Characterization and Functional Properties of Lactic Acid Bacteria Isolated from Fermented Maize Dough Used for the Preparation of Doklu

Abstract

Lactic acid bacteria (LAB) has long been safely applied in the production of fermented foods and beverages. These bacteria are important for their contribution to food quality and also for their undeniable effects on health. In Africa, despite the abundance of isolated food sources and the diversity of identified microorganisms, the market for probiotics and functional foods based on selected local strains is almost non-existent. This paper aims to determine some technological properties of LAB isolates from fermented maize dough used for doklu production for potential application in food and probiotic products. A total of 25 LAB strains isolated from maize dough fermentation processes during doklu production were identified by 16S rDNA gene sequencing. Technological studies such as growth and acidification kinetics, diacetyl production, hydrogen peroxide production, and proteolytic activity were carried out. Their survival and growth under unfavorable conditions of temperature, salt concentration and pH were also analyzed. The isolates were identified as Pediococcus acidilactici (56%), Lactobacillus fermentum (24%), Pediococcus pentosaceus (12%) and Lactobacillus plantarum (8%). The technological properties of the LAB strains showed that 10 of them rapidly acidify the medium with pH variation (ΔpH) greater than 1 after 6 hours of fermentation. Good production of diacetyl and hydrogen peroxide, as well as good proteolytic activity, were obtained for several strains. Pediococcus acidilactici S15, S55, S56; Lactobacillus plantarum S32, S121 and Lactobacillus fermentum S44 showed the best technological properties. However, only 5 of them obtained good resistance following the various survival and growth under unfavorable conditions of temperature, salt concentration, and pH. This work has therefore demonstrated that the lactic acid bacteria involved in the natural fermentation of maize dough have interesting properties for various applications whether in the processing of food products as well as in the development of probiotic products.