Physicochemical Changes and Antioxidant Activity of Juice, Skin, Pellicle and Seed of Pomegranate (cv. Mollar de Elche) at Different Stages of Ripening.

Luana Fernandes,Domingo M Salazar,Isabel Lopéz-Cortés,Elsa C D Ramalhosa,José Alberto C Pereira,

doi:10.17113/ftb.53.04.15.3884

Abstract

In the present work, we investigate how the degree of ripeness (low, low-medium, medium and medium-high) affects the physical and compositional changes, as well as antioxidant properties of pomegranate fruit (cv. Mollar de Elche). The skin, pellicle, seed and juice were analysed. The fruit mass increased and the fruit skin became reddish (higher a* and lower h*) as the fruit ripening progressed. The lowest concentrations of flavonoids and hydrolysable tannins were recorded in skin and pellicles at medium-high maturity stage, which explains the decrease in the total phenols and reducing power during ripening of pomegranate. On the contrary, the highest concentration of flavonoids (165 mg of quercetin equivalents per 100 mL of juice) was determined in the juice at the most advanced ripening stage, concomitant with the highest total phenols (1695 mg of gallic acid equivalents per 100 mL of juice). Higher DPPH scavenging activity and an increase in the reducing power of juice were also observed during ripening. The trend of the above-mentioned properties allowed describing the fruit development and maturity.

Highlights

Spain is considered one of the most important producers of pomegranate in Europe
The low ripening stage is characterised by immature pomegranates with green skin colour, the low-medium is an early ripening stage in which the skin colour is still green or yellow-green, medium stage pomegranates with reddish-yellow colour are suitable for the export market, and the medium-high stage includes ripe pomegranates with reddish skin colour (Fig. 1a)
Legua et al (32) found that the total soluble solid (TSS) remained constant throughout the ripening of two clones of the Spanish Mollar de Elche cultivar (ME5 and ME17). These results show that there is a great variability in TSS values among pomegranate cultivars, and the lowest values are always reported at earlier ripening stages

Summary

Introduction

Spain is considered one of the most important producers of pomegranate in Europe. Its production is concentrated in the Communities of Valencia, Andalusia and Murcia (1); 90 % of the production is from Alicante (in the south of Valencian Community), of the municipalities of Elche, Albatera and Crevillente, in order of importance (2).The main cultivar planted in Spain is Mollar de Elche, followed by Valenciana (3). Valenciana cultivar, for example, is harvested in early August (3), with very little sun damage and lower risk of pest attack or bad weather, but it has low yield, average to poor internal fruit quality, and small fruit size (3). Mollar de Elche cultivar is harvested much later (late September to mid-November) (3), providing more sun damage and cuts. It is characterised by greater productivity, excellent quality, larger fruits and better acceptance by consumers (3). The harvesting time is an aspect of particular importance since an early harvest may inhibit the development of the characteristic colour, flavour and aroma of pomegranate, while fruits harvested too late may have a reduced shelf life and greater sensitivity to disease (6)

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