Transcript teachers/uploads/blester/uploads/File/Simple_Sugars_ch_8_Bx

Carbohydrates
part B
Dissacharides
Dissacharides
• Sugars in nature is generally not monosaccharide
• Glucose + glucose- maltose
• Glucose + galactose lactose
• Glucose + fructose sucrose
grains (least sweet)
milk (contributes to milk color)
beet/cane
• Hydrolysis can break disaccharides down (reduce)
3 conditions can trigger hydrolysis
• 1. presence of an enzyme to set off reaction
• Digestion of sucrose uses sucrose from saliva
• Making lactose free milk
• Each sugar type requires different enzymes in order to break down
• Change ose end to ase end:
• Sucrase (aka invertase) for sucrose
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invert sugar= mixture of glucose and fructose from hydrolysis of sucrose
• Lactase for lactose etc
• 2. Addition of an acid
• 3. Addition of heat
Carbohydrates-disaccharides- lactose
• Lactose 0.2 r.s*= galactose plus glucose
Cow’s milk contains about 4-5 %
Human milk contains about 6-8%
Fermented by lactic acid bacteria
( example yogurt, and cheeses) - lactic acid ( acidulant, preservative)
*R.S. = relative sweetness
Carbohydrates-disaccharides- lactose
• Lactose intolerance
• Hydrolized by the enzyme Lactase
• Lactose-hydrolyzed milk
Class activity :
• Sample the two types of milk
• Regular
• Lactose reduced
• Will there be a difference in taste between them? Yes/ No?
• Why, Why not?
Carbohydrates- disaccharides- Maltose
• Maltose (.3 r.s.)= glucose- glucose
• Formed from starch by
enzymatic (amalase) or acid hydrolysis
Class activity– unsalted crackers
• Dissolve cracker in mouth
• Cracker should become sweet as AMALASE starts breaking down
starch
Carbohydrates- disaccharides- Maltose
Starch amylose
(Not sweet)
amylase or acid
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maltose/ malt sugar
(slightly sweet)
Carbohydrates- sugar alcohols
• Organic compounds with –OH group= alcohols
• Less cariogenic ( cavity causing) or even anti-cariogenic
• Less impact on blood sugar (slow absorption)
• As sweet as or slightly less sweet than sugar
• BUT – some laxative effect ( threshholdof20-40 g/day)
• Eg) maltitol, xylitol- especially in chewing gum,confectionary
Carbohydrates- sugar alcohols
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Organic compounds with –OH group= alcohols
Sugars have multiple –OH groups plus O with double bond
Alcohol beverages (ethanols) have high caloric content (7 cal/g)
Ethanol (ethyl alcohol)- made from sugar and starch source
Methanol (wood alcohol) can cause blindness, nerve damage or death
Isopropanol (rubbing alcohol)from petroleum
“sweet” alcohols: glycerol, mannitol, sorbitol, xylitol
• Glycerol can be made from animal fats
• See pg 218- “the sweet alcohols”
Sources of sugar
• 4 cal/g
• Common sugars:
• granulated,brown, confectionary (10x), honey, corn syrup, molasses, maple
syrup
• Sugar exrtracts:
• Plants:Cane, beet, maple trees, corn. Sorghum, agava,
• Bees: honey
Sugar Cane
• Crude boiled liquid from sugar cane= molasses
• Cane sugar that is not completely refined= brown sugar
• All flavors, minerals and coloring removed= granulated sugar
• Grinding to a finer texture= confectionary sugar (4x, 6x, 10x)
• 4x for cough drops, gum, marshmallows and choc
• 6x for cream fillings fondants,icing, toppings
• 10x fine icings and fillings
Sugar beets
• No difference in sugars
• Beets are less expensive
• Food allergies to beets might be
an issue for consumers
Sugar sources:Maple syrup
= 40 gallons of sap to make 1 gal syrup
Sugar source: corn syrup
• Processed by hydrolyzing cornstarch to glucose
• Benefits of corn syrup:
• Cost
• Availaablitiy
• Flexible properties:
• Increase viscosity ( thickness)
• Control sweetness
• Used for wider variety of food than sucrose
Sugars-high fructose corn syrup (HFCS)
Starch amylose
Glucose isomerase
Synthetically developed
amylase or acid
maltose
isomerization
HFCS- very sweet
hydrolysis w/maltase
glucose
+ glucose
Carbohydrates- functional properties of
simple sugars
• Sweetening
• Crystalize
• Viscosity/mouth feel
• Fermentation
• Preservative (antimicrobial agent)
• Humectancy
Carbohydratesfunctional properties of simple sugars
• Sweetening power
• Relative sweetness ( R.S)
• Sweetness is NOT correlated to calories
• Eg fructose and lactose = 4 cal /g
• Yet fructose (1.8 r.s.) is 9 x sweeter than lactose ( 0.2 r.s.)
• Only need 1/9th as much fructose for an equivalent sweetening power to lactose1/9th
less caloric intake
Properties of simple sugars
• Crystallization
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Sugar can exist in both soluable (as syrup) abd crystalline states
Easily dissolves in water ( due to the OH)
Crystallized from solution= e.g. table sugar( sucrose ) from sugar cane juice
Sugars melt upon heating and recrystallize when cooled (different crystal form
and size)
• Hard candy production
Properties of simple sugars
• Body and mouth feel
• Swish sugar water in mouth vs plain water
• Fermented by microorganisms
• Yeast must have sugar to ferment
• Yeast acts on sugar until strong enough to convert starches to sugar
• Antimicrobial agents
• Jelly, Jams and Preserves via water reduction in products
Properties of simple sugars
• Reactants in non-enzymatic browning
• 1. caramelization
• Heating sugar alone to a high temperature (200 degrees C)
• Aroma compounds ( caramel, butterscotch flavors) & brown pigments
• - eg caramel candy, toffees
• Color used in cola beverages is created by caramelizing sucrose
Properties of simple sugars
• Reactants in non-enzymatic browning:
• Mailard browning
• Reducing sugar + amino compounds ( proteins or amino acids)
• Reducing sugars contain a “ free” aldehyde or keytone group
• Eg. Glucose, fructose, galactose, lactose
• Sucrose is a non reducing sugar
• ( but can be hydrolyzed to glucose and fructose by high temperature or acid)
Properties of simple sugars
• Products of Maillard browning reaction:
• 1. Low molecular weight interactive compounds
• Aroma/flavor both desirable and undesirable
• 2. High molecular weight polymers (melanoidians)
• Brown and black pigments
• Eg) toast, roasted coffee, potato chips, bread
• Sunless tanning lotions too.
Properties of simple sugars
• Humectancy
• Influence state of water in food systems
• Chewy candies
• Sticky lollypops
• Invert sugars ( fructose and glucose are very hygroscopic)
• Attract water from the atmosphere
Properties of simple sugars
• Ripening
• Invertase is added to the crystalline firm center
• Storage
• Enzyme slowly Inverts sucrose=
• Mixture of sucrose, fructose and glucose
• This mixture does not crystalize easily (vs. glucose alone)= soft centers
Relative sweetness
• See page 223 text
Properties of simple sugars summary:
• Sweetening
• Humectancy
• Crystalize
• Caramelization
• Viscosity/mouth feel
• Non enzymatic browning
• Fermentation
• Ripening
• Preservative (antimicrobial agent)
Assign
• Read text pg 224-233
• Sugars