Carbohydratespart B

Dissacharides

Dissacharides

• Sugars in nature is generally not monosaccharide

• Glucose + glucose- maltose grains (least sweet)• Glucose + galactose lactose milk (contributes to milk color)• Glucose + fructose sucrose 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• 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- MaltoseStarch amylose amylase or acid maltose/ malt sugar (Not sweet) (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

• 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 amylase or acid maltose hydrolysis w/maltase glucose + glucose

Glucose isomerase isomerization Synthetically developed HFCS- very sweet

Carbohydrates- functional properties of simple sugars• Sweetening• Crystalize• Viscosity/mouth feel• Fermentation• Preservative (antimicrobial agent)• Humectancy

Carbohydrates- functional 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 lactose1/9th less caloric intake

Properties of simple sugars• Crystallization• 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• Crystalize• Viscosity/mouth feel• Fermentation• Preservative (antimicrobial agent)

• Humectancy• Caramelization• Non enzymatic browning • Ripening

Assign

• Read text pg 224-233• Sugars