When air comes into contact with frozen food, it can cause dry, gray brown spots on the food. It doesn't make the food unsafe. Just cut it away before cooking/using it. Many foods can be frozen but dry out if not used with 6-8 months, some foods are short as 3 months for freezer storage.
Crystals form when freezing takes up more space than water, for some foods like meat having flexible cell walls, can over come this. The ice crystals break down the cell walls in vegetables and some fruits, and when thawed causes the food to collapse. Faster the food freezes, the smaller the crystals.
Freezing stops microorganisms in food from growing but it doesn't kill them. Thawing can reactivate them so one should cook foods promptly.
I know that some foods change in texture from fresh prepared when given that quick from the freezer to the microwave, or stove top cooking. I am wondering about your consistency holding solid once thawed and ready for use.