Dinâmica da microbiota presente no processo fermenativo da mandioca para produção de tucupi.

Abstract

In South American, Asian, and African countries, cassava serves as the substrate for various fermented foods and forms the foundation of their diets. In Brazil, it is one of the main traditional crops in the agricultural sector, as it serves as a source of food for families in the northern and northeastern region of the country, where many rural inhabitants lack the production and processing of cassava flour for their livelihood. Tucupi, a fermented sauce, is produced from the spontaneous fermentation of manipueira, a liquid byproduct resulting from the pressing of grated cassava dough. This ingredient is highly valued in the cuisine of Pará and northern Brazil, standing out for its yellow color, low pH, high total acidity, low protein, and total and free cyanide content. The objective of this study was the molecular characterization of the microbiota involved in the cassava fermentation process to produce tucupi, using selected starter cultures to improve the quality of the final product. Furthermore, samples collected during the fermentation and the final product were evaluated for volatile compound profiles by a gas chromatography combined with mass spectrometry (GC-MS). For this purpose, samples collected from tucupi production, and the final product were subjected to the isolation of lactic acid bacteria (LAB) on Man, Rogosa, and Sharpe (MRS) agar, yeasts on malt extract and yeast (YM) agar, and Bacillus cereus on Mannitol Egg Yolk Polymyxin (MYP) agar. Molecular identification was performed by the Restriction fragment length polymorphism (RFLP) technique for LAB, the Polymerase Chain Reaction (PCR) fingerprinting GTG5 technique for yeast, and MALDI-TOF for Bacillus sp. The extraction of volatile compounds was performed using absolute ethyl alcohol and sodium tripolyphosphate (1:1:1), and the compounds were detected by GC-MS. From 119 samples obtained, LAB (n = 67), yeast (m = 57), and Bacillus sp. (n = 100) were isolated. The RFLP technique included two LAB species: Lactiplantibacillus plantarum subsp. plantarum and Limosilactobacillus fermentum, with L. plantarum being the most prevalent species. The PCR technique identified Pichia scutulata and Yarrowia lipolytica species, with P. scutulata being the most predominant. The MALDI-TOF technique included Bacillus cereus sensu stricto (69%), Bacillus subtilis (8%), Bacillus atrophaeus, Bacillus mojavensis, and Bacillus subtilis subsp. subtilis, representing 1% of the isolates. The starter culture P1, which contained L. plantarum, L. fermentum, and P. scutulata, showed better performance for L. plantarum, the most present species during the fermentation. P. scutulata reached its highest count in the first 5 hours of fermentation when combined with L. plantarum (P5). The species B. cereus s.s. was found in all samples of the final product, and all exceeded the limit of 102 CFU/ml established by Adepará Normative Instruction No. 1 of 2008, demonstrating that hygienic-sanitary conditions are flexible about the presence of this pathogen. Among the carboxylic acids identified, acetic acid stands out as the predominant compound during the cassava fermentation process to produce tucupi on a pilot scale.