3.1. Determination of the carotenoid content
HPLC with diode array detector (HPLC–DAD) was used to identify
the carotenoids content (lycopene, beta-carotene and lutein) in the
extract from different parts of gac fruit. The HPLC–DAD chromatogram
of standard carotenoids (Fig. 1) showed that the elution order
and retention times in minutes were: lycopene, 3.464; beta-carotene,
3.754 and lutein, 5.632. The concentrations of the major
carotenoids extracted from different parts of gac fruit are summarised
in Fig. 2. The major carotenoids found in the samples analysed
in this study were lycopene, beta-carotene and lutein. One gram of
extracted fruit pulp contained 1.8–6.2 mg of lycopene, 3.0–5.4 mg
of beta-carotene and 2.0–18.1 mg of lutein. One gram of extracted
fruit peel contained 1.6–3.4 mg of lycopene, 1.6–5.9 mg of beta-carotene
and 7.9–52.02 mg of lutein. The lycopene and beta-carotene
in the aril were found to be much higher than in the pulp and peel.
Lycopene was a major carotenoid in all fractions being highest in aril
(7.02 mg/g) and lowest in pulp (green; 1.69 mg/g) but not detected
in seed. Aoki et al. (2002) have analysed the caroteneoid of gac and
found that lycopene and beta-carotene in the aril are higher than
that in the fruit pulp. Remarkably, the highest content of lutein
was found in peel (yellow) fractions (52.02 mg/g), which was substantially
higher than other fractions. Its amount was 8-fold that
of aril and 2.8-fold that of pulp (green).