Lecture 9: Sugars & Sweeteners Flashcards
Fact or Folklore: If it’s natural, it must be good for you.
FOLKLORE
- No correlation between naturalness and healthfulness
- FDA & USDA don’t define “natural”
- The most toxic substances known are perfectly natural (botulin toxin, Aflatoxin B)
Fact or folklore: If you can’t pronounce it, you shouldn’t eat it.
FOLKLORE
-Names are just labels –> they don’t tell you anything about the chemical or structure
Fact or folklore: You shouldn’t have chemicals in your food.
FOLKLORE
- Everything is a chemical or a collection of chemicals and has a chemical name
- Real concern = whether the chemicals are healthful or harmful and in what amount
Macronutrients
- Bulk of our diet
- Determine the properties of foods
- Nutritional implications (carbohydrates, fats, proteins)
Carbohydrates
- Most abundant organic molecules
- Initial source of all food (photosynthesis)
- “carbon hydrates” = carbon hydrated with H2O
- Formula = Cn(H2O)n
Sugar nomenclature
- Suffix = “-ose”
- Classified according to the # of carbon atoms
- Most foody sugars of made of hexoses (6 carbons)
How are sugars drawn?
Cyclized or sometimes straight-chained
What do carbohydrates provide?
- Energy (~4.5 Cal/g)
- Carbon (to make other things)
- Fiber (no energy)
- Taste
Sucrose
-A disaccharide composed of 2 monosaccharides (glucose & fructose)
What are other names for glucose & fructose?
- Dextrose & levulose
- Grape sugar & fruit sugar
List the stages/degrees of sugar refining in order of increasing processing.
- Molasses
- Raw sugar
- Brown sugar
- White sugar
Molasses
- Concentrate juices from sugar-bearing plants (most often sugar cane)
- Contains substances other than simple sugars
- Various grades and darknesses of color
What are the two different processes used to make molasses?
- Open kettle
- Centrifugal
Industrial processing of molasses
- Edible sugars are made in a way that no foreign objects get into it
- Non-food version of sugars
- Ex) biofuels
Raw sugar
- Should be the first crystallization of sugar from boiling down (concentrating) sugar cane extract
- Some products now refer to this as “crystallized cane extract” (sounds more natural)
Brown sugar
- Has more taste/flavor than white sugar
- Hygroscopic = holds moisture and makes things stay moist
Refined sugar
- Sucrose is its common chemical name
- White table sugar
- Only taste it has is sweetness
- Uniform quality = 99.99+% purity
- “Empty calories”
- Keeps indefinitely
Corn syrup
- Cheapest sweetener produced on a large scale
- Obtained from hydrolysis of corn starches by acids or enzymes
- Less sweet than sucrose
- Hygroscopic
- Mixture of polymers and fragments
- Inhibits crystallization of sugars (recall Alton’s vid)
Hydrolysis
Process of splitting a molecule apart and adding the equivalent of a water molecule to the products
High fructose corn syrup
- Ordinary corn syrup can be treated with enzymes to produce HFCS
- Sweeter than regular corn syrups
- Cheaper product than sucrose
- Can adjust the fructose:glucose ratio
Enzyme nomenclature
Suffix = “-ase”
Invertase
HONEY
-Sucrose from plants is converted from a disaccharide to 2 monosaccharides by invertase
Concern about honey
- Has bacterium Clostridium botulinum
- Infants who died from SIDS have been found with spores of C. botulinum
Hydrogenation
Process of adding hydrogen to molecules
