Carbohydrates Overview Quiz

Carbohydrates

• Essential macronutrients providing energy
• Composed of carbon, hydrogen, and oxygen
• Made by photosynthesis
• Two main types: starch and sugar
• Starch produces slower releasing energy than sugar and has a lower GI (glycaemic index)
• Found in grains, potatoes, fruits, vegetables, and dairy products
• Classified into monosaccharides, disaccharides, and polysaccharides
• 1g of carbohydrate produces 4 kcals of energy, the same as protein

Monosaccharides

• Simplest form of carbohydrates
• Examples: glucose, fructose, and galactose

Glucose

• Simple sugar used by the body for energy
• Found in many fruits and vegetables, both fresh and dried
• Present in sugar cane, sugar beet, corn, and honey

Fructose

• Naturally occurring sugar found in fruits and honey

Galactose

• Sugar that combines with glucose to form lactose
• Found in milk and milk products, as well as honey and avocados

Disaccharides

• Formed by the joining of two monosaccharides
• Types: sucrose, lactose, and maltose

Sucrose

• Composed of glucose and fructose
• Major source: sugar cane and sugar beet
• Common ingredient in processed foods

Lactose

• Naturally found in milk, key nutrient for infants
• Also found in dairy products like cheese and yogurt

Maltose

• Found in plant foods like sweet potatoes, soybeans, barley, and wheat
• Product of starch breakdown

Polysaccharides

• Complex carbohydrates made up of many monosaccharide molecules
• Examples: starch, cellulose, pectin

Starch

• Storage form of carbohydrates found in plants
• Good sources: potatoes, bread, rice, pasta
• Classified as a slow release carbohydrate, provides a steady release of energy

Cellulose

• Found in the cell walls of plants
• Not digestible by humans, considered dietary fiber

Pectin

• Found in the cell walls of fruits
• Soluble fibre used as a gelling agent in jams and jellies

Effects of Carbohydrate Intake

• Too Few Carbohydrates:
  • Low blood sugar
  • Fat burning
  • Protein breakdown
• Too Many Carbohydrates:
  • Fat storage
  • Weight gain
  • Liver disease
  • Heart disease

Glycemic Index (GI)

• Ranking system for how carbohydrates affect blood sugar levels
• Measures how quickly different carbohydrate foods raise blood sugar levels
• High GI: Faster digestion, quicker rise in blood sugar
• Low GI: Slower digestion, slower rise in blood sugar

Dextrinisation

• Occurs when starches are subjected to dry heat (baking, grilling, toasting)
• Breaks down starch molecules into smaller glucose molecules called dextrin
• Causes changes in color, smell, and texture
• Burnt toast is an example of dextrinisation with carbon as a result of heat driven off hydrogen and oxygen

Caramelisation

• Process of heating sucrose (sugar)
• Results in changes to texture, taste, and color
• Sucrose melts, forms a syrup, then boils
• As sucrose breaks down, water evaporates, leading to colour changes from colorless to golden brown to dark brown to black
• Taste profile changes from sweet to toffee to caramel to bitter
• Texture changes from sugar crystals to syrup to brittle toffee
• Ideal temperature for caramelisation is 160-170°C
• Stirring during caramelisation can lead to large, hard lumps
• Foods containing natural sugar (like onions) will caramelize when sautéed or roasted

Gelatinisation

• Process of heating starch in a liquid
• Starch granules absorb water, swell, and burst
• Starch molecules release into the liquid, forming a 3-dimensional network that traps water molecules
• Results in thickening of the liquid and formation of a gel when cooled
• Occurs during cooking of foods containing starch
• Changes the liquid from transparent to opaque as starch is released
• Temperature ranges from 60°C to 100°C
• Regular stirring prevents lumps by ensuring even distribution of starch granules