Introduction to Carbohydrates
Where do Carbohydrates Come From? (see p. 213)
Summary of Photosynthesis

Energy for process:

Equation:

Carbohydrate storage in plants:
Carbohydrate Terminology
 “Simple sugars”
 Monosaccharides
 Disaccharides
 “Complex carbohydrates”
 Polysaccharides
The Monosaccharides
 Single-sugar units
 Chemical formula:
 Cyclic or ring structures
 Examples:
The Disaccharides
 Double-sugar units
 Common types include glucose
 Examples:
Making and Breaking Disaccharides (Fig. 4-6, p. 104)

Condensation reaction

Hydrolysis reaction
Nutr 12
Mono- and Disaccharides in Food
Monosaccharides
Disaccharides

Glucose
•
Sucrose

Fructose
•
Maltose

Galactose
•
Lactose
Digestion of Sugars
Small intestinal enzymes: the disaccharidases

Maltase:

Sucrase:

Lactase:
Lactose Intolerance
 Lactose intolerance = __________________
 Secondary lactose intolerance
 Symptoms of lactose intolerance
 Prevalence of lactose intolerance
 Should milk be avoided in lactose intolerance?
 Food choices in lactose intolerance
 Related intolerances…
Consumer Nutrition - Sugars
I. Food labels (names for added sugars)
•
Calculating the sugar content of food products…
•
Concept check: should you buy “low-sugar” food products?
II. Common Consumer Questions
o What is high-fructose corn syrup? Is it worse for you than table sugar?
o
Are honey and molasses healthier than table sugar?
 Nutrients in honey and molasses
 Blackstrap molasses
Refined Sugars and Health
 “Empty” calories
 Tooth decay
Why does sugar/starch cause dental caries?
 Streptococcus mutans
 Dietary culprits
Reminder: baby bottle tooth decay
Sugar intakes have NOT been linked to:
 Hyperactivity in kids
 Criminal behavior
 Heart disease, but…
 Diabetes, but…
Preview: Dietary Sugar vs. Blood Sugar
Alternative Sweeteners
1. Sugar alcohols
2. Artificial sweeteners
The Sugar Alcohols

Extra “alcohol” group

Poorly absorbed

Kcal/g

Symptoms of excess intake:
Foods with Sugar Alcohols
Sugar Alcohol Diarrhea Thresholds
Some food labels report “net carbs”…
(what are “net carbs”??)
Popular Artificial Sweeteners
1. Saccharin
2. Aspartame
3. Sucralose
Artificial Sweeteners…chemical structures
Stevia – a sweet leaf
Truvia: a processed stevia product
Carbohydrate Summary
Finished:
1. Simple carbohydrates (sugars)
– Monosaccharides
– Disaccharides
Next:
2. Complex carbohydrates
– Starches, Fiber
– Glycogen