Transcript Ch 9 Minerals PPT

Key Concepts and Facts
 Minerals are single atoms that cannot
be created or destroyed by any ordinary
means
 Minerals are components of body
structures and play key roles in the
regulation of body processes
 Deficiency diseases occur when too little of 1
or more of the 15 essential minerals is
provided; overdoses occur when too much is
provided
 Inadequate intakes associated with chronic
disorders like osteoporosis, iron deficiency,
and hypertension
What are Minerals?
 Minerals are elements the body needs in varying
amounts
 Minerals needed in amounts of 0.1g or more each day
are called MACRONUTRIENTS or MAJOR MINERALS
 Sodium
 Calcium
 Phosphorus
 Chloride
 Potassium
 Sulfur
 Magnesium
What are Minerals?
 Minerals the body needs in amounts of 0.01g or less
each day are known as MICRONUTRIENTS or TRACE
MINERALS
 Iron
 Zinc
 Iodine
 Copper
 Manganese
 Fluorine
. . . and others
Sodium
 Sodium is found in the body as positive sodium ions.
 Sodium helps maintain the balance that allows water
to flow freely in and out of cells.
 Salt is the primary source of sodium.
 We only need 1 teaspoon per day at maximum: about
2.5 grams
Sodium and Water Balance
 Consumption of a salty
meal or snack
 Makes you thirsty to dilute
the salt
 Makes you excrete the salt
(and water)
 Makes you thirsty to
replace lost water
Sodium Excess
 Excessive amounts
of sodium can be
problem to those
with high blood
pressure or heart
disease.
 Excessive amounts
can LEAD to these
problems, too!
Sodium and Food Processing
Examples of how processing increases the sodium content of foods’
sodium values are for a 3-ounce serving of each food shown
Label Watch
 Not all processed foods with added sodium
taste salty
 Increasingly, low-salt processed foods are
entering the market and can be easily
identified by the “low-salt” message on the
label
 To be considered low-sodium, foods must
contain 140 milligrams or less of sodium per
serving
Calcium
 Calcium is important to the body’s structure.
 Calcium is needed to build and maintain strong teeth
and bones; it also circulates in the body and maintains
cell membranes.
 Calcium ensures proper muscle action, regular heart-
beat and blood clotting.
 High levels of calcium is found in milk
Too Little Calcium
 Only 14% of girls and 36% of boys between 12 and 19
consume recommended calcium
 Calcium is also important to growing children and
women throughout their life.
 Low calcium intake during growing years increases
probability of fractures and osteoporosis
Deficiency of Calcium
 A lack of calcium can cause osteoporosis.
(left) Electron micrograph of healthy bone (right) Electron
micrograph of bone affected by osteoporosis
Osteoporosis
 44 million adults in the United States
have osteoporosis. 1.5 million suffer
broken bones each year due to the
disease
 Osteoporosis increases with age
 Much osteoporosis can be prevented
 Build dense bones during childhood and
keep bones dense as you age
How NOT TO lose Vitamins and Minerals
Enzymatic Browning
 When fruits are cut or bruised oxygen enters the damaged
tissues so browning occurs.
 The brown compounds that are produced are called
melanins.
 Although unappetizing, they are safe to consume. Fruits that are
susceptible to enzymatic browning include apples, pears,
bananas, avocados and others.
Prevention of enzymatic browning
 To prevent enzymatic browning, the enzyme may
be denatured by:
 blanching
 inhibited by adding acid to reduce the pH.
 addition of either lemon or lime juice, with an average
pH of 2.3 and 2.2 respectively, is a good method of
preventing browning
 Fruits may be protected from exposure to
oxygen by covering them with syrup
Blanching and Such
 Products such as Fruit Fresh, which contain vitamin C
in dried form, also prevent the browning reaction; they
are available in the grocery store.
 Fruits (and vegetables) that are to be frozen are usually
blanched first; that is, they are briefly placed in boiling
water. The short heat treatment is sufficient to
inactivate the enzyme and prevent browning from
occurring during frozen storage.
Preparation of Fruits
 Fruit is often served raw because the texture is usually
more desirable than that of cooked fruit.
 Heating causes several changes in fruits. They soften,
due to softening of pectin
 Normally, the cell membrane allows water to pas
through it, but not solutes such as sugars or minerals.
 The water moves from a low concentration of solutes to
a higher one, until the solution concentration is equal
on both sides of the membrane. This is known as
osmosis.
 If sugar is sprinkled on fruit such as
strawberries, water will move out of the cells to
the surface, where the solute concentration is
higher, and sugar syrup will develop around the
fruit.
 Heating destroys the membrane’s ability to
prevent loss or uptake of solutes through the cell
wall. Solutes can then freely pass across the
membrane until solute concentrations are equal
on both sides. This is termed diffusion.
 This principle must be taken into consideration when
cooking fruit. If sugar is added to the fruit before it is
cooked, it will help to retain its shape and firmness
during cooking (especially if the fruit is not stirred),
because the sugar enters the cells as the water leaves.
Depending on the sugar concentration, the fruit may
actually shrink. On the other hand, if fruit is cooked
without sugar, the water moves into the cells and sugar
moves out; this causes the fruit to swell and
disintegrate. This is desirable if making a fruit sauce; if
sugar is needed for flavor, it is best to add it at the end
of the cooking period in this case.
 Nutrient Content
 Fresh vegetables are naturally low in calories,
cholesterol, sodium and fat, and are good sources of
fiber, vitamins, minerals and phytochemicals.
Phytochemicals are non-nutritive compounds found in
plants that possess health-protective benefits. The
cruciferous vegetables (broccoli, Brussels sprouts,
cabbage, cauliflower, kale, etc.), as well as
strawberries, pineapples and green peppers, contain
phytochemicals that appear to inhibit cancer in
laboratory animals. Tomatoes contain lycopene, which
has also been identified as a phytochemical.
A: Fruits- Enzymatic Oxidative
Browning
 To observe the effects of various treatments on
development of browning on the cut surface of apples.
 To explain the mechanism by which various
treatments inhibit oxidative browning.
 To compare browning tendencies of the selected foods.
B: Vegetable- Effects of Cooking
Treatments on Vegetable Pigments
 To observe the effects of cooking time on plant
pigments.
 To observe the effects of acid and alkali on plant
pigments.