ISHS Acta Horticulturae 1396: VII International Conference Postharvest Unlimited
Evaluation of a ripening gradient across the blood orange fruit at ten maturity stages |
| Authors: | M.E. García-Pastor, J. Puente-Moreno, F. Garrido-Auñón, D. Valero, M. Serrano |
| Keywords: | anthocyanins, colour, gradient, total acidity |
| DOI: | 10.17660/ActaHortic.2024.1396.2 |
| Abstract:
Fruit colour is the first characteristic perceived by consumers and, therefore, is one of the key factors influencing market value. In the case of blood oranges, the changes in colour that take place during ripening are related to the synthesis and degradation of three major pigments, namely chlorophylls, carotenoids, and anthocyanins. Chlorophylls are the predominant pigments in the green skin of an unripe citrus fruit, while the yellow-orange colours, of a mature fruit are due to carotenoids and the purple-red colours of flesh and skin in some citrus cultivars are due to anthocyanins. In the present experiment, a ripening gradient across the blood orange fruit, ‘Sanguinelli’, at different maturity stages (S1 to S10), was evaluated. These ten maturity stages of blood orange fruit were chosen according to the external fruit colour and each fruit was cut into four sections (the peduncle, proximal equator, distal equator, and the stylar end), in which total soluble solids (TSS), total acidity (TA), internal colour and the content of total anthocyanins in both juice and skin were measured. Results showed that the external hue angle significantly decreased from S1 to S10, leading to a colour change from green to orange and then, to red. On the other hand, differences on internal colour among sections were only significant after the S5, where both proximal and distal equators showed a deeper colour than the peduncle and the stylar end. On the other hand, both equator sections showed the higher amount of TSS, this difference being greater from S7. Contradictorily, the highest differences in TA were obtained at S7, and the peduncle and the stylar end were those sections with the higher TA values. Finally, the total anthocyanins content of juice and skin was significantly higher at both equators and the stylar end from the S1, these differences being among sections minimized at the most advanced stages of maturity. In conclusion, results show that maturation along the longitudinal section of blood orange fruits evolves in a different way, starting at equatorial areas, as the central sections of fruit, and going on distal and basal sections. | |
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