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
How are sugar alcohols prepared?
By hydrogenation simple sugars
Maple products
- Sugars from maple sap
- Flavors & color produced during “boil down” (boiling off water)
- Maple syrup is composed of: 2/3 sugars, 1/3 water
Issues with artificial sweeteners
- Implied that it helps with weight control
- Studies are showing that it has no effect or that it’s actually correlated with increased obesity
How is there a correlation between artificial sweeteners and obesity?
- Peeps on weight-gain trajectory are more likely to use low-cal sweeteners
- Sugar consumption causes a feeling of satiety –> feel full faster when you eat sugar
- Satiety feeling not activated with AS –> overcompensation (eat more)
- Low blood sugar suppresses metabolism –> lower BMR –> burn calories more slowly
- AS are sweeter than regular sugars –> increase sweetness tolerance
List the approved low Cal sweeteners
- Acesulfame-K
- Aspartame
- Neotame
- Saccharin
- Sucralose
Acesulfame-K
- Aka Sunett
- Manufactured by Nutrinova
- Approved for products such as baked goods, frozen desserts, candies, and beverages
- About 200x sweeter than sugar
- Calorie free
Aspartame
- aka NutraSweet
- Composed of 2 natural amino acids (Aspartic acid + Phenylalanine)
- Label must have a warning that it contains phenylalanine
- 200x sweeter than sucrose
- Not heat stable
Neotame
- 6000x sweeter than sucrose
- Phenylalanine not released (unlike Aspartame)
Saccharin
- Sweet N Low
- 300x sweeter than sucrose
- Used to be declared a carcinogen, but repealed b/c it is only harmful in extremely large amounts
Sucralose
- Splenda
- 600x sweeter than sucrose
- Cannot be digested, so it doesn’t add any calories to food
List the low calorie sweeteners not yet approved by the FDA
- Alitame = 2000x sweater than sucrose
- Cyclamate = 30x sweeter than sucrose (banned from U.S. b/c of political factors)
Xylitol
5 carbon sugar alcohol found in birch bark
