RESUMO
Research background: Cocoa honey and cocoa pulp are both highly appreciated fruit pulp, but until now, cocoa honey has been less processed than cocoa pulp. In this work, we investigate the applicability of Saccharomyces cerevisiae strains to ferment cocoa honey complemented with cocoa pulp to obtain fruit wines and improve cocoa honey commercialization. Experimental approach: The strain, previously isolated from cachaçaria distilleries in Brazil, was selected based on its fermentation performance. The following conditions for fermentation with S. cerevisiae L63 were then studied: volume fraction of cocoa honey (φ CH) complemented with cocoa pulp, sucrose addition (γ suc), temperature (t) and inoculum size (N o). The best conditions were applied in order to obtain fermentation profiles. Results and conclusions: S. cerevisiae L63 (N o=107-108 cell/mL) is capable of fermenting φ CH=90 and 80% for 24 or 48 h with γ suc=50 and 100 g/L at t=28-30 °C resulting in wines with ethanol volume fractions from 8 to 14%. Additionally, the wine produced from φ CH=90% had lower residual sugar concentration (<35 g/L) than the wine produced from φ CH=80% (~79 g/L) which could be classified as a sweet wine. In general, S. cerevisiae L63 resulted in a similar fermentation performance as a commercial strain tested, indicating its potential for fruit pulp fermentation. Novelty and scientific contribution: Saccharomyces cerevisiae L63 can ferment cocoa honey complemented with cocoa pulp to produce fruit wines with good commercial potential, which may also benefit small cocoa producers by presenting a product with greater added value.
RESUMO
The enzyme tannase is of great industrial and biotechnological importance for the hydrolysis of vegetable tannins, reducing their undesirable effects and generating products for a wide range of processes. Thus, the search for new microorganisms that permit more stable tannase production is of considerable importance. A strain of P. mangiferae isolated from cocoa leaves was selected and investigated for its capacity to produce tannase enzymes and gallic acid through submerged fermentation. The assessment of the variables affecting tannase production by P. mangiferae showed that tannic acid, ammonium nitrate and temperature were the most significant (8.4 U/mL). The variables were analyzed using Response Surface Methodology - RSM (Box-Behnken design), with the best conditions for tannase production being: 1.9% carbon source, 1% nitrogen source and temperature of 23 °C. Tannase activity doubled (16.9 U/mL) after the optimization process when compared to the initial fermentation. A pH of 7.0 was optimal for the tannase and it presented stability above 80% with pH between 4.0 and 7.0 after 2h of incubation. The optimal temperature was 30 °C and activity remained at above 80% at 40-60 °C after 1 h. Production of gallic acid was achieved with 1% tannic acid (0.9 mg/mL) and P. mangiferae had not used up the gallic acid produced by tannic acid hydrolysis after 144 h of fermentation. A 5% tannic acid concentration was the best for gallic acid production (1.6 mg/mL). These results demonstrate P. mangiferae's potential for tannase and gallic acid production for biotechnological applications.
