In vitro propagation of insectivorous plants for phytochemical purposes

Dissertação mest., Engenharia Biológica, Universidade do Algarve, 2009

Conservação dos frutos de duas cultivares de framboesa (Sevillana e Maravilla) em fresco e em doce

Dissertação de mest., Tecnologia de Alimentos, Instituto Superior de Engenharia, Univ. do Algarve, 2012

The effect of alginate-based edible coatings enriched with essential oils constituents on Arbutus unedo L. fresh fruit storage

The effect of coating Arbutus unedo fresh fruit with alginate-based edible coatings enriched with the essential oils compounds (EOC) eugenol (Eug) and citral (Cit) was studied. The minimum inhibitory concentrations (MIC) against the main postharvest pathogens were determined for Eug and Cit giving values of 0.10 and 0.15 (w/v), respectively. Twelve formulations of edible coatings were used: sodium alginate (AL) was tested at 1 and 2% (w/v) with incorporation of Eug and Cit at MIC and double MIC or their combination at MIC. Arbutus berries were dipped in those solutions for 2 min, and then stored at 0.5 degrees C. Control consisted of uncoated fruit. On days 0, 14 and 28, samples were taken to perform physicochemical and biochemical analysis [color CIE (L*, h degrees), firmness, soluble solids content (SSC), weight Loss, trolox equivalent antioxidant capacity (TEAC), microbial growth and taste panels]. Results showed that edible coatings of 1% AL were the best to maintain most quality attributes of the commodity through storage at 0.5 degrees C. The incorporation of Cit and Eug into the alginate edible coatings improved the coatings in most cases, AL 1% + Eug 0.20% and AL 1% + Cit 0.15% + Eug 0.10% being those that better preserved sensory and nutritional attributes and reduced microbial spoilage. Thus, these coatings may be useful for improving postharvest quality and storage life of fresh arbutus fruit. (C) 2014 Elsevier B.V. All rights reserved.

Effect of high CO2 and ocean acidification on photosynthesis and response to oxidative stress in seagrasses

Climate change scenarios comprise significant modifications of the marine realm, notably ocean acidification and temperature increase, both direct consequences of the rising atmospheric CO2 concentration. These changes are likely to impact marine organisms and ecosystems, namely the valuable seagrass-dominated coastal habitats. The main objective of this thesis was to evaluate the photosynthetic and antioxidant responses of seagrasses to climate change, considering CO2, temperature and light as key drivers of these processes. The methodologies used to determine global antioxidant capacity and antioxidant enzymatic activity in seagrasses were optimized for the species Cymodocea nodosa and Posidonia oceanica, revealing identical defence mechanisms to those found in terrestrial plants. The detailed analysis and identification of photosynthetic pigments in Halophila ovalis, H.stipulacea, Zostera noltii, Z marina, Z. capricorni, Cymodocea nodosa and Posidonia oceanica, sampled across different climatic zones and depths, also revealed a similarity with terrestrial plants, both in carotenoid composition and in the pigment-based photoprotection mechanisms. Cymodocea nodosa plants from Ria Formosa were submitted to the combined effect of potentially stressful light and temperature ranges and showed considerable physiological tolerance, due to the combination of changes in the antioxidant system, activation of the VAZ cycle and accumulation of leaf soluble sugars, thus preventing the onset of oxidative stress. Cymodocea nodosa plants living in a naturally acidified environment near submarine volcanic vents in Vulcano Island (Italy) showed to be under oxidative stress despite the enhancement of the antioxidant capacity, phenolics concentration and carotenoids. Posidonia oceanica leaves loaded with epiphytes showed a significant increase in oxidative stress, despite the increase of antioxidant responses and the allocation of energetic resources to these protection mechanisms. Globally, the results show that seagrasses are physiologically able to deal with potentially stressful conditions from different origins, being plastic enough to avoid stress in many situations and to actively promote ulterior defence and repair mechanisms when under effective oxidative stress.

Avaliação da atividade biológica e teor em fenóis de diferentes extratos de palmeira anã (Chamaerops Humilis L.)

Tese de mestrado, Engenharia Biológica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Estudo de plantas silvestres comestíveis da região mediterrânica como fontes de compostos bioativos

Dissertação de mestrado, Engenharia Biológica, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Incorporation of selenium on microalgae as supplement to artemia and zebrafish

Dissertação de mestrado, Aquacultura, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Antioxidant activities of eight Algerian plant extracts and two essential oils

Total phenol, hydroxycinnamic acid derivatives, flavone/flavonol and flavanones/dihydroflavonol contents of hydro-alcoholic extracts, obtained by sonication, from the aerial parts of Artemisia campestris L., Anthemis arvensis L., Haloxylon scoparium Pomel, Juniperus phoenicea L., Arbutus unedo L., Cytisus monspessulanus L., Thymus algeriensis Boiss et Reut, Zizyphus lotus L (Desf.) collected in Djebel Amour (Sahara Atlas, Algeria) were quantified by spectrophotometric methods. The chemical composition of the essential oils obtained by hydrodistillation from Artemisia campestris L. and Juniperus phoenicea I aerial parts were also evaluated by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). The antioxidant activity of the extracts and essential oils was assessed measuring the capacity for preventing lipid peroxidation using two lipidic substrates (egg yolk and liposomes), the capacity for scavenging DPPH, ABTS, superoxide anion radicals, hydroxyl radicals and peroxyl radicals. Anti-inflammatory activity was assessed by measuring the capacity for inhibiting lipoxygenase. Reducing power and chelating capacity were also assayed. The results showed different amounts of total phenols depending on the method used: A. campestris extract had the highest levels of total phenols when the measurement was made at lambda = 280 nm, whereas H. scoparium and A. unedo extracts showed the highest levels of total phenols with Folin-Ciocalteau. C. monspessulanus had the highest levels of flavones/flavonols and flavanones/dihydroflavonols. The essential oils of A. campestris and J. phoenicea were mainly constituted by alpha-pinene, beta-pinene and sabinene; and a-pinene, respectively. The methods used for assaying the capacity for preventing lipid peroxidation revealed to be inadequate for extracts due to the great interferences detected. The essential oils were more active than the generality of extracts for scavenging peroxyl radicals and for inhibiting lipoxygenase, whereas A. unedo extract was the most active for scavenging ABTS, DPPH, superoxide anion radicals and it also had the best reducing capacity. In a general way, the great majority of the antioxidant activities correlated well with the phenol content although such correlation was not so clear with the flavonoid content. (c) 2013 Elsevier B.V. All rights reserved.