Quantification of Carotenoids, α-Tocopherol, and Ascorbic Acid in Amber, Mulligan, and Laird's Large Cultivars of New Zealand Tamarillos (Solanum betaceum Cav.)

Abstract

Amber (yellow), Laird's Large (red) and Mulligan (purple-red) cultivars of New Zealand tamarillo fruit were separated into pulp (endo- and mesocarp) and peel (exocarp), and analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) for carotenoids, α-tocopherol and ascorbic acid contents. Fresh Mulligan pulp had the highest content of β-carotene (0.9 mg/100 g), α-tocopherol (1.9 mg/100 g), and ascorbic acid (28 mg/100 g). Higher concentrations of β-carotene and ascorbic acid, and lower concentrations of α-tocopherol were detected in pulps compared with peels. Compared with standard serves of other fruit, tamarillo had the highest β-carotene (9-20% RDI (recommended dietary intake)/serve), high ascorbic acid (67-75% RDI/serve), and α-tocopherol (16-23% adequate intake/serve). All cultivars had diverse carotenoid profiles dominated by provitamin A carotenoids (β-carotene and β-cryptoxanthin) and xanthophyll carotenoids (lutein; zeaxanthin and antheraxanthin). Favorable growth conditions (high light intensity and low temperature) may explain the higher antioxidant vitamin content in New Zealand tamarillos compared to those from other countries. Tamarillo peels may be used as natural food coloring agent to reduce waste and deliver sustainable production.

Keywords: ascorbic acid; carotenoids; dietary antioxidants; provitamin A; tamarillo; α-tocopherol; β-carotene.

Figure 1

Multiple Reaction Monitoring (MRM) chromatograms of α-tocopherol, β-carotene and ascorbic acid standards.

Figure 2

Average contents of β-carotene (A), α-tocopherol (B), and ascorbic acid (C) in the peel and pulp of three New Zealand tamarillo cultivars (■ Amber, ■ Laird’s Large, ■ Mulligan). Data are presented as mean (mg/100 g FW) and error bar (standard deviation) (n = 3). Different letters indicate statistical difference (p < 0.05).