Antagonistic effects of raffia sap with probiotics against pathogenic microorganisms

Introduction. Probiotics are known for their beneficial properties. Numerous studies have been conducted to find advantages that probiotics can provide. This study aimed to evaluate the functional properties of raffia sap, a Cameroonian drink, fermented with probiotics by investigating its antagonistic activity against pathogenic bacteria. Study objects and methods. The study objective was raffia sap fermented by Lactobacillus fermentum and Bifidobacterium bifidum. Box-Behnken design with four factors (seeding rates of L. fermentum and B. bifidum, temperature, and incubation time) was used to generate mathematical models. The disc diffusion method was used to evaluate an antagonistic effect of the probiotics against four pathogenic bacteria (Escherichia coli, Listeria monocytogenes, Salmonella sp., and Bacillus cereus). An optimization of mathematical models of the inhibition diameters allowed to determine the optimal conditions of antagonistic effect. Results and discussion. The experimental data showed that zones of inhibition were 0‒21 mm for Salmonella sp., 0‒23 mm for E. coli, 0‒20 mm for L. monocytogenes, and 0‒22 mm for B. cereus. ANOVA results and the mathematical models obtained showed that L. fermentum was effective against B. cereus and B. bifidum against Salmonella sp., E. coli, and B. cereus. The optimization ofthe models revealed maximum zones of inhibition at the seeding rates of L. fermentum and B. bifidum of 2 and 10%, respectively, incubation time of 48 h, and temperature of 37°C. Conclusion. Raffia sap fermented by L. fermentum and B. bifidum demonstrated antagonistic effect against pathogenic bacteria such as E. coli, L. monocytogenes, Salmonella sp., and B. cereus. © 2020, Mbarga et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix, transform, and build upon the material for any purpose, even commercially, provided the original work is properly cited and states its license

Compositional, spectroscopic and rheological analyses of mucilage isolated from taro (Colocasia esculenta L. Schott) corms

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Assessment of Probiotic Potential of Lactic Acid Bacteria Isolated from Bottle Gourds (Calabash) of Milk Fermentation of Mbere, Cameroon

Background and Aim: Lactic acid bacteria (LAB) became a field of interest by scientists in recent years due to their technological and probiotic properties. The aim of this work was to study the technological and probiotic properties of LAB isolated from the bottle gourds (calabashes)of milk fermentation, in Mbere, Cameroun. Methods: Five different bottle gourds from milk fermentation were collected and used for LAB isolation. These LABs were characterized using conventional cultural method, the technological (such as proteolytic, lipolytic activities) and probiotic properties (including acid and bile salt tolerance, cholesterol assimilation and antioxidant activities) were assessed. Results: From these samples, 30 LABs were isolated and among them, 21 exhibited great lipolytic and proteolytic activities with the maximum values of 18 and 29 mm respectively. In addition, 10 LAB isolates showed interesting antimicrobial activity against pathogens germs tested and good tolerance ability under acid and bile salt stress after 24h of incubation. Cholesterol assimilation and antioxidant tests revealed that isolated BC4 and BC3 have the greatest activity (35 and 39 mm respectively) while, BC4 and BL4 have the greatest antioxidant activity (IC50 = 0,15 and 0,13 respectively). Conclusion: LAB isolated from the bottle gourds (calabashes) of milk fermentation, in Mbere, Cameroon can be used to develop dairy industry and manage the cardiovascular diseases