Fernanda Furlan Gonçalves Dias

Screening of Supports for the Immobilization of β-Glucosidase

A set of supports were screened for the immobilization of a partially purified extract of β-glucosidase from Aspergillus sp. These supports, namely, Eupergit, Amberlite, alginate, gelatin, polyvinyl alcohol- (PVA-) based matrices (Lentikats), and sol-gel, have proved effective for the implementation of some other enzyme-based processes. The initial criterion for selection of promising supports prior to further characterization relied on the retention of the catalytic activity following immobilization. Based on such criterion, where immobilization in sol-gel and in Lentikats outmatched the remaining approaches, those two systems were further characterized. Immobilization did not alter the pH/activity profile, whereas the temperature/activity profile was improved when sol-gel support was assayed. Both thermal and pH stability were improved as a result of immobilization. An increase in the apparent K M (Michaelis constant) was observed following immobilization, suggesting diffusion limitations.

Brazilian Capsicum peppers: capsaicinoid content and antioxidant activity

BACKGROUND Capsicum peppers are known as a source of capsaicinoids, phenolic compounds and antioxidants. Brazilian Capsicum peppers are important spices used in foods worldwide. However, little information is available on the chemical composition and antioxidant activity of these peppers. RESULTS Capsaicin, dihydrocapsaicin, total phenolic compounds and antioxidant activity were investigated in extracts of three Brazilian peppers: Capsicum frutescens, C. chinense and C. baccatum var. pendulum, in two different harvest years and at two ripening stages. The bioactive compound content was dependent on harvest year, and changes in the concentration profiles were found for capsaicin. Mature fruits of C. chinense harvested in the first year had the highest capsaicin concentration (2.04 mg g-1 fresh pepper), and mature fruits of C. frutescens harvested in the same first year had the highest dihydrocapsaicin content (0.95 mg g-1 fresh pepper). Mature fruits of C. frutescens harvested in the first year showed the major total phenolic compound content (2.46 mg g-1 fresh pepper). The total phenolic compound content was directly related to antioxidant activity. CONCLUSION Our results suggest that phenolic compounds significantly contribute to the antioxidant activity of the investigated peppers. Also, these data add valued novel information that enhances current knowledge of Brazilian pepper fruits.