Chapter 8: Sugar: The Simplest of Carbohydrates Flashcards
What are carbohydrates made up of?
C, O, H
Name some bodily functions of carbs.
- Major source of E
- Vital part of cell structure
- Base of DNA (and RNA) molecules
What do carbohydrates include?
Sugars, starches and fibre
What is the simplest form of carb?
Sugars
What is the chemical name for sugars?
Saccharides
What are saccharides composed of?
One or more hydroxyl groups
What do monosaccharides contain?
C, H, O atoms in a central ring structure
Name the 3 monosaccharides and examples.
Fructose: fruit, honey
Galactose: milk
Glucose: basic source of E
What are disaccharides
2 monosaccharides
Name the 3 disaccharides.
Sucrose
Lactose
Maltose
What is maltose made up of?
Glucose + Glucose (malted grains)
What is sucrose made up of?
Glucose + Fructose (table sugar)
What is lactose made up of?
Glucose + Galactose (milk)
How do we digest disaccharides?
Hydrolysis (add H2O)
Do all disaccharides use the same enzyme to digest?
No, all require a different one
What is invert sugar?
The fructose and glucose mixture that results from the hydrolysis of sucrose by sucrase is called invertase
-> sugar comes from broken down sucrose
What do alcohols all contain?
At least one OH- group
Name 4 types of alcohols and give examples.
- Ethanol (alcoholic beverage)
- Methanol (burning wood without O)
- Isopropanol (rubbing alcohol)
- “Sweet alcohols”: glycerols
Give examples of “sweet” alcohols.
Glycerol, mannitol, sorbitol, xylitol
Which “sweet” alcohol is a cryoprotectant?
Glycerol
How many kcals/g do carbs have?
4kcal/g
How are sources of sugar listed on a food label?
Listed seperately
Why are artificial sweeteners used? How are they extracted?
- Used to optimize sweetness + cheap
- Extracted from plants
Who developed sugar cane extraction processes?
Chinese
How is molasses made?
Crude boiled liquid pressed from sugar cane
What is brown sugar?
Unrefined or partially refined cane sugar
How is confectioner’s sugar made?
Granulated sugar that is ground into a fine powder
What do sugar beets perform the same function as?
As sucrose from cane sugar but CHEAPER
How is maple syrup made?
Sap of sugar maple trees, slowly simmered to make syrup
How is maple syrup adultered?
Corn syrup
How is corn syrup processed?
Hydrolyzing cornstarch into glucose
What is corn syrup composed of?
Varying amounts of dextrose, maltose, dextrins or polysaccharides
How is high fructose corn syrup made?
Enzymatically converting some of the dextrose in corn syrup to fructose
How is sorghum made?
Sap extracted from sorghum canes and boiled to evaporate excess H2O
What does sorghum ressemble?
molasses
How is honey made?
bees extract invert sugar from the pollen of flowers and store in hives
What does the taste of honey depend on?
type of flower
What is isomalt made of?
mannitol, sorbitol, beet sugar
How is isomalt used?
blown, spun, shaped sugar sculptures - does not form crystals
it liquefies at 154oC
Name the 6 functions of sugar in food preparation.
1) Sweeten foods
2) Act as preservatives
3) Act as tenderizers
4) Act as crystallizing agents
5) Act as caramelizing agents
6) Act as fermenting agents
What causes the ability to sweeten?
sugars have up to 10 units of monosaccharides
What influences sweetness?
Sweeter the sugar, simpler the structure
How does the body recognize sugar?
Sugar binds to taste buds via H-bonds
How do sugars act as preservatives?
prevent food spoilage by drawing H2O away from bacteria (lowers Wa)
Which sugar is most affective in maintaining freshness of baked goods?
Invert sugar
How does sugar affect crumbs?
The + sugar a baked product contains, the more tender the crumb
How does sugar change viscosity?
Sugar interferes with flour’s ability to form an elastic structure
-> pours easier with sugar
Why does sugar dissolve in H2O?
large number of hydroxyl groups, forms hydrogen bonds, water molecules surround sugar, suspending sugar in a water solution
What happens when sugar solutions are heated?
H2O evaporates, increasing sugar concentration
What does supersaturated mean?
If a sugar solution has been heated to concentrate it and is then cooled: any solution that has been heated to dissolve more solute than the water would normally hold is called supersaturated
How is candy made?
When sugar crystals separate from a supersaturated sugar solution during cooling
What differentiates high and low quality chocolate?
High quality = fine sugar crystals
Name the 5 factors affecting crystal formation.
1) Cooling time
2) Ripening
3) Type of sugar
4) Interfering agent
5) Agitation
What is cooling time?
cooler syrup = crystalizes rapidly = creamy smooth
What is ripening?
allowing candy to rest promotes a smooth creamy texture (ex: fondant)
What is the type of sugar?
sucrose increases sugar size (large crystals), invert sugar slows crystal formation
What are interfering agents?
corn syrups, butter, egg white, cream of tartar, cream, vinegar = prevent/slow crystal growth
- corn syrup = much glucose -> finer, smaller crystals
- Fat and protein in eggs: suspend and separate sugar crystals
- acid: hydrolyze the sucrose in a sugar solution
What is agitation?
stirring -> large crystals in hot syrup, but prevents them in cooled syrups
Name 2 candy making tips.
- Monitor temp with candy thermometer
Concentration of the sugar solution
Size of the sugar crystals - Follow preparation directions carefully
1) Concentration of the sugar solution
2) Size of the sugar crystals
How do sugars act as caramelizing agents?
Caramelization occurs when sugar is heated for a prolonged period and darkens to brown liquid
How do sugars function as fermenting agents?
fuel for microorganisms growth needed for fermented products (yeast breads, beer, wine)
Glucose + yeast -> ethanol (alcohol byproduct)
What does fructose and lactose become?
glucose in liver
Where does excess glucose go?
Stored as glycogen in muscles and liver
Name 3 bodily functions of sugar
Needs sugar for digestion of fats and proteins
Needed for brain function
Sugars release serotonin (calming effect, addictive)
What is dietary guideline for added sugar?
6.5% ADDED MAX of total kcals
Name 3 sugar health concerns.
- Dental caries
- Diabetes mellitus
- Weight gain
How do cavities form?
bacteria feeds on sugar -> produces plaque
How does diabetes form?
body’s inability to move glucose from bloodstream to cells because of insulin levels
How does weight gain form?
consuming excess kcals
How much is the earth’s biomass made of carbohydrate? Its dry mass?
Biomass: 50% Dry mass (land plants and seaweed): 75%
Why is baby corn sweeter than its full-size counterpart?
Since initially all carbs = glucose. As the plant matures, it changes into more complex starches
Define an organic compound.
Containing MORE than 1 carbon
What is a hydroxyl group?
OH bound together
Name differences between a-D-glucose and b-D-glucose.
a-D-glucose: OH down, basic source of energy for humans
b-D-glucose: OH up, main component of dietary fibre, undigestible
Define riboses.
Sugars that contain only five carbon atoms.
Why are sweetened drinks not as thirst quenching as plain water?
Part of the H2O is used to digest the sugar and is not available for other functions
Name the 3 conditions that can trigger hydrolysis.
1) Presence of an enzyme
2) Addition of an acid
3) Addition of heat
How is lactose-free milk produced? Why is it sweeter?
Adding an enzyme to hydrolyze the sugar, sweeter because the lactose is broken down into glucose and galactose
What produces lactase? Why is milk difficult to digest after taking antibiotics? Why does eating yogurt help?
- Bacteria in the small intestines
- Antibiotics will kill these bacteria
- Yogurt may contain an active culture of Lactobacillus acidophilus
Name a source of glycerol.
Animal fats
What is the composition of molasses (which varies by degree of refinement)?
- 35-50% sucrose
- 15-20% invert sugar
- 20-25% water
- 2 to 5% mineral
What is the composition of brown sugar?
85 to 92% sucrose
What gives brown sugar its moist moist texture and distinctive colour?
Molasses
What happens when brown sugar is left in the open?
Loss of moisture, becomes hard and crumbly, moist texture can be regained by adding apple slices or a slice of fresh bread to the container (sugar will absorb moisture from substances)
Define granulated sugar.
When further processing removes all minerals, flavourings, and colouring agents from brown sugar, leaving only the crystalline structure.
What does most confectioner’s sugar has added to help prevent caking during storage?
Cornstarch
What does the number of Xs on the label of confectioner’s sugar refer to?
How finely the sugar has been ground - the larger the nb, the finer the powder (4X, 6X, 10X)
Give examples for the different types of confectioner’s sugar.
4X: cough drops, chewing gum, marshmallows, chocolate
6X: cream fillings, uncooked fondants, icings, sprinkled on buns, pies and pastries
10X: finest icings and fondant fillings
How many gallons of tree sap do you need to make maple syrup?
40 gallons of tree sap, slowly simmered down, to make one gallon of maple syrup
Define dextrose.
The name for glucose used by the confectionary trade.
How can we make corn sweeteners? How can its sweetness be altered?
Technology has made it possible to use enzymes to convert starch from abundant corn supplies into sweet syrups. Its sweetness can be altered by varying the hydrolysis process
Which sweetener was the first used in food preparation?
Honey
What is the composition of honey?
75% invert sugar, 15-20% water
What is the composition of HFCS?
55% fructose and 45% glucose
Which sugar helps products such as cakes stay moist the best?
Invert sugar maintain freshness considerably longer than sucrose
What happens when bread does not contain any sugar?
Paler colour and chewier texture (sugar as tenderizer)
What does invert sugar occur naturally in?
Honey and molasses; is also produced commercially
How does invert sugar help in candy making?
Helps prevent the crystallization and resulting graininess of candy caused by cane and beet sugar because invert sugar is made of two monosaccharides (and not two disaccharides) - so finer texture
What happens when you don’t let candy cool and you stir too early?
Cause crystals to come out of the slightly supersaturated mixture - causes crystallization to occur slowly rather than rapidly –> larger crystals / grainy texture
ex: taffies and fondants are cooled on a marble slate
Why do some fondants have invertase added after cooking?
Furthers hydrolysis of disaccharides into invert sugar -> candy has a smooth, fine, even texture that is semisoft to liquid
Why do certain cookbooks never recommend to make fudge on a rainy day?
Since a very humid day will change the sugar-water balance in candy as it cools, may reduce sugar concentration to keep fudge from setting
Name some examples of caramelization.
- Brown crust on baked goods and toast
- Beige colour of sweetened condensed milk
- Colour of caramel candy
- Flan (caramel custard)
What might explain caramelization?
Dehydration is at least partially responsible for the browning and resulting flavour changes
What do the Dietary Guidelines recommend limiting added sugars to? What is the average intake in the US?
Recommend: 6.5%
Average: 16%
How is invert sugar made commercially?
Addition of acids to sucrose, followed by a neutralization process
What is the equation for photosynthesis?
6 CO2 + 6 H2O + sunlight -> C6H12O6 + 6 O2
