1. Lecture V CHO Reactions III
Anomeric hydroxyl group
Both carbonyl & hydroxyl groups
Hydrolysis
Lecture #5 - CHO Reactions III
Will cover Rxs of
...Anomeric hydroxyl group
...Both carbonyl & hydroxyl groups
...Hydrolysis

2. Reactions of Carbohydrates IV Anomeric hydroxyl group
Carbonyl group (only)
Hydroxyl groups
Anomeric hydroxyl group
Both carbonyl & hydroxyl groups
Hydrolysis
Dehydration/degradation

3. Reactions of Carbohydrates IV Anomeric hydroxyl group
Formation of glycosyl halides
Oxidation to lactones*
Note: Asterisks indicate common biochemical reactions

4. Reactions of Carbohydrates IV Glycosyl halides
A Walden Inversion O
CH2OAc
OAc
AcO O
CH2OAc
OAc Br
AcO
AcOBr
an a-glycosyl halide -
acetobromo sugar
b-D-glucose pentaacetate

5. Reactions of Carbohydrates IV Glycosyl halides
Another
Walden Inversion O
CH2OAc
OAc Br
AcO O
CH2OAc
OAc OR
AcO
ROH
Ag2CO3
a-glycosyl halide -
acetobromo sugar
Anhy MeOH
Na metal(trace)
b-D-glucose tetraacetate
CH2OH O OR OH
Note, “Ac” = CH3C- =O HO OH
b-glycoside

6. Reactions of Carbohydrates IV Anomeric hydroxyl group
Formation of glycosyl halides
Oxidation to lactones*
Note: Asterisks indicate common biochemical reactions

7. D-Glucono-d-lactone (GDL)
LACTONES O OH
HOH2C C H
D-Gluconic acid
CH2OH C OH
COOH
-H2O
D-Glucono-1,4-lactone or
D-Glucono-g-lactone
+H2O O
CH2OH OH
GDL
D-Glucono-1,5-lactone or
D-Glucono-d-lactone (GDL)

8. Reactions of Carbohydrates V Carbonyl & hydroxyl groups
Carbonyl group (only)
Hydroxyl groups
Anomeric hydroxyl group
Both carbonyl & hydroxyl groups
Hydrolysis
Dehydration/degradation

9. Reactions of Carbohydrates V Carbonyl & Hydroxyl Groups
Formation of cyclic hemiacetals (rings)*
Formation of acetals (glycosides)*
Mutarotation
Aldose <--> ketose isomerizations
Note: Asterisks indicate common biochemical reactions

10. RING FORMATION H O C CH2OH OH H O HO C CH2OH CH2OH CH2OH O C OH H HO6
CH2OH C OH O 5 4 3 2 1 H 6
CH2OH 5 C OH 3 2 1 H 4 HO O O
CH2OH OH 6 5 4 3 2 1 6
CH2OH 5 C O OH 3 2 1 H 4 HO

11. Glycosides alkyl D-glucopyranoside D-glucose aglycon CH2OH CH2OH O O
+ ROH O
CH2OH OH O
CH2OH OH OR
+ H2O H+
alkyl
D-glucopyranoside
D-glucose

12. Monosaccharide isomerization
CH2OH C OH O H
CH2OH C OH H
CH2OH OH C O
D-Fructose
trans-enediol
D-Glucose
CH2OH C HO OH O H
CH2OH C OH H
trans-enediol
D-Mannose

13. Reactions of Carbohydrates VI Hydrolysis
Carbonyl group (only)
Hydroxyl groups
Anomeric hydroxyl group
Both carbonyl & hydroxyl groups
Hydrolysis
Dehydration/degradation

14. Starch (Amylose), considered as a condensation polymer of glucose

15. Reactions of Carbohydrates VI Hydrolysis
Mechanism
Products of hydrolysis
Corn Syrups
Compositions
DE (dextrose equivalents)

16. Reactions of Carbohydrates VI Hydrolysis MechanismOR H + OH
ROH
H2O
-H+
Mechanism of acid-catalyzed hydrolysis of alkyl pyranosides

17. Reactions of Carbohydrates VI Hydrolysis
Corn Syrups
Production
Typical composition
DE (dextrose equivalents)
(% reducing power, compared to dextrose)

18. Reactions of Carbohydrates VI Hydrolysis
Corn Syrups
Production
Reversion

19. Reactions of Carbohydrates VI Hydrolysis
Corn Syrups
Production
Corn Syrup Solids (CSS)
( DE)
hygroscopic
humectant

20. Reactions of Carbohydrates VI Hydrolysis
Corn Syrups/CSS
Uses/Applications
Table Syrups
Humectants
Bulk & body
Sweeteners
Dairy products (ice cream), jams, jellies, pickle relish, confections, etc.

21. Reactions of Carbohydrates VI Hydrolysis
High Fructose Corn Syrups (HFCS)
Production
Jet cooking of starch w/ enz
Cool, further treat w/ enz
Clarify, decolor, concentrate

22. Jet Cooker picture/schematic

23. Reactions of Carbohydrates VI Hydrolysis
HFCS/Glucose/Fructose
Production
Clarified syurp - seed w/ glucose for D-glucose
Fructose - treat glucose soln w/ glucose isomerase
Ion Exchange resin treatment

24. Typical, Commercial HFCS Products
NOTE: % figures are on dry basis