Search Results (136)

This study presents an experimental evaluation of the bioenergy potential of Enterolobium cyclocarpum (“orejero”) fruit peel residue, an underutilized agroforestry by-product in tropical America. Although the species is widely used for shade and fodder in livestock systems, its fruit peel has not yet been characterized for energy recovery purposes. Fruit samples were collected in rural areas of Tesalia (Huila, Colombia), and the peel fraction was analyzed in certified laboratories. The moisture content of the peel was determined as 11 wt%, and the lower heating value was measured as 0.015 TJ/t following ASTM E711-06. Elemental analysis according to ASTM D5373-16 yielded (dry basis): 37.2 wt% C, 4.09 wt% H, 0.45 wt% N and 0.13 wt% S. Based on Colombian cultivation and production data, the theoretical energy potential was estimated as 3.6 TJ/year per hectare. The technical energy potential reached 0.18 and 0.21 TJ/year per hectare for combustion and gasification, respectively. CO₂-equivalent emissions were also estimated for both conversion routes, revealing a trade-off between the higher energy yield and higher specific emissions associated with gasification. Overall, the results show that E. cyclocarpum fruit peel residue has a calorific value comparable to widely used agri-food residues in Colombia (e.g., sugarcane bagasse and oil palm fiber), but with a substantially higher per-hectare energy potential due to its large residue fraction. Its high availability, favorable fuel properties, and compatibility with decentralized combustion and gasification technologies support its use as a promising feedstock for bioenergy generation in rural or off-grid areas, in line with circular economy and sustainable energy transition strategies. Full article

The ever-growing global consumption of coffee generates millions of tons of spent coffee grounds (SCG) annually, posing a significant waste disposal problem. Although some SCG find use in composting or biogas production, a large portion remains underutilized. This study introduces a novel circular waste-to-energy pathway to tackle this challenge. Our proposed technology employs a cascading valorization approach, utilizing non-catalytic supercritical transesterification of pyrolytic oil derived from SCG for liquid hydrocarbon production. The process begins with pyrolysis, which converts SCG into pyrolytic oil. This oil is then upgraded via supercritical transesterification with methanol. Experiments were conducted using a 1:6 oil-to-methanol ratio at precisely controlled conditions of 239.4 °C and 1200 psi for 20 min. This optimized process yielded an impressive 96% of valuable liquid hydrocarbon product. The resulting product exhibited highly favorable characteristics, including a density of 755.7 kg/m³, a viscosity of 0.7297 mm²/s, and a high heating value (HHV) of 48.86 MJ/kg. These properties are remarkably comparable to conventional biofuels and standard fossil fuels, demonstrating the product’s potential as a viable energy source. Full article

This article explores the multifaceted potential of tomato pomace (TP) as a sustainable resource for the cosmetic and pharmaceutical industries, with a particular focus on the critical discussion surrounding peel–seed separation processes. Despite the significant volume of TP generated globally, valued molecules such as carotenoids, polyphenols, and high-quality oils remain underutilized. The separation of seeds from peels is highlighted as a critical step in the valorization of TP, as both components offer distinct physicochemical properties and bioactive constituents that significantly influence extraction efficiency and product quality. Various separation methods, including wet and dry techniques, have been innovatively developed; however, they present challenges such as resource consumption, operational complexity, and environmental concerns. The discussion advocates for a whole-pomace processing strategy that could streamline operations, enhance extraction efficiency, and create sustainable pathways for resource optimization. Additionally, the article highlights the importance of incorporating TP-derived compounds into cosmetic formulations and pharmaceutical products, which could lead to the development of new enzymes, antioxidants, and colorants that contribute to health and wellness. By championing the valorization of TP, the article advocates for a redefined perception of food waste, encouraging its utilization in sustainable practices that align with environmental goals. Full article

Moringa oleifera has been recognized for its adaptability, nutritional richness, and multipurpose potential, particularly in resource-limited regions. While most research has focused on its leaves, moringa seeds remain underutilized despite their broad applicability in the environmental, agricultural, and food sectors. This review systematically and critically examines recent scientific literature on the use of M. oleifera seeds across these fields, emphasizing their functional value, applications, and challenges for sustainable use. The review follows the SALSA methodology (Search, Appraisal, Synthesis, and Analysis), a structured and iterative framework designed to identify, evaluate, and integrate scientific evidence from diverse sources. The analysis encompasses three main areas: (i) water treatment, where moringa seed extracts have achieved turbidity removal efficiencies above 90% and effective adsorption of dyes and potentially toxic elements; (ii) agriculture, where seed-derived fertilizers improve soil fertility, nutrient availability, and crop yield compared to conventional inputs; and (iii) the food industry, where moringa seed derivatives enhance the nutritional, functional, and antioxidant properties of bakery, beverage, and oil-based products. Overall, M. oleifera seeds emerge as a versatile and sustainable resource with proven potential as a natural coagulant, biofertilizer, and nutraceutical ingredient. By integrating findings from both English and Spanish language studies, this work highlights their contribution to sustainable water management, agricultural productivity, and food innovation, while emphasizing the need for further safety evaluation and process optimization to support large-scale application. Full article

Brewers’ spent grain (BSG) represents the major byproduct of the brewing industry and remains largely underutilized. While BSG contains a rather high amount of protein, poor functional properties limit its use as a functional ingredient for foods without additional processing. In this work, we investigate emulsifying peptides embedded in the major BSG proteins based on a mass spectrometry-based proteomic analysis and subsequent bioinformatic prediction to explore the utilization of BSG as a raw material for the production of protein-based emulsifying ingredients. Forty-eight peptides were selected based on EmulsiPred score, amino acid sequence, and protein abundance for evaluation. All peptides effectively reduced the interfacial tension between oil–water, but only 15 could produce and stabilize emulsions with droplet sizes below 5 µm. Some peptides were able to produce stable emulsions with sub-micron droplet sizes, implying very promising emulsifying properties. This study demonstrated promising emulsifying properties of BSG peptides and suggested that the functionality could be predicted using bioinformatic tools. However, the used tool needs to be further optimized for higher success rate. Full article

Green coconut husk is an abundant and underutilized agro-industrial residue in Brazil, contributing significantly to landfill overload. This study investigates the pyrolysis of pellets derived from this biomass as a technological alternative for its valorization, focusing on the integrated characterization of the three resulting products. Pellets were subjected to pyrolysis in a fixed-bed reactor under two distinct conditions: at 400 °C to maximize biochar production, and at 600 °C to enhance gas generation. The raw material and resulting solid, liquid, and gaseous fractions were characterized using physicochemical, thermal, morphological, and chromatographic analyses. Pyrolysis at 400 °C yielded biochar with high fixed carbon content (67.03%) and elevated heating value (27.80 MJ/kg), suitable for soil amendment and carbon sequestration. At 600 °C, the non-condensable gas exhibited a higher hydrogen concentration (35.84%) and an H₂/CO ratio of 1.84, favorable for chemical synthesis applications. Notably, palletization resulted in a significant bio-oil and gas yield even under 400 °C. The bio-oil underwent chemical upgrading, which significantly increased the phenolic content and raised its heating value to 20.40 MJ/kg. Additionally, combustion tests revealed that the gas produced emitted lower levels of NOx compared to natural gas. Full article

Mulberry leaf glutelin (MG), a nutrient-rich protein fraction from mulberry leaves, remains underutilized due to limited studies on its physicochemical functional properties and biological activities. In this study, seven varieties of MG (TSG, DSG, 109G, C1G, C2G, C3G, C4G) were evaluated for amino acid composition, secondary structure (FTIR), solubility, water-holding capacity (WHC), oil absorption capacity (OAC), foaming capacity (FC), foam stability (FS), emulsifying activity index (EAI), emulsion stability index (ESI), in vitro digestibility, and pancreatic lipase inhibitory activity (PLI). The results showed that MG contains four secondary structures and 17 amino acids, being rich in glutamic acid, aspartic acid, and leucine. C3G exhibited superior solubility (96.32%) at pH 10, while C4G showed optimal WHC (9.27 g/g), FC (73.75%), and FS (92.80%). TSG exhibited the highest OAC (9.58 g/g) and EAI (15.79 m²/g), and DSG demonstrated an excellent ESI (117.25 min), digestibility (88.17%), and PLI (70.54%). These findings provide valuable insights for the application of MG in food processing and innovation, enhancing its potential value for the food industry and human health. Full article

Sea buckthorn (Hippophae rhamnoides L.) is a rich source of bioactive compounds, including vitamin C, polyphenols, carotenoids, and dietary fiber. In this study, sea buckthorn pomace, an underutilized by-product of oil processing, was incorporated into wheat bread at levels of 0, 3, 6, 9, and 12% (based on flour weight). The technological performance (dough yield, baking loss, loaf volume, texture, and color), nutritional composition (protein, fat, dietary fiber fractions, mineral content, and caloric value), and sensory attributes of the resulting breads were comprehensively evaluated. Pomace addition markedly increased the protein content of bread (from 13.5% to 16.8%) and more than doubled total dietary fiber (from 5.4% to 11.6%), while reducing caloric value by approximately 5.6%. Increasing pomace levels also affected dough behavior and bread structure: water absorption rose from 59.9% to 68.9%, specific loaf volume decreased by 11–28%, and crumb hardness increased from 3.8 N (control) to 12.4 N (12% addition). Sensory acceptability remained high up to 6% pomace incorporation (acceptability index > 90%), whereas breads containing 9–12% received significantly lower scores, mainly due to darker crumb color and intensified sour or bitter notes. Overall, sea buckthorn pomace can be effectively used as a nutritionally enriching, value-added ingredient in wheat bread, enhancing fiber and protein content while maintaining desirable technological and sensory properties at moderate substitution levels. Full article

Vitamin A deficiency (VAD) affects millions of people around the world, particularly in populations with limited dietary diversity. The present study aimed to develop β-carotene-fortified coconut oil using Pouteria campechiana (Canistel), which is an underutilized tropical fruit rich in β-carotene. A solvent-free fortification process was optimized using response surface methodology (RSM) with a central composite design to evaluate the effects of oil percentage (50–100% w/v) and heating temperature (30–60 °C) on β-carotene retention and oil quality. The quadratic model showed excellent fit (R² = 0.9970; lack of fit p = 0.6815), while optimum conditions were identified at 52.4 °C and 50% (w/w) oil, yielding a predicted β-carotene concentration of 2.22 µg/mL. The fortified oil exhibited significantly higher polyphenolic (17.37 ± 2.04 mg GAE/g), total flavonoid (11.33 ± 0.89 mg QE/g) contents, and antioxidant activity (9.78 ± 0.53 mg TE/g) compared with commercial coconut oil. The optimized oil demonstrated enhanced oxidative stability, reflected by lower peroxide (0.05 ± 0.01 meqO₂/kg) and acid values (0.10 ± 0.01 mg KOH/g). The validated quadratic model and optimized process produced a nutritionally enriched, stable coconut oil, supporting its use as a clean-label functional ingredient. These findings highlight the potential of β-carotene-fortified oils to deliver provitamin A and antioxidant benefits. Future studies should focus on evaluating the bioavailability, storage stability, and sensory acceptability of β-carotene enriched coconut oil to confirm its nutritional and commercial potential. Full article

Rambutan seed waste from fruit processing remains underutilized, while conventional biodiesel routes face high feedstock costs and food-versus-fuel concerns. This study investigated a novel catalyst-free process for biodiesel production from rambutan seed waste using supercritical ethanol and ethyl acetate as renewable reactants to valorize fruit by-products. Batch reactions on the semi-solid fraction of rambutan seed oil (RSO) were conducted at 15 MPa to evaluate the effects of temperature (275–375 °C), reactant-to-oil molar ratio (20:1–40:1), and reaction time (15–50 min) on fatty acid ethyl ester (FAEE) yield. Under optimal conditions, FAEE yields of 59.92 and 41.92% were obtained using ethanol (350 °C, 40:1, 30 min) and ethyl acetate (350 °C, 30:1, 40 min), respectively. However, severe conditions degraded unsaturated esters, revealing a conversion–stability trade-off. The ethanol system exhibited faster reaction kinetics and lower activation energy than ethyl acetate. Applying the optimized ethanol-based conditions to the liquid fraction of RSO, which contained a lower proportion of saturated fatty acids, resulted in a markedly improved FAEE yield of 94.16%. This study demonstrated a catalyst-free supercritical route for converting rambutan seed waste into biodiesel, advancing waste-to-energy strategies and circular bioeconomy. Full article

Rice is a staple food for global nutrition, and its processing generates large volumes of waste with a consequent environmental impact. The industry needs to improve its capacity to manage and treat this waste with more sustainable options than traditional management methods, thereby mitigating the environmental impact of the rice industry. Among the waste streams generated, rice bran represents a significant fraction that is largely underutilized. This study proposes a comprehensive approach to rice bran recovery, aiming to transform 100% of the waste into bio-based products through a three-stage biorefinery approach that combines chemical and biological operations. The process began with the ethanolic extraction of rice bran, which yielded 20.58% (w·w⁻¹) rice bran oil. This oil, evaluated through both in vitro and in vivo trials, has demonstrated effectiveness when combined with commercial edible coatings, reducing post-harvest damage in grapes and lemons by 15–20%. Following extraction, the remaining defatted rice bran, accounting for 79.42% (w·w⁻¹) of the initial material, was used as a carbon-rich substrate for microbial fermentation by Haloferax mediterranei. This step converts 28.75% (w·w⁻¹) of rice bran into microbial biomass and 12.75% (w·w⁻¹) into polyhydroxybutyrate-valerate. The undigested residual biomass, comprising 37.95% (w·w⁻¹) of the starting material, was further valorized through the purification of high-value products such as cellulose (13.08% (w·w⁻¹)), hemicellulose (14.58% (w·w⁻¹)), and lignin (10.29% (w·w⁻¹)). Overall, the biorefinery model recovers 100% of the initial waste and demonstrates, under laboratory conditions, the model’s ability to transform rice bran into six products of industrial interest, offering an option with the potential to effectively manage rice bran waste and help circularize the production model of an industry that traditionally operates under a linear production model. Full article

The valorization of olive oil production residues represents an innovative and sustainable strategy aligned with circular economy principles and the United Nations Sustainable Development Goals. In this study, we aimed to explore the phytochemical composition and neuroprotective potential of organic extracts obtained from olive pomace of the Arbequina and Arbosana cultivars. Extracts were prepared through solid–liquid extraction and analyzed by high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS), enabling the comprehensive identification of bioactive metabolites. The analysis revealed a diverse profile of phenolic compounds, including hydroxytyrosol, tyrosol, and multiple oleuropein derivatives, as well as triterpenic acids such as oleanolic and maslinic acids. These compounds are widely recognized for their antioxidant, anti-inflammatory, and neuroprotective activities. The antioxidant potential of the extracts was evaluated in vitro using DPPH and ABTS radical scavenging assays, showing significant activity comparable to that of standard antioxidants. Moreover, cholinesterase inhibitory assays demonstrated moderate to strong inhibition of acetylcholinesterase, an enzyme implicated in neurodegenerative diseases such as Alzheimer’s disease. To further elucidate the molecular basis of these effects, in silico molecular docking studies were performed on the most abundant compounds, revealing favorable binding affinities and interactions with key active site residues of acetylcholinesterase. Overall, these findings highlight olive pomace as a promising, underutilized source of bioactive compounds with potential applications in the development of functional foods, nutraceuticals, and neuroprotective therapeutic agents. The integration of in vitro and in silico approaches strengthens the evidence supporting the use of these extracts in future biomedical and industrial applications. Full article

Background/Objectives: Orange peels (OP), a major by-product of the juice industry, are rich in bioactive compounds (phenolic compounds, pectin, carotenoids, and essential oils). Its valorization represents a promising route to reduce food waste and foster a circular bioeconomy. This review aimed to map scientific progress in OP upcycling, focusing on the extraction of bioactive ingredients for human nutrition and integrated biorefinery approaches aligned with zero-waste principles. Methods: A bibliometric analysis and a scoping review were conducted covering studies published between 2003 and 2023. Scopus database and VOSviewer was usedto identify research trends, hotspots, and gaps. Conventional and emerging green extraction methods were critically compared, and integrated biorefinery strategies for maximizing OP valorization were systematically assessed. Results: The analysis revealed an exponential rise in OP research over the past decade, reflecting growing interest in sustainable food waste valorization. Polyphenol- and pectin-rich extracts are currently the focus of research and applications, driven by their high economic and nutritional value. Innovative multi-extraction and zero-waste biorefinery models have emerged, yet most remain at low technological readiness levels. Carotenoids and other bioactive compounds remain underexplored, and challenges persist regarding standardization and scalability. Conclusions: OP valorization is shifting towards integrated green extraction and biorefinery frameworks that address clean-label demands, promote circular economy goals, and align with the Sustainable Development Goals. Future research should prioritize (i) standardized protocols, (ii) scalable green extraction technologies, (iii) the inclusion of underutilized compounds such as carotenoids, and (iv) regulatory pathways to accelerate industrial translation. Full article

As the global imperative to decarbonize infrastructure intensifies, wastewater treatment plants (WWTPs) are emerging as critical nodes for implementing circular and energy-positive solutions. Among these, thermal energy recovery from sewage sludge presents a transformative opportunity to reduce greenhouse gas (GHG) emissions, enhance energy self-sufficiency, and valorize waste streams. While anaerobic digestion remains the dominant stabilization method in large-scale WWTPs, it often underutilizes the full energy potential of sludge. Recent advancements in thermal processing, including pyrolysis, gasification, hydrothermal carbonization, and incineration with energy recovery, offer innovative pathways for extracting energy in the form of biogas, bio-oil, syngas, and thermal heat, with minimal carbon footprint. This review explores the physicochemical variability of sewage sludge in relation to treatment processes, highlighting how these characteristics influence thermal conversion efficiency and emissions. It also compares conventional and emerging thermal technologies, emphasizing energy yield, scalability, environmental trade-offs, and integration with combined heat and power (CHP) systems. Furthermore, the paper identifies current research gaps and outlines future directions for optimizing sludge-to-energy systems as part of net-zero strategies in the water–energy nexus. This paper contributes to a paradigm shift toward sustainable, decarbonized wastewater management systems by reframing sewage sludge from a disposal challenge to a strategic energy resource. Full article

A sustainable economy and the drive to reduce agro-industrial waste worldwide motivate the increased interest in alternative uses of traditionally cultivated plants such as tobacco. Tobacco seeds are an underutilized resource with enormous potential for application in various areas of human life. The present study aims to characterize the phytochemical composition and nutritional potential of Oriental tobacco seeds grown in Bulgaria, in order to support their possible application in areas outside the tobacco industry. Two Oriental tobacco varieties (“Krumovgrad 90” and “Krumovgrad 58”) from three production regions were explored and comparatively evaluated in terms of their physical and chemical indicators, determined by standardized methods. The results showed high protein (22.57–23.84%) and energy content (482–531 kcal/100 g), combined with relatively low carbohydrate levels (3.79–4.03%) and the presence of bioactive compounds, such as polyphenols (288–357 mg GAE/100 g). The seeds contained significant amount of oil (36.31–39.24%), of which the fatty acid profile included 16 identified components, with linoleic (72.0–74.4%), oleic (11.2–13.5%), palmitic (9.6–10.2%), and stearic (1.8–2.5%) acids taking the greatest share. The sterol fraction was dominated by β-sitosterol (43.5–46.8%), followed by sitostanol, campesterol and stigmasterol, with a stable distribution between the samples. The main tocol was γ-tocotrienol (56.5–61.4%), with α-tocotrienol being detected only in one of the varieties (“Krumovgrad 58”, 13.3%). The phospholipid fraction showed variations between the samples, with a dominant presence of phosphatidylinositol (18.0–20.4%). The results from the study confirmed the tangible potential of tobacco seeds as a source of biologically active substances in the development of functional foods and dietary supplements. Full article