Through a study called 'A holistic approach to authenticate organic sweet oranges (Citrus Sinensis L. cv Osbeck) using different techniques and data fusion', a group of researchers of the Cordoba-based Alameda del Obispo center, which belongs to IFAPA, have developed a system to differentiate organically-grown oranges from conventional ones. This is done by combining physical and chemical techniques to analyze different parts of the fruit, obtaining 100% accurate results. The traceability of organic products; that is, knowing where they come from and who has handled them, is essential for the market and for the consumer. Thus, this new methodology provides precision and rigor to a confirmation task that until now was carried out by having technicians visit the farms.
“The oranges were processed by separating the flavedo (skin), the pulp, and the albedo (white part). This is the part of the fruit that offered the best data,” says IFAPA researcher Gema Pereira, co-author of the study. On the one hand, the fruit's nutrients were studied by analyzing their humidity, firmness, acidity and sugar levels. Then two more specific analyzes were also carried out.
The first of them looked into the polyphenols, which are antioxidant compounds. Different results were obtained in oranges that had been grown without chemical additives. The second test evaluated the nitrogen levels. This is an element that undergoes slight isotopic changes when it is part of compounds such as ammonium, urea or nitrates, depending on whether fertilizers have been used or not.
The use of mass spectrography, which makes it possible to know the chemical elements of a substance, and liquid chromatography, used to physically separate the compounds present, contributed to the precision of the study.
The next step is to facilitate access to the technique, once 100% reliability has been achieved.