A nutrient is a chemical substance in food
that helps mantain the proper functioning
of any organism. We can divide them into
six categories.
water
59%
fat
20%
protein
13%
vitamins and
minerals
7%
carbohydrates
1%
water
fat
protein
vitamins and minerals
carbohydrates
-nutritional value is the amount of nutrients
in food products, expressed in g / 100g of
the product
-food energy- the amount of chemical
energy that animals (including humans)
can get from food in the process of cellular
respiration
1kcal=4,184kJ
GDA- Guideline Daily Amounts
it refears to the amount of kcal and nutrients
contained in one portion of the product
PROTEINS
-protein is essential for growth and repair and keeping cells healthy
-protein is made up of building blocks called amino acids;
different foods contain different amounts and different combinations of amino acids.
-animal sources contain the full range of essential amino
acids needed by the body -plant sources typically contain fewer essential amino acids -proteins consists of: C, O, N, H, S, P
SOURCES OF PROTEIN
Animal: • meat • fish • eggs • milk • cheese
Plant: • nuts • seeds • pulses, e.g. beans, lentils • soya products.
XANTOPROTEIC REACTION
• xanthoproteic reaction is a method that
can be used to determine the presence
of proteins in products, using
concentrated nitric acid (HNO3)
• the test gives a positive result in amino
acids carrying aromatic groups, especially
in the presence of tyrosine
BIURET REACTION
-the biuret test is a chemical
test used for detecting the
presence of peptide bonds
(proteins). In the presence of
peptides, a hydroxide
copper(II) Cu(OH)2
ion forms mauve (purple)
colored coordination
complexes
FATS
-fat is made up of different types of fatty
acids and glycerol
-high intakes of saturated fat may raise
blood cholesterol and increase the risk of
heart disease and stroke
• Fats in many organisms undergo
hydrolisys; fats fall apart to glycerol and
fatty aicids with using water and enzymes
• Fatty acids undergo oxydation, in which
proces we get water (H2O ), carbon dioxide
(CO2) and ATP
• Fats also have an insulating function- they
protect organisms from loss of energy and
water
ACROLEIN TEST
• When you want to separate oily substance
from fat you need to do the acrolein test
• You heat both substances and the one
which produces fumes (acrolein) is fat
CARBOHYDRATES
-all types of carbohydrate are compounds of
carbon, hydrogen and oxygen
-mostly common in usage is sucrose
obtained from betroots and sugar cane
-starch occurs mainly in potatoes and grains
disaccharides undergo hydrolises
saccharose= glucose+fructose
maltose= 2x glucose
Lactose= glucose+galactose
Celobiose= 2x glucose
TROMMER’S TEST
• detection of glucose
• We pour copper suflate into sodium
hydroxide (we get copper hydroxide) and
add glucose solution
• We get copper oxide (I)
TOLLEN’S TEST
• used to determine the presence
of aldehyde, aromatic aldehyde
• Tollens’ reagent oxidizes an aldehyde into
the corresponding carboxylic acid
• the reduction of silver ions in Tollens’
reagent turn into metallic silver
WATER
• the main ingredient of the body
• transport function
• Excreted in the form of sweat and urine
VITAMINS
• Unlike carbohydrates, fats and proteins,
• vitamins DO NOT provide energy(calories)
• Functions in the body:
• Help regulate the many chemical processes in the body
• There are 13 different vitamins needed for the proper functioning of the body every day.
• Food sources:
• Fruits, vegetables, milk, whole-grain breads
Fat soluble vitamins:
Vitamins A, D, E, K
Require fat for the stoach to allow them to be
carried into the blood stream for use (absorption)
Can be stored in the body for later use
Water soluble vitamins
Vitamins C and B-complex
Require water for absorption
Easily absorbed and passed through the body as waste
MINERALS
Functions in the body:
The body depends on minerals for practically every process necessary for life.
Minerals make up to 4% of the body
The body requires 16 minerals daily.
Food sources:
Meats, beans, nuts, fruits,
vegetables, dairy products and grains
MINERALS- FUNCTIONS IN THE
BODY
Calcium – bones, teeth
Phosphorus – bones, teeth, nervous system
Magnesium – healthy immune system, heart
beat , muscles
Sodium – helps maintain right balance of fluids,
helps transmit nerve impulses
Potassium – helps lower blood pressure
Iron – helps make hemoglobin in red blood cells
NUTRIENT DEFICIENCY
A nutritional deficiency occurs when your body doesn't get enough nutrients
Symptoms: At first we can experience: tiredness, difficulty
sleeping or concentrating, frequent colds, and weight loss or gains
However, if the deficiency is not corrected the symptoms may get more serious and effect the skin, eyes and bones
The best way to avoid this is to eat a well balanced diet