Freeze-drying and Dehydrating: What You Need to Know
Wondering about the difference between freeze-drying products versus the more common method of dehydrating them using heat? Here is a deeper explanation as to why we prefer the former when preparing our fruit.
If you’re a parent of school-age kid, you’re probably asking yourself the same question.
Especially with the start of the school year approaching, you’re likely working to determine the best options for convenient, wholesome and packable snacks to put in your kids’ lunches.
Like most of us, you’re probably looking for something that checks all the boxes for a healthy, practical treat: tastes great, delivers nutrition and can’t be easily squished on the way to school.
Dried fruit—whether prepared through simple dehydration or freeze-drying—is a popular choice for health-conscious parents. That’s because it travels well, requires no refrigeration and delivers vitamins and nutrients.
However, despite these similarities, the method used to dry the fruit affects the taste, texture and longevity of the final product in ways you might not expect.
Read on to learn more.
What is dehydration?
Removing water from food by drying it—also known as dehydration—is one of the oldest food processing methods in the world. Technically, to be considered dehydrated, there must be no more than 2.5% moisture left in the food – otherwise it’s just considered “dried.”
Today, scientific research has taught us that dehydration works by preventing the growth of microorganisms that can cause the food to spoil, giving it a longer shelf life. Additionally, advances in modern science have allowed us to reap the advantages of dehydration using increasingly complex techniques.
Two of these include simple dehydration (using heat) and freeze-drying.
Dehydration can be achieved with an electric food dehydrator, which uses high temperatures to remove the water through evaporation, essentially “boiling” the water out. The temperature must be high enough for the water to evaporate, but not so hot that it cooks the food.
Some heat-drying methods include drums, ovens, continuous drying belts or even laying the food out in the sun. The downside of this type of dehydration is that it can result in loss of vitamins and leave up to 10% of moisture in the food (which makes it harder to preserve over long periods). Also, drying it in the sun requires very specific and continuous hot, dry weather conditions and some special treatment steps afterward (such as pasteurization and conditioning) to ensure the food is safe to eat.
Dehydration using freeze-drying
Freeze-drying works by freezing the food product and then removing its water content through a process called sublimation. Here, low temperatures are combined with low pressure to allow moisture to be removed from the product as a vapour—without the water melting first. This means food such as fruit can be preserved without any damage to any of its heat-sensitive components.
Here at Nova Scotia Organics, we prefer to freeze-dry our fruit because it preserves more of the good stuff—like nutrients, flavour, colour and texture—that simple dehydration can leave behind. Freeze-drying also prevents the rubbery texture sometimes found in heat-dehydrated products, and instead gives fruit a crispy crunch (which kids love!). In fact, many researchers agree that freeze-drying is the best way to improve the look, taste and feel of dehydrated food products.
Freeze-drying also removes more moisture than simpler dehydration methods, so the fruit can last longer without the use of preservatives. Our freeze-dried fruit can last up to two years!
The freeze-drying process reduces the weight of fruit, making Nova Scotia Organics’ freeze-dried, organic blueberry & pineapple snacks easy to pack for occasions like picnics, hikes and—of course—school lunches.
Check out our freeze-dried fruit snacks and smoothies to make sure that when it comes to snacks, your family is always packing the best. And be sure to visit our blog for other helpful nutritional tips.