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Climate change is driving global endeavours to achieve carbon neutrality and renewable energy expansion. Sludge, a nutrient-rich waste, holds energy potential yet poses environmental challenges that need proper management. We conducted a comprehensive life cycle assessment to evaluate the energy balance and environmental footprint of the most commonly used sludge management scenarios in BRICS countries, namely Brazil, Russia, India, China, and South Africa. Technologies such as incineration and anaerobic digestion with energy recovery units (i.e., cogeneration unit) maximize energy balance and minimize the environmental footprint, with incineration showing a superior performance. Shifting sludge management scenarios from the worst to the best can boost energy production by 1.4-98.4 times and cut the environmental footprint by 1.5-21.4 times. In 2050, these improvements could lead to a 98-fold boost in energy generation and a 25-fold drop in carbon emissions, according to the Announced Pledges Scenarios. Optimizing parameters such as volatile solids and anaerobic digestion efficiency further boosts energy output and minimizes the environmental footprint. This study offers robust evidence to support sustainable sludge management and thus promote energy recovery and carbon neutrality goals, guide technological transitions, and inform policymaking for sustainable development.

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Consumer buying behavior can be defined as all the different steps that consumers follow before purchasing a good or service. Web browser research, involvement in online networking discussions, and a range of other activities might be a part of this process. Despite the negative effects of its production chain on the environment, and on the socio-economical condition of local farmers, chocolate products are among the most distributed food and beverage items in the world. In this review, the consumer responsibility for sustainable cocoa production is described. This study determines the consumer opinions and attitudes on the different operations pursued in the production chain of chocolate, from the collection of cocoa beans to their processing into different final products. For this, data on life cycle assessment from some studies was gathered to identify and investigate links between the production chain of different types of chocolate (dark, white, milk) and its impact on natural resources so that the sensitivity of consumers to purchase more sustainable products can be evaluated. This approach revealed that consumers will not only purchase chocolate because of its good quality or health benefits, but they also consider it the most sustainable product.

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Sluggish interfacial water dissociation and the O2 evolution reaction (OER) kinetics are the main obstacles that limit the photocatalytic overall water-splitting performance. A molten salt modulation of potassium-nitrogen-carbon is herein demonstrated as the formation of highly crystalline potassium-doped poly(triazine imide) (KPTI). The in situ X-ray diffraction patterns and theoretical calculation show that the KCl melt can significantly reduce the free energy for the polycondensation of triazine building blocks owing to the formation of a kinetically stable KPTI. Benefiting from the presence of potassium-carbon-nitrogen moiety, the catalyst not only weakens the excitonic confinement to improve the separation efficiency of photogenerated charge carriers but also enhances the stability of carbon sites by suppressing the undesired C═O formation. Moreover, KPTI accelerates water dissociation by forming interfacial K·H2O clusters with an ordered structure, which supplies sufficient protons for the H2 evolution reaction and lowers the energy barrier to enhance the kinetics of OER. Therefore, a stable photocatalytic overall water-splitting performance can be achieved over KPTI with a stoichiometric generation of products (H2 and O2). Life cycle assessment shows that a carbon-neutral scenario can be achieved on KPTI production in the near term with an increase in green power in the electricity grid.

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The industrial sector is a major source of greenhouse gas (GHG) emissions due to process emissions and a heavy reliance on fossil fuels for heat and power. Methods exist to produce low carbon versions of products made in industrial clusters, including hydrogen, carbon capture and storage and alternative production methods, but these could increase burdens to other areas of the environment, such as resource depletion and water scarcity. This study compares different decarbonisation pathways for ammonia, cement, methanol and steel produced in the UK, to determine whether decarbonising could result in unintended environmental consequences. To determine this, life cycle assessment was applied to compare 267 different pathways to the conventional (fossil fuel) baseline. We find that most pathways lead to GHG emission reductions (43 to 78 % on average) but would increase impacts to other areas of the environment, including metal resources and ecotoxicity (8 % to 5-fold and 19 % to 24-fold, on average respectively). This study is the first to assess decarbonisation pathways for unintended environmental impacts and is of interest to industry, policy makers and anyone modelling industrial lifecycle emissions.

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The development of new building elements, such as concrete and mortar with sustainable materials, which produce a lower carbon footprint, is an achievable milestone in the short term. The need to reduce the environmental impact of the production of cement-based materials is of vital importance. This work focuses on the evaluation of the life-cycle assessment, production costs, mechanical performance, and durability of three mortars and three concrete mixtures in which mixed recycled aggregates (MRAs) and biomass bottom ash from olive waste (oBBA) were included to replace cement and aggregates. Powdered MRA and oBBA were also applied as complementary cementitious materials with a reduced environmental footprint. Chemical and physical tests were performed on the materials, and mechanical performance properties, life-cycle assessment, and life-cycle cost analysis were applied to demonstrate the technical and environmental benefits of using these materials in mortar and concrete mixtures. This research showed that the application of MRA and oBBA produced a small reduction in mechanical strength but a significant benefit in terms of life-cycle population and environmental costs. The results demonstrated that finding long-term mechanical strength decreases between 2.7% and 14% for mortar mixes and between 1.7% and 10.4% for concrete mixes. Although there were small reductions in mechanical performance, the savings in environmental and monetary terms make the feasibility of manufacturing these cement-based materials feasible and interesting for both society and the business world. CO2 emissions are reduced by 25% for mortar mixes and 12% for concrete mixes with recycled materials, and it is possible to reduce the cost per cubic meter of mortar production by 20%, and the savings in the cost of production of a cubic meter of concrete is 13.8%.

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Developing countries primarily rely on fossil-based energy sources to meet their energy demands. The use of fossil fuels has several adverse environmental repercussions that damage the biosphere both directly and indirectly. Among fossil fuels, coal brings about the heaviest environmental externalities, yet its abundance makes its use widespread, particular in countries having significant power generation deficits, such as Pakistan. This study presents an environmental, technological, and economic analysis of a supercritical coal-based power unit located in Pakistan and used for electricity generation. For environmental assessment, the CML-1A baseline method in OpenLCA software was used, and eight midpoint impact indicators were selected. The functional unit chosen was 1 MWh of generated electricity. The results indicated that the category of ozone layer depletion has the least impact, whereas global warming potential has the highest impact score. Except for photochemical oxidation and human toxicity, the plant operational stage dominated most of the selected impact categories. The current paper also reveals that the removal efficiency of CO2 and other pollutants is higher in supercritical compared to subcritical plants. Moreover, the economic feasibility of supercritical plant is compared with chemical looping combustion (CLC)-based supercritical coal-fired power plant, and results shows that CLC-based coal-fired power plant is a more competitive and environmentally friendly option. The utilization of a scientific cleaner energy-management system in real-time, as exemplified in this study, may facilitate the development of a optimal policy framework that encourages for the adoption of cleaner coal power generation in developing countries, ultimately resulting in improved energy sustainability. Furthermore, this paper also presents some policy implications which could be helpful for policymakers, researchers, and industrialists to improve the sustainability of energy in emerging economies.

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Green roof systems have been developed to improve the environmental, economic, and social aspects of sustainability. Selecting the appropriate version of the green roof composition plays an important role in the life cycle assessment of a green roof. In this study, 10 compositions of an intensive green roof for moderate zone and 4 green roof compositions for different climatic conditions were designed and comprehensively assessed in terms of their environmental and economic impacts within the "Cradle-to-Cradle" system boundary. The assessment was carried out over a 50-year period for a moderate climate zone. The results showed that asphalt strips and concrete slab produced the highest total emissions. It was found that most greenhouse gases emissions were released in the operational energy consumption phase and in the production phase. The energy consumption phase (48.78%) for automatic irrigation and maintenance caused the highest Global Warming Potential (GWP) value (758.39 kg CO2e) in the worst variant, which also caused the highest life cycle cost (878.47€). On the contrary, in the best variant, planting more vegetation and lower maintenance and irrigation requirements led to a reduction in GWP (445.0 kg CO2e), but in terms of cost (506.6€) this composition didn't represent the best variant. The Global Warming Potential Biogenic (GWP-bio) compared to the Global Warming Potential Total (GWP-total) represents a proportion ranging from 0.8% to 78% depending on the proposed vegetation. Overall higher biogenic carbon values (up to 1525 kg CO2e) were observed for the proposed tall vegetation of Magnolia, Red Mulberry, Hawthorne, Cherry, and Crab-apple Tree. Based on the results of the multicriteria analysis, which included core environmental & economic parameters, biogenic carbon emission levels, the outcome of this paper proposed optimal green roof composition. Optimal intensive green roof composition was subjected to a sensitivity analysis to determine the impact of changing climatic conditions on CO2 emissions and life cycle costs. The results of the sensitivity analysis show that the optimal variant of the green roof can be implemented in the cold and subtropical zone with regard to CO2 emissions, but not with regard to life cycle costs.

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Plastic additive-related chemicals, particularly in polyvinyl chloride (PVC) plastics, have become a key issue in plastic pollution. Although addressing plastic pollution through the life-cycle approach is crucial, the environmental impacts of typical plastic additive-related chemicals in PVC plastics during the cradle-to-gate stage remain unexplored. Consequently, managing the life-cycle environmental impacts of these additives remains challenging. Herein, the environmental impacts of 23 typical plastic additive-related chemicals and six PVC plastic products were evaluated throughout the cradle-to-gate life-cycle stage using a life cycle assessment-material flow analysis (LCA-MFA) coupled model. The results indicate that plastic additives significantly contribute to the environmental impacts of PVC plastic products across various end point indicators, ranging from 8.7 to 40.6%. Additionally, scenario analysis (SA) reveals that conventional strategies for addressing plastic pollution may not be highly effective in mitigating the environmental impacts associated with plastic additives. Specifically, compared to primary polymers, these additives exhibit 4 to 13% lower mitigation potential under the same policy scenarios. However, technical adjustment strategies targeting additives show a mitigation potential of 12 to 39%, suggesting that guiding the plastic additive industry toward green transformation is a key strategy for reducing environmental impacts.

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This study presents a comprehensive analysis of greenhouse gas (GHG) emissions associated with waste transfer and transport, incorporating derived leachate treatment-a factor often overlooked in existing research. Employing an integration model of life cycle assessment and a vehicle routing problem (VRP) methods, we evaluated the GHG reduction potential of waste transfer and transport system. Two Chinese counties with different topographies and demographics were selected, yielding 80 scenarios that factored in waste source separation as well as vehicle capacity, energy sources, and routes. The functional unit (FU) is transferring and transporting 1 tonne waste and treating derived leachate. The GHG emissions varied from 12 to 39 kg CO2 equivalent per FU. Waste source separation emerged as the most impactful mitigation strategy, not only for the studied system but for an integrated waste management system. Followings are the use of larger capacity vehicles and electrification of the vehicles. These insights are instrumental for policymakers and stakeholders in optimizing waste management systems to reduce GHG emissions.

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The Water-Energy-Food (WEF) nexus approach is increasingly being used for supporting a transition to sustainable development, with initiatives involving the concept of circular economy (CE). In the agricultural sector in particular, assessing this nexus is crucial to ensure food security, control the consumption of key resources such as water and energy, as well as measure atmospheric emissions linked to climate change. This manuscript aims to propose a novel approach by coupling the WEF nexus with a circularity indicator, seeking to capture in a single index (the WEF+CEi) both performances in a sample of companies. The novel approach is applied to 30 dairy farms located in Galicia (NW Spain) to benchmark them in a holistic manner. To do this, the WEF nexus of each farm was represented through the following indicators: carbon footprint, water footprint, energy footprint, and food productivity. In addition, the percentage of circularity for each farm, and for the agro-industrial cooperative was measured thanks to the application of a circularity tool in percentage terms. Finally, the WEF+CEi indicator was obtained using the multicriteria mathematical tool of Data Envelopment Analysis (DEA). The results show that without considering the agro-industrial cooperative, the system is 51 % circular. On the other hand, considering the farms and the cooperative, the system goes up to 80 % of circularity. Finally, the proposed approach can support decision-making and provide insights for producers and stakeholders in the area.

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With increasing textile consumption and limited sorting and recycling capacities, the EU faces major challenges in terms of managing its textile waste. This study investigates the environmental and socio-economic impacts of explorative policy scenarios for a more sustainable textile waste management system in Europe. These scenarios differ substantially in the amounts of textile waste generated and separately collected, closed-loop recycling capacities and textile waste exports. Our results show that sustainable textile waste management remains highly relevant for the sector. Still, without addressing in parallel prevention of textile waste generation via production and consumption patterns, a climate-neutral and circular textiles sector will be hard to achieve. Interventions in the waste management of textiles could reduce global warming impacts by up to 22.3 Mt CO2 per year, which translates to an 18% sector-wide impact by 2035. Depending on the intervention(s), the estimated required investment at present amounts to between 7 and 33 billion EUR. The study provides a valuable starting point for evidence-based decisions on future textile policymaking in Europe.

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The increase in the negative effects of global change promotes the search for alternatives to supply the demand for food worldwide aligned with the Sustainable Development Goals (SDGs) to ensure food security. Animal protein, which is a main source of nutrients in the diet of today's society, especially beef, which is one of the most demanded products nowadays, has been criticized not only for its high water consumption and land occupation for production but also for the emission of greenhouse gases (GHG) from enteric methane generated in the fermentation process within the bovine rumen and deforestation for the adaptation of pastures. This study is mainly motivated by the lack of quantifiable scientific information in Colombia on the environmental impacts of beef production. Therefore, it is intended to estimate some of the impacts of beef production in extensive systems using the life cycle assessment (LCA) method under a particular scenario considering all the production phases (from raw material to fattening, where the cattle are ready to be slaughtered). The study was conducted with data supplied by a farm in Antioquia, Colombia, and the functional unit (FU) was defined as 1 kg of live weight (LW). The scope of this study was gate-to-gate. "The 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories" (IPCC  2006; IPCC 2019) was used to calculate methane and nitrous oxide emissions. LCA modeling was developed with Ecoinvent database v3.8 and the Umberto LCA + software. It was found that the most affected category of damage was ecosystem quality, which represents 77% of the total, followed by human health at 17% and resources at 6%. The category impact of agricultural land occupation is the one that represents the most significant contribution to the ecosystem quality endpoint, with a percentage of 87%, due to the soil's compaction and the loss of the soil's properties. Additionally, the obtained carbon footprint for the system was 28.9 kg of CO2-eq/kg LW.

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Geopolymer concrete is a sustainable construction material developed with industrial by-products to eliminate the use of cement in concrete production. However, a cradle-to-cradle life cycle assessment (LCA) that accounts for the impact of service life is essential to comprehensively assess the environmental advantages of GPC. In this study, a comparative cradle-to-cradle LCA was performed for circular geopolymer concrete (CGPC), geopolymer concrete (GPC), and circular ordinary concrete (COC), as alternatives to Portland cement concrete (PCC). Also, the biases of common LCA resulted from ignoring service life and end-of-life scenarios were identified. Finally, the sustainability potentials of the alternative scenarios were evaluated. According to the cradle-to-cradle LCA using the adopted functional unit, GPC and CGPC significantly alleviated the environmental impact of cement production, such as global warming potential by about 53%. Ignoring the service life and end-of-life scenarios considerably changed the critical midpoint (ionizing radiation for CGPC and GPC) and endpoint indicators (resources for CGPC and GPC) and priority of alternative concretes. Finally, the CGPC and GPC showed a substantial increase of 213% and 276% in sustainability potential compared to PCC, respectively.

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Urban water systems in China are facing multiple challenges, including rapid urbanisation, climate change and infrastructure ageing. It is crucial to evaluate their environmental performance from a holistic perspective in planning and management processes. To the best of our knowledge, there is a lack of nationwide life cycle assessment (LCA) studies on China's urban water systems that cover all system stages. Therefore, this study aims to present a comprehensive and nationwide LCA analysis that pinpoints the environmental hotspots and their major sources across China. This study was conducted based on water utility databases at the province level, covering water abstraction and treatment, waterwork sludge treatment, water distribution, sewage collection, stormwater drainage, wastewater treatment and sewage sludge treatment. Nine environmental impact categories were calculated and analysed. The results reveal the inequity of environmental impacts across provinces, with overall impacts geographically higher in the east and south, lower in the west and north. However, at the functional unit level, the impacts in the northern and northeastern provinces are higher than other regions. Most environmental categories are dominated by multiple water system stages. The analyses of underlying drivers found that purchased electricity is the primary source of several environmental impacts. This study provides a holistic understanding of the environmental performance of China's urban water systems, offers some insights for comprehensive decision-making support on sustainable water system management, and can also serve as a benchmark for future scenario analysis to explore options for reducing environmental impact.

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Carbon dots (CDs) are fluorescent carbon-based nanomaterials with remarkable properties, making them more attractive than traditional fluorophores. Consequently, researchers focused on their development and application in fields such as sensing and bioimaging. One potential advantage of employing CDs is using organic waste as carbon precursors in their synthesis, providing a pathway for waste upcycling for a circular economy. However, waste-based CDs often have low fluorescence quantum yields (QYFL), limiting their practical applications. So, there is a need for a well-defined strategy to consistently produce waste-based CDs with appreciable QYFL, irrespective of the starting waste material. Herein, we developed a fabrication strategy based on the hydrothermal treatment of waste materials, using citric acid as a co-carbon precursor and ethylenediamine as N-dopant. This strategy was tested with various materials, including corn stover, spent coffee grounds, cork powder, and sawdust. The results showed consistently appreciable QYFL, reaching up to ~40%. A Life Cycle Assessment (LCA) study demonstrated that producing these waste-based CDs has lower environmental impacts compared to CDs made solely from commercial reagents. Thus, we have established a framework for the environmentally friendly production of CDs by upcycling different waste materials without significant sacrifices in performance (QYFL).

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This research analyses 24 years of oil extraction in blocks 16 and 67 of the Yasuní National Park (YNP) in the Amazonian Forest of Ecuador, one of the most biodiverse spaces in the world and with the current presence of ancient indigenous communities. As a novel contribution, we have carried out a Life-Cycle Assessment (LCA) that quantifies the footprints associated with the extraction, transportation, refining, distribution and final uses of the oil in four different scenarios (oil for asphalt use, electricity, marine fuel and passenger car transport). This study also sheds light on the energy return at the point of use of different oil-derivatives, and complements this with a qualitative analysis of the social, cultural and environmental implications for the Waorani communities. We conclude that the environmental burdens of the extraction process in blocks 16 and 67 in 2015 were greater than those of countries such as the United States, Saudi Arabia and Indonesia, based on the analysis of 11 impact categories. The blocks' operation is the most unfavourable for the categories of Terrestrial Acidification Potential (TAP), Global Warming Potential (GWP), Terrestrial Ecotoxicity Potential (TEP) and Ecosystem Quality Loss Potential (EQL), with increments of 804.15 %, 105.36 %, 506.29 % and 210.73 %, respectively, in relation to the average of the rest of the extraction systems analysed. Specifically, the present case study shows 75.18 % higher impacts in the blocks addressed, when compared to the Ecuadorian average. During the period 1999-2022, the carbon emissions associated with the oil extraction in these blocks have increased by 139.01%. It has been detected a neo-colonial economic behaviour: while the Ecuadorian state received 21% of the sales, the Spanish government and the oil companies received, on average, 38% and 41% of the per-litre average fuel price, respectively. Thus, 79% of the income stayed in the Global North. We conclude that, on average, 19.64 % of the impacts associated with crude oil production and consumption occur in the Amazonian region of the YNP, depending on the fuel used and the consumption mechanism. For the Global Warming Potential (GWP) impact category, the extraction process carries, on average, 34.51 % of the weight in all of the life-cycle impacts, depending on the consumption scenario. It was also estimated that to be able to use 0.33 kWh of electricity from fuel combustion, 0.47 kWh of energy for goods transport and 0.20 kWh for passenger transport, an investment of 1 kWh is required, with an average extended EROI of 1:3.33. According to the qualitative analysis performed, it has been concluded that the main local impacts are related to the obstacles in environmental monitoring and information, the economic dependence of the communities on the oil extraction company, and cultural transformations; impacts that are not easily quantifiable or detectable using other methodologies. The combination of the qualitative analysis and LCA showed that the neo-colonial economic distribution did not compensate the social and environmental impacts of the oil extraction occurred in the YNP.

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Recycled aggregate concrete (RAC), mainly made from recycled materials such as construction and demolition waste (CDW), has emerged as a sustainable alternative to natural aggregate concrete (NAC). While RAC offers potential benefits in waste reduction and resource conservation, a comprehensive understanding of its environmental impact and sustainability compared to NAC has been lacking. This study addresses this gap by conducting a thorough review and analysis of comparative Life Cycle Assessment (LCA) studies between RAC and NAC. This paper synthesizes current literature to evaluate the environmental impact of both materials throughout their life cycles, from raw material extraction to disposal. It examines key factors such as energy consumption, greenhouse gas emissions, and resource depletion to provide a thorough comprehension of the effects on the environment of each concrete type throughout their life cycles. Challenges in using RAC as a sustainable concrete option, such as sourcing and quality control, are also discussed, along with recommendations for future research and industry practices. The findings indicate that the environmental impact of RAC compared to NAC is significantly influenced by transport distances and modes. In addition, the choice of functional units in LCAs substantially affects the comparison between RAC and NAC, with strength reliability offering a clear benefit by addressing concrete property variability and better reflecting real-world conditions.

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The conversion of biomass to bioenergy is one of the approaches to creating a sustainable society. In this study, the life cycle assessment and the net energy analysis of converting mixed sewage sludge and beverage waste into bioenergy via a combined hydrothermal liquefaction-anaerobic digestion (HTL-AD) system was carried out. Primary sludge (PS), winery rose lees (RL), brewery Trub (BT), the mixture of brewery trub and primary sludge (BTPS) and the mixture of winery rose lees and primary sludge (RLPS) were the feedstocks considered. Efficient energy utilization [in form of net energy ratio (NER)], and environmental emissions were evaluated. The NER of BT (2.07) and RL (1.76) increased when mixed with PS (3.18) to produce BTPS (3.20) and RLPS (2.85). Also, the HTL phase of the combined HTL-AD system produced a greater NER than the AD phase in BT, BTPS, and PS and vice-versa in RL and RLPS. Six environmental impact categories were studied namely global warming, terrestrial acidification, ionizing radiation, terrestrial ecotoxicity, human carcinogenic toxicity, and human non-carcinogenic toxicity. RL produced the greatest environmental impact while BTPS produced the least impact, thus indicating the advantage of feedstock combination. This study shows that the combination of feedstocks for bioenergy production in an HTL-AD system does not only increase the quality and quantity of products but also increases the overall NER as well as reducting the environmental impacts. The study also proved that an integrated HTL-AD system is an energy efficient system with greater resource utilization and less environmental footprint than the constituent systems.

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Pork belly is a meat cut valued for its rich flavour and texture, attributed to its high fat content, which also makes it susceptible to oxidation. Therefore, meat producers and processors must carefully select packaging options to maximise shelf life while meeting consumer preferences. This study aimed to develop customised packaging strategies for sliced pork belly with varying fat content to extend shelf life while minimizing environmental impact. The research compared three packaging solutions: modified atmosphere packaging (MAP1: 70:30% O2:CO2, MAP2: 30:40:30% O2:CO2:N2) and vacuum skin packaging (VSP) for pork bellies with low (LF: 16.07 ± 1.87%), medium (MF: 37.39 ± 4.41%), and high fat content (HF: 57.57 ± 2.36%). Samples packaged in VSP exhibited the longest shelf life (13-14 days) with lower purge and reduced fat and colour oxidation compared to MAP-packaged samples for all studied belly types. Nonetheless, the impact of MAP on shelf life depended on the belly type. HF bellies, with lower proportions of unsaturated fatty acids, showed less purge, and greater colour and fat stability, resulting in a longer shelf life compared to LF and MF bellies. LF and MF bellies in MAP2 showed the shortest shelf life (around 6 days), followed by LF and MF in MAP1 (around 7-8 days). Life Cycle Assessment indicated VSP generally as the most environmentally favourable option for LF and MF bellies, whereas for HF bellies, the choice among the three packaging solutions depended on the specific impact category under consideration.

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