The abbreviation FD is an acronym for Freeze Dried and refers to vacuum freeze drying technology. Unlike deep-frying or baking and spray-drying when making powders, freeze-drying is dehydrating and drying food by placing the frozen food in a vacuum environment to sublimate it.

FD freeze-drying technology is a mature black technology that first appeared in the United States and Russia, applied in the field of aerospace food, and is now very popular in Japan, Germany and other developed countries. In an article by Mother Jones in the United States, it was mentioned that Garistona, a professor of medicine at the Medical College of Wisconsin, found that freeze-dried berries retained 90 percent of their anthocyanins.

According to Diane Barrett, a food science and technology expert at the University of California, Davis, once freeze-dried food is rehydrated, its nutritional value is similar to that of fresh food, retaining the color, aroma, taste and shape of the ingredients, as well as more than 97% of the nutrients, without any preservatives, and can be preserved for a long time at room temperature. This technology has been applied to freeze-dried fruit slices, freeze-dried instant soup, freeze-dried dehydrated seafood and vegetables.

Freeze-drying vs.

1.Freeze-drying
Freeze-drying is the sublimation of water, while drying is the evaporation of water. The former is that the moisture in the ingredients is directly changed from solid to gaseous state, so in the drying process. Maximum maintenance of the physical structure of the ingredients, while the latter is the moisture from the liquid state into a gaseous state.

So far the best method is vacuum freeze drying. Because in the low-temperature low-pressure state, the physical structure of the ingredients is basically unaffected. Not because of the cell wall inside and outside the existence of the humidity gradient and infiltration leads to surface pore contraction or internal water loss occurs dried, and in the low-pressure vacuum state so that the sublimation point rises, so the drying efficiency is higher.

2.Drying
Drying is also known as thermal drying, is the use of heat carriers and wet carriers to cooperate with each other to complete the drying process, usually hot air at the same time as the heat and wet carriers, that is, heating the air and then let the air heat the ingredients, ingredients evaporated water and then taken away by the air and discharged.

Because the role of heat drying on the ingredients is the temperature from the outside to the inside, humidity from the inside to the outside (opposite), and the speed of the limit, that is, the ingredients in the limit of the temperature can withstand, the internal diffusion of water to the outside of the maximum speed, the speed of the speed of too large a large number of epidermal contraction caused by the reduction of drying speed, too slow to affect the efficiency of the same time, while the temperature is too high will cause the internal vaporization of water too fast, too late to discharge through the capillary tube and the expansion that occurs, causing some nutritional damage, resulting in cellular rupture. It will cause cell rupture, resulting in a certain loss of nutrients.

Freeze-drying process needs to invest more cost, so in general the price of freeze-dried food is mostly higher, drying products will be relatively cheaper.

Freeze-dried food

In recent years, some casual snack brands have begun to launch FD freeze-dried fruits and vegetables, and these snack brands include Three Squirrels, Liangpin Pavilion, Bacchus Flavor, and Laiyifen. Xiaomi Yuping has launched the Yantai freeze-dried food company’s and Kitchen’s brand of FD freeze-dried instant noodles, a pet food startup has made FD freeze-dried pet food its core product line, and another coffee startup has launched FD freeze-dried cold-dried instant coffee powder.

Advantages of freeze-dried food

1. High Nutrition

Vacuum freeze-drying is a drying process under the condition of very low temperature and high vacuum, when processing the ingredients are basically in an oxygen-free and completely light-proof environment, with little thermal variability, which effectively maintains the color, aroma, taste and shape of the fresh ingredients and maximizes the preservation of various vitamins, carbohydrates, proteins and other nutrients, as well as chlorophyll, bio-enzymes, amino acids, etc. and flavor substances in the ingredients. Flavor substances.

2. Palatability
Due to the freeze-drying process, the moisture in the ingredients will be precipitated in the original position, which avoids the general drying method, due to the migration of the internal moisture to the surface of the ingredients flow and carry the nutrients to the surface of the ingredients, resulting in the loss of nutrients and hardening of the surface of the ingredients and other undesirable phenomena.

Fresh vegetables, fruits after dehydration, due to the flavor, sugar is concentrated, eat than the original more sweet and tasty. The flavor of fresh meat after dehydration is more delicious than the original, improving the palatability and excellent rehydration.

3.High rehydration
In the process of freeze-drying, solid ice crystals sublimation into water vapor in the food material after leaving the empty space, so the vacuum freeze-dried food has a dry sponge-like porous structure, and therefore has the ideal quick solubility and rapid and almost complete rehydration. As long as you add the right amount of water when eating, it can be restored to nearly fresh and delicious in a few seconds to a few minutes.

4.Ultra-long freshness, easy to use
Freeze-dried food is thoroughly dehydrated and lightweight, so it is very convenient to use or carry, and most of the freeze-dried pet food is vacuum-packed or nitrogen-filled packaging, protected from light. This kind of sealed package can be stored at room temperature for 3 to 5 years or even longer.