Because pressure canning requires intense heat for long periods of time, your veggies are going to be significantly depleted of any nutrients, vitamins, as well as flavor and texture compared to a fresh veggie. Because frozen vegetables are only blanched for a short period of time, they are a higher quality than when canned.
So for those of us who can rely on a freezer and spare the space, know that freezing is always a safe alternative to canning (pressure or hot water bath canning). Frozen fruit or veg can be used in an instance where cooked fruit or veg is used. For example, I made a fruit crisp last weekend out of frozen berries and rhubarb.
When I made the crisp, I mixed frozen rhubarb chunks, whole frozen strawberries, and fresh blackberries. The crumb mixture I used from the Joy of Cooking was disappointing; I should have added oats. But the recipe is below, if you'd like to doctor it to an oat crisp topping, which I will next time!
To freeze rhubarb, simply wash and cut the stalks into 1" pieces. Pack into freezer grade bags or rigid plastic containers. You do not need to add sugar or sugar syrup to preserve rhubarb in the freezer. The procedure for freezing berries is the same; just hull, peel, or pit your fruit as needed before freezing.
The procedure for freezing vegetables is just as easy as freezing fruit with one added step for improving the quality of your frozen vegetables. Vegetables should be blanched before frozen, to kill any enzymes that will cause your vegetable to continue to ripen in the freezer. The ripening process will cause a loss of flavor and texture in your product. After blanching, shock veggies in an ice bath, dry, and pack into freezer grade containers.
Specific blanching times for vegetables can be found at the National Center for Home Food Preservation.
Apple or Fruit Crisp
From Joy of Cooking
8 medium apples (about 2.5 lbs.)
or the same amount of slightly sugared rhubarb or pitted cherries
3/4 cup all-purpose flour
3/4 cup packed brown sugar
1/2 teaspoon salt
1 to 1 1/2 teaspoon cinnamon
1 stick cold butter, cut up into pieces
Preheat the oven to 375 degrees F. Have ready an unbuttered 2-inch deep 2-quart baking dish. Wash, peel, core and cut fruit into chunks. Spread evenly in the baking dish.
Combine dry ingredients in a bowl and add butter. Using a pastry blender or two knives, cut the butter into the dry ingredients until the mixture resembles coarse bread crumbs. Scatter the topping evenly over the fruit. Bake until the topping is golden brown, the juices are bubbling, and the apples are tender, 50 to 55 minutes. Serve hot or cold with whipped cream (or vanilla ice cream, duh).