Browsing by Author "Fernandes, Luana"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Extraction solvents’ influence on the content of bioactive compounds and antioxidant activity of pansiesPublication . Ramalhosa, Elsa; Fernandes, Luana; Pereira, José; Saraiva, Jorge; Casal, SusanaIntroduction: Pansies (Viola×wittrockiana) are a rich source of natural antioxidants with beneficial effects on human health. Objetives: The aim of our study was to investigate solvents’ influence (water, methanol, water:acetone (6:4, v/v)) on the extraction of bioactive compounds and antioxidant activity of pansies extracts. Methods: The bioactive compounds analyzed were the following: flavonoids, hydrolysable tannins and monomeric anthocyanins, as well as total phenols by the total reducing capacity assay (TRC). The antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power assays. A Principal Component Analysis (PCA) was performed to differentiate pansies extracts. Results: The solvents that yielded extracts with the highest contents of hydrolysable tannins and TRC were methanol and water:acetone (6:4, v/v). To extract the highest contents of monomeric anthocyanins, methanol should be used (5.93 mg Cy 3-glu/g flower, d.w), while for flavonoids, water:acetone (6:4, v/v) was the preferred yielding an extract with 115 mg QE/g flower d.w. Water turned out to be the least effective solvent, giving extracts with the lowest antioxidant activity. In addition, methanol or water:acetone extracts were clearly distinguished from aqueous ones through a PCA analysis. Conclusions: Our results show that the bioactive compounds and antioxidant activity of pansies’ extracts are affected by the solvent used.
- Physico-chemical and sensory characterization of fruit jams of S. Tomé and PríncipePublication . Ramalhosa, Elsa; Sousa, Agostinho; Fernandes, Luana; Delgado, Teresa; Fidalgo, Maria; Pereira, JoséIntroduction: São Tomé and Príncipe has a wide variety of fruit trees, being most of the fruits consumed in fresh. In certain periods of the year, fruits are available at significant amounts; however, it is not common to use the surplus of those fruits. Thus, this excess may be used in the preparation of other fruit based products (ex. jams), in order to increase product diversity and allow the annual consumption of these seasonal fruits. Objetives: Valorise fruits’ production in S. Tomé and Príncipe. Methods: Preparation of jams of banana, ambarella, guava (dark and light) and papaya, with two levels of sugar, and perform their physico-chemical characterization (color, pH, moisture and acidity). Furthermore, sensory analysis was also done, through preference and acceptability tests. Results: The jams prepared had different colours, acidity values, and moisture and ash contents, demonstrating the possibility of producing different products by changing the formulation. Regarding jams preference, 60% of the consumers preferred the less sweet in the case of banana and guava (light), whereas, over 67% of the panellists preferred the sweetest ambarella jam. Concerning dark guava and papaya, the percentages were similar for both sugar contents. For all attributes analysed (appearance, colour, taste, acidity, sweetness and global evaluation), most of the panellists liked slightly all jams.Conclusion: Jams production in S. Tomé and Príncipe may be a promising activity.