Proteins

Examples of High Protein Foods

• Chicken
• Beef
• Pork
• Eggs
• Fish
• Peas & Beans (Pulses/Legumes)

Elements of Proteins

• Carbon
• Hydrogen
• Oxygen
• Nitrogen
• Sometimes small amounts of Sulfur

Proteins are made up of Sub Units called Amino Acids.

There are about 20 Amino Acids.

Test for Proteins

Biuret Test for Proteins

1. Add 2cm3 of protein solution to test tube.
2. Add 1cm3 of dilute sodium hydroxide.
3. Add 2-3 drops of copper sulfate solution (blue in color).

Results

• If it turns violet in color, proteins are present.
• If it remains blue in color proteins are not present.

Carbohydrates

Examples of High Carbohydrates Foods

• Potato
• Bread
• Oats
• Pasta/Macaroni
• Roti
• Ground Provisions (sweet potato, yam, dasheen)

They provide energy

They are broken down into glucose and used for energy in the form of ATP (Adenosine Triphosphate).

Excess glucose are converted into fat and stored for later use if needed.

Elements of Carbohydrates

• Carbon
• Hydrogen
• Oxygen

Types of Carbohydrates

Monosaccharides/Reducing Sugars

These are carbohydrates which are made up of only 1 sugar unit;

Example: Glucose

Properties

1. They are soluble in water.
2. They taste sweet.
3. They are crystalline in

Test For Reducing Sugars (Benedicts test for reducing sugars)

1. Add 2cm3 of Glucose to a boiling Tube.
2. Add 2cm3 of Benedict Solution (blue) to the boiling tube.
3. Gently heat over a Bunsen

Results

• Turns into a brick red color when reducing sugars are present.
• Remains blue when reducing sugars are not present.

Disaccharides/Non-Reducing Sugars

These are carbohydrates which are made up of 2 sugar units, joined together by a condensation reaction (where water is eliminated);

All our Disaccharides are non reducing sugars except maltose.

Examples: Sucrose, Maltose, Lactose

Properties

1. They are soluble in water.
2. They taste sweet.
3. They are crystalline in nature.

Test for Non Reducing Sugars

You will only test for non reducing sugars when you get a negative result from the reducing sugars test.

1. Add 2cm3 of Sucrose to a boiling tube.
2. Add 2cm3 of Hydrochloric Acid to the same boiling tube CAREFULLY.
3. Gently boil.
4. Add Sodium Carbonate.
5. until fizzing stops.

Results

• Turns Brick Red if non reducing sugars are present.

Polysaccharides

These carbohydrates which are made up of many sugar units joined together via condensation reactions (where water is eliminated);

Example: Cellulose

Properties

1. They are insoluble in water.
2. They do not taste sweet.
3. They exist in powdered forms.

Test for Starch

1. Add 1cm3 of Starch Solution to a test tube.
2. Add 2-3 drops of Iodine Solution (yellow/brown).

Results

• Turns blueish black when starch is present.
• remains yellow/brown when starch is not present.

Fats

Sources of Fat

• Butter
• Margarine
• Coconut oil
• Lard
• Nuts

Elements of Fats

• Carbon
• Hydrogen
• Oxygen

Fats are made up of fatty acids & glycerol.

Function of Fat in your Diet

1. They store energy.
2. They form cell membranes.
3. They supply energy for respiration.
4. They store the fat soluble vitamins:
5. 1. A
   2. D
   3. E
   4. K

Test for Fats

Grease Spot Test

Emulsion Test

1. Add a small amount of ethanol to a test tube.
2. Add some fat to the test tube.
3. Shake the test tube until the fat has dissolved in the ethanol.
4. Add an equal amount of water.

Results

If a cloudy emulsion is formed, fats are present.

Roughage/Fiber

• Adds bulk to your food. For Example when in the large intestine, it scrapes against the intestine and removes stuck particles.
• Made up of Plant Material
• Prevents constipations

Water

• Makes up most of the Cytoplasm and enables chemical Reactions.
• Should drink 8 cups of water.
• Assists in Respiration.

Vitamins

Minerals

Enzymes

• These are Biological Catalysts and they alter the rate of reactions taking place in the body
• Without Enzymes, reactions would occur at a very slow rate.

• Enzymes can be categorized into 2 types:

Builder Enzymes

• Involved in reactions that take simple molecules and convert them to a more complex ones.

Breaker Enzymes

• Involved in reactions that break down complex substances into simpler ones.
• e.g. All Digestive Enzymes
• Substrates fits perfectly into an active site, where it is broken down/catalyzed forming product, the active site is left vacant and another substrate enters and is catalyzed and turned into product...this process is repeated.

Properties of Enzymes

They all are proteins.

Enzymes are proteins

• They are made up of:
• • Carbon
  • Hydrogen
  • Oxygen
  • Nitrogen
  • Sometimes small amounts of Sulfur
• Amino Acids join together to form proteins.
• There are about 20 amino acids.
• By simply changing the order & sequence of amino acids, we can make new enzymes

They all are affected by temperature.

• Temperature & Rate increases from A to B, forming Kinetic Energy among the enzymes. It then forms the Enzyme Substrate Complex.
• Point B is at Optimum Temperature (Temperature at which the enzyme works at its best/fastest).
• B - C, the rate decreases as the temperature continues to rise. Beyond optimum temperature there is too much Kinetic Energy causing the enzymes to vibrate and breaks the bonds holding them together, they can no longer perform their job and is said to be denatured.

They are affected by pH

• Has a narrow range of work/tolerance.
• Enzymes work in a very narrow range for pH. Anything below/above optimum pH, the enzyme becomes denatured.

pH

A measure of acidity or alkalinity

• Measured on pH scale
• • 0-6 is acidic
  • 7 is neutral
  • 8-14 is alkaline

They are specific

This means the enzyme can only break down one ONE substrate. When the substrate is broken down, it turns into product , which is then a substrate that can be broken down by a specific enzyme. The process continues.

They are reusable

Once the enzyme has broken down a substrate, it can be used again for another specific substrate.

Reference Vids

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