Κατεύθυνση Χημική Ανάλυση-Έλεγχος Ποιότητας
Library of the School of Science

2014-10-23

2014

Σταϊκίδου Χρυσούλα

Μ. Τσιμίδου Καθηγήτρια (επιβλέπουσα), Ι. Παπαδογιάννης Καθηγητής, Α. Παρασκευοπούλου Επίκουρη Καθηγήτρια

Ανίχνευση της παρουσίας του καρμινικού οξέος στο άρτυμα σαφράνι

Greek

Detection of carminic acid in saffron

Carminic acid (E 120) a natural dye is reported to be used as a bulking agent
for the adulteration of saffron. The aim of this study is the detection of
carminic acid in saffron from relatively small levels of addition until its
complete substitution from the dye. The techniques used were macro and micro
observation, FT-IR, tristimulus colorimetry, UV-Vis and fluorescence. In
addition, some preliminary work was conducted using RP-HPLC. The potential of
various analytical techniques, from simple to more sophisticated ones was
examined in order to develop tools for both small and large size enterprises
involved in trading and packing of saffron. Mixtures of carminic acid:saffron
at ratios of 100:0, 75:25, 50:50, 25:75, 20:80, 15:85, 10:90, 5:95, 1:99,
0.5:99.5 and 0:100 w/w were prepared. Additional mixtures were prepared where
necessary. The adulterant was determined in the presence of endogenous saffron
pigments, the water soluble crocins, to reduce sample pretreatment of the
tested aqueous extracts. No significant differences were observed among
saffron, carminic acid and their mixtures powder after macroscopic examination.
Differences were observed only when water was added to a specific quantity of
powder, the red color of carminic acid is obvious in mixtures with more than
15% w/w level of addition. For the FT-IR examination KBr disks were prepared
and spectra were recorded in the mid infra red region (4000-400 cm-1). After
examination of the spectra the data was subjected to Principal Component
Analysis. Results showed that the detection limit of carminic acid with FT-IR
is possible at 15-20 % w/w level of addition. The technique of tristimulous
colorimetry, which use aqueous extracts, show that the detection of carminic is
possible to relatively low levels of addition due to the changes observed in
color parameter of hue angle from 60ο to 40ο, i.e. from yellow-orange toward
the orange-red region. UV-Vis examination in the region of 200-600 nm and
spectra derivatization showed that the detection of carminic acid was possible
at up to 2% w/w level of addition. For lower levels of addition separation
techniques such as HPLC have to be employed.

Saffron, Adulteration, Carminic acid, FT-IR, UV-Vis

Yes

v-viii

Yes

82

viii, 114

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https://pergamos.lib.uoa.gr/uoa/dl/object/1316209