Week3-Course1 Flashcards
In 2016, ……. Increased in the world after a steady period of decline. It now affects 815 million people.
world hunger
In the developed countries, … of adults are obese.
28%
What are monosaccharides?
the fundamental units from which other carbohydrates are built up.
What is the active form of the carbohydrates?
Open chain form.
When changing from cyclic to open chain format, one of the ____ groups becomes a ___ group
hydroxyl
carbonyl (either aldehyde (glucose and galactose) or ketone :fructose)
Complete : _____ (FOS) and ___ (GOS) are _____
fructo-oligosaccharides
galacto-oligossacharides
pre-biotics
What is the most common polysaccharide in food?
starch
What is starch made off?
polymers of α-D-glucose
What are the two polymeric form of starch?
- Amylose
2. Amylopectin
What type of bond link the glucoses to form the amylose
α-D-glycosidic link
T or F : amylose has less glucose units than amylopectin
T, amylopectine is commonly 1000 units while amylose has 250-300 units
Where are the branch points of amylopectine?
every 15-25 units
What is the functional role of starch in food system?
thickening and texture modification (ONLY IF GELATINIZATION CAN OCCUR)
What is required in order to have gelatinization?
Heat and water
___ is the process by witch granules are disrupted due to the increase in energy and start to absorb water and swell
gelatinization
Complete : ____ increase with _____ until it reach a certain point. Beyond that point, the ____ begins to decrease.
Viscosity
temperature
Viscosity
Explain the formation of a gel
When gelatinized starch (that didn’t went beyond the maximum viscosity point) cool down, the hydrogen bonds reform and traps the water molecules in the newly formed 3-D structure.
What is the difference between gelatinized starch and gel starch
in gelatinized starch the water molecules are trapped in the hydrogen bonds original to starch while in gel starch, the water molecules are trapped in newly formed hydrogen bonds.
What is retrogradation?
firmer gels due to the over formation of hydrogen bonds between the starch chains
What is syneresis?
loss of water molecules during retrogradation. The over formation of hydrogen bonds will eventually push water out of the 3-D structure.
Name three factors that affect the gelatinization behavior and tendency to retrogradation
- Size of the granules
- amylose/amylopectin ratio
- Average length of amylose and amylopectin
What is the goal of chemical modification of starch?
obtaining a much wider range of functionality
Give examples of chemical modification you can make to starch
- pregelatinized tarch
- hydrolysed starch
- cross-linked starch
- derivatized starch
Cellulose is a polymer of _____ units:
β-D-glucose
What makes the cellulose indigestable from humans
the β-D-glucosidic bond
T or F : amylase are the enzymes capable of breaking the β-D-glucose polymer chain in humans
F
What are the functional roles of MCC? (11)
1- anti-caking agent 2-stabilize foams 3- stabilizes emulsions 4-replaces fats and oils 5-forms gel 6-modify texture 7-improves quality of low solids tomato sauces 8-retards ice crystal growth 9-extends starches 10-suspending agent in icecream 11-tabletting agent
What is CMC
Carboxymethylcellulose (CMC) is a chemically modified cellulose: some CH2OH groups are replaced by CH2COOH groups to increase solubility in water.
Complete : _____ are polysaccharides and are substance derived from shrubs or trees
vegetable gum
Witch vegetable gum is used in the gluten free baked goods to improve the consistency?
Guar gum
What is the difference between cellulose and starch?
The glycosidic bond. For starch it is alpha-d and for cellulose it is beta-d
T or F : polysaccharides are indigestible
f
T or F : the oligosaccharides don’t give energy since they are not digested
False, because they produce organic acid and these have calories that can be used.
T or F : Fos and Gos are digestible
false
T or F : starch is unsoluble
true
T or F: the starch granules are functionnally useless as is
true, they have a function if heated (gelatininization)
