Search

Marine macroalgae are present in the daily life of several coastal populations. Its production and commercialization are more important in Asian countries but are beginning to increase in Western countries. Macroalgae are widely used in the traditional diet of several Asian countries. However, its applications are not limited to use in human food, but are also used in animal feed, and can be used as sources of natural biomolecules with interesting properties in the formulation of cosmetic, nutraceutical products and pharmaceuticals. More recently its potential for application in the bioenergy industry has been investigated. Porphyra algae have a large market worldwide. They are mainly produced in aquaculture in China, Japan and Korea. However, adapting the production methods used in Asia is not a simple process, and the production of certain species requires an in-depth study of local strains. ALGplus produces Porphyra dioica and Porphyra umbilicalis in an integrated multi-trophic aquaculture system. The work carried out within the scope of the dissertation focused on the development and optimization of new methods of cultivation of these species of Porphyra, seeking to establish a method of obtaining mass releases of conchospores, which were seeded on various types of substrates. Cultivated substrates were subjected to treatments to prevent the development of contamination. The growth of Porphyra blades was promoted through controlled culture conditions such as electron flow and medium temperature. Substrates with blades were obtained in the laboratory with a high density of cultivation and in conditions to be transferred to the earth tanks, however, it was not possible to obtain healthy and growing biomass in earth tanks. Likely, the growing conditions were not ideal for the growth of Porphyra, so it is necessary to repeat the tests in the autumn or winter months. The modifications to the biomass maintenance method in the laboratory made throughout the work allowed to reduce the production time of blades by about 1 month. With this work, it is concluded that it is possible to produce local strains of Porphyra spp in an artificial substrate, however, more study will be needed to draw conclusions about the yield of the process and how it varies throughout the year. As macroalgas marinhas têm sidos usadas na alimentação em diversas populações costeiras. A sua produção e comercialização tem maior expressão nos países da Ásia, contudo a procura de macroalgas tem vindo a aumentar nos países ocidentais. As macroalgas são muito utilizadas na alimentação tradicional em países asiáticos. No entanto as suas aplicações não se limitam ao uso na alimentação humana, sendo também utilizadas na alimentação animal e em diversas aplicações industriais, como a produção de hidrocoloides para cosmética e farmacêutica, extratos para nutracêutica e mais recentemente para a aplicação na indústria da bioenergia e biorrefinaria. As algas do Género Porphyra têm um grande mercado a nível mundial. Elas são produzidas maioritariamente em aquacultura na China, Japão e Coreia, no entanto a adaptação dos métodos de produção utilizados na Ásia não é um processo simples, e a produção de certas espécies requer o estudo aprofundado das estirpes locais. A ALGplus produz Porphyra dioica e Porphyra umbilicalis num sistema de aquacultura multitrófica integrada. O trabalho realizado no âmbito da dissertação de mestrado teve como objetivo o desenvolvimento e otimização de novos métodos de cultivo destas espécies de Porphyra. Para alcançar os objetivos propostos foram estabelecidos e otimizados métodos para de obter libertações em massa de conchosporos, e foram posteriormente testadas sementeiras em diferentes tipos de substratos artificiais. Os substratos em cultivo foram submetidos a tratamentos para evitar desenvolvimento de contaminações e o crescimento de lâminas de Porphyra foi promovido através de condições cultivo controladas como fluxo de eletrões e temperatura do meio. Os resultados obtidos ao longo do trabalho culminaram na obtenção de substratos com lâminas em laboratório com alta densidade de cultivo e em condições para serem transferidos para os tanques de terra no exterior. No entanto não foi possível obter biomassa saudável e em crescimento em tanques de terra. É provável que as condições de cultivo não fossem ideais para o crescimento de Porphyra, pelo que será necessária otimização dos métodos de cultivo no exterior. As modificações ao método de manutenção da biomassa em laboratório feitas ao longo do trabalho permitiram reduzir o tempo de produção de lâminas em cerca de 1 mês. Com este trabalho, conclui-se que é possível produzir estirpes locais de Porphyra spp em substrato artificial, no entanto serão necessários mais estudo para tirar conclusões acerca do rendimento do processo e como este varia ao longo do ano. Mestrado em Biotecnologia

Enzymatic hydrolysis has been employed to modify protein functional properties and discover new sources of antioxidants. In this study, the effect of different enzymatic treatments on antioxidant activity of Porphyra dioica (blades and protein isolate (PI)) was investigated. Protein nitrogen content of P. dioica blades and PI were 23 and 50% (dry weight), respectively. Blades and PI were hydrolyzed with Prolyve&reg, and Prolyve&reg, plus Flavourzyme&reg, Peptide profiles and molecular mass distribution of the hydrolysates were investigated. The hydrolysis promoted generation of peptides and low molecular mass components &lt, 1 kDa. Antioxidant activity was assessed using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPHž) scavenging, 2,2&prime, azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTSž+) inhibition, and reactive oxygen species scavenging ability, i.e., oxygen radical absorbance capacity (ORAC) and hypochlorous acid (HOCl) scavenging assays. In general, enzymatic hydrolysis of P. dioica blades and PI enhanced the in vitro antioxidant activity. Direct hydrolysis of blades improved ORAC values up to 5-fold (from 610 to 3054 &mu, mol Trolox eq./g freeze dried sample (FDS). The simultaneous release of phenolic compounds suggested a potential synergistic activity (ORAC and ABTSž+ assays). Such hydrolysates may be of value as functional food ingredients.

Aqueous extracts of commercially available red macroalgae Porphyra dioica were integrated as inner coatings of food-grade polypropylene (PP) films through use of electrospinning and electrospraying technologies. Two coating formulations (A = 5 wt% P. dioica extract and 7.5 wt% polyvinyl alcohol (PVA), B = 1 wt% P. dioica extract, 1 wt% PVA, and 17% gelatine) were evaluated as to their capacity to delay spoilage of minced chicken breasts, through monitoring of microbial growth (total mesophile aerobic colony counts), colour stability, lipid oxidation (thiobarbituric acid reactive substances (TBARS)), and sensory analysis over a 4-day refrigerated storage. Scanning electron microscopy (SEM) imaging revealed an increased nanofiber and nanoparticle density on extract-enriched fibers, without compromise to their morphology or the homogeneity of the coatings. Total microbial counts on coating B samples was significantly (p &lt, 0.001) reduced compared to uncoated plastic wraps. The coated samples also exhibited fewer colour degradation, though the coatings did not differ substantially from uncoated plastic wrap. Sensory analysis test subjects successfully distinguished the raw samples based on their treatment and gave a positive approval rating (66.7%) to the extract-enriched coatings when asked about edibility post storage.

Porphyra dioica macroalgae can be regarded as a food-grade protein source that can be used for the stability of dispersed food systems. This work is focused on the foaming properties of a seaweed protein concentrate (SWE) from Porphyra dioica. The characterisation of air-water (A/W) interfacial layers formed after the SWE adsorption was carried out by means of interfacial tension, interfacial viscoelastic measurements and step deformation tests. These results were related to those obtained for SWE stabilized foams. Interfacial shear measurements indicate that not extensive protein-protein interactions at the A/W interface were developed (G's = 1.0 ± 0.1·10−2 mPa m), whereas the dilatational response (E's = 23.5 ± 0.5 mN/m) match with the formation of a rigid interface as a result of a densely packed structure. Even if the foaming properties obtained for SWE (overall foam capacity, OFC, = 0.74 ± 0.01 mL/s) are similar to those reported for other commercial protein systems, its lower stability (t1/2 = 204 ± 4 s) would indicate the need of adding stabilizers for an adequate shelf life of the final food product. The suitability of combining dilatational and interfacial shear rheology to predict the dynamics of dispersed systems was proven to be relevant to acquire insights of complex interfaces.

Porphyra dioica is a commercial seaweed consumed all over the world, mostly in the shape of nori sheets used for “sushi” preparation. It is a well-known part of the Asian diet with health benefits, which have been associated, among others, to the high levels of n-3 and n-6 fatty acids in this red alga. However, other highly valued lipids of Porphyra are polar lipids that remain largely undescribed and can have both nutritional value and bioactivity, thus could contribute to the valorization of this seaweed. In this context, the present work aims to identify the lipidome of two life cycle stages of the Atlantic species Porphyra dioica: the early life stage conchocelis produced in an indoor-nursery, and young blades produced outdoors using an integrated multitrophic aquaculture (IMTA) framework. Both the blades (gametophyte) and conchocelis (sporophyte) are commercialized in the food and cosmetics sectors. Liquid chromatography coupled to Q–Exactive high resolution-mass spectrometry (MS) platform was used to gain insight into the lipidome of these species. Our results allowed the identification of 110 and 100 lipid molecular species in the lipidome of the blade and conchocelis, respectively. These lipid molecular species were distributed as follows (blade/conchocelis): 14/15 glycolipids (GLs), 93/79 phospholipids (PLs), and 3/6 betaine lipids. Both life stages displayed a similar profile of GLs and comprised 20:4(n-6) and 20:5(n-3) fatty acids that contribute to n-3 and n-6 fatty acid pool recorded and rank among the molecular species with higher potential bioactivity. PLs’ profile was different between the two life stages surveyed, mainly due to the number and relative abundance of molecular species. This finding suggests that differences between both life stages were more likely related with shifts in the lipids of extraplastidial membranes rather than in plastidial membranes. PLs contained n-6 and n-3 precursors and in both life stages of Porphyra dioica the n-6/n-3 ratio recorded was less than 2, highlighting the potential benefits of using these life stages in human diet to prevent chronic diseases. Atherogenic and thrombogenic indexes of blades (0.85 and 0.49, respectively) and conchocelis (0.34 and 0.30, respectively) are much lower than those reported for other Rhodophyta, which highlights their potential application as food or as functional ingredients. Overall, MS-based platforms represent a powerful tool to characterize lipid metabolism and target lipids along different life stages of algal species displaying complex life cycles (such as Porphyra dioica), contributing to their biotechnological application.

Mestrado em Mestre em Bioquímica, ramo da Bioquímica Clínica Marine macroalgae, or seaweeds, have gained an increased interest in recent times for the use in various biotechnological applications, due to the added-value of their chemical constituents. Among them, glycolipids and phospholipids display several commercial applications in a wide spectrum of industries, such as food, pharmaceutical and cosmetic. In an effort to further understand the lipid composition of macroalgae, the present work reports, for the first time, the isolation and characterization of the polar lipid profile of the red macroalgae Porphyra dioica cultivated on a land-based integrated multi-trophic aquaculture (IMTA) system, using a lipidomic-based approach employing hydrophilic interaction liquid chromatography-eletrospray ionization mass spectrometry (HILIC-ESI-MS). The fatty acid profile of this species of seaweed was also determined, accounting for season variability and its life cycle. The polar lipid profile of P. dioica revealed the presence of over 69 molecular species, corresponding to glycolipids (sulfoquinovolsyldiacylglycerols, sulfoquinovosylmonoacylglycerols, digalactosyldiacylglycerols) and glycerophospholipids (lyso- and phosphatidylglycerols), lyso- and phosphatidylcholines), as well as phytyl derivatives. Some of these polar lipids contain polyunsaturated fatty acids (PUFAs), namely arachidonic acid (C20:4) and eicosapentaenoic acid (C20:5), thus revealing the ability of P. dioica to biosynthesize this long chain PUFAs. P.dioica from the winter season revealed to be richer in PUFA content, accounting for 37.0% of total fatty acid (TFA) content, as opposed to P. dioica from the summer season (25.0% of TFA content). Eicosapentaenoic acid (EPA) content was revealed to be being significantly higher in the winter season (25.2% of TFA content). The diploid sporophyte conchocelis phase of P. dioica showed to possess the highest amount of PUFAs (47.0% of TFA content), with arachidonic acid being the most abundant fatty acid (21.2% of TFA content). Several of the lipids identified have been reported to possess nutritional and health benefits, thus allowing the valorisation of P. dioica from IMTA as a source of bioactive compounds, adequate for the use in a wide range of different applications and as a functional food, rich in omega-3 fatty acids. As macroalgas têm vindo a ganhar um interesse cada vez maior para o uso em diversas aplicações biotecnológicas, devido ao valor acrescentado dos seus diferentes constituintes. Entre estes, os glicolípidos e os fosfolípidos podem ser usados comercialmente em diferentes indústrias, tais como as indústrias alimentar, farmacêutica e cosmética. Com o objetivo de compreender melhor a composição lipídica das macroalgas, o presente trabalho relata, pela primeira vez, a caracterização do perfil de lípidos polares da macroalga vermelha Porphyra dioica, cultivada num sistema de aquacultura multi-trófica integrada (IMTA), utilizando para esse fim uma abordagem lipidómica baseada na espectrometria de massa (HILIC-ESI-MS). Foi também determinado o perfil de ácidos gordos da referida espécie de alga, tendo em consideração a variabilidade sazonal e o seu ciclo de vida. O perfil de lípidos polares da alga P. dioica revelou a presença de mais de 69 espécies moleculares diferentes, correspondendo a classes de glicolípidos (sulfoquinovosildiacilgliceróis, sulfoquinovosilmonoacilgliceróis e digalactosildiacilgliceróis), fosfolípidos (liso- e fosfatidilglicerol, liso- e fosfatidilcolinas) e derivados fitil. Alguns destes lípidos polares contêm ácidos gordos polinsaturados (PUFAs) na sua composição, nomeadamente o ácido araquidónico (C20:4) e ácido eicosapentaenóico (C20:5), revelando, assim, a capacidade da alga P. dioica em biossintetizar este tipo de ácidos gordos polinsaturados de cadeia longa. Considerando a variação sazonal do conteúdo em ácidos gordos, a P. dioica cultivada no inverno revelou ser mais rica em PUFAs, correspondendo a 37.0% do conteúdo total de ácidos gordos, contrariamente à P. dioica cultivada no verão (25.0%). O conteúdo em ácido eicosapentaenóico (EPA) é significativamente maior na estação de inverno (25.2%). O perfil em ácidos gordos também variou com o ciclo de vida P. dioica, sendo que na fase de conchocelis a quantidade de PUFA é significativamente mais elevada (47.0% de conteúdo de ácidos gordos), sendo o ácido araquidónico o ácido gordo mais abundante (21.2% de conteúdo de ácidos gordos).Várias classes de lípidos polares foram identificados como possuindo benefícios nutricionais e para a saúde, permitindo assim a valorização da alga vermelha P. dioica produzida em IMTA como uma fonte de compostos bioativos, adequados para o uso numa grande variedade de aplicações como um alimento funcional, rica em ácidos gordos polinsaturados ómega-3.

Aspects of the life history of Porphyra dioica collected in Porto, Portugal, were investigated under laboratory and field conditions. This is one of the most common Porphyra species on the north coast of Portugal and can be found throughout the year. Field studies showed higher percentage cover, from 23% to 66%, from February to May in 2001 and 2002, compared to other times of the year. The effects of temperature, photon flux density (PFD) and photoperiod on growth and reproduction were tested. Zygotospores germinated fastest at 15°C and a PFD of 25 μmol photons m−2 s−1. Growth rate of the conchocelis was more affected by temperature than by photoperiod. In the three photoperiods tested, growth rate was maximal at 15°C, under 25–75 μmol photons m−2 s−1. Conchosporangium formation was greatest at 15°C, 25–75 μmol photons m−2 S−1 light and short-day, 8: 16 h light–dark conditions. In all conditions tested, conchosporangium formation was almost nonexistent in free-floating conditions. Optimal condit...

A seasonal study of the blade phase of Porphyra dioica at its type locality, Sidmouth, Devon, UK, undertaken between June 1999 and May 2000 revealed that individuals were present in the middle and lower littoral zones all year. Field-collected specimens were vegetative (8%), or possessed male (40%) or female (47%) reproductive structures, or had both on the same blade (6%) but totally segregated by a distinct line. Mean wet mass of individuals was greatest in June and least in February. There were no significant differences between the wet mass of individuals with male or female gametangia. Mean frond length was greatest in June and least in February. Mean frond width was greatest in May and least in February. Reproductive sori were marginal and pale straw-yellow for male gametangia, cream to pale green in unfertilized female gametangia, and bright red to dark red-brown once fertilization had taken place. Male gametangia were found in packets of 64 [2 X 4 in surface view (SV)]. Individuals with f...

The life history of Porphyra dioica collected in Porto, Portugal, was investigated under laboratory conditions. This is one of the most common Porphyra species on the North Coast of Portugal and can be found throughout the year. Field studies showed higher percentage cover, from 23 to 66%, during February through May. Varying temperature, light intensities and photoperiods were tested. The zygotospores germinated faster at 15°C, and at 25 μmol m−2·s−1. Growth rate of the conchocelis was affected by temperature rather than by photoperiod. In the three photoperiods tested, growth rate was always higher at 15°C, under 25 to 75 μmol m−2·s−1, although not significantly different from that at 20° C. Difference between these two temperatures and 5 and 10°C was significant. Conchosporangia formation was higher in 15°C and at short-day, 8:16, Light:Dark and 25 to 75 μmol m−2·s−1 and was almost non-existent in free floating conditions. Optimal conditions for conchosporangia maturation, 15° C, 8:16, Light:Dark and 5 to 25 μmol m−2·s−1 also promoted spore release after 18 weeks. Aeration appeared to be crucial for normal blade development. No archeospores were observed. The first findings of the optimal conditions for growth of the gametophyte stage will also be discussed.

Mestrado em Mestre em Bioquímica, ramo da Bioquímica Clínica Submitted by Carla Jesus (cjesus@ua.pt) on 2017-05-19T12:43:01Z No. of bitstreams: 1 Tese_Vítor Azevedo_45563.pdf: 1590206 bytes, checksum: f34c3f504b4a13e998103e9d0e97cc6a (MD5) Made available in DSpace on 2017-05-19T12:43:01Z (GMT). No. of bitstreams: 1 Tese_Vítor Azevedo_45563.pdf: 1590206 bytes, checksum: f34c3f504b4a13e998103e9d0e97cc6a (MD5) Previous issue date: 2016-07-20