What is freeze-drying
Freeze-drying is a method of using low temperature (below -30°C) and vacuum to directly sublime the moisture in the ingredients, so as not to destroy the ingredients in a large process In the case of nutrition and color, the moisture is removed, so that the ingredients can be stored for a longer time.
The freeze-drying process is generally divided into three steps: pre-freezing, sublimation drying and analytical drying. Both sublimation drying and desorption drying need to be done in a vacuum environment. The whole process of freeze-drying takes more than a few hours (freeze-drying is not fast freezing for dozens of seconds!).
What are the benefits of freeze-drying
The benefits of freeze-drying are obvious, in short, less nutrient loss, less shape change, long storage time, good recovery and palatability.
1. Less nutrient loss
The whole process of physical freezing and dehydration, less protein and vitamin denaturation, to a large extent Reduced nutrient loss.
2. Less shape change
Freeze-drying can generally maintain the color, smell and structure of the original ingredients in a larger process, and it looks better on the senses.
3. Long storage time
Freeze-drying can remove more than 95% of the water, so that the food can be stored for a long time without deterioration. Usually the shelf life is about 10 months.
4. Strong water absorption and recovery, good palatability
Freeze-dried can be quickly recovered in the case of adding water, and it can be restored to the state of fresh meat to a large extent. At the same time, some cats like the crispy texture of freeze-dried.
How to eat freeze-dried
According to the nutritional positioning of freeze-dried, it can be divided into staple food freeze-dried and snacks Freeze-dried.
Freeze-dried feeding:
1) direct feeding,
2) feeding after reconstitution with water,
3) with other food to eat.
Freeze-dried minefield
Although freeze-dried is good, the freeze-dried products on the market are mixed. There are many minefields:
1. The process is not up to standard, and the freeze-drying becomes air-drying
The whole process of the vacuum freeze-drying process usually takes more than several hours. Long-term low temperature vacuum requires good equipment and consumes a lot of electricity.
There are many freeze-dried products on the market, and the process is not up to standard. Low-temperature sublimation takes a long time. In order to maximize profits, many businesses will increase the temperature to speed up the dehydration speed, so that the final product is not freeze-dried, but air-dried and roasted. Secondly, the equipment of many factories cannot fully meet the vacuum degree. If the process is not up to standard, it will destroy the original nutrition of the ingredients, and at the same time increase the possibility of bacteria exceeding the standard.
2. Bacteria exceeding the standard
Freeze-drying can not completely sterilize, but can only inhibit the production of microorganisms. Therefore, whether the raw materials are of high quality, whether there are fewer microorganisms, and whether the storage and transportation process is safe, determine whether the final freeze-dried finished bacteria meet the standards. Many freeze-dried products may have dozens or even hundreds of times more bacteria than the standard.
Several suggestions for choosing freeze-drying
1. Choose products from regular factories
The product needs to have formal factory information, and it is not recommended to buy three-free products.
2. Choose good ingredients
The most important thing for food is to look at the ingredients, preferably the meat source of human consumption brands.
3. Avoid abnormally low prices
Expensive is not necessarily good, but it is definitely not good if it is too cheap to be separated from the basic price of ingredients. 1kg of freeze-dried ≈ 5kg of fresh meat, and then the power loss of freeze-drying and dehydration, you can know the approximate cost of a freeze-dried product.
4. Transparent packaging is not recommended
It is not recommended to buy transparent packaging products such as transparent plastic buckets. Food spoils easily when exposed to sunlight. It is recommended to choose opaque airtight packaging, vacuum packaging is better.
Transparent box packaging
5. It is not recommended to choose freeze-dried quails
The economic value of male small quails is low, and quail farms will process male small quails Lose. The processing and storage process of the whole small quail is not necessarily safe and hygienic, so it is not recommended to buy freeze-dried small quail.
6. It is better to have irradiation sterilization
Because freeze-drying cannot be completely sterilized, for example, Listeria cannot be killed by freezing. There is a link of irradiation sterilization.
7. Add water to test the recovery ability
The better the freeze-drying process, the faster the recovery with water, and the fuller it will be after recovery. You can try to buy different brands of jerky, and add water to compare the recovery.
