Analytical and chemometric strategies for elucidation of yerba mate composition.

Yerba mate, a popular plant consumed mainly as an infusion, possesses nutritional and medicinal properties attributed to its secondary metabolites. This study aimed to develop strategies to elucidate the phenolic composition of yerba mate samples from Brazil, Argentina, Uruguay, and Paraguay. Optimization of ultrasonic-assisted extraction (UAE) was performed, and the extracted compounds were characterized using ultra-high-pressure liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UHPLC-QTOF-MS), molecular fluorescence and high-pressure liquid chromatography with diode-array detection (HPLC-DAD). Chemometric analysis, including parallel factor analysis (PARAFAC) and principal component analysis (PCA) explored metabolite profiles and identify patterns. PARAFAC modelling of the molecular fluorescence results revealed higher pigment content in Brazilian samples, while other countries' samples exhibited higher phenolic content. PCA modeling of HPLC-DAD results indicated that cultivated yerba mate contained higher chlorogenic acids levels, and samples from Argentina, Paraguay, and Uruguay exhibited higher concentrations of chlorogenic acids and flavonoids.

Production of volatile compounds by yeasts using hydrolysed grape seed oil obtained by immobilized lipases in continuous packed-bed reactors.

Lipases CAL-B, TLL, and RML were used in the synthesis of free fatty acids of grape seed oil as heterogeneous substrate. The best enzyme was used to optimize the reaction variables temperature, enzyme content, and molar ratio of water:oil in batch reactions using experimental planning. The ideal conditions to produce free fatty acids using pure RML were 45 °C, 12:1 substrate molar ratio, and 15% enzyme, resulting in 66% of oil hydrolysis and a productivity of 0.54 mol L-1 min-1 in 4 h of reaction at 180 rpm. Repeated batches of reaction were performed testing the operational stability of RML, results showing that this enzyme could be used for at least 20 cycles keeping more than 80% of its initial activity, suggesting its potential use in industrial processes. The synthesis of free fatty acids was then evaluated in continuous reactions using packed-bed reactor (PBR). The highest productivity in the continuous process was 6.85 mol L-1 min-1, using only RML, showing an operational stability higher than 80% of its initial conversion capacity after 11 days of operation, at a flow rate of 0.13 mL min-1 at 45 °C. We evaluated the use of this hydrolyzed oil as substrate for lactone bioproduction using Galactomyces geotrichum UFMG-CM-Y3276, G. geotrichum UFMG-CM-Y3558, and Geotrichum klebahnii UFMG-CM-Y3014 screened for their oil-hydrolysis ability. Volatile compounds were qualitatively identified in GC-MS as γ-octalactone and γ-nonalactone.