Enzymatic and antioxidant activity of camel milk fermented with different strains of lactic acid bacteria

The aim of the present study was to compare antioxidant activity of different LAB viz Lactobacillus delbrueckii sub sp. Bulgaricus, Lactobacillus casei, Lactobacillus plantarum and Streptococcus thermophilus. The camel milk was fermented with Lactobacillus delbrueckii sub sp. Bulgaricus, Lactobacillus casei, Lactobacillus plantarum and Streptococcus thermophilus at 37°C upto 12 hr. The resulting fermented camel milk was evaluated with respect to the changes of pH, acidification) and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), 2,2'-azino-di-(3- ethylbenzthiazoline sulfonic acid (ABTS) inhibition assay and enzymatic assay including Catalase, Sod and GST during 0 h to 12 hr fermentation time at 37°C. L. plantarum and S. thermophilus increases the acidityof fermented milk more rapidly (p < 0.05). The Lactobacillus delbrueckii showed highest ABTS activity (61.84 ± 0.34) and S. thermophilus showed lowest ABTs activity (43.60 ± 0.40), while Lactobacillus casei fermented milk had highest DPPH activity (7.52 ± 0.13) at different fermentation time. The Lactobacillus plantarum showed highest value of SOD (4.54 ± 0.013), catalase (200.17 ± 0.95) and GST activity (9.13 ± 0.155) at different fermentation time. In conclusion, compared to Lactobacillus delbrueckii sub sp. Bulgaricus, Lactobacillus casei and Streptococcus thermophilus, Lactobacillus plantarum showed higher antioxidant activity and can be used as a potential probiotics. It also found that the variation in antioxidant activity of fermented camel milk with 4 different LAB could be due to the change in pH, change in fermentation time or formation and breakdown of bio-active peptides during fermentation process.