Blood oranges, an unknown gem in Spain with excellent properties.

The project, currently in an intermediate phase, aims to study the influence of suitable patterns for the cultivation of pigmented oranges, as well as the evaluation of different varieties of this type of oranges that best adapt to climate change, with a special emphasis on Mediterranean conditions. The goal is to revive the cultivation of this type of fruit, currently absent in Spain, and of great interest to both producers and exporters.

The sweet orange (Citrus sinensis) is the most cultivated Citrus species in the world, reaching a global production of 79 million tons. Varieties of sweet oranges can be divided into two main groups: the white oranges that we commonly consume, and the blood orange or pigmented orange, widely popular in Italy but almost unknown in Spain. Blood oranges exhibit reddish tones in the pulp and skin (intensity varies depending on the variety of pigmented orange). Anthocyanins are the pigments responsible for this characteristic coloration in the pulp, peel, and juice of pigmented oranges. Under specific environmental conditions (high daytime temperatures and low nighttime temperatures), the tree biosynthesizes these pigments in high concentrations, resulting in the distinctive coloration of blood oranges. The health benefits of anthocyanins have been well-documented in scientific literature, as they act as potent antioxidants that can contribute to improving the population's diet and, consequently, potential long-term health gains.

The Mediterranean climate is conducive to the cultivation of these blood orange varieties, making Italy the leading country in blood orange production, where 70% of cultivated sweet oranges are of blood orange varieties. The "Newblood" project aims to promote the cultivation of blood oranges in Spain. In our country, the percentage of produced blood oranges does not exceed 1% of the total, indicating that Spain has significant potential to develop the cultivation of these varieties and expand its market.

When cultivating citrus from seeds, one would need to wait for the plant to complete its juvenile period before bearing fruit, which in some cases could take up to 10 years. This is why patterns or rootstocks are employed. One of the objectives of the "Newblood" project is to study the agronomic behavior of different graft/rootstock combinations, allowing for optimal and specific selection according to the requirements of farmers and consumers. Simultaneously, the project aims to select varieties that are more resilient to the demanding environmental conditions brought about by climate change. To achieve this, the project has already conducted a study comparing different combinations of blood orange varieties on two different rootstocks (Citrus macrophylla and Citrus reshni), demonstrating the suitability of both rootstocks for blood orange cultivation but with differences in agronomic parameters (fruit size, fruit weight, juice quantity) and the amount of bioactive compounds (anthocyanins, flavones, etc.).

Another objective of the "Newblood" project is the morphological, chemical, and biochemical characterization of various pigmented orange varieties, with the aim of understanding the plant material and the quality of the products of interest. The project has studied the main morphological parameters of the fruit, as well as the composition of its juice and the content of primary and secondary metabolites in 8 varieties of blood oranges, finding differences among them. These findings represent an undeniable advancement for Spanish fruit cultivation, allowing access to varieties with higher productivity, organoleptic quality, and nutritional value.

The "Newblood" project not only focuses on finding varieties and patterns to ensure resilient crops in current environmental conditions but also considers future applications based on sustainable utilization and economy. In this regard, the project has studied the chemical composition of the skin of different blood orange varieties, concluding that the extract from the skin of these oranges could have potential applications in the development of food preservatives or nutraceutical products, thanks to its bioactive compounds.

Finally, in the project's yet-to-be-executed final phase, post-harvest life of pigmented oranges will be studied through the application of different conservation treatments and evaluation of fruit quality to extend the shelf life of the oranges. It is known that one of the challenges of blood oranges is their short conservation period before developing overripeness symptoms.