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Lignin valorization through heterogeneous photocatalysis is a promising pathway for obtaining value-added products, including chemical building blocks, biofuels, etc. However, several challenges still demand attention and resolution in this field. One of the key parameters in the heterogeneous photocatalytic process is the synthesis of efficient photocatalysts that can accomplish efficient and selective reactions. Selective conversion of lignin can be achieved by using heterojunction photocatalysts which can efficiently separate charge carriers' and promote selective reactions by band structure modulation. This work details a straightforward approach for synthesizing heterojunction photocatalysts based on Bi4Ti3O12 and BiOI involving the hydrothermal and co-precipitation methods. Additionally, the synthesized composites were employed in the selective oxidation of veratryl alcohol, a lignin-derived model compound, to produce high-value-added veratraldehyde. The experimental results showed that the BiOI/Bi4Ti3O12 heterojunction (12.5 mol % BiOI) showed superior activity with a veratraldehyde yield of 5.4 and 27.2 times higher than those of Bi4Ti3O12 and BiOI, respectively. The mechanistic studies revealed that the improved activity and selectivity were due to the enhanced charge carriers' separation and the suppression of reactive oxygen species formation through modulation of band structure. This study allows a green approach to lignin-derived biomass valorization to obtain high-value chemicals.

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This study investigates the valorization potential of yellowfin tuna (Thunnus albacares) tails to produce high-value commercial products. Firstly, the tuna tails were placed in a perforated stainless-steel cylinder, and hydraulic pressure was applied to separate the skin from the muscle in the tails. The extracted muscle was then utilized as a nitrogen source for the growth of the proteolytic enzyme producer Bacillus subtilis, while the skins were employed for gelatin extraction. The proteases from B. subtilis were partially purified and used to produce antioxidant peptides from the obtained gelatin. The gelatin formed a gel upon cooling, with gelling and melting temperatures of 16 °C and 22 °C, respectively, and a Bloom strength of approximately 160. Response Surface Methodology (RSM) was employed to determine the optimal hydrolysis conditions to achieve the highest antioxidant activity (35.96% measured as DPPH radical scavenging activity), which were 50 °C and 6.5 IU of enzyme. The findings emphasize the importance of an integrated approach to maximize the value of tuna by-products, promoting sustainability within the framework of a circular bioeconomy. Overall, these results contribute to the efficient utilization of tuna by-products, waste reduction, and enhanced economic viability of the tuna industry.

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The urgent need for a simple and cost-effective thermochemical process to produce biochar has prompted this study. The aim was to develop a straightforward thermochemical process under O2-limited conditions for the production of coconut-based biochar (CBB) and to assess its ability to remove methylene blue (MB) through adsorption, comparing it with CBB produced by slow pyrolysis. CBBs were obtained under different atmospheric conditions (O2-limited, muffle furnace biochar (MFB); and inert, pyrolytic reactor biochar (PRB)), at 350, 500, and 700 °C, and for 30 and 90'. MFB and PRB were characterized using FTIR, RAMAN, SEM, EDS, and XRD analyses. Adsorption tests were conducted using 1.0 g L-1 of MFB and PRB, 10 mg L-1 of MB at 25 °C for 48 h. Characterization revealed that atmospheric conditions significantly influenced the yield and structural features of the materials. PRB exhibited higher yields and larger cavities than MFB, but quite similar spectral features. Adsorption tests indicated that MFB and PRB had qt values of 33.1 and 9.2 mg g-1, respectively, which were obtained at 700 °C and 90', and 700 °C and 30', respectively. This alternative method produced an innovative and promising lignocellulose-based material with great potential to be used as a biosorbent.

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Agro-industrial residue valorization under the umbrella of the circular bioeconomy (CBE) has prompted the search for further forward-thinking alternatives that encourage the mitigation of the industry's environmental footprint. From this perspective, second-life valorization (viz., thermoplastic composites) has been explored for agro-industrial waste (viz., oil palm empty fruit bunch fibers, OPEFBFs) that has already been used previously in other circular applications (viz., the removal of domestic wastewater contaminants). Particularly, this ongoing study evaluated the performance of raw residues (R-OPEFBFs) within three different size ranges (250-425, 425-600, 600-800 µm) both before and after their utilization in biofiltration processes (as post-adsorbents, P-OPEFBFs) to reinforce a polymer matrix of acrylic resin. The research examined the changes in R-OPEFBF composition and morphology caused by microorganisms in the biofilters and their impact on the mechanical properties of the composites. Smaller R-OPEFBFs (250-425 µm) demonstrated superior mechanical performance. Additionally, the composites with P-OPEFBFs displayed significant enhancements in their mechanical properties (3.9-40.3%) compared to those with R-OPEFBFs. The combination of the three fiber sizes improved the mechanical behavior of the composites, indicating the potential for both R-OPEFBFs and P-OPEFBFs as reinforcement materials in composite applications.

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Catalytic biomass pyrolysis is one of the most promising routes for obtaining bio-sustainable products that replace petroleum derivatives. This study evaluates the production of aromatic compounds (benzene, toluene, and xylene (BTX)) from the catalytic pyrolysis of lignocellulosic biomass (Pinus radiata (PR) and Eucalyptus globulus (EG)). Chilean natural zeolite (NZ) was used as a catalyst for pyrolysis reactions, which was modified by double ion exchange (H2NZ) and transition metals impregnation (Cu5H2NZ and Ni5H2NZ). The catalysts were characterized by nitrogen adsorption, X-ray diffraction (XRD), ammonium programmed desorption (TPD-NH3), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) allowed us to study the influence of natural and modified zeolite catalysts on BTX production. XRD analysis confirmed the presence of metal oxides (CuO and NiO) in the zeolite framework, and SEM-EDS confirmed successful metal impregnation (6.20% for Cu5H2NZ and 6.97% for Ni5H2NZ). Py-GC/MS revealed a reduction in oxygenated compounds such as esters, ketones, and phenols, along with an increase in aromatic compounds in PR from 2.92% w/w (without catalyst) to 20.89% w/w with Ni5H2NZ at a biomass/catalyst ratio of 1/5, and in EG from 2.69% w/w (without catalyst) to 30.53% w/w with Ni5H2NZ at a biomass/catalyst ratio of 1/2.5. These increases can be attributed to acidic sites within the catalyst pores or on their surface, facilitating deoxygenation reactions such as dehydration, decarboxylation, decarbonylation, aldol condensation, and aromatization. Overall, this study demonstrated that the catalytic biomass pyrolysis process using Chilean natural zeolite modified with double ion exchange and impregnated with transition metals (Cu and Ni) could be highly advantageous for achieving significant conversion of oxygenated compounds into hydrocarbons and, consequently, improving the quality of the condensed pyrolysis vapors.

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Cheese whey (CW), by-product of cheese production, has potential as a valuable resource due to its nutritional composition. Although options for CW degradation have been explored, a biological treatment with black soldier fly larvae (BSFL) has not been reported. This study evaluated the growth and composition of BSFL in four experimental diets with CW under different conditions. Results show that the use of CW allows larval development and weight gain, also, the conversion into larval biomass was up to 0.215. Diets ED3 (fresh CW, 38 °C) and ED4 (fresh CW, room temperature) allowed higher weight accumulation (final weight up to 0.285 g); the highest fat accumulation (12 % higher than control) was observed in ED3 (up to 45.57 %), which had less protein. Moreover, higher amounts of saturated fatty acids are generated. This study highlights the importance of an appropriate pretreatment designed for a specific waste to control desired by-products.

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The Cerrado is one of the most biodiverse biomes in the world, characterized by a wealth of native fruits with unique nutritional characteristics. In this sense, the social, economic, and environmental importance of fully utilizing food is widely recognized. Therefore, generally considered waste, fruit shells can be transformed into a coproduct with high added value. The objective of this work was to carry out a comprehensive assessment of the physicochemical properties, carbohydrate and fatty acid profile, phytochemical compounds, phenolic profile, and antioxidant potential of the recovered extracts of buriti (Mauritia flexuosa) shells in natura and dehydrated at 55 °C (flour). In addition, the functional properties were verified by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) from buriti shell flour. The results indicated high fiber content and energy value for the sample processed at 55 °C (58.95 g/100 g and 378.91 kcal/100 g, respectively) and low lipid and protein content (1.03 g/100 g and 1.39 g/100 g, respectively). Regardless of the sample analyzed, maltose was the majority sugar (37.33 - 281.01 g/100 g). The main fatty acids detected were oleic acid (61.33 - 62.08 %) followed by palmitic acid (33.91 - 34.40 %). The analysis of the mineral profile demonstrated that the samples did not differ significantly from each other, showing that the drying process did not interfere with the results obtained (p ≤ 0.05). The analysis of individual phenolics allowed the identification of six phenolic compounds in buriti shells. However, it is possible to observe that the drying method had a positive and significant influence on the phenolic profile (p ≤ 0.05), with chlorogenic acid (2.63 - 8.27 mg/100 g) and trigonelline (1.06 - 41.52 mg/100 g), the majority compounds. On the other hand, it is important to highlight that buriti shells have a high content of carotenoids, mainly ß-carotene (27.18 - 62.94 µg/100 g) and α-carotene (18.23 - 60.28 µg/100 g), also being positively influenced by the drying process at 55 °C (p ≤ 0.05). The dried shells showed a high content of phytochemical compounds and high antioxidant activity based on the different methods tested. The results show that buriti shell flour can be fully utilized and has nutritional and chemical aspects that can be applied to develop new sustainable, nutritious, and functional food formulations.

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Water treatment plants (WTPs) produce thousands of tons of sludge annually, which is destined for landfill disposal, an environmentally and economically impractical alternative. Chemical, mineralogical, and morphological characterization besides environmental classification has been performed for WTP sludge and it was evaluated application potential in building materials, from a literature review. The characterization was carried out by X-ray fluorescence spectrometry, X-ray diffraction, scanning electron microscopy analysis, and leaching and solubilization tests. The results show that the presence of activated charcoal residues from water treatment in one type of sludge was of little relevance for changes in the properties of the waste. Both sludges have a wide range of particle sizes, consisting mainly of silica, aluminum and iron oxides, as well as kaolinite, quartz, and iron minerals. Special attention must be paid to the solubilization of metallic contaminants to avoid contamination risks and order to make the application safer and more effective, it is necessary to study deeply ways to inert the WTP sludge. The sludges studied have a high potential for application in ceramic products, mortars, geopolymers and concrete paving stones. Depending on the type of building material, different contents of sludge in natural or calcined state can be incorporated.

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Cocoa tree plantations aim to harvest grains found in the cob to produce cocoa and chocolate. There has been a growing interest in valorizing the secondary components of the cocoa fruit, such as the peel, placenta, and mucilage/pulp, as valuable sources of nutrients for healthy food preparation. In other words, by-products derived from these raw materials are an exploitable source of nutrients in the preparation of healthy food. In the present study, two varieties of cocoa, National Cocoa Fino de Aroma (NCFA) and Colección Castro Naranjal 51 (CCN-51), were evaluated and harvested during both dry and rainy seasons. This evaluation was based on the profiling of the cob, peel, grain, placenta, and mucilage in different stages of ripeness (underripe, ripe, and overripe). Also, from the ripe raw material, a fermented beverage prototype was developed, such as kombucha, with different concentrations of mucilage (40, 60, 80, and 100 g/L). Physicochemical analyses, such as acidity, °Brix, pH, moisture, ash, protein, fat, fiber, vitamins, sugars, and polyphenols of the raw mucilage material and acidity, °Brix, and pH values of the fermented kombucha, were carried out. The best performances were obtained with the CCN-51 variety in the rainy season. Among the fermented drink panelists, the CN40 treatment (Nacional Mucilage + 40 g/L of sugar) received the highest acceptability and was considered the best. Given its efficiency, nutritional content, and potential applications, this product presents a promising strategy to address Sustainable Development Goals related to zero hunger, health and well-being, and climate action.

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Recognized for its bioactive compounds, açaí has become a functional food, but it has a low pulp yield, and the seeds are the main waste. This study investigates the potential of açaí seeds (Euterpe oleracea Mart.) to produce mannooligosaccharides (MOS) through enzymatic hydrolysis. Using response surface methodology (RSM), the research optimizes MOS extraction while minimizing mannose production and reducing processing time, achieving MOS production of about 10 g/L, a value within the range of similar investigations. The RSM quadratic models establish correlations between MOS production (M2-M5) and enzymatic hydrolysis conditions, with R2 values ranging from 0.6136 to 0.9031. These models are used to emphasize MOS performance (M2-M5) while reducing mannose production, which also promotes profitability by reducing time. Experimental validation agrees with model predictions, highlighting optimal conditions near 40 °C, intermediate enzyme loading, and basic pH that effectively promotes MOS generation on mannose within an accelerated processing time frame. With predictions of experimental results within a margin of error of < 9%, the validity of the models was acceptable. This research contributes to the advancement of the understanding of the enzymatic hydrolysis of açaí seeds, which is a step toward the sustainable use of resources with a focus on process engineering aspects.

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There is a growing interest in exploring new natural sources of colorants. This study aimed to extract anthocyanins from broken black bean hulls (Phaseolus vulgaris L.) by modifying water with a eutectic mixture (choline chloride:citric acid (ChCl:Ca)). Ultrasound-assisted extraction (UAE) was employed and optimized in terms of temperature (30-70 °C), ultrasound power (150-450 W), and eutectic mixture concentration in water (1-9% (w/v)), resulting in an optimal condition of 66 °C, 420 W, and 8.2% (w/v), respectively. The main quantified anthocyanins were delphinidin-3-O-glycoside, petunidin-3-O-glycoside, and malvidin-3-O-glycoside. The half-life of the anthocyanins at 60 °C increased twelvefold in the eutectic mixture extract compared to the control, and when exposed to light, the half-life was 10 times longer, indicating greater resistance of anthocyanins in the extracted eutectic mixture. Additionally, the extracts were concentrated through centrifuge-assisted cryoconcentration, with the initial cycle almost double the extract value, making this result more favorable regarding green metrics. The first concentration cycle, which showed vibrant colors of anthocyanins, was selected to analyze the color change at different pH levels. In general, the technology that uses eutectic mixtures as water modifiers followed by cryoconcentration proved to be efficient for use as indicators in packaging, both in quantity and quality of anthocyanins.

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Lignocellulosic biomass is widely available in the world. However, a consensus has yet to be established to evaluate the biomass valorization alternatives. The chemical composition is the primary technical limitation in selecting a transformation route to obtain value-added products. In this paper, the bagasse from non-centrifuged sugar (NCS) production and Pinus patula (PP) wood chips were analyzed in terms of complete chemical composition to establish their potential for selecting the transformation routes. A strategy to select the best route based on the chemical composition was applied and a feedstock criteria model was proposed. Schemes were obtained and compared using a bioprocess selection strategy proposed in previous works. As a result, the preliminary biorefinery schemes were finally defined. The assessment of schemes derived from the outlined strategy included technical, economic, environmental, and social analyses. The environmental evaluation was complemented with a geolocation assessment, revealing a 0.75-ton CO2-eq/yr contribution to the carbon footprint for local distribution. The sustainability index for the PP biorefinery and the bagasse from NCS production was analyzed, resulting in indices of 44.8 and 60.9, respectively. These values were primarily derived from the economic and environmental analyses of both processes.

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Currently, approximately 34% of fruit is lost and wasted in emerging economies due to inefficient post-harvest processes, technological shortcomings, lesser valorization of surpluses, and byproducts. Peach (Prunus persica L.) is a fruit with a good yearly growth rate but higher postharvest losses in Colombia. One way to take advantage of this type of product is through the application of drying processes that increase its shelf life and its inclusion in the food chain. Refractance Window Drying (RWD) is a fourth generation drying technique implemented by the food industry in the last few decades and has been applied to several dehydrated food products. This study compared the effects of different drying methods on the physical and sensory properties of peaches surplus. Treatments consisted of (i) peaches were sliced (1, 2, and 3 mm thickness) and dried using RWD at 86°C, (ii) peach pulp mixed with maltodextrin (MD) (0.12-0.33 kg of MD/kg of sample) and RWD (RWD-MD), and (iii) conventional oven drying (OD) at 60°C (3 mm thick) dried for 24 h. The study found that the drying method significantly (p < 0.05) affected the texture, color, and general taste of peaches. The results showed that processing treatments combined with different drying conditions affected the physical properties of the peach. RWD in slices reduced water content to 0.05 kg H2O/kg in 40 min, showing fewer effects on color attributes. A surface response analysis on RWD showed good correlations for water activity (R2 = 0.8652-0.9894) and moisture content (R2 = 0.7048-0.9826). A higher diffusion coefficient (1.63 × 10-6 m2 s-1) was observed for RWD in slices with 3 × 10-3 m of thickness; however, for RWD-MD, differences in diffusion coefficients were present for the lowest MD addition (0.12 kg/kg), vitamin C was not detected on the dried slices, and higher concentration of ß-carotene (175.88 µg/100 g) was found on the thinner slices. Principal component analysis showed that RWD in the slices was the most suitable drying process, followed by OD. Sensory analysis showed good acceptability for RWD slices after 30 days of storage.

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The present study demonstrates, for the first time, the feasibility of a two-step process consisting of Electro-Fenton (EF) followed by microalgae to treat highly loaded real food processing wastewater along with resource recovery. In the first step, EF with a carbon felt cathode and Ti/RuO2-IrO2 anode was applied at different current densities (3.16 mA cm-2, 4.74 mA cm-2 and 6.32 mA cm-2) to decrease the amount of organic matter and turbidity and enhance biodegradability. In the second step, the EF effluents were submitted to microalgal treatment for 15 days using a mixed culture dominated by Scenedesmus sp., Chlorosarcinopsis sp., and Coelastrum sp. Results showed that current density impacted the amount of COD removed by EF, achieving the highest COD removal of 77.5% at 6.32 mA cm-2 with >95% and 74.3% of TSS and PO43- removal, respectively. With respect to microalgae, the highest COD removal of 85% was obtained by the culture in the EF effluent treated at 6.32 mA cm-2. Remarkably, not only 85% of the remaining organic matter was removed by microalgae, but also the totality of inorganic N and P compounds, as well as 65% of the Fe catalyst that was left after EF. The removal of inorganic species also demonstrates the high complementarity of both processes, since EF does not have the capacity to remove such compounds, while microalgae do not grow in the raw wastewater. Furthermore, a maximum of 0.8 g L-1 of biomass was produced after cultivation, with an accumulation of 32.2% of carbohydrates and 25.9% of lipids. The implementation of the two processes represents a promising sustainable approach for the management of industrial effluents, incorporating EF in a water and nutrient recycling system to produce biomass that could be valorized into clean fuels.

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Pectin is widely used in several products in the industry. Conventionally, strong and harmful acids are used for its extraction. This study optimized the extraction of orange peel's pectin using citric acid, considering yield and degree of esterification (DE) as response variables. Proximal analyses were performed, and the samples were subjected to a Box-Behnken design on three central points, considering as variables the temperature, time, and pH. The results of proximate analyses of the orange peels revealed 11.76 % moisture content, 87.26 % volatiles, 0.09 % ash, 50.45 % soluble carbohydrates, 70.60 % total carbohydrates, 0.89 % fixed carbon, 5.35 % lipids, and 36.75 mg GAE/g of phenolic compounds. The resulting second-order polynomial model described the relation of the input and output variables related to each other. The best performance to obtain a higher yield (18.18 %) of high methoxyl pectin (DE 50 %) was set at 100 °C/30 min/pH 2.48. Pectin showed antioxidant properties by ABTS and DPPH assays and similar thermal properties to the commercial polymer. Its equivalent weight was 1219.51 mol/g, and the methoxyl and anhydrouronic acid were 2.23 and 67.10 %, respectively. Hence, pectin extraction with citric acid results in a high-quality polymer and could be used as a gelling agent, stabilizer, or texturizer in food products.

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In the present work, a study was carried out on the dosage of wastes from the chemical industry (tannery sludge) and civil construction (concrete and plaster) in mixtures used in concrete blocks' production. The objective was the application of these blocks in paving. The characterization of the materials used was performed employing X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The effect of the different residues on the blocks' properties was evaluated through compressive strength, flexion-traction, water absorption, abrasion resistance, and leaching tests. The results indicated that the concrete paving blocks produced with the addition of residues did not obtain gains in the values of mechanical resistance to compression and traction in bending compared to blocks made with standard raw material. However, the blocks produced with construction waste presented satisfactory results for application in street paving after 7 days of concrete curing, reaching values between 36.54 and 44.6 MPa for the mentioned properties. These values also increased to 21.4% within 28 days of curing. The blocks produced with plaster showed values between 37.03 and 39.85 MPa after 28 days of curing, allowing their use for street paving. On the other hand, the blocks containing residues from the chemical industry had lower strengths, reaching a maximum of 29.36 MPa after 28 days of curing. In addition, it was also noted that the blocks produced with recycled concrete showed an improvement in performance for a composition of 50% recycled material.

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In the cheese industry, whey, which is rich in lactose and proteins, is underutilized, causing adverse environmental impacts. The fractionation of its components, typically carried out through filtration membranes, faces operational challenges such as membrane fouling, significant protein loss during the process, and extended operating times. These challenges require attention and specific methods for optimization and to increase efficiency. A promising strategy to enhance industry efficiency and sustainability is the use of enzymatic pre-treatment with the enzyme transglutaminase (TGase). This enzyme plays a crucial role in protein modification, catalyzing covalent cross-links between lysine and glutamine residues, increasing the molecular weight of proteins, facilitating their retention on membranes, and contributing to the improvement of the quality of the final products. The aim of this study is to review the application of the enzyme TGase as a pretreatment in whey protein filtration. The scope involves assessing the enzyme's impact on whey protein properties and its relationship with process performance. It also aims to identify both the optimization of operational parameters and the enhancement of product characteristics. This study demonstrates that the application of TGase leads to improved performance in protein concentration, lactose permeation, and permeate flux rate during the filtration process. It also has the capacity to enhance protein solubility, viscosity, thermal stability, and protein gelation in whey. In this context, it is relevant for enhancing the characteristics of whey, thereby contributing to the production of higher quality final products in the food industry. © 2023 Society of Chemical Industry.

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The substitution of synthetic food dyes with natural colorants continues to be assiduously pursued. The current list of natural carotenoid colorants consists of plant-derived annatto (bixin and norbixin), paprika (capsanthin and capsorubin), saffron (crocin), tomato and gac fruit lycopene, marigold lutein, and red palm oil (α- and ß-carotene), along with microalgal Dunaliella ß-carotene and Haematococcus astaxanthin and fungal Blakeslea trispora ß-carotene and lycopene. Potential microalgal sources are being sought, especially in relation to lutein, for which commercial plant sources are lacking. Research efforts, manifested in numerous reviews and research papers published in the last decade, have been directed to green extraction, microencapsulation/nanoencapsulation, and valorization of processing by-products. Extraction is shifting from conventional extraction with organic solvents to supercritical CO2 extraction and different types of assisted extraction. Initially intended for the stabilization of the highly degradable carotenoids, additional benefits of encapsulation have been demonstrated, especially the improvement of carotenoid solubility and bioavailability. Instead of searching for new higher plant sources, enormous effort has been directed to the utilization of by-products of the fruit and vegetable processing industry, with the application of biorefinery and circular economy concepts. Amidst enormous research activities, however, the gap between research and industrial implementation remains wide.

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In the pursuit of sustainability, managing agro-industrial and food processing residues (AFR) efficiently is crucial. This study proposes a systematic approach to convert AFR into valuable products via solid-state fermentation (SSF). Using fungal enzyme production as a case study, this adaptable methodology suits any SSF bioprocess. Initially, AFR's physicochemical properties were evaluated to assess their feasible use as carbon sources and solid matrices for SSF. Then, five strains were screened for their capability to produce enzymes (Xylanase, X; pectinase, P; cellulase, C). Apple pomace (AP) and brewery spent grain (BSG) with Aspergillus sp. (strain G5) were selected. Subsequent steps involved a two-phase statistical approach, identifying critical factors and optimizing them. Process conditions were screened using a Plackett-Burman design, narrowing critical variables to three (BSG/AP, pH, humidity). Response Surface Methodology (Central Composite Design) further optimized these factors for co-synthesis of X, P, and C. The humidity had the most significant effect on the three responses. The optimum conditions depended on each enzyme and were further validated to maximize either X, P or C. The obtained extracts were used for pectin extraction from orange peels. The extract containing primarily xylanase (X = 582.39, P = 22.86, C = 26.10 U mL-1) showed major pectin yield recovery (12.33 ± 0.53%) and it was obtained using the optimal settings of BSG/AP (81/19), humidity (50.40%), and pH (4.58). The findings will enable adjusting process conditions to obtain enzymatic cocktails with a tailored composition for specific applications.

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The methanation of CO2 is of great interest in power-to-gas systems and contributes to the mitigation of climate change through carbon dioxide capture and the subsequent production of high-added-value products. This study investigated CO2 methanation with three Ni catalysts supported on Al2O3 and ZrO2, which were simulated using a mathematical model of a packed bed reactor designed based on their chemical kinetics reported in the literature. The simulated reactive system was fed with syngas obtained from residual coffee pulp obtained after a solvent phytochemical extraction process under several gasification conditions. The results reflect a high degree of influence of the catalyst support, preparation method, and syngas composition on CO2 and H2 conversions and CH4 selectivity. For all the syngas compositions, the Ni/ZrO2 catalysts showed the best values for CO2 conversion and H2 conversion for the Ni/Al2O3 catalyst except in gasification at 700 °C and using the Ni/ZrO2p catalyst.