Nutrition and Food Tests

Nutrition and Food

Nutrition is the process by which organisms obtain and use food.
Nutrients are substances that an organism needs for growth, repair, and normal metabolism. These include carbohydrates, proteins, fats (lipids), vitamins, minerals, and water.
Humans require a balanced diet that includes the right proportions of each type of nutrient. Too much or too little of certain nutrients can lead to health problems.

Carbohydrates are made up of units of sugar and can be divided into three main types: monosaccharides, disaccharides, and polysaccharides.
Monosaccharides are single sugar units, for example, glucose and fructose.
Disaccharides consist of two sugar units, for example, sucrose (table sugar) and lactose.
Polysaccharides consist of many sugar units and include starch and dietary fibre.

Proteins are large molecules made up of chains of amino acids.
They are essential for growth, repair, and normal function of the body.
The body can synthesize most amino acids, but there are nine ‘essential’ amino acids that must be obtained from the diet.
Foods rich in protein include meat, eggs, dairy, legumes, and soy products.

Fats are a source of energy and are essential for certain body functions.
They can be categorized as saturated (mostly in animal-based foods) and unsaturated (mostly in plant-based foods and fish).
The body also needs small amounts of ‘essential’ fatty acids from the diet, which it cannot synthesize itself.

Vitamins and minerals are needed in small amounts for various body functions.
Most vitamins cannot be synthesized by the body and must be obtained from the diet.
Common examples include Vitamin C (for tissue repair and immune function) and calcium (for healthy bones and teeth).

Understanding the nutritional content of food is important and can be determined by various tests.
Starch test: This involves adding iodine solution to the food sample. If starch is present, the sample will turn blue-black.
Sugar test: Adding Benedict’s solution to the food and heating it; if sugar is present, the solution will change from blue to green, yellow, or brick-red.
Protein test: Adding biuret solution to the food sample; if protein is present, the solution will change to lilac or purple.
Fat test: Rubbing the food on a piece of paper; if fat is present, the paper will become translucent.