Evaluating the emulsifying, antioxidant, antimicrobial and anti-biofilm properties of postbiotic extracted from Lactobacillus casei and its application in milk chocolate

Abstract

Abstract Introduction and purpose : Oral and dental diseases are one of the most common diseases in the world. The occurrence of these diseases depends on various causes, including habits and diet, as well as bacterial infection. Streptococcus mutans is the main bacteria that causes tooth decay. Since the resistance of bacteria to conventional drugs and antibiotics is increasing, there is always a need to search for new antibacterial agents. Recently, probiotics are one of the options to control the growth of S. mutans, and several studies have been conducted in this field and confirmed their favorable effect. Part of the antibacterial effect of probiotics is related to metabolites such as exopolysaccharides that they produce. Therefore, according to some clinical concerns and industrial challenges that probiotics have due to their living nature, postbiotics can be considered due to their non-living nature, the presence of antibacterial and antioxidant agents. and also consider being safe and stable as an alternative. Therefore, in the present study, while investigating the antibacterial and antioxidant effects of the postbiotic derived from Lactobacillus casei, the mentioned postbiotic was added to the chocolate formulation and the physicochemical properties, rheological, sensory and product characteristics were investigated . Materials and methods : In this study, minimum inhibitory concentration (MIC) and minimum bacteriocidal concentration (MBC) tests were used to investigate the antibacterial properties of postbiotic (exopolysaccharide) against caries-causing bacteria, S. mutans. Then, using the crystal violet method, the post-biotic effect on the reduction of biofilm formation (adhesion) by S. mutans bacteria was investigated. In addition, the antioxidant properties of these compounds were measured using the DPPH method, as well as their emulsifying properties. Finally, after the initial tests, the lyophilized exopolysaccharide powder was added to the chocolate formulation and the sensory, texture and physicochemical characteristics of the produced postbiotic chocolate were evaluated. Results : The results of this study showed that exopolysaccharide has a significant inhibitory effect on the growth of S.mutans. The minimum inhibitory concentration as well as the minimum bacteriocidal concentration are 18.75 and 37.5 milligrams per milliliter, respectively. The results indicated that the concentration of 18.75 mg/ml and higher concentrations significantly reduce biofilm adhesion. The results of the evaluation of the antioxidant property show that exopolysaccharides show good antioxidant properties at much lower concentrations (4 mg/ml) . Conclusion : It seems that the use of postbiotics instead of probiotics has a similar effect and it can prevent and treat many oral and dental diseases caused by pathogens like S. mutans and the results of the present study confirm this. However, this study it is only a laboratory study during which the effects of antibacterial, anti-adhesion, antioxidant and so on the applicability of postbiotics in chocolate formulation was investigated and confirmed. To prove the preventive and therapeutic effects more precisely, human clinical studies should be conducted to determine their effectiveness and the appropriate dosage for food and medicinal use. Keywords : Postbiotic, antioxidant, anti-biofilm