Volatile constituents and polyphenol composition of Opuntia ficus-indica (L.) Mill from Morocco

The aim of this study is the extraction and the identification of volatile organic compounds (VOCs) and total phenolic compounds of three Opuntia ficus-indica (L.) Mill., species from Morocco, namely Dellahia, Aissa and Shoul. The VOCs were extracted with Solid-Phase Microextraction (SPME) associated to gas chromatography-mass spectrometry (GC-MS) analysis. The antioxidant compounds in extracts were determined by liquid- Chromatography-Mass Spectrometry (LC-MS). The study allowed the identification of forty-six compounds for the VOCs. The most abundant compounds in the three varieties (Dellahia, Aissa and Shoul) were 2-hexanal and n-hexanol with a percentage of 10.6%, 10.9% and 44.0% for the first compound and 10.3 %, 59.0%, 18.7% for the second, successively. The extraction of phenolic compounds permitted the identification and quantification of 15 fractions of flavonoids and phenolic acids. Caffeic acid was the most abundant phenolic acid with 16.0 and 10.8 mg/100g of plant material respectively for Dellahia and Aissa. For flavoinoids composition, isorhamnetin was the major compound. It accounted respectively for 40.5% and 43.2% for Dellahia and Aissa. We can conclude that cactus pear fruits are a good source of natural antioxidants and the major compounds responsible of flavor in the studied varieties are 2-hexanal and n-hexanol.