Q: I have a problem with bread going stale. I live alone and am rarely able to use an entire loaf of bread before it turns stale. I have tried storing bread in the refrigerator but find that once I do that it never tastes the same. What is it about refrigeration that ruins bread?
A: Bread turns stale as its starch undergoes a change in structure. Although stale bread has a dried-out appearance, a loss of moisture is not the complete explanation -- a loaf will even turn stale in a well-sealed, never-opened package. Temperature, it turns out, is the key.
There are two main types of starch, or carbohydrate, in bread. Over time, each will change from a random to a more rigid arrangement. The first of the two starches changes as freshly baked bread cools to room temperature. The settling of the second starch takes about a week. As the second starch changes, though, the texture of the bread shifts from soft to hard, or as we call it, stale.
It was reasonable for you to consider refrigeration as a way to extend shelf life as it is useful to slow down many of the ways by which food goes bad. For example, mold, another spoiler of bread, grows slower at refrigerator temperatures.
With bread, however, refrigeration is a mixed blessing, as the starch tends to settle faster. Your bread won't get moldy, but it will be stale in about a day. This is the reason refrigeration is not recommended for the storage of any raised bread product.
Freezing may provide a solution. Freezer temperatures not only inhibit mold, but the settling of the starch comes to a halt. If you are unable to get through an entire loaf before it goes stale, consider splitting your loaf after purchase and storing half in the freezer.
Another possible solution is to look for breads that use preservatives, called emulsifiers. They can slow down the settling of starch and effectively extend shelf life. The most common emulsifiers in bread, the mono- and di-glycerides, are effective, yet harmless additives.
However you decide to store your bread, make sure the package is always well sealed.
Q: Carrots in the refrigerator get soft and flexible after a few days and eventually they shrivel. At what point are they no longer safe to eat?
A: Carrots, a root crop, is the way water from the soil is transported to the rest of the plant. The fibrous part of the carrot contains flexible little compartments that fill and hold on to water until needed by the rest of the plant above.
When the carrot sits, exposed to the air, the water evaporates. Over a matter of days, this will result in the more flexible vegetable you described. Eventually the carrot will wilt and rot. To retain moisture and firmness, carrots should first be washed, the excess water shaken off, and then place in a plastic bag in the refrigerator crisper.
If you buy carrots with greens attached, remove them after purchase as they tend to draw the water out of the carrot. Carrots can be considered safe as long as they're not discolored, overly shriveled or slimy in feel.
If a carrot has only begun to lose its firmness, it can often be brought back by soaking in cold water.
Q: I recently saw a brand of eggs from vegetarian-hens. Will this make a difference in the nutritional value of the egg? What are the nutritional differences between fertile and non-fertile eggs?
A: Laying hens are normally fed a meal that contains meat scraps as a source of dietary protein. Vegetarian-diet hens rely on vegetable protein sources. The vegetarian diet is more costly and this is usually reflected in the price of the eggs.
Fertile eggs come from hens having had sexual contact with roosters. The eggs, if properly incubated, could develop into new chickens. The typical eggs found in most stores are infertile.
There are no nutritional differences between any of these eggs.