Percorrer por autor "Vieira, Margarida"
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- Advances in the food packaging production from Agri-Food waste and by-products: Market trends for a sustainable developmentPublication . Cristofoli, Nathana L.; Ribeiro Lima, Alexandre; Tchonkouang, Rose Daphnee; Quintino, Andreia; Vieira, MargaridaAgricultural waste has been a prominent environmental concern due to its significant negative impact on the environment when it is incinerated, disposed of in landfills, or burned. These scenarios promoted innovations in the food packaging sector using renewable resources, namely agri-food waste and by-products such as bagasse, pulps, roots, shells, straws, and wastewater for the extraction and isolation of biopolymers that are later transformed into packaging materials such as bioplastics, biofilms, paper, and cardboards, among others. In this context, the circular bioeconomy (CBE) model is shown in the literature as a viable alternative for designing more sustainable production chains. Moreover, the biorefinery concept has been one of the main links between the agri-food chain and the food packaging industry. This review article aimed to compile recent advances in the food packaging field, presenting main industrial and scientific innovations, economic data, and the challenges the food packaging sector has faced in favor of sustainable development.
- Alicyclobacillus acidoterrestris spores as a target for Cupuacu (Theobroma grandiflorum) nectar thermal processing: kinetic parameters and experimental methodsPublication . Vieira, Margarida; Teixeira, A. A.; Silva, F. M.; Gaspar, N.; Silva, C. L. M.The kinetic parameters of thermal inactivation of a spore former, Alicyclobacillus acidoterrestris, in a tropical fruit nectar [25% of Cupuaca (Theobroma grandiflorum) pulp and 15% sugar] were determined by the isothermal method (IM), under batch heating, and by the paired equivalent isothermal exposures (PEIE) method, under non-isothermal continuous conditions. The isothermal experiments were repeated three times, every 4 months, with the same spore suspension kept frozen between experiments. The aging of spores, under frozen storage, seemed to produce a notorious increase in the z-value from experiment to experiment: Experiment I (z = 7.8 +/- 2.6 degreesC, D-95 (degreesC) = 5.29 +/- 0.96 min), Experiment 2 (z = 22 +/- 5 degreesC, D-95 (degreesC) = 5.99 +/- 0.63 min), and Experiment 3 (z = 29 +/- 10 degreesC, D-95 degreesC = 3.82 +/- 0.48 min). The evaluation of the kinetic parameters by the PEIE method was carried out in parallel with Experiment 3, with the same aged spores, and the results (z = 31 +/- 6 degreesC, D-95 (degreesC) = 5.5 +/- 1.2 min) were close to the ones obtained in this experiment. From this work, it seems that the PEIE method can also be applied to evaluate the reduction parameters of a spore-forming microorganism, and in a more realistic way, since the continuous system eliminates the errors caused by come-up and cool-down times (CUT and CDT) that are unavoidable in isothermal experiments. Therefore, when designing a thermal process for a continuous system, the PEIE method should be used, or the chances are that the process would be underdesigned, risking that the desired level of spore inactivation would not be achieved. An optimization of the thermal processing conditions was next performed for Cupuacu nectar, considering a 5D reduction in A. acidoterrestris spores. If a pasteurization process is considered, the conditions that ensure safety (9 min at 98 degreesC only allow a 55% retention of ascorbic acid (AA). If sterilization is considered, 8 s at 115 degreesC will ensure a safe product and retain 98.5% of the original ascorbic acid. Therefore, if A. acidoterrestris is considered as the target microorganism, the nectar should undergo an aseptic high temperature short the principle (HTST) process to achieve a 5D reduction in this acidophilus spore former. However, if the hot-fill-and-hold pasteurization process is preferred, the product should be fortified with ascorbic acid. (C) 2002 Elsevier Science B.V. All rights reserved.
- Assessing the viability of chitosan-based films reinforced with cellulose nanofibers from salicornia ramosissima agro-industrial by-product for food packagingPublication . Ribeiro Lima, Alexandre; Sautron, Laurence; Kalamaridou, Aliki; Lazzarotto Cristofoli, Nathana; Quintino, Andreia; Amaral, Renata A.; Saraiva, Jorge A.; Vieira, MargaridaThis study investigates the valorisation of Salicornia ramosissima agro-industrial by-product by using cellulose nanofibers (CNFs) extracted from this halophyte to reinforce chitosan-based films. The physical, mechanical, and thermal properties of chitosan films containing 0% (control), 1%, and 2% (w/w) CNF were evaluated. Films were produced by solvent casting with glycerol as a plasticiser. At the 2% CNF concentration, films exhibited a reduced moisture content and increased solubility in aqueous solutions. The water vapour transmission rate (WVTR) decreased as CNF content increased under constant humidity but increased at higher temperature and humidity. Control films were more transparent, yet CNF-reinforced films had higher tensile strength and Young’s modulus, reflecting greater stiffness. Maximum elongation at break decreased markedly with the addition of CNFs. SEM revealed that reinforced films had more heterogeneous, rougher surfaces, particularly at 2% CNF. Thermogravimetric analysis showed that 2% CNF adversely affected the thermal stability of the chitosan film. ATR-FTIR spectra indicated that CNF reinforcement protected against UV-induced degradation. Degradability tests in soil and seawater confirmed that the chitosan–CNF mixture preserved degradability, especially at 1% CNF. These findings demonstrate that reinforcing chitosan-based films with CNFs from S. ramosissima can improve functional properties and suggest the potential of this approach for biomaterials development in food packaging applications.
- Bacterial lipopeptides from bacillus: natural biostructuring agents for improving texture and stability in tomato-based functional foodsPublication . Gharsallah, Houda; Ngameni Tchonkouang, Rose Daphnee; Mabrouk, Aymen Ben; Jaoued, Najeh; Tas, Ozan; Boufi, Sami; Vieira, Margarida; Oztop, Mecit Halil; Zarai, ZiedIntroduction: Recent advances in functional food formulation have highlighted bacterial lipopeptides as natural biomolecules capable of replacing synthetic additives while enhancing the physicochemical properties of food systems. Their amphiphilic structure makes them promising candidates for improving texture, stability, and emulsification in complex matrices such as tomato-based products. Methods: In this study, lipopeptides produced by Bacillus strains were structurally characterized using 1 H-NMR and two-dimensional 1 H–1 H COSY spectroscopy to confirm their amphiphilic nature. Tomato-based formulations (juice and sauce) were enriched with lipopeptides at concentrations of 0.5, 1.0, and 2.0 g/L. Rheological behavior was evaluated under steady-shear conditions to assess flow properties and time-dependent structural changes. Results: Spectroscopic analysis confirmed the presence of characteristic aliphatic fatty acid chains and peptide residues, validating the lipopeptidic structure. All formulations exhibited shear-thinning behavior; however, the addition of lipopeptides significantly influenced time-dependent rheological properties. Improved texture, viscoelasticity, and stability were observed, with optimal performance achieved at low-to-moderate concentrations (H6: 0.5–1 g/kg; S15: up to 2 g/kg). Higher concentrations led to partial network disruption and reduced system stability. Discussion: These findings demonstrate that bacterial lipopeptides act as effective natural bio-structuring agents in tomato-based products. Their ability to enhance microstructural integrity and emulsification without compromising stability at optimal concentrations highlights their potential as sustainable alternatives to synthetic additives in functional food development.
- CIBIA XII - Iberoamerican Congress of Food Engineering, 2019Publication . Cruz, Rui; SILVA, L. M.; Vieira, MargaridaClimate change enhanced the need to decarbonize the food production and supply chain covering food processing, packaging, transport, retailing, and end-of-life disposal. Today's way food products are offered to consumers contributes to 30% of the greenhouse emissions (GHE), which is more than 2 tons of CO₂ per person per year in the United States and Europe. Alternatives to decrease this number include lowering meat intake and replacing it with plant-based protein, as the highest greenhouse gas emissions are released during meat production. Another solution is using raw materials produced locally or in the surroundings to produce food products, avoiding food transportation in ships, airplanes, or trains from long distances or overseas. Replacing non-biodegradable materials in food products packaging with new, bio-based, and biodegradable ones is another suitable alternative. Also, reducing food waste is of crucial importance as its carbon emissions account for approximately 6% of GHE, mainly due to decomposing process of the organic matter in landfills.
- Combined pre-treatments effects on zucchini (Cucurbita pepo L.) squash microbial load reductionPublication . Neves, Filipa. I. G.; Silva, Cristina L. M.; Vieira, MargaridaFreezing vegetables requires pre-treatments to reduce microbial load and destroy enzymes that impair the frozen product quality. So far blanching has been the most effective pre-treatment, preferred by the food industry, despite its severity: heating up to temperatures close to 100 °C for 1-3 min causes sensory and texture changes in most horticultural products. Alternative blanching treatments, using UV-C radiation combined with milder thermal treatments or with thermosonication, may improve the quality of the final frozen vegetables. Zucchini (Cucurbita pepo L.), the vegetable under study, has an availability in fresh restricted to a season, needing therefore to be often frozen to be used throughout the year. In this study, its surface was first inoculated with two vegetable contaminants, Enterococcus faecalis and Deinococcus radiodurans cells, which are resistant, respectively, to high temperatures and to radiation and then submitted to several blanching treatments, single or combined, and the effect on these microorganisms reduction was evaluated. As single treatments, water blanching (the control treatment, as it is the blanching treatment traditionally used) was applied up to 180 s at temperatures ranging from 65 to 90 °C, and UV-irradiation applied in continuous. As combined pre-treatments, water blanching combined with UV-C (continuous or in pulses), and thermosonication (20 kHz at 50% of power) combined with UV-C pulses were also studied. The continuous UV-C radiation incident irradiance was 11 W/m2 up to 180 s, and the pulses at incident radiance of 67 W/m2, lasting 3.5 s each (35 pulses). Mathematical modeling of bacterial reduction data was carried out using the Bigelow, the Weibull and Weibull modified models, and estimation of their respective kinetic parameters proved that the latter models presented a better fit below 75 °C. The best results proved to be the combination of water blanching at temperatures as low as 85 °C during <2 min with 25 pulses of UV-C (incident irradiance of 67 W/m2) or thermosonication at 90 °C also combined with UV-C pulses, both resulting in 3 log reductions of both microorganisms under study. These results proved to overcome what industry is requiring so far (a 2 log microbial reduction in 3 min), hence minimizing quality changes of frozen zucchini.
- Comparative study of the production of cellulose nanofibers from agro-industrial waste streams of Salicornia ramosissima by acid and enzymatic treatmentPublication . Ribeiro Lima, Alexandre; Cristofoli, Nathana L.; Rosa Da Costa, Ana; Saraiva, Jorge A.; Vieira, MargaridaThe study of the suitability of two isolation processes to produce cellulose nanofibers (CNFs) from Salicornia ramosissima waste, with potential applicability as a reinforcing agent of polymeric composites was carried out. To separate the cellulose fibrils from the cell wall and obtain CNFs an alkaline treatment was applied followed by a bleaching treat-ment and, the insoluble residue was next hydrolyzed by either an acid treatment (AT) or an enzyme treatment (ET). SEM and TEM images indicated fiber exposure caused by both treatments. The diameter, length, aspect ratio, and polydispersity index, were measured for both CNFs. CNF (ET) showed high zeta potential values suggesting that ET produces more electrically stable and thinner nanofibers. The FTIR spectra revealed that both treatments effectively removed the amorphous components allowing the CNFs isolation, and XRD patterns evidenced the increase in the degree of crystallinity of both CNFs. Nonetheless, CNF(AT) presented a lower mechanical resistance due to its smaller particle size, compared to the CNF(ET). In summary, the (ET) could successfully isolate CNFs from the Salicornia waste, encouraging the use of this treatment, once when compared to (AT), it does not generate toxic residues, presents mild thermal conditions, and produces CNFs with higher-value applications.
- Development of a novel formulation of a functional tomato saucePublication . Ngameni Tchonkouang, Rose Daphnee; Martey, Dorcas Martekie; Bal, Murad; Oztop, Mecit Halil; Gago, Custódia; Guerreiro, Adriana; Estêvão, Maria Dulce da Mota Antunes de Oliveira ; Vieira, MargaridaA functional tomato sauce was developed through the enrichment of high-lycopene tomato pulp (TomP) with pea protein (PP), freeze-dried olive powder (OP), and tomato peel powder (TPP) to achieve good sensory acceptability and a high antioxidant level using a 4-component (X1-TomP, X2-PP, X3-OP, X4-TPP) D-optimal mixture design. Responses: Y1-color, Y2-aspect, Y3-aroma, Y4-flow/texture, Y5-taste, Y6-sourness, and Y7-aftertaste, were evaluated by a non-trained sensory panel to obtain polynomial models for all responses. Numerical optimization resulted in the formulation: TomP (93.05%), PP (1.82%), OP (1.66%), and TPP (3.47%). Sensory analyses of the developed sauce revealed that the product was appreciated by untrained and trained panelists. Sensory profile analyses by the trained panel consensus concluded that the sauce has a good flavor profile with well-balanced sweetness and saltiness, slightly perceptible astringent notes, and no off-taste. Analyses of antioxidant activity (ABTS and FRAP), polyphenols, lycopene and beta-carotene were carried out. The sauce had concentrations of 35.37±1.85 mg/100 g (lycopene), 5.72±0.52 mg/100 g (beta-carotene), and 58.30±0.91 mg GAE/100 g (phenolic content) while the pulp had concentrations of 23.54±0.76 mg/100 g, 3.03±0.01 mg/100 g and 39.06±2.99 mg GAE/100 g, respectively. The developed tomato sauce compares favorably with the pulp in terms of lycopene, beta-carotene, and phenolic content. The remarkable increase in phenolic content, lycopene, and beta-carotene (known for their antioxidant properties) in the sauce enriched with powdered additives contributes significantly to its antioxidant potential. Therefore, the developed sauce is a good source of such health-promoting compounds and has the potential to be consumed as a functional food.
- Documentos das provas de agregação de Maria Margarida Cortez Vieira. Titulo da Lição: Embalagem ativa de alimentos numa economia biocircularPublication . Vieira, MargaridaPara apreciação em provas de agregação em Ciências Biotecnológicas de acordo com a alínea iii) do ponto 3 do art. 4º do Regulamento de Atribuição do Título Académico de Agregado da Universidade do Algarve publicado em anexo ao Despacho n.º 2251/2020 ao abrigo do nº 2 do artº 4º do Decreto-Lei nº 239/2007, de 19 de junho 2023. Na escolha do tema desta lição que segundo o regulamento deve ser “dentro do âmbito do ramo do conhecimento ou especialidade em que são prestadas as provas”, foi tido em consideração a dedicação durante toda a minha vida académica a uma área do conhecimento em Ciência dos Alimentos, a Conservação dos Alimentos e em particular à Embalagem de Alimentos Ativa e a ao Desenvolvimento de Novos Materiais de embalagem biodegradáveis. Esta dedicação incluiu por um lado a docência de várias unidades curriculares, e por outro a investigação. Ainda, era imperioso que o tema refletisse a atualidade com grande relevância científica e tecnológica. No início da lição é dada uma explicação fundamentada sobre a razão de se considerar a temática desta lição, muito relevante na conjuntura presente, introduzindo-se primeiro a temática dos problemas ambientais do século XXI e referindo-se depois a evolução do conceito de resíduo de embalagem numa economia linear para um novo conceito de subproduto numa economia bio circular. É então introduzido o conceito de embalagem smart, desenvolvendo-se depois mais conhecimento sobre a embalagem ativa e introduzindo a embalagem de libertação controlada (LC) como uma subdivisão da embalagem ativa (EA). Após ser explicado o fundamento deste tipo de embalagem são enunciados todos os fatores que se deve ter em conta quando se projeta uma embalagem de LC para um alimento específico. De seguida a modelação matemática do processo LC de um composto ativo (CA) da embalagem para a superfície do alimento é explicada. A aula termina com uma apresentação do trabalho que tem vindo a ser desenvolvido pelo grupo de investigadores que trabalham na área de embalagem ativa no Departamento de Engenharia Alimentar do ISE/UAlg.
- Enhancing carob flour (Ceratonia siliqua L.) for by-product utilization in food industries: carob syrup production, functional profiling and applicationPublication . Vilas-Boas, Ana Martins; Brassesco, María Emilia; Quintino, Andreia; Medronho, Bruno; Vieira, Margarida; Brandão, Teresa R. S.; Silva, Cristina L. M.; Silva, Beatriz; Azevedo, Miguel; Pintado, ManuelaThe focus on by-product valorization in the food industry, particularly from the carob pod, underscores a commitment to sustainability and resource efficiency. This fruit, sourced from the leguminous evergreen carob tree (Ceratonia siliqua L.), is renowned for its adaptable flavour and nutritional value, in Mediterranean regions such as Portugal. Its production yields significant by-products, presenting environmental challenges when not managed efficiently. Innovative approaches, including integral carob flour production, aim to optimize utilization while minimizing waste and energy consumption. This study repurposed carob waste to produce novel, value-added ingredients like carob syrup, by thermal hydrolysis of integral carob flour using water at 1:3 solidto-liquid ratio - obtaining up to 50 % solubility yield. The resulting syrup exhibited 72 % ◦Brix, a melting temperature (Tm) of approximately 130 ◦C and predominantly viscous behavior with minimal elastic (solid-like) response. Lastly, the syrup was incorporated into a carob-based brigadeiro, replacing conventional glucosefructose syrup. Simulated gastrointestinal digestion revealed enhanced bioaccessibility of sugars and phenolics, and increased antioxidant activity during the intestinal phase. Despite sugar availability, the prebiotic activity of the syrup decreased when embedded in the brigadeiro matrix, potentially due to interactions with polyphenols or organic acids. Cytotoxicity and permeability assays confirmed safety at ≤0.5 % (w/v) and supported intestinal barrier integrity. These findings support the use of integral carob flour for producing multifunctional ingredients, contributing to circular economy models while meeting consumer demands for healthier, sustainable food products.
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