Jams and Spreads
Jams were developed in ancient times as a means of preserving fruits that
would otherwise quickly spoil. When preserved, fruits resist spoilage
because they lack the water that microorganisms need in order to grow.
Surface molds can be prevented by sealing homemade preserves with an
airtight layer of paraffin.
Fruits boiled in sugar will gel
via the interaction of fruit acids and pectin, a soluble fiber that is drawn
out of the fruit cell walls by cooking. Apples, grapes, and most berries
contain enough natural pectin; other fruits, such as apricots and peaches,
need to have it added. Low-calorie, reduced-sugar jams are gelled with a
special pectin that sets at lower acidity and with less sugar. These
products are often sweetened with concentrated fruit juice and thickened
For nutritional value, there's no
comparison between jams and fresh fruits, because most of the vitamin C and
other nutrients in fruits are destroyed by intense cooking. While fruit
preserves contain substantial amounts of pectin – a soluble fiber that helps
control blood cholesterol levels – this benefit is offset by their high
sugar content. Simple sugars, however, make jams a source of quick energy.
The majority of the peanuts grown
in North America are ground into peanut butter. The high fat content of
peanuts makes them easy to grind into a paste, but the oil quickly turns
rancid when exposed to oxygen and light. many commercial peanut butters are
made with preservatives, stabilizers, and added salt and sugar; you can
avoid these ingredients by buying fresh-ground peanut butter made solely
from nuts. The oil that rises to the top of the jar can be poured off to
reduce the fat content. It's best to store peanut butter in a glass
container in the refrigerator, where the darkness prevents the loss of B
vitamins and the cold retards oil separation. Peanut butters that don't
separate usually contain hydrogenated vegetable oils. This means they are
full of trans fatty acids, which are bad for the heart.
Peanut butter can be a valuable
nutritional resource for children, who need extra dietary fat for proper
growth and development. One tablespoon contains about 95 calories, with 5 g
of protein, 8 g of polyunsaturated fat, and significant amounts of B
vitamins, calcium, potassium, and magnesium, along with 100 mg of sodium and
traces of iron and zinc.
The supermarket shelves are
stocked with many types of spreads, ranging from soft processed cheese
products to chocolate-flavored nut butters and whipped marshmallow. Most of
the cheese-based products provide small amounts of vitamin A and calcium but
are high in sodium, fat, and cholesterol. Chocolate and marshmallow spreads
offer little more than calories.