It is required to seal the sauce quickly and keep the sauce temperature above 85 degrees, because the temperature will drop when the sauce is filled into glass bottles or other packaging containers. After the decline, the effect of secondary sterilization cannot be guaranteed. Because the initial temperature can not be reached, the heat transfer process of secondary sterilization can not meet the requirement that the central temperature should be above the safe temperature of sterilization. Rapid sealing means avoiding excessive temperature drop and ensuring the vacuum degree after sealing. The safety of jam is more secure.

Fruits heated for a long time will produce some bad changes. Such as color browning, flavor loss, etc. This requires that the heating time be shortened as much as possible. So that the cooking time of fruits at high temperature is as short as possible. When the fruit is exposed to high temperature above 95 degrees, the high temperature can inactivate and kill the enzymes in the fruit, and the enzymes are the main cause of enzymatic browning. In the middle temperature range, such as 40-70 degrees, it can promote the reaction of enzymes, that is, accelerate browning. Therefore, when processing jam, the temperature should be raised as quickly as possible. It is able to quickly cross the middle temperature range and quickly reach the high temperature range. The main purpose of rapid heating and cooling is to avoid browning of fruits as much as possible.