Sous Vide Cooking Technology (Part Two)
Packaging materials
On the one hand, packaging materials isolate the material exchange between moisture and food ingredients in the process of
slow cooking at low temperature, and reduce the loss of flavor in food ingredients; on the other hand, it reduces the influence of external environment on the flavor of food materials during storage, such as foreign flavor and oxidized flavor. It is necessary to use packaging materials that conform to food safety. At the same time, attention should also be paid to whether the packaging materials can be heated for a long time, and whether they are puncture-resistant enough to accommodate some meat or seafood with shells.
Vacuum packaging
The main advantage of
vacuum packaging is that the heat of water bath can be efficiently transferred to food or ingredients, instead of heat transfer by heating the air in the bag. Vacuum can eliminate oxygen around food materials, reducing the possibility of oxidation during processing and storage, decreasing odor and discoloration, and preventing food from being polluted by the outside during transportation.
Circulating water boiling and water cooling
Circulating water bath can produce very uniform temperature whether heated or cooled, and the internal temperature fluctuation is usually less than 0.1℃ (in kitchen equipment). When cooking, completely immerse the food package packed in vacuum in water, and avoid overlapping and over-close. When heating at a higher temperature, the food package may swell and surface (because the water in the food package evaporates), so it is necessary to press the food package below the water surface with a net rack or other things.
In large-scale food processing industry, the application of
Sous Vide cooking technology is boiling-cooling: after boiling, heating and pasteurizing at a certain temperature, the food in the
vacuum sealed bag is quickly cooled by circulating cold water, and then stored and distributed by refrigeration or freezing. The pasteurized vacuum food package can be stored for 3-4 weeks at a temperature lower than 3.3℃. In large-scale industrial production, circulating water bath has higher heat conduction efficiency than static water and air, which cooks and cools food more quickly. Compared with steam heating, water bath heating will not cause excessive heating of food surface and energy loss of condensed hot water.
(Industrial Sous Vide application focuses on productivity, efficiency, energy consumption and food safety)
Time control
The heating temperature set by the
low-temperature slow cooking technology is lower than that of the traditional cooking method, so it will not bring about rapid changes in the temperature of food materials, which leads to a longer heating time than that of the traditional cooking method. However, both chefs and food scientists can calculate the whole heating time according to the type, shape, thickness and heating temperature of ingredients. Good vacuum low-temperature slow cooking equipment can finish the whole cooking process unattended and keep it at this temperature until it is taken out. In large-scale food industrial production, heating time means processing efficiency, so it is common practice to reduce the thickness of food package, which will greatly improve the production of each batch and significantly reduce the processing time.