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Lyophilizer Freeze Dryer In The Food Industry

Freeze drying is a technique that preserves the structure of food by removing moisture from it. We'll take a deep dive into how you freeze-dry candy and what are the best candies for freeze-drying.

How to make freeze-dried candy?

First of all you need a freeze dryer, ZZKD has a freeze dryer that is very suitable for home use - DZF- 6050 vacuum drying oven. The food is first frozen inside, then it creates a vacuum chamber to remove all moisture. The resulting dry food can be stored for extended periods of time without refrigeration and spoilage, making it ideal for astronauts or military rations.

 lyophilizer freeze dryer

Now that you know what to try, tell us the exact process you need to make the best freeze-dried candy at home. We've explained manual and mechanical methods so everyone can try it at

1. Pretreatment of candy

Of course, you need candy, but the process starts with choosing the type of candy. Each candy is different in shape, size and texture. If you are doing this for the first time, we recommend that you read this article carefully. To cut your candy into small pieces, we need to dry the moisture of each candy to get the perfect taste and texture. Evaporating moisture from chunks of candy can be tricky and can result in a poor experience. However, if your candy is already in small pieces, you don't need to do this-freeze dry candy machine.

2. Process

This process includes the energy consumption of heating, vacuum and refrigeration systems.

Heating part

Food absorbs a certain amount of heat during the sublimation process. If there is no external heat source to provide heat, the temperature of the food itself will decrease, and the saturated vapor pressure of the ice crystal will also decrease, resulting in a decrease in the sublimation speed. Therefore, it is necessary to provide a certain amount of heat to the frozen food. heat. In order to prevent the food from being thawed due to excessive heating, the temperature of the food is generally controlled between -10 °C and -30 °C. The heat sources used mainly include heating plates, radiation heating plates and microwave generators. At present, radiation heating plates are mostly used as heat sources. Both heat and mass transfer are in the drying layer, but in opposite directions. With the deepening of drying, the thickness of the drying layer increases, and the resistance of heat and mass transfer increases gradually. Since heat and mass transfer are carried out from both sides, the drying speed faster.

Vacuum part

The food is placed in a vacuum box to increase the sublimation pressure to increase the effective thermal conductivity of the dried layer of the food, but too much or too little pressure will reduce the speed of sublimation. Different food has its corresponding pressure to make sublimation faster in sublimation drying, this pressure is called the better sublimation pressure of the food. In the sublimation drying process, in order to ensure the quality and freeze-drying rate of the freeze-dried food, and reduce unnecessary energy loss, the pressure in the vacuum box must be strictly controlled.

Cooling system

After the sublimation of the ice crystals in the food is completed, the sublimation stage is over, and the next stage is the drying process of the water vapor, and the water vapor formed by the sublimation is drained to the outside in time. The vacuum pump is mainly used to remove the non-condensable gas in the drying box, because the pressure in the box is very low and the specific volume of water vapor is very large, and a large amount of water vapor can easily damage the vacuum pump after entering the vacuum pump. Therefore, a vapor trap should be installed between the vacuum pump and the drying box, and its surface temperature is lower than that of the drying box. The condensation of water vapor is driven by the pressure difference formed by the temperature difference between the box and the trap. In order to reduce the investment cost and daily operating cost of the refrigerator, it should be ensured that the trap has a large enough water catching area.

freeze dry machine for candy

What is the difference between freeze drying and dehydration?

Most people confuse the freeze drying and dehydration process. They think they are the same, but they are not. Actually, the two methods are completely different from each other.
The main purpose of these two processes is to remove moisture from food so that it does not break down, age, etc. Studies have shown that dehydration removes approximately 90 to 95 percent of water, while freeze-drying removes approximately 98 to 99 percent.
We go through pretty much the same process, but freeze-dried foods have lower humidity, a longer shelf life, and are more palatable than dehydrated foods. Plus, freeze-dried foods rehydrate faster and retain their original texture, shape, and color.
Both processes are designed to remove moisture from foods, and freeze drying is much better than dehydration.

What kind of food can be freeze-dried?

We just talked about the process of getting the best freeze-dried candy, but candy isn't the only food you can try. There are many more, the main ones include:
Ice Cream: This process does not change the shape of the ice cream. Instead, it makes food firm, light, and crispy.
Fruit: Fruit gets smaller, a process that concentrates sugar, making it easier to eat more servings at once than newer forms of fruit.
Some other popular items that people freeze dry include coffee, fruit and juices, vegetables, meat, fish and seafood, eggs and other dairy products.

 freeze-dried strawberries

What can't be freeze-dried?

There's nothing wrong with freeze drying any food, but some things don't freeze dry well, and don't work well after serious effort. Therefore, we do not recommend freeze drying rice, noodles, potatoes, cream cheese, whole vegetables, block cheese, dressings and other condiments.
Even if you're trying, make sure to cut them into small pieces so that most of the area stays in contact with the air. It might give you a good experience, but it's not worth it.

Advantages of freeze dryer:

There are many myths about the freeze drying process, some say it destroys nutrients and makes food inedible. At the same time, however, others support the process because it offers an extended shelf life.
From what we understand, we did a quick assessment based on the pros and cons for ease of understanding.

Make food lighter

Once all the moisture has been removed, the food will be lighter and more suitable for the diet. Even so, you can easily take it with you and enjoy your favorite snacks anytime, anywhere.

Nutrients intact

During the freeze drying process, we do not remove anything other than water from the food. Therefore, all of their nutritional quality and taste remains the same. Despite the change in shape and size, we don't think it matters.

Free you from refrigeration

Dry foods do not require refrigeration as they can easily be stored at room temperature for over 20 years. Their increased shelf life makes them an easy-to-consume product.

Can effectively hydrate

Rehydrating lyophilized products is simple. You have to add hot water to a bowl of freeze-dried food, or add water and heat it in the microwave or cook it on the stovetop.
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