Browning in freeze dried fruits can result from various factors, with enzymatic browning being the most common, particularly in fruits such as apples, bananas, and pears. The simplest and most effective method to prevent this is blanching at 60℃-90°C, followed immediately by cooling to minimize any impact on taste.
As for collapse in freeze dried fruits, the primary causes are insufficient freezing and inadequate temperature control. If the temperature does not drop below -25°C, large ice crystals form and create an unstable structure, which can lead to collapse and severe deformation during sublimation.
Our Kemolo freeze dryers offer rapid freezing temperatures between -40°C and -35°C, completing the freezing process within 2 to 3 hours. This effectively prevents collapse and ensures product integrity.
