Carbohydrates Flashcards
Carbohydrates definition
Main source of energy in living organisms
What are carbs made up of
- Carbon
- Hydrogen
- Oxygen
What is the requirements of carbohydrates
Obtained from the diet
Why are carbs essential
Body cannot make it ourselves and if we don’t have it it causes a negative health balance
What are the 4 types of carbohydrates
- Monosaccharides (1)
- Disaccharides (2)
- Oligosaccharides (3-9)
- Polysaccharides (10+)
Nomenclature of CHO
Monosaccharides definition
Consists of 3-7 carbon atoms which is generally in a ring form
Monosaccharides sources
- Glucose
- Fructose
- Galactose
Monosaccharides physiology
Absorbed from the small intestine
Disaccharides definition
Polymer of 2 monosaccharides linked by glycosidic bond
Disaccharides sources
- Sucrose
- Lactose
- Maltose
- Trehalose
Disaccharides physiology
Absorbed in small intestine
Oligosaccharides definition
Consists of 3-4 or more monosaccharide units oinked by glycosidic bonds (short chain carbs)
Malto-oligosaccharides definition
Derived from starch
Malto-oligosaccharides sources
Used in the food industry as sweeteners and fat substitutes
Malto-oligosaccharides physiology
Digested and absorbed as rapidly as sugar
Other oligosaccharides
Prebiotics
Foods containing oligosaccharides
Probiotics
Live micro-organisms added to food
Types of starch
- Rapidly digestible starch
- Slowly digestive starch
- Resistant starch
- Physically undigested
- Resistant starch
Dietary fibre definition
- Carbohydrate polymers with 10+ monomeric units
- Hydrolysed by the endogenous enzymes in the small intestines
- Edible
Non-Strach polysaccharides (NSP) definition
Principally polysaccharides of the plant cell wall
Soluble fibre
- Soft and sticky
- Slows digestion
Insoluble fibre
- Rough
- Enhances transit time
Sugar alcohol
Alcohols of glucose and other sugars, found naturally in some fruits
What happens when glucose is too high
Insulin via beta cells
What happens when glucose is too low
Glycogen via alpha cells
Glucose homeostasis
Glycogen
Free sugars
Monosaccharides and disaccharides added to foods by manufacturer
Dental caries definition
The soft decayed area in a tooth
Carbohydrate overfeeding
The conversion of excess carbohydrate to fatty acids which can then be stored as adipose tissue
Lactose intolerance
large amounts of milk leas to unabsorbed lactose which often results in rapid gas production resulting in abdominal pain and diarrhea
Glycemic index
The rate at which a food causes the level of glucose in the blood to rise
Glycemic load
GI x grams of carbs per serving ÷ 100
High GI
70 +
- Quick digestion
- Rapid rise in blood glucose
- White bread, cornflakes
Intermediate GI
55-70
- Basmati rice, green bananas
Low GI
55 and under
- slow rise in glucose
- slower digestion
- Apple, lentils, oats
Factors influencing GI ranking
- Types of starch
- Cooking
- Food processing
- Acid content
- Protein content
- Fat content
- Type of sugar
- Viscosity of fibre
- Physical structure
