Food Chem Flashcards
Why are sugars called polyhydroxy sugars?
Because sugars (carbohydrates) have a hydroxyl group and either an aldehyde or a ketone group
Sucrose (a disaccharide), also known as table sugar is composed of ____ + ____
glucose and fructose
Give examples of disaccharides
Sucrose, Lactose, Maltose (most abundant)
Also known as milk sugar
Lactose
Also known as malt sugar
Maltose
Lactose is made up of ____ + _____
glucose and galactose
Maltose is made up of ____ + _____
Glucose and glucose
What is a trisaccharide?
it is a carbohydrate composed of 3 monosaccharides
Oligosaccharides are composed of ______ monosaccharides
2 to 10
Where are the most abundant disaccharides (sucrose, lactose, maltose) found?
Sucrose - found in most fruits and veg
Lactose - found in milk and dairy products
Maltose - found in malted drinks
Monosaccharides are joined together by the ______.
Glycosidic bond/linkage
Polysaccharides can either be ______ or ______.
Homopolysaccharides or heteropolysaccharides
Give examples of Homopolysaccharides
starch and cellulose
Give examples of Heteropolysaccharides
pectins, gums
Monosaccharides are simple sugars composed of ____ carbons in a chain
3 to 7
Monosaccharides with an aldehyde group at C1 are called _____, while those with a ketone group at C2 are called ______
aldoses, ketoses
What does the R/S configuration mean, also the D/L configuration
R/S configuration, also known as the D/L configuration is used to describe the steriochemistry of sugars.
R configuration or Dextro means (+) sign
S config or Levo means (-) sign
All naturally occurring sugars have what configuration?
R configuration; naturally occurring sugars are D-sugars
Where is the -OH group located in naturally occurring sugars?
OH is located FARTHEST from the carbonyl group and at the RIGHT in a Fischer projection
TRUE or FALSE:
D-glucose is readily metabolized by the body while L-glucose is not
TRUE
What is the most abundant type of aldoses?
Glucose
a type of reaction involving water
Glucose is made from what?
reaction between homopolysaccharides
Glucose is made from the hydrolysis of starch and cellulose
identify the type of reaction involving water
Galactose is made from what?
rxn with heteropolysaccharides
Galactose is made from the hydrolysis of fruit pectins
choose which one
All monosaccharides are reducing or nonreducing sugars
All are reducing sugars