Freeze dried fruits are fruits that undergo the freeze drying process. This process removes moisture such a water from the fruit. The food is frozen and placed into a strong vacuum, which causes the water to sublime and vaporize from ice to vapor quickly. Freeze drying technique is commonly use in the food industry to preserve food and made food last longer.
Freeze dried fruit is both economical and convenient. It enables you to take advantage of bargains and purchase large quantities of fruitS that can be stored and defrosted whenever you need it. Almost any fruit can be frozen, says the United States Department of Agriculture. Because the fruit is already partially preserved through the drying process, it is especially receptive to freezing. It’s very simple to prepare dried fruit for freezer storage, and if done properly, it retains its basic flavor, texture and nutrient content.
What is freeze drying?
Freeze drying is a relatively recent method of preserving food. It involves freezing the food, then removing almost all the moisture in a vacuum chamber, and finally sealing the food in an airtight container. Freezedried foods can be easily transported at normal temperatures, stored for a long period of time, and consumed with a minimum of preparation. Once prepared, freeze-dried foods have much the same look and taste as the original, natural products.
The freeze-drying process was developed during World War II as a method of preserving blood plasma for battlefield emergencies without requiring refrigeration or damaging the organic nature of the plasma. The technology was applied to consumer food products after the end of the war. Coffee was one of the first freeze-dried products to be marketed on a large scale. Today, many fruits, vegetables, meats, eggs, and food flavorings are freeze-dried.
Freeze-dried food has many advantages. Because as much as 98% of the water content has been removed, the food is extremely lightweight, which significantly reduces the cost of shipping. This also makes it popular with boaters and hikers who have to carry their food with them. Because it requires no refrigeration, shipping and storage costs are even further reduced. Freeze-dried food is also relatively contamination-free since the dehydration process makes it virtually impossible for yeast and potentially harmful bacteria to survive. Finally, since the physical structure of the food is not altered during the freeze-drying process, the food retains much of its color, shape, texture, and flavor when it is prepared for consumption by reintroducing water. This makes it more attractive to consumers than food preserved by some other methods.
How to Freeze-Dry fruits?
We will also present some other methods in freeze-drying if you don’t have a machine for it.
1. Using your freezer
This can be a substitute to the freeze-drying machine if you don’t mind the long process. This long process is estimated to be several weeks at maximum.
To start with it. First, you will need a perforated tray. In choosing the food that you want to freeze-dry, better start with small stuff like fruits. Chop the fruit into small pieces and arrange it neatly on the perforated tray.
Small pieces are preferred because the moisture can easily be removed that way. Choose the freshest ones because when they’re rehydrated, they will still be fresh in the next years.
For the next several hours, the fruit will undergo freezing. However, the long process here will be the sublimation that will take several weeks as stated.
The water will sublimate from solid form into a gas form. Your sliced pieces of fruit will then be thoroughly dried after waiting a long time.
The way to test if your freeze-dried fruit is ready is to thaw it first. If the drying process is not complete, your fruit will turn black after melting. Return it right away to your freezer and wait for a few days.
Test it again by thawing and if doesn’t turn into a black color, that would entail that the freeze-drying process is complete. Your freeze-dried fruit is then ready to be stored in an airtight bag for storing.
2. Dry Ice
Dry ice (or cardice) is carbon dioxide in the solid phase. Freeze-drying food in this method is relatively faster than putting it directly into your freezer. The way to use dry ice is to prepare a large container, twice the size of the food you’re going to freeze-dry.
The food (in this context, fruit) that you should freeze-dry should never be in contact with dry ice, so you need to place it in a sealed plastic bag.
After you placed the food in the plastic bag then into the large container (the bottom base should already have one layer of dry ice), you can now cover the whole container with dry ice. Word of caution for this method is to always wear gloves.
Dry ice should never be melted prematurely, and that’s why you will need to store it in a freezer. Dry ice can make the moisture evaporate from the food because the environment is already at zero humidity.
As the dry ice will sublime and gas will escape, you should punch holes on your large container.
Regularly check your container every 24 hours. You will know the freeze-dried fruit is ready when all the dry ice had sublimed. After that, the freeze-dried fruit is ready for storing.
3. Vacuum Chamber
This process could take one week or more depending on the water content of your fruit.
To start with this, the prepared fruit that you want to freeze-dry should be frozen isolated.
You don’t want ice crystals to form, so don’t open the freezer door until several hours had passed.
Then, removing the fruit from the freezer, place it immediately inside the vacuum chamber.
The recommended temperature and pressure of the chamber should be at least 10⁰C and 120 Torr, respectively. Sublimation process will then occur and may drag on for one week. Test if the freeze-drying is complete and then it’s ready for storage.
4. Freeze-Drying Machine
This is the most expensive method but the duration in preparing the freeze-dried food takes lesser time than all of the methods mentioned above.
A typical freeze-drying machine consists of a freezing coil attached to a compressor, shelves attached to heating units, and a vacuum pump.
To use this machine, place the fruit inside the heated shelves and through the compressor, the temperature is lowered to a freezing temperature. The frozen fruit will then begin sublimation.
This is by the vacuum pump that lowers the atmospheric pressure inside by pumping it outside. The pressure becomes very low that the ice immediately shifts into a vapor form.
The food is undergoing a long process of sublimation that could take a few days at maximum.
Excellent Benefits of Freeze-Dried Fruits
For people who are too busy to prepare nutritious snacks that are easy to pack, freeze-dried fruits are the way to go. There is no question about their convenience.
Here are some thoughts about the freeze-dried fruit craze and some reasons why freeze-dried fruits are a great choice for those looking for nutritious, delicious and convenient snacks!
Fresh taste and appearance
Despite all the steps freeze-dried fruits went through, they are still as flavorful as their fresh counterparts. The fresh fruits’ moisture is all taken out by flash freezing them, leaving them in their purest form. Without changes in their appearance, shape, and texture, what’s left are crispy fruits that are slightly sweeter for us to enjoy!
The fruits’ aroma and flavor also do not change because they are not dried via heat processing. The freeze-drying process maintains most of the original fruit’s nutritional content. Freeze-drying simply takes out the water, not the flavor.
Lasting freshness and longer shelf-life
Freeze-dried ingredients can be stored for years in theory. The freeze-drying method removes water from the prepared fruits. To guarantee the lasting freshness of these fruits, cans, and pouches have oxygen taken out. Oxygen absorbents may be added as well. This will help make the fruits taste fresh. So, to make it short, the main benefit of these freeze-dried fruits is that they last longer. These ingredients can live in your storeroom. They can also save you space in your area if you choose these freeze-dried fruits for smoothies and shakes over huge bags of frozen fruits inside your freezer.
Since these freeze-dried fruits are lightweight, they are very handy and convenient for traveling. You can eat them out of the bags, create smoothies on-the-go or even sprinkle them in your oatmeal.
Rich in nutrients
Freeze-dried fruit contains nutrients that offer several health benefits, making it a good addition to a well-balanced diet.
According to research, freeze-dried fruits hold up to 90% of their original nutritional content. One small serving pack could still be a huge nutritional feast. You can have your daily dose of Vitamin C, Vitamin A, different nutrients and minerals with the convenience of not always holding a huge chunk of fresh fruit.
Low in calories
Different brands of freeze-dried fruits have a different calorie count. Some freeze-dried fruits contain less than 40 calories per 10-gram serving. If you want to satisfy your sweet tooth and lose weight at the same time, low-calorie foods like freeze-dried fruits are for you. Freeze-dried fruits do not contain any additional sweeteners and preservatives, so they’re a guilt-free delicious snack that you can enjoy wherever, whenever you want.
Not only are freeze-dried fruits low in calories, but they are also filled with fiber. Fiber is a vital nutrient. With the right amount of fiber which regulates your digestive system and keeps your cholesterol levels low, you will surely have a well-balanced diet. It also helps reduce the risk of heart diseases. Adding the right amount of fiber in your diet also lowers your chance of developing colon cancer. It prevents you from eating unhealthy snacks between meals.
For example, a bag of freeze-dried raspberries, strawberries or bananas could contain up to two grams of dietary fiber, making it an outstanding choice for health-conscious people.
Freeze-dried fruit is easy to prepare. Its process only requires quick rehydration of the fruit, which is ideal for storing. Most freeze-dried foods are reformed back by adding warm water.
Freeze-dried fruits help you create a number of desserts and dishes that you and your family can enjoy. Like when you have stored freeze-dried strawberries or freeze-dried raspberries, you can use them to make fruity breakfast cereals, fruit salads, overnight oats and many more.