Geographic authentication and quality assessment of Canary Islands Aloe: An isotopic and phytochemical approach

The increasing European demand for high-quality, safe agricultural products have led to the development of stringent control measures to certify product authenticity and geographical origin, protecting both producers and consumers from potential fraud. This study focuses on Aloe Vera, a plant containing around 200 potentially active compounds of interest in the health and wellness industry, including vitamins, minerals, anthraquinones, and polysaccharides. The Canary Islands has a unique climate, which, combined with young volcanic soils, produce exceptionally high-quality Aloe Vera. However, fraudulent Aloe Vera products falsely labelled as having Canarian origin currently represent a 21 million euros market. This situation necessitates the development of reliable scientific protocols for geographical tracing of Canarian Aloe Vera and its derivatives (juices, gels, creams, cosmetics). Chemical profiling of Aloe Vera across the Canary Islands and the Iberian Peninsula includes the determination of strontium isotopic ratios (⁸⁷Sr/⁸⁶Sr) by thermal ionization mass spectrometry (TIMS) to trace geographic origin at certified grower plantations, complemented by phytochemical profiling to verify optimal growing conditions and quantitative quality standards. Complete Aloe Vera plants have been analysed, revealing distinct bioactive organic compounds of interest, including phenolic acids, flavonoids, terpenoids, anthraquinones and derivatives, among others. ⁸⁷Sr/⁸⁶Sr ratios in Canarian Aloe Vera plants are higher (0.7065-0.7078) than those expected from their dominantly basaltic volcanic soils (0.7032-0.7068), but lower than soil values observed in mainland Spain (0.7089-0.7124). Therefore, development of a full ´fingerprint´ profile of Canarian Aloe Vera must also quantify ⁸⁷Sr/⁸⁶Sr contributions from irrigation water sources and additives used in the growing and manufacturing process.