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Anomeric carbon?
- the carbony-bearing carbon, which becomes asymmetric when the open-chain structure closes to form the ring structure
- determine if it's a or b
- very reactive (glycosidic linkage between simple sugars)
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D vs L sugar
- based on the configuration around the highest unmbered chrial carbon.
- D= right
- L= left
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alpha vs beta
- a = ant = down
- b = bird = up
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condensation?
hydrolysis?
- con: forming bond, release water
- hydro: breaking bond, with addition of water
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invert sugar
- equimolar mixture of D-glucose and D-fructose formed by hydrolysis of sucrose
- degreesrotation of plane-polarized light is 'inverted' from psitive to negative
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reducing sugar
- the anomeric carbon reduce Fehlings/Benedicts Reagent
- most simple sugars are reducing sugars, except sucrose
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what's the significance of reducing sugars?
browning!!!!! =]
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Relative Sweetness
- from sweetest
- fructose
- sucrose
- glucose
- maltose
- galactose
- lactose
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amylose
- glucose polymer with a-1,4 bond
- liner
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amylopectin
glucose polymer with a-1,4 and 1-a,6
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vegetable gums
- complex polysaccharides that typically impart hight viscosity at low concentrations
- eg. Agar
- Alginates
- Carrageenans
- Locust bean gum
- Guar gum
- Gum arabic
- Xanthan gum
- microcrystaline cellulose
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what's vegetable gums used for?
- inhibit crystallization
- whipping aid
- foam and emulsion stabilizer
- adhesive 黏的 and binding agent
- coating agent
- prevent gel breakdown
- suspend solids
- flavor carrier
- fat replacer!
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Fiber
- cellulose (polymer of glucose linked beta 1-4)
- hemicellulose (complex polymers of zylose, glucose and various ...)
- pectin (galacturonic acid and methyl ester... a 1-4)
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