Freeze-dried food, abbreviated as FD food, is produced using vacuum freeze-drying technology. These products can be stored at room temperature for over five years without preservatives, and they are lightweight, making them easy to carry and transport.
Using Freeze Dryer, this vacuum freeze-drying technology effectively preserves the color, flavor, and nutrition of food, maintaining its appearance, aroma, taste, and texture, while retaining important nutrients such as vitamins and proteins. Before consumption, a little preparation allows it to be reconstituted into fresh food within a few minutes. Moreover, freeze-dried foods do not require refrigeration and can be stored, transported, and sold at room temperature after being sealed in packaging.
1. Process: Freeze-Dried Foods vs. Dehydrated Foods
Dehydration:
Dehydration, also known as thermal drying, is a drying process that uses both thermal and moisture carriers. Typically, hot air serves as both the heat and moisture carrier. Hot air is heated and then applied to the food, causing moisture to evaporate and be carried away by the air.
Thermal dehydration works by transferring heat from the outside in and moisture from the inside out, which has its limitations. If the temperature is too high, it can cause the outer surface to shrink, slowing the drying process, while too low a temperature can lead to inefficiency. Excessive internal moisture vaporization can cause cell walls to rupture, leading to nutrient loss.
Freeze-Drying:
Freeze-drying involves the sublimation of moisture, while dehydration relies on evaporation. In freeze-drying, moisture transitions directly from solid to gas, preserving the physical structure of the food. In contrast, dehydration changes moisture from liquid to gas.
Currently, vacuum freeze-drying is the best method available. Under low-temperature, low-pressure conditions, the physical structure of food remains largely unaffected, preventing shrinkage due to moisture gradient-induced penetration. This method also increases the sublimation point, resulting in higher drying efficiency.
2. Results: Freeze-Dried Food vs Dehydrated Food
Shelf Life:
The moisture removal rate directly influences shelf life. Dehydrated foods like dried fruits, vegetables, and powders have a shelf life of about 15-20 years; honey, sugar, salt, hard wheat, and oats can last over 30 years. In contrast, freeze-dried fruits and vegetables can last 25-30 years.
Nutritional Content:
According to research from U.S. health organizations, freeze-drying retains most vitamins and minerals. However, freeze-dried foods may lack certain vitamins, such as vitamin C, which degrades quickly. Dehydration does not change fiber or iron content, but it can lead to the breakdown of vitamins and minerals, making dehydrated foods less nutritious than freeze-dried foods. Nutrient losses can occur for vitamins A and C, niacin, riboflavin, and thiamine during dehydration.
Moisture Content:
The main goal of food preservation is to remove moisture, preventing spoilage and mold growth. Dehydration removes 90-95% of moisture, while freeze-drying can eliminate 98-99%. Home dehydration usually leaves about 10% moisture, whereas professional dehydration techniques can achieve a longer shelf life.
Appearance and Texture:
One of the main differences between dehydrated and freeze-dried foods is their appearance. Dehydrated foods become brittle and hard, while freeze-dried foods soften immediately upon entering the mouth. Freeze-dried foods are significantly lighter than dehydrated ones.
Cooking:
Dehydrated foods require cooking before consumption and often need seasoning. This means spending time boiling the products in hot water before eating. Preparing dehydrated foods can take between 15 minutes to 4 hours. In contrast, freeze-dried foods only require boiling water; simply add hot or cold water and wait 5 minutes to eat.
In conclusion, it's clear which type of food is likely to develop better in today's market. Green and healthy foods are increasingly becoming a trend that people pursue.
If you are interested in our Food Freeze Dryer Machine or have any questions, please feel free to Contact us. As a professional manufacturer of freeze dryer machine, we offer a variety of specifications, including household, laboratory, pilot, and production models. Whether you need equipment for home use or larger-scale industrial equipment, we can provide you with the highest quality products and services.
Post time: Nov-04-2024