Amílcar Duarte

The anatomy of the fruit in relation to the propensity of citrus species to split

The anatomy of the fruit has been compared in three prone-to-split mandarin hybrids (Nova, Ellendale and Murcott), several cultivars of clementine mandarin (Fino, Clementina de Nules and Orogrande), and in Owari satsuma mandarin. The fruit of the hybrids is oblate to subglobose and usually presents an open stylar end disrupted by a navel formed by the floral meristem, which is conserved near the apex of the fruit. In the non-prone-to-split clementines as well as in Owari satsuma, the floral axis protrudes inside the style, and the flower meristem is lost through abscission shortly after petal fall. The abaxial side of the carpels fuses with the flower axis forming at the stylar end of the fruit a solid tissue which externally has a small scar at the place of style abscission. Most of the fruits in these cultivars have no navel. In addition, the fruit of clementine is slightly oblate or globose. The relevance of these anatomical characteristics as regards to splitting is supported by the differences between the split and non-split fruits in Nova, the split fruit being more oblate in shape and having a bigger navel than non-split fruit. However, the effect of applied growth regulators on fruit splitting could not be correlated with their effect on the anatomy of the fruit. Additional factors not contemplated in the study also influence fruit splitting.

Pre-harvest rindstain of ‘Encore’ mandarin: initial histological signs of epicarp disturbance and extent of the disorder

Pre-harvest rindstain in ‘Encore’ mandarin starts by the injury of a few epidermal cells. The connection between the damaged epidermis and the collapsed layers of flavedo, extending in parallel with rind surface was only visible on cross-sections containing the narrow zone of injured epidermal cells. The individual cell alteration including loss of membrane integrity and the accumulation of large amounts of osmiophilic materials in the cytoplasm are the result of a degrading process. Minute disruptions in the cuticle may provide shelters for resting forms of amoeboid or plasmodial-like organisms living on the rind. Our results suggest that these organisms could be involved in the disorder expression.

Bioactive compounds of citrus as health promoters

Different chestnut species can be cultivated for fruit production, the most valorised part for nutritional purposes. However Castanea sativa Mill., the “European chestnut”, is one of the most valorised worldwide. Its fruits are consumed either raw or after processing, being boiling and roasting the most usual ones. The nutritional composition of fresh chestnut is variable, with interesting amounts of carbohydrates and fibre, together with low fat content, with differences between cultivars and producing regions. In respect to the presence of bioactive compounds, such as phenolic compounds, vitamins, fatty acids, among others, some studies had focused on the fruit benefits to human health but few reported the effect of processing in those compounds. In this context, this chapter intended to review the current knowledge on chestnut composition, together with the influence of diverse post-harvest technologies, such as refrigeration, flame peeling, freezing with CO2, irradiation, boiling and roasting on the bioactive compounds of chestnut.