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.
- 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.
- 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.
- Exopolysaccharides from porphyridium cruentum as a reinforcing agent for chitosan biopolymer-based filmPublication . Lazzarotto Cristofoli, Nathana; Ribeiro Lima, Alexandre; Costa, Sebastião; Silva, Carlos Manuel; Varela, João; Vieira, MargaridaMicroalgae exopolysaccharides (EPS), extracted from exhausted culture medium of Porphyridium cruentum, a rhodophyte able to grow in marine environments, may be useful as reinforcing agents in chitosan-based films produced by casting, using glycerol as a plasticizer. EPS were added at 1 and 2 % (w/v). The resulting hydrophilic films, EPS1 and EPS2, respectively, were opaquer than the control (CTR) chitosan-based films without EPS, resulting in increased thickness and solubility, and decreased moisture and water contact angle. EPS1 and EPS2 showed 1.5 and 2.0-fold higher tensile strength and a 2.9- and 16.3-fold higher Young’s modulus, respectively, compared to CTR. Conversely, elongation decreased by 1.9- and 8.2-fold for EPS1 and EPS2 compared to CTR. EPS1 and EPS2 showed a homogeneous matrix surface upon SEM analysis, presenting some aggregated particles with increasing EPS concentration. FTIR histograms were not influenced by the EPS concentration used. Thermal analysis showed film degradation occurred in three phases, with no significant enhancement in thermal stability. Soil biodegradability confirmed all films degraded within 35 days. This study demonstrated the feasibility of using industrial microalgae byproducts, such as EPS, as film reinforcement agents, primarily enhancing mechanical strength, thus increasing the possibilities of using these raw materials to produce sustainable food films.
- Food composition databases: does it matter to human health?Publication . Delgado, Amélia; Issaoui, Manel; Vieira, Margarida; Saraiva De Carvalho, Isabel; Fardet, AnthonyFood provides humans with more than just energy and nutrients, addressing both vital needs and pleasure. Food habits are determined by a wide range of factors, from sensorial stimuli to beliefs and, once commanded by local and seasonal availability, are nowadays driven by marketing campaigns promoting unhealthy and non-sustainable foodstuffs. Top-down and bottom-up changes are transforming food systems, driven by policies on SDGs and by consumer’s concerns about environmental and health impacts. Food quality, in terms of taste, safety, and nutritional value, is determined by its composition, described in food composition databases (FDBs). FDBs are then useful resources to agronomists, food and mechanical engineers, nutritionists, marketers, and others in their efforts to address at maximum human nutrient needs. In this work, we analyse some relevant food composition databases (viz., purpose, type of data, ease of access, regularity of updates), inspecting information on the health and environmental nexus, such as food origin, production mode as well as nutritional quality. The usefulness and limitations of food databases are discussed regarding what concerns sustainable diets, the food ‘matrix effect’, missing compounds, safe processing, and in guiding innovation in foods, as well as in shaping consumers’ perceptions and food choices.
- Particle size effect of integral carob flour on bioaccessibility of bioactive compounds during simulated gastrointestinal digestionPublication . Vilas-Boas, Ana M.; Brassesco, María E.; Quintino, Andreia; Vieira, Margarida; Brandão, Teresa R. S.; Silva, Cristina L. M.; Azevedo, Miguel; Pintado, ManuelaCarob fruit is native to the Mediterranean region and produced mainly in Portugal, Italy, Morocco and Turkey. The production of the carob fruit in Portugal is highly extensive and sustainable. Currently, carob flour (CF) production is mainly achieved after pulp separation, despite it having been demonstrated that the seeds improve the extraction efficiency of bioactive compounds such as polyphenols, promoting human health. This study aimed to produce an integral CF through an innovative process and assess its physicochemical and bioactive properties at different particle sizes throughout simulated gastrointestinal tract (GIT) digestion. The sugar content profile obtained throughout GIT digestion indicated that sucrose, the sugar present at the highest concentration in undigested CF, was digested and broken down into simple sugars, namely glucose and fructose. The total phenolic content (TPC) and antioxidant activity obtained for the ≤100 µm fraction were in accordance and gastric digestion promoted an increase in the TPC value compared to the undigested sample. The >100 µm fractions displayed a distinct profile from the ≤100 µm fraction. This study showed that the particle size affects the sugar, antioxidant and total phenolic content of CFs and also their gastrointestinal tract digestion. The ≤100 µm fraction demonstrated the most suitable profile as a functional food ingredient.
- PLA-based films reinforced with cellulose nanofibres from Salicornia ramosissima By-Product with proof of concept in high-pressure processingPublication . Ribeiro Lima, Alexandre; Lazzarotto Cristofoli, Nathana; Delahousse, Inès; Amaral, Renata A.; Saraiva, Jorge A.; Vieira, MargaridaBiocomposite films based on polylactic acid (PLA) reinforced with cellulose nanofibers (CNFs) extracted from Salicornia ramosissima by-products were developed and characterised using solvent casting (SC) and electrospinning (ES) techniques. The primary objective was to assess their suitability as sustainable food packaging materials that are compatible with high-pressure processing (HPP). The SC films exhibited a transparent, homogeneous morphology with superior ductility and water vapour barrier performance, whereas the ES films displayed a fibrous, porous structure with enhanced tensile strength and rigidity. The incorporation of CNFs significantly improved the mechanical properties, particularly the tensile strength and Young’s modulus, with optimal reinforcement achieved at a loading of 0.5%. Thermal and spectroscopic analyses confirmed the effective integration of CNF without compromising the thermal stability of PLA. Pouch-type packages from CNF-reinforced SC films withstood industrial HPP conditions without rupture or leakage, demonstrating their technical feasibility for food packaging applications. This study presents the first demonstration of Salicornia ramosissima by-product valorisation for CNF production and its application in HPP-compatible food packaging, addressing both circular economy goals and emerging food processing technologies.