Assessing the volatile profile of carob tree (Ceratonia siliqua L.)

Biogenic volatile organic compounds (VOCs) contribute to the communication, growth, breeding, and defense of plant; their role in plant kingdomis vital. Carob tree is cultivated mainly in Middle East and eastern European countries (e.g., Spain, Italy, Greece, Cyprus) and lately in Australia, the USA, and South Africa. Therefore, it is examined as a case study for its volatile emissions in the environment. Apart from the VOCs emitted from carob flowers and fruit, carob is considered of great interest for the food industry (carob powder), not only for its health benefits but also due to its characteristic strong aroma, which can be maintained even after processing (roasting). Solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) analyses of carob flowers, fruit, and powder (commercial samples) were performed and the detected VOCs are presented and discussed. The most prominent chemical classes emitted from carob fruit and powder appeared to be acids followed by esters and aldehydes/ketones, whereas from carob flowers the terpenoids. The strongest VOCs both in carob fruits and powder were propanoic acid, 2-methyl (isobutyric acid) and in flowers ethanol. The uniqueness of carob benefits is well known in the agriculture, pharmaceutical, cosmetic, and food sector and is closely related to the agro-economy and long history of eastern Mediterranean countries.