Antioxidant and Antimicrobial Activities of Exopolysaccharides from Yoghurt Starter

Bachir Raho Ghalem

doi:10.11648/j.ab.20170505.13

Abstract

The in vitro antimicrobial and antioxidant activities of the exopolysaccharide (EPS) extracted from yoghurt starter were investigated. Antimicrobial activity tests were carried out using disc diffusion methods with Escherichia coli, Staphylococcus aureus and Streptococcus D, Proteus spp and the yeast of Candida albicans. The antioxidant properties were evaluated using the test of DPPH free radical trapping. The results show that the EPS has weak antimicrobial activity against the tested strains with inhibitions zones ranging from 9 to 13 mm. EPS could reduce the free radical (DPPH) to diphenylpicrylhydrazine a yellow-colored at 24.25% showing antioxidant activity less than that of ascorbic acid which was 69.79%.

Highlights

Antimicrobial resistance is one of the world’s most serious public health problems
The large zone of inhibition was observed against E. coli, while the lowest was recorded against the yeast C. albicans
The EPS was more active against Gramnegative bacteria (E. coli and Proteus Sp) than Gram-positive bacteria (S. aureus and Streptococcus D) and all bacteria are more susceptible than the yeast

Summary

Introduction

Antimicrobial resistance is one of the world’s most serious public health problems. Many of the microbes (bacteria, viruses, protozoa) that cause infectious disease no longer respond to common antimicrobial drugs. It has been found that free radicals and other reactive oxygen species play a cardinal role in oxidative damage to cellular constituents which leads to cell injury and death. This has been associated with pathogenesis of various chronic disease, e.g. carcinomas, coronary heart disease, and many other hearth problems related to advancing age [2]. Lactic acid bacteria (LAB) are able to produce exopolysaccharides (EPSs) in the surrounding medium as a slime or on the surface of bacterial cells to form a capsule [5]. The aim of this study was to evaluate the in vitro antioxidant and antimicrobial properties of the exopolysaccharides extracted from yoghurt starter

Objectives

Methods

Results