Determination of antioxidative activity and exopolysaccharide level production by lactic acid bacteria isolated from fermented meat

Abstract

Lactic acid bacteria (LAB) are known for their fermentative activities which enhance the hygienic and sensory qualities of fermented meat products. This study investigates some biofunctional properties such as antioxidative activity, exopolysaccharide (EPS) production and biosurfactant activity of selected LAB known for their their low spoilage, antimicrobial and safety characteristics including Enterococcus (E.) faecium (K11 and K19), Latilactobacillus (Lat.) sakei K25, Lat.sakei subsp. sakei (K22 and K26), Lactiplantibacillus (Lpb.) paraplantarum (K7, K8, K18 and K21), Pediococcus (P.) acidilactici (BK 14 and BK17), Weissella (W.) cibaria (BK2 and BK19), W. confusa (BK6 and BK11) and W.paramesenteroides BK8 strains isolated from traditional Algerian Kaddid meat. The strains Lat. sakei subsp. sakei K22 and W. cibaria BK19 exhibited the highest DPPH activity with scavenging rates of 97%. While for hydroxyl radical scavenging activity the strains Lpb. paraplantarum K18 and K21, P. acidilactici BK17 and W. confusa BK6 exhibited the highest activity ranging from 86% to ~100%. Furthermore, anti-lipid peroxidation rate was found low-to-moderate varies between 31.43% to 42.857%, However, 1mg/L of ascorbic acid used as control positive exhibited a value of 52.85% .Beside, the spoilage character of some overproducers LAB strains such as W.cibaria BK19 which can reach EPS level 2464.625 mg/L which may impact negatively the texture of dry-fermented meat. In the other hand, low-to-moderate EPS LAB producers were determined particulary in the case of E. faecium K11, Lat. sakei K25 and Lpb. paraplantarum K7, emphasizing the need for a careful selection and optimization of EPS (-) future starters. The biosurfactant activity was revealed by all the strains by drop-collapse tests, Thereby, the emulsification index was measured and no significative variations between LAB nor with SDS (1%) used as positive control. Based on those findings and the previous functional screenings studies, Lpb. paraplantarum (K18 and K21), Lat. sakei K25 and Lat.sakei subsp. sakei (K22 and K26) could be suggested as bio-functional LAB starters to be used for preparing safe, stable and healthy fermented meat products