Research background. The carob tree (Ceratonia siliqua L.) is grown primarily for its seeds that are utilized in the production of the highly-prized locust bean gum. The material left after the separation of seeds, from the pods, is utilized in the production of a range of traditional products including carob syrup usually in cottage-type industries. The international market penetration of carob syrup is rather limited and, accordingly, scant information exists on their composition and phytochemical properties in comparison with mainstream syrup. The present study aims to determine key chemical parameters, phenolic profiles, and antioxidant properties of carob syrup and benchmark these against those of date and maple syrup.
Experimental approach. Carob syrup was prepared from 19 accessions of the carob, under laboratory conditions, by a similar procedure to those practiced by small-scale producers. The syrup samples were analyzed along with branded samples of date and maple syrup for pH, browning index, proteins, minerals, hydroxymethylfurfural, sugar composition, total phenols, antioxidant capacity, and phenolic profiles.
Results and conclusions. The pH and sugar compositions of the carob syrup were intermediate to those of date and maple syrup. In general, the carob syrup contained more proteins, minerals, phenolic acids and flavonoids, and total phenols, and exhibited higher antioxidant capacity than the date and maple syrup. The carob syrups exhibited excessive browning and contained more, or comparable levels of, hydroxymethylfurfural than the date and maple syrup. The data indicate that carob syrup provides more nutrients and possesses superior antioxidative potentials to date and maple syrup. The high levels of the carcinogenic hydroxymethylfurfural of the carob syrup warrant milder heating regimens in the concentration step during production.
Novelty and scientific contribution. In contrast to studies based on commercial and/or homemade syrup, this work utilized a relatively large number of laboratory-prepared samples for creating a robust database for carob syrup. The results indicated that carob syrup possesses superior health promotion and disease-protection effects than the widely-traded date and maple syrup. In addition to their potential positive contribution to public health, carob syrup has been shown to be a promising candidate for bolstering the economic returns of farmers in carob-producing countries.
