Nutrition And Food In Health And Disease

en Limosilactobacillus fermentum RSB9: Isolation and Identification, Viability in Acidic and Bile Conditions, Antimicrobial Activity, Antioxidant Power, and Safety Properties Food Science Food Science پژوهشي Research Background and Objectives: Probiotics are an important group of living microorganisms that improve the host's metabolism, strengthen the immune system, modulate the intestinal microbiota, and demonstrate its beneficial effects in the host. Therefore, the present study was conducted with the aim of molecular identification of Limosilactobacillus fermentum RSB9 isolated from traditional yogurt and evaluation of its viability in acidic and bile conditions, antimicrobial activity, antioxidant power, and safety properties. Materials and Methods: The strain's identification involved the utilization of the polymerase chain reaction (PCR) method. The viability of the strain was assessed in both acidic conditions (with pH values of 3, 4, and 5) and bile conditions (at concentrations of 0.3%, 0.5%, and 0.7%). Further evaluations included antimicrobial activity utilizing the well diffusion agar and disc diffusion agar methods, determination of antioxidant power through ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (2,2-Diphenyl-1-picrylhydrazyl), analysis of cell surface hydrophobicity, cholesterol absorption capabilities, and safety aspects such as antibiotic sensitivity, hemolytic activity, DNase activity, and biogenic amine (BAs) production. Results: The findings of this research show the high stability of this strain against different concentrations of acid (pH values of 3, 4, and 5) and bile salts (0.3%, 0.5%, and 0.7%). The surface hydrophobicity of L. fermentum RSB9 was measured to be 54.09 ± 0.40%, with its ability to absorb cholesterol measured as 43.60 ± 0.45%. Additionally, the antioxidant activity of this isolate using DPPH and ABTS methods was determined to be 48.90% ± 0.57 and 52.50% ± 0.43, respectively, demonstrating a high potential for inhibiting free radicals. The antimicrobial potential of L. fermentum RSB9 was evaluated using agar diffusion methods with wells and disc diffusion in agar, revealing strong antimicrobial activity against the investigated pathogenic species. This bacterium was also found to be sensitive to most of the tested antibiotics. L. fermentum RSB9 did not exhibit any hemolytic or DNase activity and was unable to produce biogenic amines (BAs). Conclusions: Therefore, the study confirmed the probiotic potential of Limousin L. fermentum RSB9, highlighting its stability against different concentrations of acid and bile salts, acceptable cell surface hydrophobicity, cholesterol reduction ability, free radical inhibition, antimicrobial activity, lack of hemolytic or DNase activity, and absence of biogenic amine production. These findings support the introduction of L. fermentum RSB9 as a new probiotic strain with suitable biological and functional characteristics. Probiotic properties, Antioxidant activity, Safety evaluation, Limosilactobacillus fermentum RSB9 1 10 http://nfsr.sbmu.ac.ir/browse.php?a_code=A-10-542-5&slc_lang=en&sid=1 Behrooz Alizadeh Behbahani behrooz66behbahani@gmail.com 10031947532846006614 10031947532846006614 Yes Department of Food Science and Technology, Faculty of Animal Science and Food Technology, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran Hossein Hossein Jooyandeh hosjooy@yahoo.com 10031947532846006615 10031947532846006615 No Department of Food Science and Technology, Faculty of Animal Science and Food Technology, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran Heidar Rafiee rafiee.elmi@gmail.com 10031947532846006616 10031947532846006616 No Department of Food Science and Technology, Faculty of Animal Science and Food Technology, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran