Bioactive compounds as markers of authenticity in Citrus-based beverages and commercial juices

Citrus-based products such as commercial beverages and juices are widely consumed around the world and, in recent years, they have received much attention because of potential therapeutic benefits associated with their high content of bioactive compounds: among them, vitamins, flavonoids and polyphenols reportedly having antioxidant, anticancer and anti-inflammatory properties. These substances also have great importance for the nutritional, organoleptic and commercial properties of fruits and derived products, contributing to their sensory characteristics (colour, sweetness, bitterness and astringency). Since commercial Citrus juices and beverages represent high-value products traded on a massive industrial scale, their adulteration is a common occurrence in the marketplace. Therefore, it is very useful to develop innovative analytical methods providing reliable measurements of their bioactive substance contents, paying attention to potentially beneficial compounds as markers of authenticity. Two methods have been developed for this purpose, based on HPLC with spectrophotometric (UV) and spectrofluorimetric (F) detection. The sample pre-treatment is carried out by means of original extraction procedures. For example, auraptene and umbelliferone, two coumarin-based molecules, can be investigated in different commercial chinotto-based “soft drinks” to exclude the use of flavours instead of fresh fruits; tartaric and citric acid can be analysed in orange juice to identify frauds in commercial products. The preliminary results are very promising and the proposed analytical methods seem suitable for these purposes.