Mid Sweden University

The focus on by-product valorization in the food industry, particularly from the carob pod, underscores a commitment to sustainability and resource efficiency. This fruit, sourced from the leguminous evergreen carob tree (Ceratonia siliqua L.), is renowned for its adaptable flavour and nutritional value, in Mediterranean regions such as Portugal. Its production yields significant by-products, presenting environmental challenges when not managed efficiently. Innovative approaches, including integral carob flour production, aim to optimize utilization while minimizing waste and energy consumption. This study repurposed carob waste to produce novel, value-added ingredients like carob syrup, by thermal hydrolysis of integral carob flour using water at 1:3 solid-to-liquid ratio - obtaining up to 50 % solubility yield. The resulting syrup exhibited 72 % °Brix, a melting temperature (Tm) of approximately 130 °C and predominantly viscous behavior with minimal elastic (solid-like) response. Lastly, the syrup was incorporated into a carob-based brigadeiro, replacing conventional glucose-fructose syrup. Simulated gastrointestinal digestion revealed enhanced bioaccessibility of sugars and phenolics, and increased antioxidant activity during the intestinal phase. Despite sugar availability, the prebiotic activity of the syrup decreased when embedded in the brigadeiro matrix, potentially due to interactions with polyphenols or organic acids. Cytotoxicity and permeability assays confirmed safety at ≤0.5 % (w/v) and supported intestinal barrier integrity. These findings support the use of integral carob flour for producing multifunctional ingredients, contributing to circular economy models while meeting consumer demands for healthier, sustainable food products. 

Chitosan films with potential application in triboelectric nanogenerators (TENGs) represent a promising approach to replace non-biobased materials in these innovative devices. In the present work, chitosan with varying molecular weights (MW) and degrees of deacetylation was dissolved in aqueous acetic acid (AA) at different acid concentrations. It was observed that the MW had a greater influence on the viscosity of the solution compared to either the acid concentration or deacetylation degree. Gel formation occurred in high-MW chitosan solutions prepared with low AA concentration. Films prepared from chitosan solutions, through solvent-casting, were used to prepare TENGs. The power output of the TENGs increased with higher concentrations of AA used in the chitosan dissolution process. Similarly, the residual AA content in the dried films also increased with higher initial AA concentrations. Additionally, hot-pressing of the films significantly improves the TENG power output due to the decrease in morphological defects of the films. It was demonstrated that a good selection of the acid concentration not only facilitates the dissolution of chitosan but also plays a key role in defining the properties of the resulting solutions and films, thereby directly impacting the performance of the TENGs. 

The growing demand for sustainable materials has intensified the search for biodegradable polymers. Poly(ε-caprolactone) (PCL), though biodegradable, is fossil-derived. In this study, a novel lignin extracted from pine wood using a green solvent was incorporated into PCL and compared with commercial lignins (dealkaline, alkaline, and lignosulfonate). The lignin additions imparted antioxidant properties, enhanced thermal stability, and promoted circular economy goals through lignin valorization. Notably, the green-extracted lignin showed superior compatibility with PCL when compared with commercial lignins, as evidenced by lower water uptake and solubility, and improved surface hydrophobicity (higher contact angle). Although the addition of lignin reduced the tensile strength and elongation at break, it greatly increased the PCL radical scavenging activity (DPPH) from 8 ± 1% of neat PCL to 94.8 ± 0.3% when 20 wt% of lignin-LA was added. Among the tested lignins, lignin-LA stands out as the most promising candidate to be applied as a functional additive in biodegradable polymer blends and composites for advanced sustainable applications. Not only given its intrinsically higher sustainability but also due to its capacity for improving the thermal properties of PCL–lignin blends. 

With the global population steadily rising, the demand for sustainable protein sources has become increasingly urgent. Traditional animal- and plant-based proteins face challenges related to scalability, resource efficiency, and environmental impact. In this context, single-cell protein has emerged as a promising alternative. Derived from microorganisms such as algae, bacteria, fungi, and yeast, single-cell protein offers a high nutritional profile- including all essential amino acids and vitamins-while enabling rapid production, minimal land and water requirements, and no generation of greenhouse gas emissions. A particularly compelling advantage of single-cell protein is its ability to be produced from agro-industrial waste, converting low-cost residues into valuable nutritional resources and contributing to environmental sustainability. Among these waste streams, lignocellulosic biomass from agricultural and forestry residues stands out as a renewable, biodegradable, and abundant feedstock. This review explores the potential of lignocellulosic waste as a substrate for single-cell protein production, emphasizing both its environmental advantages and nutritional value. It highlights the single-cell protein role as a sustainable and scalable alternative to conventional protein sources. The review also identifies key scientific, economic, and regulatory challenges, and recognizes the importance of targeted investments, particularly in policy development, public awareness, and technological innovation, to enable the broader adoption and acceptance of single-cell protein -based products.

Microplastic pollution represents a significant environmental challenge, as microplastics accumulate in effluents and soils, causing serious risks to ecosystems and human health. Efficient removal of these contaminants is essential to mitigate their potential adverse effects. This review summarizes and critically analyses current methods for the removal of microplastics from effluents and soils, focusing on their effectiveness, advantages, and limitations. Conventional techniques—including filtration, flotation, chemical coagulation, flocculation, and adsorption—are discussed in the context of wastewater treatment and soil remediation. Emerging approaches, such as flocculation processes with special focus on the application of bio-based flocculants, are also highlighted as promising solutions. Key challenges in microplastic removal, including the diversity of microplastic types, their small size, and the complexity of environmental matrices, are addressed. This work intends to contribute to the urgent need for further research to develop more efficient and sustainable strategies for microplastic removal from environmental systems. 

Carob fruit utilization remains limited, with most of their commercial value derived from locust bean gum, which is obtained from seed endosperm. Efficient extraction requires dehusking, which is traditionally performed under harsh conditions. This study aims to develop and optimize a milder, more sustainable dehusking method while preserving seed quality for industrial applications. Various aqueous-based solvents were tested, leading to the selection of metanesulfonic acid (CH4O3S). A Box–Behnken design with response surface methodology optimized the process, using husk removal efficiency as the response variable. The optimized conditions were 24.5 g of seeds treated in 50 mL of a solvent mixture (41% CH4O3S and 59% H2SO4) at 90 °C for 10 min, followed by washing by 5 min with water (87 mL). The treated seeds were analyzed using colorimetry assays and diffusive reflectance spectroscopy and benchmarked against both pristine and dehusked seeds from a local company. The resulting seeds remained morphologically intact and exhibited appealing color characteristics comparable to commercial samples. The optimized method ensured intact seed morphology and color characteristics comparable to commercial standards, offering a viable alternative to conventional H2SO4-based dehusking. Furthermore, this study also highlights for the first time the effectiveness of diffusive reflectance spectroscopy as a rapid and straightforward tool for assessing the dehusking process. 

Lignin, a natural and abundant biopolymer, holds great potential for cosmetic applications. However, its limited solubility and inherently negative charge restrict its use in certain formulations. This is particularly relevant for hair conditioning, where a positively charged polymer is preferred to effectively treat negatively charged damaged hair. To overcome this limitation, lignin extracted from acacia wood residues was chemically cationized, through an etherification reaction, using 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) as cationization agent. The cationization process was optimized through a full factorial design of experiments aiming to maximize both the degree of substitution (DS) and ζ-potential of the lignin derivatives, thereby obtaining more positively charged derivatives. The reaction parameters temperature and CHPTAC-to-lignin molar ratio were selected as independent variables to be optimized. Results revealed that the reaction temperature is the most relevant parameter for lignin cationization, showing a significant positive influence on lignin modification, while the CHPTAC-to-lignin ratio has no significant impact. Under optimal conditions, soluble derivatives with a DS of 0.61 ± 0.03 and a ζ-potential of 18.79 ± 0.30 mV were obtained, confirming the success of the reaction. This straightforward and efficient approach enhances acacia's lignin solubility and charge properties, broadening its application potential. In particular, it offers a promising alternative for hair conditioning, thus contributing to the sustainable development of bio-based cosmetic ingredients. 

The carob tree (Ceratonia siliqua L.) is receiving growing attention for its agro-industrial potential, particularly due to its seeds, which are the source of locust bean gum (LBG), a galactomannan-rich polysaccharide with wide applications in food and pharmaceutical industries. Efficient dehusking of carob seeds is critical to maximize LBG purity and yield, yet current industrial methods pose environmental concerns and lack robust quality control tools. In this study, we demonstrate the use of Diffuse Reflectance Spectroscopy (DRS) and Kubelka–Munk (KM) modeling as a rapid, non-destructive technique to assess dehusking efficiency. By combining spectral data from four complementary spectrometers (450–1800 nm), we identified key reflectance and absorbance features capable of distinguishing raw, industrially treated, and laboratory-dehusked seeds. Notably, our laboratory-treated seeds exhibited a considerably lower reflectance in the NIR plateau (800–1400 nm) compared to raw and industry-treated seeds, and their KM-reconstructed skin showed enhanced absorption bands at 960, 1200, and 1400 nm, consistent with more complete husk removal and improved light penetration. Principal Component Analysis revealed tighter clustering and lower variability in lab-processed seeds, indicating superior process reproducibility. These results establish DRS as a scalable, green analytical tool to support quality control and optimization in carob processing.

This study explores the performance of novel cellulose-derived sustainable flocculants in the flocculation of different model microplastics (MPs), including polyethylene (PE), polyethylene terephthalate (PET) and polyvinyl chloride (PVC). The influence of key parameters, such as pH, flocculant structure and concentration was evaluated by Laser Diffraction Spectroscopy (LDS) and optical microscopy to access their effects on flocculation performance, kinetics and floc structure. The results reveal that a bioflocculant concentration of 0.001 g·mL−1 is ideal for effective flocculation, as lower concentrations lead to insufficient floc growth. While electrostatic interactions are a dominant factor in the flocculation process, the study also highlights the role of hydrophobic interactions, its contribution depending on the characteristics of the MPs. Overall, this research highlights the importance of understanding the key interactions governing the flocculation process. It further paves the way for designing and fine-tuning cellulose-based flocculants with improved efficiency and optimized dosages for effective MPs removal strategies. 

This study explores the potential of Arbutus unedo L. pomace, a by-product of the food industry, as a natural ingredient for skincare applications. In Portugal, A. unedo L. fruits are traditionally used to produce “Aguardente de Medronho”, a spirit with a protected geographical indication. The distillation process generates pomace, comprising skins, pulp remnants, seeds, and residual alcohol rich in phenolic compounds, whose levels are significantly increased during distillation. In addition to their documented high antioxidant content, these residues also display notable antimicrobial properties. However, their potential benefits for skin health have not yet been explored. The methodology entailed the preparation of the pomace extract and a comprehensive analysis of its polyphenolic content and antioxidant capacity under laboratory conditions and in preclinical cellular models. The by-products demonstrated a high polyphenol content and potent antioxidant activity, comparable to vitamin C. Bioscreening on human skin models (i.e., dermal fibroblasts and keratinocytes) revealed their ability to reduce reactive oxygen species (ROS) formation under oxidative stress in skin cells, highlighting their potential to mitigate skin aging and damage caused by environmental pollutants. Moreover, bioscreens in vitro revealed a high safety profile, without any interference with cell viability at concentrations up to 100 µg/mL. These findings support the use of A. unedo L. pomace extract as a sustainable ingredient for the development of antioxidant-rich and eco-friendly cosmetic or dermatologic products.