Investigating carotenoid loss after drying and storage of

3.3.4 Identification of provitamin A carotenoids
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3. Preliminary study
Several carotenoids were observed on the chromatogram of fresh sweet potato (16; 17;
24; 25; 30; 32; 33; 34; 37; 39 minute retention times) (Figure 3-8). Carotenoids were
identified by diode array by their peak spectrum at three wavelengths.
Figure 3-8: Reverse phase HPLC separation of carotenoids in raw sweet potatoes
1. non-identified polar carotenoid; 2. !-carotene 5,6 epoxide; 3. 13-cis- !-carotene, 4. all
trans-!-carotene; 5. probably 9-cis - !-carotene
Trans-!-carotene peak appeared at 37 minutes (peak 4). The spectrum of maximum
absorption wavelength was 428-452-478 nm in ethanol/hexane, slightly staggered by 2.5
mm compared to literature and % III/II= 13% was in accordance with literature
(Rodriguez Amaya and Kimura 2004). (%III/II is an indicator of fine spectral structure
calculated as ratio of longest-wavelength absorption peak III and that of the middle
absorption peak II) (Figure 3-9).
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4
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