This topic covers the classification, functions, sources, and deficiency symptoms of carbohydrates, including sugars (monosaccharides and disaccharides), s
Topic Synopsis
This topic covers the classification, functions, sources, and deficiency symptoms of carbohydrates, including sugars (monosaccharides and disaccharides), starch (complex carbohydrates), and dietary fibre.
Key Concepts & Core Principles
- Classification: Monosaccharides (glucose, fructose), disaccharides (sucrose, lactose), and polysaccharides (starch, glycogen, fibre).
- Energy provision: Carbohydrates provide 3.75 kcal per gram; glucose is the body's preferred energy source, stored as glycogen in liver and muscles.
- Functional properties: Gelatinisation (starch granules swell and thicken when heated with liquid), dextrinisation (dry heat breaks down starch into dextrins, causing browning), and caramelisation (sugars break down under heat to produce colour and flavour).
- Dietary fibre: Non-starch polysaccharides (e.g., cellulose) that aid digestion, prevent constipation, and reduce risk of bowel cancer; found in whole grains, fruits, and vegetables.
- Glycaemic index (GI): A measure of how quickly carbohydrate-containing foods raise blood glucose levels; low-GI foods provide sustained energy release.
Exam Tips & Revision Strategies
- Ensure you can distinguish between simple sugars and complex carbohydrates
- Be prepared to link carbohydrate intake to energy balance and health
- Know the specific functional properties of carbohydrates in food science, such as gelatinisation, dextrinisation, and caramelisation
Examiner Marking Points
- Identification of sugar types: monosaccharides and disaccharides
- Understanding of starch as a complex carbohydrate
- Knowledge of dietary fibre
- Functions of carbohydrates in the body
- Symptoms and consequences of carbohydrate deficiency
- Identification of food sources for sugar, starch, and fibre