Resources

43 pages, 45961 KB

Open AccessReview

Valorisation of Food Processing Wastes into High-Value Platform Chemicals: Industrial Pathways and Circular Bioeconomy Perspectives

by Sudatta Maity, Priti Pal, Akhilesh Kumar Singh, Anand Prakash, Krystyna Kondratowicz-Maciejewska, Piotr Prus and Prakash Kumar Sarangi

Resources 2026, 15(8), 98; https://doi.org/10.3390/resources15080098 (registering DOI) - 1 Aug 2026

Abstract

The world’s food industry faces significant obstacles today as it strives to meet the nutritional needs of its rapidly expanding global population while also managing an immense amount of food processing waste (FPW) generated throughout the entire food supply chain. The widespread use [...] Read more.

The world’s food industry faces significant obstacles today as it strives to meet the nutritional needs of its rapidly expanding global population while also managing an immense amount of food processing waste (FPW) generated throughout the entire food supply chain. The widespread use of traditional disposal techniques for food waste (landfilling and incineration) regularly faces challenges related to environmental sustainability and economic efficiency. This manuscript reviews the necessary transition from a linear “take-make-dispose” approach to food production to a more circular model that recycles food waste into high-value intermediate chemicals and renewable energy through the development of biorefineries. The manuscript explores the biochemical composition of food waste, with carbohydrates, lipids, proteins, and bioactive materials, making it a suitable feedstock for different multi-stage biorefinery operations. In addition, this review will evaluate a variety of existing conversion technologies for food processing waste, such as biological methods (e.g., anaerobic digestion and fermentation) and thermochemical methods (e.g., pyrolysis, gasification, and hydrothermal liquefaction), to create various platform chemicals, including organic acids, bio-alcohols and volatile fatty acids (VFAs), as well as the production of sustainable biofuels and biopolymers. The review also elucidates the three most determinative constraints on large-scale industrial implementation of food waste valorisation: feedstock variability, techno-economic feasibility, and the need for comprehensive life cycle assessments (LCAs). The alignment of food waste management strategies with the UN SDGs (in particular, SDG 12 ‘Responsible Consumption and Production’ and SDG 13 ‘Climate Action’) reflects the opportunity for food waste to serve as a foundation for a carbon-neutral, sustainable future. This review provides a strategic roadmap for academics, practitioners, and policymakers to tap into the full potential of food waste through a sustainable circular economy model. Full article

(This article belongs to the Special Issue Alternative Use of Biological Resources: 2nd Edition)

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25 pages, 7372 KB

Open AccessArticle

Hydroclimatic Variability and Water Balance Instability in Semi-Arid Steppe Ecosystems Under Climate Warming

by Raikhan Beisenova, Ainur Orkeyeva, Anar Rakhmetova, Zhanar Rakhymzhan and Rumiya Tazitdinova

Resources 2026, 15(8), 97; https://doi.org/10.3390/resources15080097 - 23 Jul 2026

Abstract

This study investigates hydroclimatic variability and water balance dynamics in the Akmola region during 2003–2023 using observations from 16 meteorological stations. The study evaluates changes in air temperature, precipitation, reference evapotranspiration (ET₀), climatic water balance, and drought conditions. Reference evapotranspiration was [...] Read more.

This study investigates hydroclimatic variability and water balance dynamics in the Akmola region during 2003–2023 using observations from 16 meteorological stations. The study evaluates changes in air temperature, precipitation, reference evapotranspiration (ET₀), climatic water balance, and drought conditions. Reference evapotranspiration was calculated using the FAO-56 Penman–Monteith method, while drought variability was assessed using the 12-month Standardized Precipitation–Evapotranspiration Index (SPEI-12). Temporal trends were analyzed using the Mann–Kendall test and Sen’s slope estimator. The results revealed significant spatial heterogeneity in hydroclimatic conditions across the region. Air temperature showed a consistent increasing trend at most stations, accompanied by increasing atmospheric evaporative demand. All stations were characterized by a persistently negative climatic water balance, with mean annual values of approximately −750 mm, indicating a regional moisture deficit. Reference evapotranspiration exhibited significant spatial variability, with the highest values observed in the southern and central parts of the region. Precipitation remained the dominant control of water balance variability (r = 0.79–0.96), while increasing temperature intensified moisture deficits through increased evapotranspiration. SPEI-12 indicated recurrent drought episodes and increasing drought vulnerability associated with warming-induced atmospheric water demand. The study demonstrates that increasing evapotranspiration is becoming a major driver of water stress in the Akmola region and highlights the importance of integrating climatic water balance and SPEI indicators for drought monitoring and climate adaptation in semi-arid steppe regions. Full article

(This article belongs to the Topic Advances in Water and Soil Management Towards Climate Change Adaptation)

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29 pages, 8563 KB

Open AccessArticle

Construction and Demolition Waste as an Urban Mining Resource in Fez, Morocco: A Spatio-Temporal Assessment Coupling Field Surveys, Permit Data, and Material Flow Analysis

by Yasmine Boukhlouf, Mohammed Benabdelhadi, Hassan Tabyaoui, Abderrahim Lahrach, Abdallah Oulmekki, Maryame El-Yazidi, Zineb El Attar Soufi and Omar Kassou

Resources 2026, 15(7), 96; https://doi.org/10.3390/resources15070096 - 17 Jul 2026

Abstract

Construction and demolition waste is one of the most voluminous yet poorly managed waste streams in developing cities, and Fez, Morocco, is no exception. With over 1.2 million inhabitants and an expanding construction sector, the city produces large quantities of building debris annually. [...] Read more.

Construction and demolition waste is one of the most voluminous yet poorly managed waste streams in developing cities, and Fez, Morocco, is no exception. With over 1.2 million inhabitants and an expanding construction sector, the city produces large quantities of building debris annually. Until this study, no systematic inventory of illegal dumpsites existed, and municipal documents contained no data on volumes, composition, or spatial distribution. We addressed this gap through three approaches: a field survey of 43 illegal dumpsites, a permit-based Waste Generation Rate (WGR) analysis with projections to 2040, and a Simplified Material Flow Analysis (MFA) integrating field-observed stocks and theoretical generation estimates into a city-scale mass balance. The 43 surveyed sites hold a combined volume of 15,626,019 m³, with an average inert content of 51.60%, below the 65% benchmark, reflecting systematic co-deposition with no sorting. Only 11.6% of sites showed high recovery potential. The waste generation rate estimates a total generation of 419,269–1,426,302 tonnes over 2016–2025, with demolition accounting for 64% of the output. The materiel flow analysis reveals a 2- to 7-fold discrepancy between observed stock levels and theoretical estimates. Without intervention, generation is projected to increase sevenfold by 2040. Fez is caught in an informal disposal trap. Three actions are needed: mandatory traceability, targeted enforcement at high-flow sites, and on-site recycling capacity. Full article

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31 pages, 5467 KB

Open AccessArticle

Decision Support Framework to Improve Mining Productivity: Prioritization of Operational Factors in Medium-Scale Mining

by Edison Ramírez-Olivares, Catalina Rojas-Rojas, Gillyan Gálvez-Rodríguez and Juan Alfaro Robles

Resources 2026, 15(7), 95; https://doi.org/10.3390/resources15070095 - 17 Jul 2026

Abstract

The mining industry faces increasing challenges in enhancing productivity within complex operational environments characterized by the interaction of technical, organizational, human, and external factors. Nevertheless, existing studies frequently examine these determinants independently, thereby limiting a comprehensive understanding of their relative importance and combined [...] Read more.

The mining industry faces increasing challenges in enhancing productivity within complex operational environments characterized by the interaction of technical, organizational, human, and external factors. Nevertheless, existing studies frequently examine these determinants independently, thereby limiting a comprehensive understanding of their relative importance and combined influence on operational performance. This study develops a decision framework to identify and prioritize the factors affecting productivity in medium-scale mining in the Coquimbo Region, Chile, through the application of the Analytic Hierarchy Process (AHP) based on expert judgment obtained from active mining operations. The AHP model was structured using two criteria, seven subcriteria, and twenty-three decision factors, whose consistency and reliability were assessed through the consistency ratio (CR) and Cronbach’s alpha coefficient. The results revealed a marked predominance of Internal factors (75.0%) over External factors (25.0%), indicating that productivity is influenced primarily by variables that can be managed at the organizational level. Among the evaluated subcriteria, Work planning achieved the highest priority (32.0%), whereas Scheduling and control (10.2%), Human factors (6.4%), and Working conditions (5.2%) emerged as the most influential decision factors. Furthermore, sensitivity analysis confirmed the robustness and stability of the model. Beyond establishing a prioritization of productivity determinants, this study provides a decision-support framework that can assist mining companies in strengthening productivity management and improving operational performance in medium-scale mining. Full article

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15 pages, 975 KB

Open AccessArticle

Process Dynamics and Nutrient Transformation During Vermicomposting of Agricultural Waste Using Eisenia fetida

by Clifftone Wanyonyi Mbuku, Rogerio Borguete Rafael and John Walker Recha

Resources 2026, 15(7), 94; https://doi.org/10.3390/resources15070094 - 16 Jul 2026

Abstract

The accumulation of agricultural waste poses significant agronomic and environmental challenges in tropical smallholder farming systems where organic wastes remain underutilized. This study evaluated the effectiveness of vermicomposting with Eisenia fetida in enhancing nutrient recovery and improving the quality of organic fertilizers produced [...] Read more.

The accumulation of agricultural waste poses significant agronomic and environmental challenges in tropical smallholder farming systems where organic wastes remain underutilized. This study evaluated the effectiveness of vermicomposting with Eisenia fetida in enhancing nutrient recovery and improving the quality of organic fertilizers produced from agricultural waste. Four substrate treatments—poultry manure and vegetable waste (T1), cow dung, chicken manure, and vegetable waste (T2), cow dung and vegetable waste (T3), and a control without earthworms (T4)—were assessed over a period of 60 days. Key physicochemical properties evaluated included bulk density, pH, electrical conductivity, organic carbon, total nitrogen, available phosphorus and potassium, and the C:N ratio. Vermicomposting significantly improved nutrient composition, with the C:N ratio decreasing from 26.43 in the control treatment to 12.23, indicating enhanced compost maturity. Treatment T2 recorded the highest concentrations of total nitrogen (2.63%), phosphorus (1.21%), and potassium (1.45%). A significant reduction in organic carbon also indicated enhanced mineralization during the decomposition process. Compared with traditional composting, vermicomposting improved nutrient availability, compost maturity, and overall compost quality. These findings demonstrate that vermicomposting is an effective resource recovery strategy for converting agricultural waste into nutrient-rich organic fertilizer while supporting sustainable and climate-resilient agricultural systems. Full article

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23 pages, 2433 KB

Open AccessArticle

Assessing Availability of Platinum Group Metals Through a Cumulative Availability Curve

by Abu Shahadat Md Ibrahim and Roderick G. Eggert

Resources 2026, 15(7), 93; https://doi.org/10.3390/resources15070093 - 14 Jul 2026

Abstract

Platinum group metals (PGM) are essential for clean-energy technologies, including proton exchange membrane (PEM) electrolyzers for hydrogen production and PEM fuel cells for hydrogen use, as well as catalytic, electronic, and advanced industrial applications. However, their supply is exposed to geological concentration, co-product [...] Read more.

Platinum group metals (PGM) are essential for clean-energy technologies, including proton exchange membrane (PEM) electrolyzers for hydrogen production and PEM fuel cells for hydrogen use, as well as catalytic, electronic, and advanced industrial applications. However, their supply is exposed to geological concentration, co-product dependence, and market volatility. This study evaluates the medium-term cost-based accessibility of known primary PGM resources using a cumulative availability curve. The analysis combines resource estimates and allocated production-cost data for 61 known PGM-bearing deposits and projects, with costs expressed in 2022 USD per metric ton of combined PGM output. Because PGM deposits differ in ore type, processing route, and co-product setting, the results are interpreted by deposit cluster rather than only by country or aggregate cost threshold. The low-cost portion of the curve is dominated by Ni–Cu sulphide by-product systems, but this cluster represents only 1.87% of the compiled resource base. In contrast, UG2/Merensky/Great Dyke reef-type systems account for 72.95%, and Platreef/Northern Limb and Platreef-type systems account for 19.82%. Thus, most known primary PGM resources occur outside the low-cost by-product segment. Cluster-weighted PGM basket-price benchmarks are used instead of individual metal-price comparisons. Several cluster-level cost ranges fall below or near indicative April 2025 basket-price benchmarks, but these comparisons are not project-level profitability tests. Overall, the cumulative availability curve provides a deposit-cluster-based framework for evaluating known primary PGM availability and informing critical-material policy, recycling strategy, supply-chain planning, hydrogen-technology deployment, and responsible resource development. Full article

(This article belongs to the Special Issue Critical Resources and Innovation for a Just and Sustainable Energy Transition)

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38 pages, 583 KB

Open AccessArticle

The Role of Country-Level Governance in the Renewable Energy–Carbon Emissions Relationship: Evidence from RECAI-Selected Countries

by Faozi A. Almaqtari, Najib H. S. Farhan, Abdulhadi Ibrahim, Amal Yamani and Khalid Hamad Alturki

Resources 2026, 15(7), 92; https://doi.org/10.3390/resources15070092 - 13 Jul 2026

Abstract

This study examines the relationship between renewable energy consumption (REC) and carbon dioxide (CO₂) emissions and investigates the moderating role of country-level governance in 39 Renewable Energy Country Attractiveness Index (RECAI) economies over the 1996–2020 period. Drawing on institutional and environmental [...] Read more.

This study examines the relationship between renewable energy consumption (REC) and carbon dioxide (CO₂) emissions and investigates the moderating role of country-level governance in 39 Renewable Energy Country Attractiveness Index (RECAI) economies over the 1996–2020 period. Drawing on institutional and environmental governance theories, this study evaluates whether governance strengthens the environmental benefits of renewable-energy consumption. Unlike previous studies that primarily focus on aggregate governance measures, this study separately examines six governance dimensions: control of corruption, political stability, rule of law, government effectiveness, regulatory quality, and voice and accountability. Using panel data from the World Bank, the analysis employs fixed-effects estimation and validates the findings through robust regression, the generalized method of moments (GMM), and panel-corrected standard error (PCSE) approaches. The results indicate that renewable energy consumption significantly reduces both CO₂ emissions per capita and total CO₂ emissions in the long run. The findings further show that governance significantly moderates the renewable energy–CO₂ emissions relationship, with stronger governance enhancing the emission-reducing effect of renewable energy consumption. Governance mitigates the environmental impacts associated with urbanization and industrialization, highlighting the importance of institutional quality in managing the structural drivers of emissions. The robustness analyses confirm the consistency of the main results across the alternative estimation techniques. This study contributes to the literature by providing evidence of the distinct roles of individual governance dimensions in shaping environmental outcomes in economies actively engaged in renewable energy development. These findings suggest that renewable energy expansion and governance reforms should be pursued simultaneously to achieve more effective carbon emission reduction strategies. Full article

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31 pages, 3230 KB

Open AccessArticle

The Paradox of Mineral Downstreaming: Evaluating Copper Ore Reserve Resilience and Structural Industrial Challenges in Indonesia

by Triswan Suseno, Zulfahmi Zulfahmi, Harta Haryadi, Edwin Akhdiat Daranin, Yuhelda Dahlan, Teuku Ishlah, Eko Widi Santoso, Tatang Padmawidjaja, Purnama Sendjaja, Mustafa Hanafi, Martua Raja Parningotan and Nendaryono Madiutomo

Resources 2026, 15(7), 91; https://doi.org/10.3390/resources15070091 - 10 Jul 2026

Abstract

This research aims to analyze the resilience of Indonesia’s copper ore reserves in supporting sustainable copper cathode production targets, in line with national downstream policies. Using a quantitative approach, this study evaluates secondary data from national mineral reserve reports and the production capacity [...] Read more.

This research aims to analyze the resilience of Indonesia’s copper ore reserves in supporting sustainable copper cathode production targets, in line with national downstream policies. Using a quantitative approach, this study evaluates secondary data from national mineral reserve reports and the production capacity of major smelters. The analysis is conducted by calculating the reserve-to-production ratio to project mine life under three scenarios of increasing domestic refining capacity, including an aggressive scenario of 1.145 million tons per year. The results indicate that based on current reserves, the estimated mine life is approximately 21 years under maximum production capacity. However, with potential resource-to-reserve conversion of approximately 4.318 billion tons and accounting for ore grade decline, the life of Indonesia’s copper ore reserves is projected to extend until 2077. The study also reveals a structural gap, where 70% of cathode production is still export-oriented due to low domestic manufacturing absorption. The uniqueness of this paper lies in the integration of geological reserve aspects with the dynamics of downstream policies and industrial structure theories. Practically, this study provides important implications for the government in formulating strategic reserve management and emphasizes the urgency of integrating upstream smelting with downstream manufacturing to ensure long-term industrial sovereignty. Full article

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27 pages, 6022 KB

Open AccessArticle

Spray-Dried Whole Red Pitaya (Hylocereus costaricensis): A Potential Source of Bioactive Compounds for Food Applications

by Igor A. G. Oliveira, Neiton C. Silva and Marcos A. S. Barrozo

Resources 2026, 15(7), 90; https://doi.org/10.3390/resources15070090 - 9 Jul 2026

Abstract

Pitaya is a tropical fruit widely recognized for its intense coloration and abundance of bioactive compounds and natural pigments, associated with antioxidant properties and potential functional applications. However, its high moisture content and structural fragility make it highly susceptible to post-harvest deterioration and [...] Read more.

Pitaya is a tropical fruit widely recognized for its intense coloration and abundance of bioactive compounds and natural pigments, associated with antioxidant properties and potential functional applications. However, its high moisture content and structural fragility make it highly susceptible to post-harvest deterioration and limit its shelf life, highlighting the need for effective preservation strategies to enable its industrial utilization. This study evaluated the production of spray-dried red pitaya (Hylocereus costaricensis) powder using the whole-fruit (pulp, peel, and seeds), since studies addressing entire fruit utilization remain scarce. The effects of air temperature (T), air flow rate (AF), maltodextrin concentration (M), and feed flow rate (FF) on moisture content, water activity, drying yield, bioactive compounds (total phenolic, flavonoid, ascorbic acid, and betalains), and color parameters were investigated. Spray drying successfully produced pitaya powders characterized by reduced moisture levels and water activity, satisfactory drying yield, and preserved bioactive compounds contents under selected processing conditions. The optimized spray drying conditions (T = 132.7 °C, AF = 1.51 m³/min; M = 9%, and FF = 0.55 L/h) were identified through the desirability function approach, indicating a balanced performance between drying efficiency and compound retention. Color parameters (L*, a*, b*, C*, H°, and ΔE) showed changes related to the operational conditions analyzed when compared with the fresh fruit. These findings support the valorization of the pitaya whole fruit and its use as a source of natural bioactive compounds for food applications. Full article

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17 pages, 310 KB

Open AccessArticle

Impact of Vermicompost from Agricultural Waste on Soil Fertility, Crop Performance, and Drought Resilience in Smallholder Farming Systems

by Clifftone Wanyonyi Mbuku, Rogerio Borguete Rafael and John Walker Recha

Resources 2026, 15(7), 89; https://doi.org/10.3390/resources15070089 - 8 Jul 2026

Abstract

A sustainable method of improving soil fertility and developing climate-resilient cropping systems is vermicomposting agricultural waste. This study hypothesized that vermicompost derived from mixed organic agricultural wastes would significantly improve soil fertility, crop productivity, and drought resilience compared to single-substrate treatments and the [...] Read more.

A sustainable method of improving soil fertility and developing climate-resilient cropping systems is vermicomposting agricultural waste. This study hypothesized that vermicompost derived from mixed organic agricultural wastes would significantly improve soil fertility, crop productivity, and drought resilience compared to single-substrate treatments and the unamended control. The effects of vermicompost generated from mixed organic wastes using Eisenia fetida on soil quality, crop performance, and drought resilience of lettuce (Lactuca sativa, Eden variety) were evaluated in this study using a randomized complete block design. Crop performance indicators included germination, growth characteristics, biomass, SPAD chlorophyll content, and yield, while soil physicochemical properties, including pH, organic carbon, total nitrogen, available phosphorus, exchangeable potassium, electrical conductivity (EC), and cation exchange capacity (CEC), were assessed both before and after amendment application. The effects of drought stress were evaluated using leaf surface temperature, wilting score, recovery time, and survival rate. The results demonstrated that vermicompost application significantly improved soil fertility and crop performance relative to the control treatment (p < 0.05). The best-performing treatment (T2) increased soil organic carbon by approximately 22–28%, total nitrogen by 18–24%, available phosphorus by 20–27%, and exchangeable potassium by 16–21% compared with the control. Fresh biomass increased by approximately 14–17%, marketable yield improved by 16–24%, and SPAD chlorophyll values increased by nearly 20%, indicating enhanced photosynthetic efficiency and nutrient uptake. T2 showed the most resilience under drought stress, with ~94.9% survival rate, reduced wilting severity, shortened recovery time and sustained stable leaf temperature (~27.8 °C), whereas low-performing treatments and the control recorded survival rates of only ~70–78%. Mixed organic waste substrates consistently outperformed single-substrate treatments, demonstrating synergistic effects on nutrient cycling, microbial activity, soil structural quality, and drought tolerance. These findings provide quantitative evidence that vermicomposting can simultaneously enhance soil fertility, crop productivity, and drought resilience, highlighting its strong potential as a scalable climate-smart strategy for sustainable agriculture, circular bioeconomy development, and organic waste valorization in smallholder farming systems. Full article

28 pages, 7844 KB

Open AccessArticle

The Effects of Resource Management, Technical Management, and Environmental Management on Production, Reproduction, and Economic Farm Performance Mediated by Operational Efficiency Among Madura Cattle Farmers

by Adi Sutanto, Iswahyudi Iswahyudi, Ristika Handarini, Marchel Putra Garfansa, Akh Fawaid, Yenni Arista Cipta Ekalaturrahmah, Siti Alfiatul Amani, Ika Oktaviana Dewi, Zhulvie Meylanzharie, Zakiyatuz Zhulva Nabila Wahyudi, Imam Wahyudi and Muhammad Ilman Wahyudi

Resources 2026, 15(7), 88; https://doi.org/10.3390/resources15070088 - 7 Jul 2026

Abstract

Madura cattle are a nationally important indigenous Indonesian beef cattle breed and a locally adapted genetic resource that supports smallholder livelihoods and beef production under tropical dryland, low-input farming conditions. As an indigenous Indonesian beef cattle breed raised predominantly by smallholder farmers in [...] Read more.

Madura cattle are a nationally important indigenous Indonesian beef cattle breed and a locally adapted genetic resource that supports smallholder livelihoods and beef production under tropical dryland, low-input farming conditions. As an indigenous Indonesian beef cattle breed raised predominantly by smallholder farmers in dryland and low-input systems, Madura cattle require integrated management practices that combine resource management, technical management, environmental management, and operational efficiency to improve farm performance. A quantitative survey was conducted with 400 farmers from Madura Island. Data were collected through structured interviews using a five-point Likert-scale questionnaire and analyzed using SEM-PLS by evaluating the measurement and structural models. The results show that all constructs met validity and reliability criteria. The model demonstrated adequate explanatory power, with adjusted R² values of 0.369 for Operational Efficiency and 0.522 for Farm Performance. Resource Management, Technical Management, and Environmental Management had positive and significant effects on Operational Efficiency. Operational Efficiency also had a positive and significant effect on Farm Performance and partially mediated the relationships between the three management variables and Farm Performance. These findings indicate that improving Madura cattle farming performance requires stronger resource, technical, and environmental management supported by operational efficiency as a strategic mechanism to enhance production, reproduction, and economic performance sustainably. Full article

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30 pages, 920 KB

Open AccessReview

Cocoa By-Products as Functional Ingredients in Food: Composition, Emerging Extraction Technologies, Food Applications and Challenges of the Circular Economy

by Marianela Díaz-Llocclla, Rebeca Salvador-Reyes, Emerson Asto-Rodriguez, Anahi Rodriguez Dominguez, Maickol Andy Cano Otañe and Gian Pierre Silvera-Otañe

Resources 2026, 15(7), 87; https://doi.org/10.3390/resources15070087 - 2 Jul 2026

Abstract

Cocoa processing generates large amounts of agro-industrial by-products, mainly cocoa bean shells (CBS), cocoa pod husks (CPH), and cocoa mucilage, which remain underutilized despite their nutritional and bioactive potential. This narrative review critically analyzes the composition of cocoa by-products and emerging technologies for [...] Read more.

Cocoa processing generates large amounts of agro-industrial by-products, mainly cocoa bean shells (CBS), cocoa pod husks (CPH), and cocoa mucilage, which remain underutilized despite their nutritional and bioactive potential. This narrative review critically analyzes the composition of cocoa by-products and emerging technologies for bioactive compound recovery. Results show that CBS and CPH are rich sources of dietary fiber (13.8–65.6%), phenolic compounds (up to 100 mg GAE/g), and methylxanthines (theobromine up to 11.6 mg/g in CBS). Emerging extraction technologies, ultrasound-assisted extraction, pressurized liquid extraction, microwave-assisted extraction, pulsed electric fields, and cold atmospheric plasma, improve extraction yield (20–150%), reduce processing time (from hours to minutes), and decrease solvent consumption compared to conventional methods. Regarding food applications, moderate CBS inclusion levels (10–20% in cookies, 2–8% in bread, 0.75–1.0% in sausages) improve dietary fiber and antioxidant capacity without compromising sensory acceptability, whereas higher levels (>20–30%) increase hardness, bitterness, and astringency. It is concluded that cocoa by-products are promising resources for sustainable functional food ingredients. However, industrial implementation remains limited by raw material variability, lack of standardized extraction protocols, sensory constraints, and insufficient biological validation of recovered compounds. Future research should focus on standardizing extraction protocols, validating bioaccessibility and bioactivity through in vivo studies, optimizing food formulations for sensory balance, assessing contaminants (heavy metals, mycotoxins), and evaluating techno-economic feasibility and life-cycle sustainability at industrial scale. Full article

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49 pages, 17682 KB

Open AccessArticle

A Renewable-Energy Resource Management Framework for Low-Carbon Network-Level Pavement Maintenance Using Simulation-Based Pavement–Energy Modeling and Multi-Agent Deep Reinforcement Learning

by Nawal Louzi, Mohammad Q. Al-Jamal, Mahmoud AlJamal, Ayoub Alsarhan and Sami Aziz Alshammari

Resources 2026, 15(7), 86; https://doi.org/10.3390/resources15070086 - 1 Jul 2026

Abstract

Sustainable pavement maintenance increasingly requires coordinated management of infrastructure condition, renewable-energy availability, carbon emissions, financial resources, and operational capacity. This study proposes a renewable-energy resource management framework for low-carbon network-level pavement maintenance using simulation-based pavement-energy modeling and multi-agent deep reinforcement learning. The proposed [...] Read more.

Sustainable pavement maintenance increasingly requires coordinated management of infrastructure condition, renewable-energy availability, carbon emissions, financial resources, and operational capacity. This study proposes a renewable-energy resource management framework for low-carbon network-level pavement maintenance using simulation-based pavement-energy modeling and multi-agent deep reinforcement learning. The proposed framework develops an AnyLogic-based pavement-energy simulation environment in which road sections, deterioration states, work zones, maintenance crews, equipment resources, photovoltaic generation, battery storage, grid support, diesel backup, carbon tracking, and budget consumption are represented within one integrated decision environment. To support adaptive maintenance control, pavement sections are modeled as interacting agents, while road connectivity, dispatch dependency, traffic interaction, and maintenance-route relationships are encoded through graph structures. A graph-based multi-agent deep reinforcement learning model, named Graph-MAPPO, is then used as the decision controller. The model integrates multi-head graph attention for spatial dependency learning, GRU-based temporal memory for deterioration-history representation, finite-element-assisted structural-risk indicators for hidden damage characterization, and constraint-aware action masking to prevent infeasible decisions under budget, carbon, energy, crew, and equipment constraints. Two calibrated datasets were generated to support the framework: a pavement network and maintenance dataset containing 4437 records and 55 features, and a renewable energy-carbon-budget dataset containing 9875 records and 38 features. The decision controller jointly selects the pavement section, treatment type, intervention timing, crew, equipment, and energy mode. Results from 20 experimental configurations show that the balanced Graph-MAPPO policy improves average

P C I

from 69.4 to 78.9, achieves an

R S L

gain of 6.8 years, reduces emissions to 58.3 tCO₂e, maintains a renewable-energy share of 74.6%, and limits the constraint-violation rate to 1.8%. Under high renewable-energy availability, the framework achieves the best overall performance, with an average

P C I

of 80.2, renewable-energy share of 84.6%, emissions of 50.8 tCO₂e, and reward of 0.90. These findings demonstrate that integrating pavement-energy simulation, renewable-energy resource allocation, carbon-aware maintenance planning, structural-risk awareness, and multi-agent decision control can support more adaptive, low-carbon, and resource-efficient pavement maintenance management. Full article

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27 pages, 338 KB

Open AccessArticle

Resource Productivity and Economic Resilience in OECD Economies: Evidence from Second-Generation Panel Estimation

by Noura Ben Mbarek and Ezer Ayadi

Resources 2026, 15(7), 85; https://doi.org/10.3390/resources15070085 - 29 Jun 2026

Abstract

Growing concerns regarding resource efficiency, economic uncertainty, and energy-market volatility have renewed interest in the relationship between material-use patterns and macroeconomic stability. Recent global disruptions affecting production systems and economic activity have intensified policy attention toward sustainable resource management and resilience-oriented growth strategies. [...] Read more.

Growing concerns regarding resource efficiency, economic uncertainty, and energy-market volatility have renewed interest in the relationship between material-use patterns and macroeconomic stability. Recent global disruptions affecting production systems and economic activity have intensified policy attention toward sustainable resource management and resilience-oriented growth strategies. Using an unbalanced panel of 30 OECD economies over the period 1995–2024, this study examines the relationship between resource productivity and economic resilience while accounting for material-use intensity and structural conditions. The empirical framework relies on second-generation panel econometric techniques that account for cross-sectional dependence and heterogeneous country dynamics. The findings indicate that resource productivity is positively associated with economic resilience, with a 1% increase in resource productivity corresponding to an approximately 0.18% increase in resilience. By contrast, domestic material consumption and material footprint display negative associations with resilience, suggesting that resource-intensive production and consumption patterns may be linked to lower adaptive capacity and macroeconomic stability. The short-run estimates additionally indicate the persistence of adjustment dynamics following economic disturbances. These findings highlight the relevance of resource-use efficiency for macroeconomic resilience and sustainable resource-management strategies in OECD economies. Full article

27 pages, 13977 KB

Open AccessArticle

Ecosystem-Based Valuation to Enhance Climate-Resilient Governance of Coastal Wetlands: The Case of the Kol Ramsar Site, India

by Srinithisathian Sathian, Brema Jayanarayanan, James Erinjery Joseph, Vijay Santhiyagu Joseph and Alexandre S. Gagnon

Resources 2026, 15(7), 84; https://doi.org/10.3390/resources15070084 - 25 Jun 2026

Abstract

Wetlands are vital ecosystems that provide critical provisioning, regulating, cultural, and supporting services that underpin biodiversity conservation and local livelihoods. Despite their importance, ecosystem service valuation is often overlooked in coastal wetland restoration, limiting recognition of their contributions to the United Nations Sustainable [...] Read more.

Wetlands are vital ecosystems that provide critical provisioning, regulating, cultural, and supporting services that underpin biodiversity conservation and local livelihoods. Despite their importance, ecosystem service valuation is often overlooked in coastal wetland restoration, limiting recognition of their contributions to the United Nations Sustainable Development Goals (SDGs). To address this gap and overcome methodological fragmentation in wetland assessments, this study develops the Integrated Ecosystem Valuation and Management of Wetlands (IEVMW) framework, which integrates the Millennium Ecosystem Assessment (MEA), Drivers–Pressures–State–Impact–Response (DPSIR) framework, IPCC climate risk assessment, and Total Economic Value (TEV) approaches into a unified methodology. The framework was applied to the Kol Wetlands in India to identify ecosystem services, assess climate-related risks, estimate economic values, and develop management recommendations. Results indicate that provisioning services contribute the highest economic value, followed by regulating and cultural services. Climate change was estimated to place approximately 11.7% and 13.0% of ecosystem service value at risk in North Kol and South Kol, respectively, corresponding to a combined economic value at risk of ₹42.9 crore, with provisioning services being the most vulnerable. The IEVMW framework provides a practical and scalable approach for linking ecosystem service valuation, climate risk assessment, and governance, thereby supporting climate-resilient wetland management and biodiversity conservation across diverse socio-environmental contexts. Full article

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17 pages, 1789 KB

Open AccessArticle

Effects of Coal Gangue–Fly Ash Volume Ratio and Particle Size Distribution on Substrate Water Content and Alfalfa Growth

by Xuehan Song, Jingling Li, Yamin Jia and Kaixuan Hao

Resources 2026, 15(7), 83; https://doi.org/10.3390/resources15070083 - 24 Jun 2026

Abstract

The dumping of coal gangue poses significant risks to human health and ecosystems, necessitating ecological restoration in coal gangue mining areas. This study investigates the physical properties and water-retention characteristics of coal gangue–fly ash (CG-FA) substrates under varying coal gangue volume ratios and [...] Read more.

The dumping of coal gangue poses significant risks to human health and ecosystems, necessitating ecological restoration in coal gangue mining areas. This study investigates the physical properties and water-retention characteristics of coal gangue–fly ash (CG-FA) substrates under varying coal gangue volume ratios and particle-size distributions, and evaluates their effects on alfalfa (Medicago sativa L.) growth. Six CG-FA volume ratios (5:5, 6:4, 7:3, 8:2, 9:1, 10:0) and seven particle-size distributions (1:1:1, 2:1:1, 3:1:1, 1:2:1, 1:3:1, 1:1:2, 1:1:3) were tested in 3 L pot experiments. Results showed that reducing coal gangue content significantly improved substrate structure, decreasing bulk density by 3.8–28.9% and increasing porosity by 9.8–64.4%, accompanied by enhanced water-retention capacity. The 5:5 volume ratio combined with a 1:2:1 particle-size distribution resulted in the highest alfalfa biomass, providing the best balance of substrate structure and water availability. From a resource-oriented perspective, the optimized CG–FA substrate enables the in situ utilization of coal-based solid wastes, reducing dependence on external soil resources while improving water retention and plant growth. These findings suggest potential advantages in resource utilization, economic feasibility, and environmental performance, providing a sustainable alternative for mine land restoration. Full article

(This article belongs to the Special Issue Mine Ecological Restoration: 2nd Edition)

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32 pages, 7374 KB

Open AccessArticle

Half a Century of Global Agricultural Commodity Connectedness Under Geopolitical Risk: The Role of Threats and Acts (1975–2026)

by Hela Ben Hamida

Resources 2026, 15(6), 82; https://doi.org/10.3390/resources15060082 - 22 Jun 2026

Abstract

Using a dataset covering January 1975 to March 2026 and six agricultural commodities, wheat, corn, soybeans, oats, sugar, and coffee, this paper explores the role of geopolitical risk (acts and threats) in shaping cross-market connectedness. It proposes a multilayer methodology based on the [...] Read more.

Using a dataset covering January 1975 to March 2026 and six agricultural commodities, wheat, corn, soybeans, oats, sugar, and coffee, this paper explores the role of geopolitical risk (acts and threats) in shaping cross-market connectedness. It proposes a multilayer methodology based on the time-varying parameter vector autoregressive (TVP-VAR), the exponential GARCH with exogenous variables (EGARCH-X), and the wavelet quantile correlation (WQC) frameworks. This methodology captures cross-market volatility spillovers, assesses the effects of geopolitical risk and its components on the strength and instability of connectedness, and incorporates nonlinearity and asymmetry across investment horizons and market conditions. The results show a time-varying pattern in agricultural cross-market connectedness. Corn and soybeans transmit volatility shocks, while the other commodities are net receivers. These commodities have a central position in the connectivity network, whereas sugar and coffee are in the peripheral zone. The EGARCH-X results show that geopolitical acts and threats do not significantly alter the overall level of connectedness but intensify its volatility, suggesting that geopolitical tensions primarily influence stability rather than the intensity of connectedness. Economic policy uncertainty and oil price volatility have similar effects. In line with these results, the WQC analysis uncovers significant nonlinearity and state-dependent linkages, underscoring that the effect of geopolitical acts and threats becomes prominent over medium- and long-term horizons and during periods of market stress. These findings contribute to the literature by differentiating the effects of geopolitical incidents on agricultural market connectedness versus volatility. From an operational standpoint, these results imply that policymakers and market operators should enhance their risk-monitoring and hedging strategies during periods of high geopolitical stress, as such events can amplify instability across agricultural commodity markets. Full article

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20 pages, 9222 KB

Open AccessArticle

Integrated Assessment of Potentially Toxic Elements in Soils and Irrigation Water and Human Health Risk in a Gold Mining-Impacted Area of Southern Ecuador

by Juan González-Menéndez, Carlos Hugo Bustamante-Torres, Bryan Salgado-Almeida, Giannella Muriel-Granda, Samantha Jiménez-Oyola and Kenny Escobar-Segovia

Resources 2026, 15(6), 81; https://doi.org/10.3390/resources15060081 - 22 Jun 2026

Abstract

Areas where mining activities overlap with agricultural production may promote the mobilization of potentially toxic elements (PTEs) into soils and water resources, thereby creating exposure pathways for populations living or working in these environments. This study analyzes the concentration of PTEs in agricultural [...] Read more.

Areas where mining activities overlap with agricultural production may promote the mobilization of potentially toxic elements (PTEs) into soils and water resources, thereby creating exposure pathways for populations living or working in these environments. This study analyzes the concentration of PTEs in agricultural soils and irrigation water from Santa Rosa, southern Ecuador, and assesses the associated health risks for exposed agricultural workers. For this purpose, 35 soil samples were collected from farms and 12 water samples from the irrigation canal during the dry season of 2025. The concentration of PTEs in soil and water was determined using X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The PTE concentration in both matrices was compared with the maximum permissible limits (MPL) established by Ecuadorian regulations. Non-carcinogenic hazard indices (

H I

) and carcinogenic risk (

T C R

) were estimated following the U.S. EPA methodology. In soil, As and Cr were the PTEs of greatest concern, exceeding the MPL in 93% of the samples and by up to 4.4 and 2.4 times, respectively, while in water, all PTEs were below the MPL. Non-carcinogenic risk was below the recommended limit for soil and water (

H I_{s o i l}

= 3.00 × 10⁻² and

H I_{w a t e r}

= 2.00 × 10⁻³), with As as the dominant contributor. Cancer risk was tolerable in soil (

T C R_{s o i l}

= 4.34 × 10⁻⁵), while in water it remained at a low level (

T C R_{w a t e r}

= 1.65 × 10⁻⁶). These findings identify As and Cr as priority contaminants and support targeted monitoring and source-control measures in mining-influenced agricultural areas. Overall, by integrating agricultural soil and irrigation water quality with an occupational health risk assessment in Santa Rosa, this study contributes evidence to support future research in mining–agriculture coexistence areas. Full article

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18 pages, 1021 KB

Open AccessArticle

Sustainable Corrosion Inhibition of Admiralty Brass Using Plant Waste Extracts: Phytochemical and Electrochemical Screening with Techno-Economic Insights

by María Belén Canchig, Mateo Oleas, Ariel Miranda, Alfredo Viloria, Ruth Oropeza, Paola E. Ordóñez, Marvin Ricaurte and Alex Palma-Cando

Resources 2026, 15(6), 80; https://doi.org/10.3390/resources15060080 - 22 Jun 2026

Abstract

Admiralty brass, commonly used in heat exchangers, is particularly susceptible to corrosion in acidic media such as those used in industrial cleaning. To mitigate this problem, the present study evaluated Musa acuminata (banana) peel and Lupinus mutabilis Sweet (Andean lupine) extracts as sustainable, [...] Read more.

Admiralty brass, commonly used in heat exchangers, is particularly susceptible to corrosion in acidic media such as those used in industrial cleaning. To mitigate this problem, the present study evaluated Musa acuminata (banana) peel and Lupinus mutabilis Sweet (Andean lupine) extracts as sustainable, low-toxicity corrosion inhibitors for admiralty brass in 0.5 M HCl. Six extracts were prepared using different solvents and characterized by qualitative and semi-quantitative phytochemical analyses (phenols, flavonoids, alkaloids). M. acuminata extracts were rich in phenolic compounds, while L. mutabilis extracts contained high levels of quinolizidine alkaloids. A comparative electrochemical screening of the agro-industrial waste-derived extracts revealed that the inhibition efficiency of M. acuminata extracts reached up to 43.6%, whereas the debittering wastewater extract of L. mutabilis (E6) achieved a maximum efficiency of 85.5% at 2000 ppm. A preliminary techno-economic analysis indicated the feasibility of industrial-scale production of the L. mutabilis-based inhibitor, yielding a net present value (NPV) of USD 9.48 million, an internal rate of return (IRR) of 27.3%, and a payback period of 6.7 years. These results demonstrate that agro-industrial residues can be valorized into effective and profitable green corrosion inhibitors, aligning with circular economy and sustainable chemistry principles. Full article

(This article belongs to the Special Issue Resource Recovery and Valorisation from Agricultural Products and Wastes)

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