Abstract in English:

Films based on pure native starch have limited applications, are easily breakable, very hygroscopic, and permeable to water vapor. One method for improving these properties is to modify starch by cross-linking. The aim was to evaluate the effect of the addition of sodium trimetaphosphate (STMP), sodium sulfate (SS) and native cassava starch (S) on the properties of modified cassava starch films using a 23 factorial design comparing the concentration of the crosslinkers (5.0, 12.5 and 20% STMP), SS (3.0, 9.0 and 15%) and native cassava starch (S) (5.0, 7.5 and 10%) m/v. All cross-linked cassava starch films had better easiness of handling, continuity, and brightness than the control film. Generally, cross-linking reduced the water solubility and tensile strength and increased thickness, elongation and the films’ yellowish color and opacity. Reagents’ concentration affected most of the dependent variables. The SMTP*SS interaction positively affected water vapor permeability (WVP), while negatively affected solubility. Tensile strength was positively affected by SMTP. As for elongation, the S*SS interaction was positive, while the effect of STMP*SS was negative. Treatment 1, using the lowest concentrations of reagents, presented positive results, such as excellent macro and microscopic appearance. These findings also qualify the crosslinked starch for use in coatings formulations.

Abstract in Portuguese:

BIOPROSPECTING OF ESSENTIAL OILS WITH POTENTIAL FOR PHARMACEUTICAL FORMULATIONS. Essential oils derived from aromatic plants have garnered significant attention for their therapeutic and medicinal properties. Among these, α-thujone and β-thujone stand out due to their notable biological effects. This study aimed to assess native and exotic aromatic plants as potential sources of these bioactive compounds. Based on the literature, five plant species were selected: Artemisia absinthium (Asteraceae), Hyptis marrubioides (Lamiaceae), Salvia officinalis (Lamiaceae), Tanacetum vulgare (Asteraceae), and Thuja occidentalis (Cupressaceae), resulting in the analysis of 19 samples. The plant leaves were dried, and their essential oils were extracted and evaluated for yield and chemical composition. The oil yields ranged from 0.15 to 1.57%. Gas chromatographymass spectrometry (GC-MS) analysis identified 82 major volatile constituents, with particular emphasis on α-thujone and β-thujone. Among the species studied, H. marrubioides (62.7%) and T. occidentalis (76.4%) exhibited the highest relative concentrations of α-thujone, while A. absinthium was especially rich in β-thujone (63.91%). Overall, α-thujone and β-thujone were detected in four samples from three species, underscoring their potential as valuable sources of these bioactive compounds. Notably, the native species H. marrubioides demonstrated an essential oil composition comparable to that of T. occidentalis in terms of thujone content, further supporting its viability for industrial and pharmacological applications.