Antioxidant properties and effect on lactic acid bacterial growth of spice extracts

The total phenolic content (TPC) and antioxidant capacity as determined by 2,2-diphenyl-1-picrylhydrazyl, 2,2ʹ-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid and ferric reducing antioxidant power assays of spice extracts such as rosemary, lemon balm, hyssop, nettle and cumin seeds were investigated. The effect of spice extracts on the growth of selected lactic acid bacteria (LAB) was also analysed. Lemon balm extract exhibited the highest TPC and antioxidant capacity while the nettle and cumin seeds extracts were characterized by the lowest values. Spice extracts had no impact on the growth of the most tested LAB except for rosemary extract, which showed an inhibitory effect towards all strains of Lactobacillus acidophilus and L. delbrueckii. These results suggest that spice extracts may be considered as additives in dairy and meat products in which LAB are present.