Abstract
The present study was to isolate and characterize the lactic acid bacteria (LAB) from crimson silage and investigates their antimicrobial, probiotic and antioxidant potentials. The Lactobacillus plantarum KCC-19 was recovered from crimson silage exhibited better antibacterial and antifungal activity and it was deposited in the Korean Collection for type culture (KACC91816P). The secondary metabolites were extracted using organic solvents from spent medium in which KCC-19 was cultivated. The compound was characterized based on the infrared, Mass, C-13 nuclear magnetic resonance (NMR), and H-1 NMR spectral data. MRS medium supplemented with corn steep liquor and phenylalanine enhanced the production of antimicrobial substances under shake flask cultivation condition. The minimum inhibitory concentration (MIC) of the extracts and isolated compound against food spoilage bacteria and fungi was investigated. The ethyl acetate extract and isolated compound showed significant minimum inhibitory concentration against tested microbes. The HPLC analysis revealed that the amount of free amino acids liberated from fermented skim milk was ranged from 1.81 mg/1000 mL to 120.5 mg/1000 mL. KCC-19 was able to survive in bile salts (0.3%), acidic conditions (pH 3) and non-virulent with the highest percentage of hydrophobicity (100%). On the other hand, the antimicrobial susceptibility pattern was an intrinsic feature of this strain. In addition, KCC-19 shows the significant antioxidant activity. Our results suggested that LAB associated with crimson silage, particularly L. plantarum KCC-19, would be valuable sources of antimicrobial, probiotic and antioxidant properties, and hence, KCC-19 was determined to be suitable for application in functional foods.