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Carbohydrates_exam1

food sci

QuestionAnswer
Carbohydrates are composed of? carbon, hydrogen, and oxygen
Empirical formula of carbohydrates is (CH_2_O)n
The two main classes of carbs are simple sugars (soluble) and complex carbs or polysaccharides (large molecules like jelly and pectin)
Carbohydrates are composed of? carbon, hydrogen, and oxygen
Empirical formula of carbohydrates is (CH_2_O)n
The two main classes of carbs are simple sugars (soluble) and complex carbs or polysaccharides (large molecules like jelly and pectin)
in plants simple sugars are a direct source of what? energy which is formed by photosynthesis
photosynthesis CO_2_ + H_2_O = (CH_2_O)n
complex carbs are used for either storage forms of energy or structural components
Sugar is not based on sweetness but structure
Monosaccharides - are made up of 5 or 6 carbons - contains a functional carbonyl group C=O - and hydroxyl groups -OH
What are some important Monosaccharides? Glucose (GLU), Galactose (GAL), Mannose (MAN), and Fructose (FRU).
These monosaccharides have different structures and functions but the same number of atoms
Disaccharides sucrose, lactose, maltose
Sucrose glu-fru (table sugar 99.5% pure)
Lactose gal-glu (found in milk)
Maltose glu-glu
Tri/tetrassacharides raffinose, stachyose (found in plants and beans)
Raffinose gal-glu-fru
stachyose gal-gal-glu-fru
linkages of sugars sugar units in oligo- or polysaccharides are linked by a condensation between hydroxyls
digestibility depends on the chemistry of the linkage between sugars and the presence of enzymes in the intestine which can break that linkage
Indigestible polysaccharides constitute dietary fiber
Properties of sugars soluble in water, crystallize easily, sometimes sweet, react with proteins and amino acids to give brown colors and flabors (when heated like baking)
Sweetness is related to the 3d structure and depends on the position of oxygen atoms and hydroxyl groups
Sweetness level fructose > glucose > galactose > mantose (most bitter)
Corn syrup natural sweetener made from corn starch (a polymer of glucose)
High fructose corn syrup is made by isomerization of glucose
Artificial and non-nutritive sweeteners Saccharin, Aspartame - a dipeptide, acesulfame K
Saccharin 1st artificial sweetener
Aspartame - A dipeptide nutersweet / can't be used in heat process or it'll lose sweetness
Acesulfame K example: Splenda Chemical derivative
Polysaccharides polymer of sugar units n(s) --> (S)n
n is usually very large > 100
Starch provides the most calorie (designed to be synthesized and broken down)
Polysaccharides exist in two forms amylose (linear) and amylopectin (branched)
Is starch digestible yes, it can form gels on cooling if the concentration is high
Cellulose all plants contain cellulose (resistant to digestion because of linkage)
Pectin is found in plant cell walls
Pectins are polymers of galacturonic acid which is indigestible
Pectins can be strengthened by cross linking with calcium
Created by: lindarim