Fortification with mushroom flour (Pleurotus ostreatus (Jacq.) P. Kumm) and substitution of wheat flour by cassava flour in bread-making: Nutritional and technical implications in eastern DR Congo

peer reviewedBackground: The import of wheat flour is the major driver for the high prices and low use of bakery products in nonproducing tropical countries such as the Democratic Republic of Congo (DRC). These products' high prices worsen the risk of malnutrition and food insecurity among rural and resource-poor populations. This study aimed at substituting the imported wheat flour with less expensive local cassava flour fortified with oyster mushroom flour in order to mitigate the nutritional crisis in the region. Methodology: Series of experiments were conducted by substituting wheat flour with cassava flour at proportions of 10-25% to find the optimal combination. In addition, oyster mushroom flour (2.5-10%) was added to the composite flour to compensate for nutrient deficiencies of cereals and tuber crops. The overall aim was to identify the optimal wheat-cassava-mushroom combination, improving the nutritional value of breads while keeping their physicochemical and organoleptic properties. Results: Results showed that 0-10% mushroom flour increased bread protein from 19.63 to 22.66%. Besides, 7.5% mushroom flour allowed rising the bread calories from 311.8 to 354.5 kcal, and the dry matter from 77.33 to 87.86%. The wheat substitution for cassava fortified with mushroom flour negatively affected the bread volume, color and taste (p < 0.001). However, other organoleptic features remained unchanged. The different breads were microbiologically stable for bacteria, but susceptible to fungal attacks. Conclusion: This study recommended 5-15-80% and 10-10-80% mushroom-cassava-wheat composite flour for better bakery results, good consistency and high protein and energy contents, for improving the nutritional status of populations in the tropical non-wheat producing regions such as DRC. Efforts are necessary to improve the taste and color of the mushroom-fortified bread to increase its uptake and competitiveness in the local markets

Stimulation of Fengycin-Type Antifungal Lipopeptides in Bacillus amyloliquefaciens in the Presence of the Maize Fungal Pathogen Rhizomucor variabilis.

Most isolates belonging to the Bacillus amyloliquefaciens subsp. plantarum clade retain the potential to produce a vast array of structurally diverse antimicrobial compounds that largely contribute to their efficacy as biocontrol agents against numerous plant fungal pathogens. In that context, the role of cyclic lipopeptides (CLPs) has been well-documented but still little is known about the impact of interactions with other soil-inhabiting microbes on the expression of these molecules. In this work, we wanted to investigate the antagonistic activity developed by this bacterium against Rhizomucor variabilis, a pathogen isolated from diseased maize cobs in Democratic Republic of Congo. Our data show that fengycins are the major compounds involved in the inhibitory activity but also that production of this type of CLP is significantly upregulated when co-cultured with the fungus compared to pure cultures. B. amyloliquefaciens is thus able to perceive fungal molecules that are emitted and, as a response, up-regulates the biosynthesis of some specific components of its antimicrobial arsenal