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4.
3’‐Epilutein
o
(3R,3’S,6’R)‐lutein
o
Not dietary—
no biological or commercial role
o
Significant epimer product and loss of lutein
o
Occurs in aqueous acid
o
Reaction likely proceeds by S
N
1 and S
N
2, but mostly S
N
2 since
conversion exceeds 50%
o
Structure
General Analytical Needs
Method should
–
Quantitatively de‐esterify all analyte forms
–
Separate and accurately quantify relevant free analytes
•
Lutein
•
Zeaxanthin
•
β‐Cryptoxanthin
•
3’ Epilutein (principal lutein metabolite)
‐
–
Determine the above in
•
Raw materials used in dietary supplement formulations
•
Finished products?