João Nunes

Dr. João Nunes


Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 July 2023 in Processes
Verified
Journal Article
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Rodrigo MartinsRodrigo Martins
Rodrigo Martins
ABAna Barbosa
Ana Barbosa
BABárbara Raquel Dias Advinha
Bárbara Raquel Dias Advinha
HSHélia Sales
Hélia Sales
RPRita Pontes
Rita Pontes
JNJoão Nunes
João Nunes
Green extraction techniques are more and more relevant due to major sustainable goals set by the United Nations. Greener extraction processes are being designed through the use of unconventional extraction techniques and green solvents, resulting in less hazardous processes which, consequently, reduces environmental impacts. This is also in line with the main principles of green chemistry. Additionally, greener extraction techniques intend to solve different drawbacks that are often related to conventional extraction techniques such as the high environmental impact. Biorefineries are a major player in developing greener extraction processes. These facilities take full advantage of several biomass sources, such as food waste, microalgae, and lignocellulosic biomass, in order to create high-value products, energy, alternative fuels, and bioactive compounds. Herein, a state-of-the-art review is presented, focused on presenting the greenest and least hazardous extraction processes that have been reported on the main biomass sources of a biorefinery—food waste, microalgae, and lignocellulosic biomass. Bioactive compounds such as phenolic compounds, bioactive pigments, and fatty acids are important in several sectors, mainly, the health, pharmaceutical, and agro-food sectors. Moreover, the bioactive compounds obtained through the aforementioned biomass sources and the different extraction procedures used will be presented and the authors will attempt to discuss, compare, and provide information about the most effective extraction techniques for each compound. Therewith, this review article should serve as a guide for industries, academics, and biorefineries in the future development of optimized and greener extraction procedures. Such analysis is lacking and could be very helpful for future research biorefinery projects since it tackles all of the major biomass sources of a biorefinery in a review article. To the best of our knowledge, this brings a novelty to the scientific community.

2 September 2023 in Foods
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Journal Article
Open access
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CNCatarina Nunes
Catarina Nunes
MSMafalda Silva
Mafalda Silva
DFDiana Farinha
Diana Farinha
HSHélia Sales
Hélia Sales
RPRita Pontes
Rita Pontes
JNJoão Nunes
João Nunes
The global food production industry faces environmental concerns exacerbated by substantial food waste. European countries are striving to reduce food waste towards a circular bioeconomy and sustainable development. To address environmental issues and reduce plastic waste, researchers are developing sustainable active packaging systems, including edible packaging made from industry residues. These innovations aim to increase food safety and quality, extend shelf life, and reduce plastic and food waste. Particularly important in the context of the growing demand for fresh and minimally processed fruits, edible coatings have emerged as a potential solution that offers numerous advantages in maintaining fruit quality. In addition to fruit, edible coatings have also been investigated for animal-based foods to meet the demand for high-quality, chemical-free food and extended shelf life. These products globally consumed can be susceptible to the growth of harmful microorganisms and spoilage. One of the main advantages of using edible coatings is their ability to preserve meat quality and freshness by reducing undesirable physicochemical changes, such as color, texture, and moisture loss. Furthermore, edible coatings also contribute to the development of a circular bioeconomy, promoting sustainability in the food industry. This paper reviews the antimicrobial edible coatings investigated in recent years in minimally processed fruits and traditional sausages. It also approaches bionanocomposites as a recently emerged technology with potential application in food quality and safety.

11 August 2023 in Bioengineering
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Journal Article
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AAAna Abreu
Ana Abreu
Rodrigo MartinsRodrigo Martins
Rodrigo Martins
JNJoão Nunes
João Nunes
Chlorella sp. and Spirulina (Arthrospira) sp. account for over 90% of the global microalgal biomass production and represent one of the most promising aquiculture bioeconomy systems. These microorganisms have been widely recognized for their nutritional and therapeutic properties; therefore, a significant growth of their market is expected, especially in the nutraceutical, food, and beverage segments. However, recent advancements in biotechnology and environmental science have led to the emergence of new applications for these microorganisms. This paper aims to explore these innovative applications, while shedding light on their roles in sustainable development, health, and industry. From this state-of-the art review, it was possible to give an in-depth outlook on the environmental sustainability of Chlorella sp. and Spirulina (Arthrospira) sp. For instance, there have been a variety of studies reported on the use of these two microorganisms for wastewater treatment and biofuel production, contributing to climate change mitigation efforts. Moreover, in the health sector, the richness of these microalgae in photosynthetic pigments and bioactive compounds, along with their oxygen-releasing capacity, are being harnessed in the development of new drugs, wound-healing dressings, photosensitizers for photodynamic therapy, tissue engineering, and anticancer treatments. Furthermore, in the industrial sector, Chlorella sp. and Spirulina (Arthrospira) sp. are being used in the production of biopolymers, fuel cells, and photovoltaic technologies. These innovative applications might bring different outlets for microalgae valorization, enhancing their potential, since the microalgae sector presents issues such as the high production costs. Thus, further research is highly needed to fully explore their benefits and potential applications in various sectors.

28 September 2020 in Applied Sciences
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Journal Article
Open access
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TRTânia Ribeiro
Tânia Ribeiro
Ana OliveiraAna Oliveira
Ana Oliveira
CCCristina Costa
Cristina Costa
JNJoão Nunes
João Nunes
AVAntónio Vicente
António Vicente
Manuela PintadoManuela Pintado
Manuela Pintado
Olive pomace management represents a great concern to the olive oil industry. This work focused on the development of a “zero waste” strategy for olive pomace based on a fractionation approach resulting in the obtention of different value-added fractions. The physicochemical composition of edible fractions obtained (liquid and pulp) was analysed. The potential use as a solid biofuel of the non-edible fraction (stones) was evaluated. High amounts of hydroxytyrosol (513.61–625.76 mg/100 g dry weight) were present in the liquid fraction. Pulp fraction was demonstrated to be a good source of fibre (53–59% dry weight) with considerable antioxidant activity both from free and bound phenolics. The stones fraction exhibited substantial high heating values (18.65–18.94 megajoule (MJ/kg). All these results support the added value of the olive pomace fractions combining the biofuel potential from the stones fraction and the functional food ingredients’ potential both from liquid and pulp fractions. The present methodology seems to be a feasible whole valorisation approach to achieve the circularity in the olive oil sector, prioritising obtaining high over low added-value products.

16 August 2023 in Sustainability
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Journal Article
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AFAna Rita Fonseca
Ana Rita Fonseca
EREdgar Ramalho
Edgar Ramalho
AGAna Gouveia
Ana Gouveia
FFFilipa Figueiredo
Filipa Figueiredo
JNJoão Nunes
João Nunes
The rising concerns about environmental harm and pollution create a setting for the search for better materials to produce more sustainable products. Plastic plays a crucial role in modern life and most of the commonly used are of fossil origin. Polylactic Acid (PLA) has been appointed as a more sustainable alternative, due to its origins in biodegradable raw materials. This paper aims to review scientific research, where Life Cycle Assessment (LCA) is performed on this material, in order to further understand the environmental impacts and to assess whether it is a more viable option when compared to the most commonly used plastics. A systematic literature review of 81 LCA studies focused on the LCA of PLA products was conducted. An assessment of key aspects, including the system boundaries, raw materials origin, and quantitative analysis of five environmental impact categories was performed. In this comparative analysis, in addition to presenting the results for PLA products, they are also compared with other fossil-based plastics. This leads to the conclusion that PLA has higher environmental impacts on Marine Eutrophication, Freshwater Eutrophication, and Human Toxicity, which are mainly related to the agricultural phase of growing the raw materials for PLA production. For Climate Change, Polystyrene (PS) presents the higher Greenhouse Gas (GHG) emissions, and for the Ozone Layer Depletion category, Polyethylene terephthalate (PET) presents the higher impact. PLA is a solution to replace fossil plastics. However, the use of alternative biomass sources without competition with the feed and food sector could be a key option for biobased materials production, with lower environmental and socioeconomic impacts. This will be a pathway to reduce environmental impacts in categories such as climate change, marine eutrophication, and freshwater eutrophication.

25 October 2023 in Sustainability
Verified
Journal Article
Open access
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AFAna Rita Fonseca
Ana Rita Fonseca
EREdgar Ramalho
Edgar Ramalho
AGAna Gouveia
Ana Gouveia
RHRita Henriques
Rita Henriques
FFFilipa Figueiredo
Filipa Figueiredo
JNJoão Nunes
João Nunes
The worldwide textile sector is one of the most polluting and consuming natural resource value chains. In recent years, trends have demonstrated a linear model driven by fast fashion, increasing the sustainability problems of this sector. The European market and industry are changing the paradigm and promoting some actions towards a sustainable value chain. This paper applies a systematic approach to reviewing scientific research, where Life Cycle Assessment (LCA) is implemented as a tool to understand the impacts considering a holistic life cycle framework, from raw materials to the end-of-life of textile products. The methodology and criteria applied resulted in 73 articles used for qualitative analysis, of which 39 met the criteria for quantitative analysis. The quantitative results reported in the studies were organized and presented by phase of the garment production life cycle (production of fiber, yarn, fabric, manufacturing, and recovery/end of life). From a cradle-to-gate perspective, wool yarn production, by worsted processing, was the material with the highest values (95.70 kg CO2 eq/kg) for climate change/global warming potential, closely followed by silk fabric (80.90 kg CO2 eq/kg). Extending to a cradle-to-grave boundary, polyester had the highest values for the previously mentioned category, reaching a potential release of 40.28 kg CO2 eq per kilogram of polyester textile. When data was available, the user phase predominantly contributed to climate change/global warming potential. Additionally, there were significant differences in maximum and minimum values for some of the materials, which were related to methodological considerations, database inventory, and frequency of use and care considered by the different authors. The study also addresses the considerations and limitations of diverse LCA impact assessment tools.