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- Characterization and modulation of fish allergenicity towards the production of a low allergen farmed fishPublication . Schrama, Denise; Rodrigues, P. L.; Kuehn, Annette; Engrola, Sofia Alexandra DiasFood allergies are a common health problem worldwide, triggering an abnormal immune response. Fish belongs to the top nine of most allergenic foods, among milk, eggs, shellfish, tree nuts, peanuts, wheat, soybeans and the most recently added sesame. The continuing increase of aquaculture production and the relatively easy access to fish worldwide, contribute to increased fish consumption which result in higher prevalence of allergies. The main allergen in fish, responsible for up to 70-95% of the allergic reactions, is a small and stable calcium-binding muscle protein named parvalbumin. This thesis was focused on parvalbumin in two economically important fish species for Southern Europe aquaculture, namely gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax). Chapter 2 characterized this allergen, determining its structure by circular dichroism, sequencing its amino acids by mass spectrometry and analyzing its stability after fish digestion or processing. Results showed that parvalbumin represents a higher content of α-helices and some β-sheets in its secondary structure, at room temperature. Parvalbumins detection reduced throughout gastrointestinal digestion, and also several processing techniques, like salting, steaming and autoclaving showed a significant reduction (p<0.05) in parvalbumins detectability. In Chapter 3, a questionnaire conducted in Portugal was performed to evaluate consumers’ willingness to pay for low allergenic fish. Results showed that not only half the consumers were willing to pay extra, but also suggested that this was explained by the presence of fish allergies in the family and by the fish unique characteristics and quality. For the modulation of fish allergenicity Chapters 4.1, 4.2 and 4.3 analyzed this possibility by the supplementation of fish diets with additives like creatine and ethylenediamine tetraacetic acid (EDTA). Results showed a 50% reduction in fish-allergic serum Immunoglobulin-E (IgE)- reactivity when 3% EDTA was supplemented in gilthead seabreams diet. This promising result showed the possibility to modulate parvalbumin in order to decrease its allergenicity.
- Measurement invariance and country difference in death anxiety: evidence from portuguese and arab samplesPublication . Gonçalves, Gabriela; AL-Dossary, Saeed A.; Sousa, CátiaDeath is something inevitable and common to all human beings. However, cultures vary in how they define and manage living with the inevitability of death and what happens when a person dies. Among the possible responses to this inescapable reality, there is death anxiety. Several instruments have proliferated in the literature to assess death anxiety. Among them, stands out the Scale of Death Anxiety (SDA) which contemplates somatic, cognitive, emotional and behavioural reactions from a symptomatic perspective. Thus, the objective of this study is the validation and measurement invariance of the SDA in Portuguese and Arab samples (N=216 and N=377, respectively). Confirmatory factor analyses, multigroup confirmatory factor analyses measurement invariance and latent mean differences were performed across cultures and gender groups. Our results provided important preliminary evidence for the validity of the scale in both samples. The structure of the SDA remained unchanged in both cultures and genders. The SDA showed partial scalar invariance across cultural groups, and full scalar invariance across gender groups. As expected, the Arab participants showed higher levels of anxiety than the Portuguese sample. The analyses also showed that females in both cultural groups obtained higher scores than males on dysphoria and fear of death. However, the two genders did not differ significantly on avoidance of death. The results show that the SDA is a reliable and valid measure for the study of death anxiety, showing to be invariant between cultures and between genders.