Effects of Fermentation on the Bioactive, Functional, and Technological Characteristics of Babassu and Brazil Nut Flours

This study provides a comprehensive evaluation of the composition, bioactivity, and techno-functional properties of babassu (Attalea speciosa) mesocarp and Brazil nut (Bertholletia excelsa) flours, highlighting their potential as novel functional ingredients. Fermentation effects of Saccharomyces cerevisiae var. boulardii-17 on these properties were also investigated. Yeast cells (10⁸ cells mL^-1) were inoculated into flour suspensions (100 mg mL^-1), and samples were collected every 4 h over a 12-h fermentation period. In babassu flour, fermentation increased protein content and reduced lipid and ash levels, whereas Brazil nut flour showed minimal compositional changes, except for a decrease in carbohydrates. Lysine content increased in both substrates after fermentation. Among fermented samples, the 12-h fermented babassu flour showed the best results for antioxidant assays, reaching 92.76, 105.07, and 181.77 µmol TE g^-1 for 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-difenil-1-picrilhidrazil (DPPH), and ferric reducing antioxidant power (FRAP) methods, respectively. Brazil nut samples also showed improved antioxidant activity after 4 h, with DPPH and FRAP values of 6.48 and 11.77 µmol TE g^-1, respectively. For babassu, α-glucosidase inhibition peaked after 8 h of fermentation (40.26%) and remained high after 12 h (35.87%). Fermentation enhanced the emulsifying capacity of Brazil nut flour, exceeding 74% from 4 h onward. Upon scale-up, improvements in ABTS and DPPH scavenging activity, α-glucosidase inhibition, and oil holding capacity were detected in babassu, whereas Brazil nut flour showed enhanced gelling properties. The results suggest the potential application of these fermented flours as functional ingredients in the formulation of plant-based food products.