Browsing by Author "Gil, Maria M."
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- Assessment of traditional mayonnaise enriched with Aurantiochytrium sp. extractPublication . Pinheiro, Joaquina; Garcia, Adriana; Paulo, Maria; Coutinho, Joana; Baptista, Teresa; Bernardino, Susana M.; Tecelão, Carla; Gil, Maria M.; Lemos, Marco F.Mayonnaise, a food product widely consumed since the 1900s, traditionally prepared from a mixture of oil, egg yolk and vinegar, has a reduced shelf-life primarily due to lipid oxidation (Kwon et al., 2015). The addition of synthetic antioxidants like BHT (butylated hydroxytoluene), BHA (butylated hydroxyl anisole), and EDTA (ethylenediaminetetraacetic acid) has been used to control this problem (Gray, 1978). However, these synthetic antioxidants showed several disadvantages such as the easily decomposition at higher temperatures, and an increased health risk for chronic consumers (Martinez-Tome et al., 2001). Natural antioxidants, derived from marine algae, show great potential for improving oxidative stability, extending the shelf-life of stored food products with additional health-promoting benefits (Hermund et al., 2015). Since 2004, the DHA-rich oil derived from the microalgae Aurantiochytrium sp. has been recognized as safe, available for food use and for dietary supplements. In general, Aurantiochytrium sp. became a popular source of protein-rich biomass and of valuable compounds like pigments, antioxidants and essential fatty acids. The potential of heterotrophic microalgae Aurantiochytrium sp. as a source of functional ingredient applied in mayonnaise product has not been evaluated yet. The aim of this study was to evaluate the quality of mayonnaise enriched with Aurantiochytrium extract by colour (L*, a*, b*, and ºh), texture (hardness, adhesiveness, resilience, cohesion, springiness, gumminess, and chewiness) and antioxidant capacity (DPPH and total phenolics content). The mayonnaise without extract was used as control sample. Colour results indicated that the luminosity of mayonnaise enriched with extract increased and the a* and b* colour parameters decreased, promoting a colour enhancement. Also, with the addition of Aurantiochytrium extract, a decrease in all texture attributes obtained by TPA profile test, with exception of cohesion and springiness, was observed. A correlation between antioxidant activity and total phenolics content was denoted, in all samples. The high antioxidant capacity can be related to high radical scavenging activity, high total phenolic content, and high carotenoid content of the extract. This study demonstrates that Aurantiochytrium sp extracts have the potential to be used as a nutraceutical/functional ingredient in mayonnaise, a product widely consumed by different age groups.
- Bioaccessibility of target essential elements and contaminants from Fucus spiralisPublication . Francisco, João; Cardoso, Carlos; Bandarra, Narcisa; Brito, Pedro; Horta, André; Pedrosa, Rui; Gil, Maria M.; Delgado, Inês Margarida; Castanheira, Isabel; Afonso, CláudiaFucus spiralis is an edible brown seaweed (SW) found in the Portuguese Coast that is still undervalued and not very well studied. However, SW are known to be nutritious and healthy foods, in part, for their potential to supply mineral nutrients to the body. Nevertheless, with the increasing levels of pollution in the coastal areas, SW can also accumulate some contaminants. Therefore, to expand the knowledge about this marine resource, the contents of Mg, Mn, Co, I, Cd, Pb, As and Hg in fresh and freeze-dried Fucus spiralis were determined before and after in vitro human digestion simulation. Magnesium was the major element with 11.86 mg/g dry weigh (DW), but it must be highlighted that I in this SW presented concentration values of approximately 135 μg/g DW. Concerning contaminants, F. spiralis seems to have low levels of Cd, Pb, and Hg. The elements’ bioaccessibility was always high, ranging between 45.8% (I – Fresh SW) and 88.5% (Hg – FD SW). The freeze-drying process seemed to enhance element bioaccessibility.
- Bioactivity screening of Aurantiochytrium sp. for antioxidant activitiesPublication . Pinheiro, Joaquina; Garcia, Adriana; Paulo, Maria; Coutinho, Joana; Baptista, Teresa M.; Bernardino, Susana M.; Tecelão, Carla; Gil, Maria M.; Lemos, Marco F.L.Aurantiochytrium sp. is a heterotrophic microalgae that, in certain growth conditions, besides producing significant amounts of squalene, may potentially produce other bioactive compounds with high value and commercial interest such as docosahexaenoic acid (DHA), carotenoids, among others. Antioxidant compounds, naturally occurring in microalgae sources, have been identified as free radical or active oxygen scavengers, with beneficial effects on oxidation and oxidative damage inhibition in human body and foods. Several in vitro methodologies have been proposed to evaluate the antioxidant capacity, such as free radicals: 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), and reactive species including hydrogen peroxide (H2O2), singlet oxygen (O2), and superoxide anion (O2-) (Balboa et al., 2013). The main objective of the present study was to evaluate the antioxidant activity of aqueous and ethanolic extracts of Aurantiochytrium sp., by means of different methodologies: reducing and scavenging activity by total phenolics content (TPC, Singleton & Rossi, 1965), DPPH (Custódio et al., 2012), and oxygen radical absorbance capacity (ORAC, Dávalos et al., 2004). The obtained results indicated that the microalgae Aurantiochytrium sp. is rich in antioxidant compounds, by reducing activity through total phenolics and DPPH, as well as scavenging activity by ORAC. Moreover, it is evident the higher selectivity of ethanol as solvent for the extraction of antioxidants compounds. The potential of this microalgae biomass as a good, natural and sustainable source for use as a functional food ingredient is evident, representing an opportunity with additional benefits due to the antioxidant role in diseases prevention and treatment.
- CATA vs. FCP for a rapid descriptive analysis in sensory characterization of fishPublication . Silva, Frederica; Duarte, Ana M.; Mendes, Susana; Pinto, Filipa R.; Barroso, Sonia; Ganhão, Rui; Gil, Maria M.Storing non-marketable fish aboard fishing vessels takes up valuable storage space and, consequently, it is usually discarded. Therefore, the strategy to minimize the amount of discarded fish and boost the fishing economy should entail measures to turn unexploited species into marketable fish. The use of sensory descriptive analysis is usually the first step in the characterization of foods and assess their baseline appeal to the final consumer. In this study, the sensory characterization of five unexploited fish species was conducted, using a semi-trained panel, with the objective of establishing the appeal and marketability of these species. Check-all-that-apply (CATA) and Free Choice Profiling (FCP) were used to obtain descriptive attributes. Correspondence Analysis (CA) was used to examine CATA data and to compare both sensory methods, while Principal Component Analysis (PCA) was used for FCP data analysis. The results obtained with CATA method allowed to differentiate species by appearance, odor and flavor, while appearance and odor were statistically significant descriptors in FCP. CATA method was found to be more suitable to discriminate fish species, presenting a higher discriminatory power than FCP.
- Chemical-based methodologies to extend the shelf life of fresh fish: a reviewPublication . Amaral, Renata A.; Pinto, Carlos A.; Lima, Vasco; Tavares, Jéssica; Martins, Ana P.; Fidalgo, Liliana G.; Silva, Ana M.; Gil, Maria M.; Teixeira, Paula; Barbosa, Joana; Barba, Francisco J.; Saraiva, Jorge A.Due to its characteristics, fresh fish is a highly perishable food with a very short shelf-life under refrigeration. Several methods have been introduced to slow down its deterioration, such as by means of oxygen depletion of the food package (vacuum packaging), or by changing the natural atmosphere that is in contact with the fresh fish (modified atmosphere packaging), or by the use of chemicals generally recognized as safe: such compounds can be directly applied (by dipping or spraying) or incorporated into packaging materials and slowly migrate to the product, exerting a hurdle effect against microbial development and lipid oxidation (active packaging). This review aims to cover the most recent advances in chemical-based approaches for fresh fish preservation, applied either singly or in combination. Vacuum packaging, modified atmosphere, and active packaging preservation methodologies are presented, along with the inclusion of chemical additives, such as organic acids and natural extracts, and their combination with icing systems. Advantages and disadvantages of these methodologies and their impact on fresh fish quality and shelf-life are discussed, reaching the conclusion that both are positively influenced overall. Indeed, the contribution of hemical-based strategies for fresh fish preservation is undeniable, and is expected to be a research topic of increasing interest in the future.
- Effect of tuna skin gelatin-based coating enriched with seaweed extracts on the quality of tuna fillets during storage at 4 °CPublication . Vala, Milene; Augusto, Ana; Horta, André; Mendes, Susana; Gil, Maria M.; GilNowadays, consumers demand high quality food products with an extended shelf-life without chemical additives. Edible coatings (EC) containing natural compounds are a promising preservation technology for raw seafood without compromising fresh-like appeal and nutritional content. The aim of this work was to evaluate the effect of Thunnus obesus skin gelatin-based EC containing Codium spp. or Fucus vesiculosus extracts on raw tuna preservation. Three gelatin-based EC (gelatin (5 %) + glycerol (25 %); gelatin (5 %) + Codium spp. (1 %) + glycerol (25 %); gelatin (5 %) + Fucus vesiculosus (1 %) + glycerol (25 %)) were applied directly on the surface of tuna fillets. Functional properties of gelatin and gelatin-based EC containing seaweed extracts were also studied. The gelatin was extracted by an acid-swelling process in the presence/absence of pepsin, followed by subsequent heating/refrigeration, after a pre-treatment with NaOH. The type of acid, temperature and concentration of NaOH greatly influence the process yield. The higher extraction yield was achieved using acetic acid in the presence of pepsin by subsequent refrigeration, especially when skins were previously treated with NaOH (0.2 M). Tuna quality was assessed over 12 days of storage at 4 ± 1 °C in terms of chemical and microbial indices. Results showed that tuna skin gelatin-based EC avoids tuna deterioration. Microbial growth, assessed by total viable counts, and total volatile basic nitrogen were maintained below the maximum limits recommended, contrarily to the control. Additionally, the use of EC increased the stability of red colour during storage.
- Food texture design by 3D printing: a reviewPublication . Pereira, Tatiana; Barroso, Sónia; Gil, Maria M.An important factor in consumers’ acceptability, beyond visual appearance and taste, is food texture. The elderly and people with dysphagia are more likely to present malnourishment due to visually and texturally unappealing food. Three-dimensional Printing is an additive manufacturing technology that can aid the food industry in developing novel and more complex food products and has the potential to produce tailored foods for specific needs. As a technology that builds food products layer by layer, 3D Printing can present a new methodology to design realistic food textures by the precise placement of texturing elements in the food, printing of multi-material products, and design of complex internal structures. This paper intends to review the existing work on 3D food printing and discuss the recent developments concerning food texture design. Advantages and limitations of 3D Printing in the food industry, the material-based printability and model-based texture, and the future trends in 3D Printing, including numerical simulations, incorporation of cooking technology to the printing, and 4D modifications are discussed. Key challenges for the mainstream adoption of 3D Printing are also elaborated on.
- Influences of physicochemical stresses on injury and inactivation behaviour of Listeria innocuaPublication . Miller, Fatima A.; Ramos, Barbara; Gil, Maria M.; Brandao, Teresa R. S.; Teixeira, Paula; Silva, Cristina L. M.Many minimally processed foods depend on a combination of inhibitory factors to reduce the hazard of foodborne illness. Therefore, inactivation of Listeria innocua was studied according to a 24 factorial experiment designed to draw conclusions about temperature (52.5 °C and 65.0 °C), pH (4.5 and 7.5), water activity (aw=0.95 and 0.99) and solute type (NaCl and glycerol) effects. Three different recovery media were used to assess injured cells. Survival data were fitted with a Gompertz-based model and kinetic parameters (shoulder, maximum inactivation rate – kmax, and tail) were estimated. Results showed that shoulder was affected by temperature, pH and combined effects; kmax was influenced by all factors and their combinations; and tail was affected by aw, temperature and aw/pH combination. Results demonstrated the potential occurrence of microbial cross-protection survival techniques between the various stresses, e.g. heat and osmolarity. Indeed, this work clearly established that, to avoid hazards, Listeria inactivation must be evaluated with a maximum of environmental factors that undergo alterations. Only thus, appropriate food preservation treatments can be developed and consequently, the safety of food products can be assured.
- Lipid oxidation inhibition by natural tocopherols increases the nutritional value of tuna salamiPublication . Sousa, Rita; Pedrosa, Rui; Gil, Maria M.Introduction: The quality attributes of fish products deteriorate due to the lipid oxidation during processing and storage. Tuna salami is highly susceptible to oxidation, which can precipitate health hazards and economic losses in terms of inferior product quality. Methods: The effect of adding different natural antioxidants on the lipid oxidation, colour and fatty acid profile of tuna salami after nine days of storage at 4 ºC was assessed. Three different commercial mixes of tocopherols were added during the production of the tuna salami and samples were sliced and refrigerated for 9 days. Results: The lipid oxidation increased from 0.98 to 4.03 mg of malondialdehyde/kg. The oxidation process was inhibited by DLT-100 and VIT-100; however, RNX10 did not blunt the oxidative process. VIT and dose-limiting toxicity (DLT) reduced the total unsaturated fatty acid reduction. The RNX did not prevent the reduction of the a* value. Conclusion: It was concluded that tocopherols supplementation kept the nutritional value of tuna salami mainly by lipid oxidation inhibition.
- Motivation and preferences of Portuguese consumers’ towards sea urchin roePublication . Lourenço, Sílvia; Mendes, Susana; Raposo, Andreia; Santos, Pedro M.; Gomes, Ana S.; Ganhão, Rui; Costa, José L.; Gil, Maria M.; Pombo, AnaSea urchin roe is a gastronomic delicacy appreciated worldwide and Portugal is the third largest consumer nation of seafood. However, sea urchin roe is recognized as a seafood by few members of the national coastal communities. Motivated by an increasing interest of gastronomic and aquaculture sectors in producing this seafood, a survey was conducted among the participants of gastronomic festivals aiming to characterize the motivations and preferences regarding sea urchin roe. The results showed that a high percentage of consumers would be willing to eat sea urchin roe in a restaurant, and approximately half of these were not motivated to buy it in the supermarket. The consumers willing to buy sea urchins in the supermarket, would buy it as the whole urchin or the chilled/frozen roe. In conclusion, sea urchin roe can be characterized as a high valued shellfish to be consumed in restaurants.