Andreia S. Ferreira

Influence of grape pomace extract incorporation on chitosan films properties

Chitosan has been studied as a renewable polymer to form edible films allowing the incorporation of functional compounds. The aim of this work was to evaluate the effects in the chitosan films properties of the incorporation of grape pomace extracts: 0.15% of hot water extract (mainly polysaccharides), 0.15 and 0.3% of chloroform extract (wax), and 0.3 and 0.75% of n-hexane extract (oil). The evaluation of the surface morphology revealed that the films with the aqueous extract had the most homogeneous and smoother topography. The incorporation of higher proportion of wax and oil led to changes in mechanical properties of the films, namely lower resistance and stiffness. The chitosan-based films with 0.75% oil demonstrated a 75% decrease of solubility in water, due to their hydrophobicity, as confirmed by the contact angle and surface free energy measurements. The hydrophobic films showed higher antioxidant capacity in organic medium (ABTS and DPPH assays) whereas the most hydrophilic films showed an improvement in FRAP and reducing power assays. Therefore, all the chitosan-based films prepared by incorporation of these grape pomace extracts are promising for food shelf life extension.

The Key Role of Sulfation and Branching on Fucoidan Antitumor Activity

There is an urgent need for antitumor bioactive agents with minimal or no side effects over normal adjacent cells. Fucoidan is a marine-origin polymer with known antitumor activity. However, there are still some concerns about its application due to the inconsistent experimental results, specifically its toxicity over normal cells and the mechanism behind its action. Herein, three fucoidan extracts (FEs) have been tested over normal and breast cancer cell lines. From cytotoxicity results, only one of the extracts shows selective antitumor behavior (at 0.2 mg mL-1 ), despite similarities in sulfation degree and carbohydrates composition. Although the three FEs present different molecular weights, depolymerization of selected samples discarded Mw as the key factor in the antitumor activity. Significant differences in sulfates position and branching are observed, presenting FE 2 the higher branching degree. Based on all these experimental data, it is believed that these last two properties are the ones that influence the cytotoxic effects of fucoidan extracts.

Full length articleStudent bystander behavior and cultural issues in cyberbullying: When actions speak louder than words

This study aims to investigate whether student bystander interventions can influence the relationship between being a bystander of a cyberbullying incident and being the victim or the aggressor. Another aim is to understand the specific behavior presented by students bystanders, namely whether they noticed incidents of cyberbullying and interpreted these events as an emergency and which actions they determined as being appropriate in providing assistance. Following a cross-cultural perspective to reach these aims, a total of 788 Portuguese and Brazilian college students answered to the Cyberbullying Inventory for College Students. Moderation analysis revealed that intervening moderated the relationship between being the bystander of cyberbullying and being the victim and/or aggressor. A three-way interaction showed that this relationship was stronger in Brazilian students, revealing that the bystanders who were inactive were more likely to also become a victim or an aggressor themselves, whereas those who intervened were less likely to become a victim or an aggressor. Implications for future research and interventive action are discussed. The importance of bystander behavior in cyberbullying, victimization and aggression.Intervening influences the possibility of overlapping roles in cyberbullying.Cultural issues influence the possibility of overlapping roles in cyberbullying.Intervening and cultural issues moderate the overlapping roles in cyberbullying.

Surface Morphology of Chitosan Films with Incorporation of Grape Pomace.

The use of edible films and coatings in food protection and preservation from renewable biopolymers has recently increased due to its nontoxicity, biocompatibility, and antimicrobial properties. Further, edible films can be an efficient vehicle for incorporating functional compounds, which improve its characteristics [1]. Grape pomace consisting of skins, seeds, and stems, is a rich source of phenolic compounds, lipids, polysaccharides and proteins. Since grape pomace is an abundant by-product, there is a high interest to use its extracts in order to improve the chitosan films properties.

Comparison of high pressure treatment with conventional red wine aging processes: impact on phenolic composition

High hydrostatic pressure (HHP) applied to wine in flexible plastic bottles has been studied as an enological practice for red wine aging, due to the oxidative reactions that can be promoted by this technology. To evaluate the effect of HHP on wine phenolic composition, a red wine treated with HHP was compared with different conventional wine aging processes, such as the use of wood and microoxygenation. The wine was pressurized at 500 MPa for 5 min at 20 °C and the same wine was also stored in oak barrels and treated with oak chips with or without microoxygenation. For comparison of the HHP effect, all wines were stored in polyethylene bottles. After 5 months, the monomeric anthocyanins, phenolic acids, and flavonols content of pressurized wines were lower in comparison with the other wine treatments. Nevertheless, pressurized wines showed a similar degree of tannin polymerization, pyranoanthocyanins content, and percentage of prodelphinidins in relation to the wine treated with microoxygenation and oak chips. HHP, possible by promoting a higher diffusion of oxygen into the wine, has the potential to be a novel oenological practice, producing red wines with a polymeric phenolic composition similar to those treated with wood aging processes.

Knowledge Society/Economy and Managerial Changes

In Portugal, reforms in higher education (HE) have been mainly conducted under the influence of a new political rationality. The dominant global trace of this rationality is the extension of economic and managerial logics to the set of HE activities, as well as the way of managing them and the professionals involved in their achievement.