â-Cryptoxanthin (cis and all-trans) (â,â-Caroten-
3-ol). Peak 3 was tentatively identified as cis-â-cryptoxanthin
by the visible absorption spectrum which was
similar to that of trans-â-cryptoxanthin, but with the
maxima at lower wavelengths (difference of 6 nm), a
positive isomerization reaction for cis isomer (bathochromic shift), and a negative epoxide test, both reactions
monitored by HPLC diode array detector.
all-trans-â-Cryptoxanthin (peak 4) was identified by
its visible spectrum (similar to that of trans-â-carotene),
a positive trans isomer reaction, and coelution with the
â-cryptoxanthin standard. The mass spectrum showed
the molecular ion (C40H56O) of 552 m.u. and fragments
at m/z 534 [M - H2O]+, corresponding to the loss of a
hydroxyl group, and at m/z 460 [M - 92]•+, due to
toluene elimination from the isoprenic chain. The ratio
[M]•+/[M - 18]•+ obtained was higher than 1.0; that is,
the intensity of the molecular ion peak exceeded that
of H2O elimination, indicating that the hydroxyl group
was not allylic