When water molecules escape a food through its packaging in the freezer, freezer burn can result. Freezer burn isn't harmful on its own, but it can signal a resulting deterioration of the food, especially if the food has a lot of freezer burn. A benefit of using a metal pan or dish or aluminum foil to store items in the freezer is that water molecules are less able to evaporate from the food through the metal thus resulting in less freezer burn.

On the Other: Certain Metals Can React with Acidic Foods

Acidic foods, including certain fruits such as berries, will react with certain metals and take on an unsavory flavor and appearance. Reactive metals include copper, cast iron and aluminum. Stainless steel is much more resistant to this reaction, and would be a better choice than aluminum for storing acidic foods in the freezer.

Bottom Line

While acidic foods are best stored for long periods in a freezer in stainless steel or plastic, most foods store well in metal containers, including aluminum foil, because they are less likely to get freezer burn than they would in paper or paperboard. Just make sure that the food is well sealed before freezing.

Source:

aces.edu: The Do's and Don't of Freezing Foods

Help with Cooking: Guide to different types of materials used to wrap and store food in the freezer

Wise Geek: What is a Non-Reactive Bowl?

More Information:

Help with Cooking: Freezer Packaging for Freezer Storage