Freeze drying is considered to be a method that preserves the nutritional content of food due to several reasons
Freeze drying involves freezing the food at extremely low temperatures and then gradually removing the frozen water through sublimation, where ice converts directly into vapor without passing through the liquid phase. This gentle process helps to minimize heat exposure, which can degrade or destroy sensitive nutrients.
Retention of Structure
Freeze drying preserves the cellular structure of the food. During the process, ice crystals form within the food, and when the water is removed, these ice crystals leave behind empty spaces. This helps maintain the food’s original structure and prevents the loss of nutrients.
Preservation of Heat-Sensitive Nutrients
Many nutrients, such as vitamins and enzymes, are heat-sensitive and can be easily damaged by traditional preservation methods that involve high temperatures. Freeze drying, with its low-temperature processing, helps to protect these heat-sensitive nutrients, preserving their integrity and bioavailability.
Minimization of Oxidation
Freeze drying reduces the exposure of the food to oxygen, which helps to minimize oxidation reactions. Oxidation can lead to nutrient degradation and loss. By removing water through freeze drying, the potential for oxidation is significantly reduced, helping to preserve the nutritional value of the food.
Reduced Nutrient Loss
Compared to other drying methods, freeze drying has been found to result in minimal nutrient loss. The low temperatures and vacuum conditions used in freeze drying help to minimize nutrient degradation and loss during the process.
freeze drying is recognized for its ability to preserve the nutritional content of food by employing a gentle processing technique, preserving the food’s structure, protecting heat-sensitive nutrients, minimizing oxidation, and reducing nutrient loss. This makes freeze-dried food a viable option for those seeking to retain the nutritional value of food for extended periods.