Browsing by Author "Martins, V."
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- Alga Fucus sp. extracts to produce edible filmsPublication . Martins, V.; Machado, M.; Costa, E.; Gomes, A. M.; Poças, F.; Pintado, M.; Morais, R. M. S. C.; Morais, A. M. M. B.Introduction: Macroalgae are a good source of nutrients, such as carbohydrates (dietary fiber and polysaccharides), proteins, lipids and minerals [1,2]. Fucus sp. is composed of valuable bioactive compounds, such as fucoxanthin, vitamins, water-soluble (vitamin C and of complex B) and fat-soluble (vitamins A, D, E and K), phenolic compounds, lipids (MUFA and PUFA), and polysaccharides (fucoidans and alginic acid) [1]. This brown alga has been associated with health benefits, such as antioxidant, antimicrobial, anti-tumoral and anti-cancer properties [2]. Its application in the production of edible films presents high potential in food packaging, extending the shelf life of food products. Objectives: To evaluate the antioxidant activity and cytotoxicity bioactive extracts from Fucus sp. To produce an edible film based on PS enriched with the bioactive extracts. To test the antioxidant activity of the edible film. To test physico-chemical properties of the edible film, such as the color, thickness, solubility and water vapor permeability. Conclusions: Extraction at 300 W during 20 minutes is recommended for highest TPC and AA of the liquid extract. This extract showed no cytotoxicity for cells line HaCat. The edible film based on the PS extracted from Fucus sp. enriched with bioactives extracted also from this alga shows antioxidant activity, presents a high water vapor permeability, and 100 % solubility in water, which simulates hydrophilic foods, and lower solubility in hydroalcoholic solutions, which simulate hydrophobic foods. It has a brown color, characterized by relatively low luminosity and saturation values. This edible film has potential to be used in food packaging, whereas presenting high biodegradability.
- Characterization of alga Fucus sp. extracts and residues and their application in producing edible filmsPublication . Martins, V.; Coelho, M.; Machado, M.; Costa, E.; Gomes, A. M.; Poças, F.; Pintado, M.; Morais, R. M. S. C.; Morais, A. M. M. B.Introduction: Macroalgae are a good source of nutrients, such as carbohydrates (dietary fiber and polysaccharides), proteins, lipids and minerals, and they are sustainable, because they do not compete with food crops for arable land and potable water [1,2]. Fucus sp. is composed of valuable bioactive compounds, such as fucoxanthin, vitamins, water-soluble vitamins (vitamin C and of complex B) and fat-soluble vitamins (vitamins A, D, E and K), phenolic compounds, lipids (MUFA and PUFA), and polysaccharides (fucoidans and alginic acid) [1]. This brown alga has been associated with health benefits, with antioxidant, antimicrobial, anti-tumoral and anti-cancer properties [2]. Its application in the production of edible films presents high potential in food packaging, extending the shelf life of food products. Objectives: The integral valorization of Fucus sp. macroalgae, by extracting bioactive compounds, such as phenolic compounds, and extracting polysaccharides (PS). To evaluate the cytotoxicity and antioxidant activity of the bioactive extracts. To produce an edible film based on PS enriched with the bioactive extracts from Fucus sp. To test the physico-chemical properties of the edible film, such as the solubility. The nutritional characterization of the residues from the extractions. Conclusions: Extraction at 300 W during 20 minutes is recommended for highest TPC and AA of the liquid extract. This extract showed no cytotoxicity for cells line HaCat. The edible film based on the PS extracted from Fucus sp. enriched with bioactives extracted also from this alga presents 100 % solubility in water, which simulates hydrophilic foods, and lower solubility in hydroalcoholic solutions, which simulate hydrophobic foods. This edible film has potential to be used in food packaging, whereas presenting high biodegradability.
- Edible coatings with polysaccharides and bioactive compounds from exhausted olive oil pomace to extend the shelf life of strawberryPublication . Martins, V.; Lopes, A.; Pintado, M.; Morais, R. M. S. C.; Morais, A. M. M. B.Introduction: Exhausted or delipidified olive oil pomace (EOP) is a by-product generated from the olive pomace after air drying and hexane extraction of residual oil [1]. This by-product is rich in phenolic compounds, such as hydroxytyrosol, tyrosol and catechol, with associated properties: antioxidant, antimicrobial, anti- inflammatory, anti-diabetic, anti-carcinogenic and anti-HIV [1, 2]. Coatings and films are materials used for example to increase the shelf life of perishable fruits and vegetables. They can be made of polysaccharides, lipids and proteins from natural sources. It is essential to include bioactive compounds in the formulation to achieve bioactive properties, such as antimicrobial and antioxidant activities [3]. In this work a coating was performed using alginate and an extract rich in phenolics from EOP to increase the shelf life of strawberry (Fragaria ananassa). Objectives: To develop an edible coating using alginate and an extract rich in phenolics from EOP. To apply the coating to a perishable fruit, such as strawberry. To determine the moisture loss of the coated strawberry. To observe the natural decay of strawberry. To determine the growing curves of mesophilic aerobic bacteria, psychrophilic bacteria, Enterobacteriaceae, yeasts and molds in the coated strawberry. Conclusions: The formulation 2 % alginate + 5 % EOP extract can be successfully used as an edible coating. The application of the coating on strawberry are effective to prevent moisture loss, maintaining the quality of the fruits. It prevents the proliferation of several bacteria, such as psychrophilic bacteria, mesophilic aerobic bacteria, yeasts and molds.
- Screening methodologies to extract polyphenols from olive oil pomacePublication . Martins, V.; Ribeiro, T. B.; Pintado, M.; Morais, R.M.C.S.; Morais, A.M.M.B.Olive oil is a product from the fruits of the plant Olea europaea L. About two million ton of olive oil are produced annually, whereas Spain, Italy and Greece are the major producers. Its production worldwide causes 30 million m3 of olive mill waste each year 1, which consist of olive oil pomace and olive wastewater. Following the goals of the ONU agenda for 2030, under the topic of circular economy that includes “zero waste production”, an economy model uses the residues as resources to be valorized 2. The olive oil pomace contains bioactive compounds, such as the hydroxytyrosol, tyrosol, oleuropein 3, which have shown to present antimicrobial and antioxidant proprieties, with applications in the food industry. This works aims to test and optimize different extraction techniques to obtain bioactive compounds from the olive oil pomace byproduct. Techniques such as maceration in water or hydroalcoholic solutions, with or without enzymes, assisted or not by ultra-turrax, ultrasound or microwave. Preliminary results showed that the use of enzymes in extraction allowed a higher yield of extraction. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) were used to identify the bioactive compounds present in the extract. Relevant compounds with antimicrobial and antioxidant proprieties will be used in packaging as films or coatings for food applications.