Determination of chemical composition, antibacterial and antioxidant properties of products obtained from carob and honey locust

Abstract

Objective: The objective of this study was to characterize flours and syrups, obtained from pods of carob (Ceratonia siliqua L.) and honey locust (Gleditsia triacanthos). Method: Flours and syrups, produced by carob and honey locust were analyzed for moisture, ash, protein content, dietary fibers, minerals composition, total phenolic content, as well as antibacterial and antioxidant activity. Results and discussion: Carob flour contained high amounts of protein (22.56%) and dietary fibres (28.17%), respectively. Dietary fibers in honey locust flour (33.12%) were higher than that of carob flour (28.17%). The total phenolic content of carob flour (4.53 ± 0.08) was lower than this of honey locust (25.31 ± 0.06) (mg gallic acid equivalent [GAE]/g dry weight). Gleditsia triacanthos flour showed higher antioxidant potential – from 127.52 ± 2.43 to 540.28 ± 2.47 μM TE/g dw. Carob syrup in an amount of 0.15 cm3 demonstrated pronounced antibacterial activity against Listeria monocytogenes, Escherichia coli, Salmonella enterica and Staphylococcus aureus, respectively. Conclusion: The current study demonstrated that flour and syrup, obtained from carob (C. siliqua L.) and honey locust (G. triacanthos) pods presented products rich of protein and dietary fiber (both above 20%), good sources of antioxidants, especially poliphenolic compounds and minerals (Mg, Fe and Zn).