-cooling: The cooled vegetables need to be fully drained to prevent excess water from forming frost during quick freezing, which will affect the appearance and quality of the finished product.