Chromoplast Morphology and β-Carotene Accumulation during Postharvest Ripening of Mango Cv. ‘Tommy Atkins'

Accumulation of β-carotene and trans−cis isomerization of ripening mango mesocarp were investigated as to concomitant ultrastructural changes. Proceeding postharvest ripening was shown by relevant starch degradation, tissue softening, and a rising sugar/acid ratio, resulting in a linear decrease (R 2 = 0.89) of a ripening index (RPIKS) with increasing ripening time. A modest accumulation of all-trans-β-carotene and its cis isomers resulted in a slight pigmentation of the mango chromoplasts, because ambient temperatures of 18.2−19.5 °C provided suboptimal ripening conditions, affecting color development and β-carotene biosynthesis. The ultrastructures of chromoplasts from mango mesocarp and carrot roots were comparatively studied by means of light and transmission electron microscopy. Irrespective of the ripening stage, mango chromoplasts showed numerous plastoglobuli varying in size and electron density. They comprised the main part of carotenoids, thus supporting the partial solubilization of the pigment...