Facteur de qualité pendant le processus de congélation IQF

Quality Factor During Freezing IQF Process!

1. The effect of cooling medium temperature

Under the process conditions of IQF Freezing, the lower the temperature of the cooling medium, the faster the product freezes under the same conditions. At present, according to the specific situation in China, most of the ammonia is used as a refrigerant, and the evaporation temperature is generally selected between -35 and -45 °C. Under the IQF process, if a forced air continuous freeze is used, the temperature of the cooling medium is also related to the frosting speed of the evaporator. That is, when the evaporating frost layer reaches a certain thickness, the temperature of the cooling medium is correspondingly increased due to a decrease in the heat transfer effect. Therefore, in order to ensure the quality of the frozen, it should be done in time to defrost.

2.The effect of air flow rate

Dans le cadre du processus de congélation IQF, le débit d'air est le principal facteur affectant la valeur du coefficient exothermique. Par conséquent, une augmentation appropriée du débit d'air peut augmenter le degré de fin de congélation. Par exemple, les haricots verts communs gèlent dans l'air statique de -30°C, ce qui prend environ 2 heures. À la même température, le débit d'air augmente à 4.5-5 m/s et le temps de congélation n'est que de 10 minutes.

Dans certaines conditions, le changement entre la vitesse de congélation et le débit d'air n'est pas linéaire, de sorte que le débit d'air doit être déterminé de manière globale d'un point de vue économique.

3. The effect of freezing termination temperature

The freezing termination temperature is lower than the storage temperature (-18 ° C), which is beneficial to maintain the structure under rapid freezing. If the freezing termination temperature is higher than -18 °C, the unfrozen water inside the vegetable tissue will generate large ice crystals, which will result in the destruction of the tissue structure and the increase of juice loss during thawing, which will affect the nutritional value and flavor of the product. If you interested lear more about freezing IQF, please click gf-machine