Search Results (62)

Prunus avium L. and Prunus spinosa L. are valuable fruit-bearing trees known for their bioactive compounds and medicinal properties. However, limited research exists regarding their kernel oils. This study aimed to compare the chemical composition, quality parameters, and bioactive potential of the kernel oils extracted from Prunus avium L. and Prunus spinosa L. The kernel oils’ fatty acid and tocopherol profiles were characterized, and the presence of bioactive compounds were identified and quantified. Total polyphenol content (TPC) and antioxidant activity (AAC) were also measured, indicating the presence of bioactive compounds in both oils. Additionally, the main quality parameters, including oxidative status, were evaluated. The fatty acid analysis revealed a higher proportion of polyunsaturated fatty acids compared to monounsaturated fatty acids in both kernel oil samples. Linoleic acid (57–64%) and oleic acid (18–29%) were the major fatty acids in both Prunus avium L. and Prunus spinosa L. kernel oils. α-Eleostearic acid (11.87%) was quantified only in Prunus avium kernel oil. Furthermore, the α-, β-, γ-, and δ-tocopherol content were determined, and it was found that both kernel oils contained γ-tocopherol as the major tocopherol (~204–237 mg/Kg). TPC in Prunus avium L. kernel oil was measured at 9.5 mg gallic acid equivalents (GAE)/Kg and recorded as ~316% higher TPC than Prunus spinosa L. kernel oil. However, the recorded AAC were 11.87 and 14.22 μmol Trolox equivalent (TE)/Kg oil, respectively. Both oils recorded low peroxide values (~1.50 mmol H₂O₂/Kg), and low TBARS value (~0.4 mmol malondialdehyde equivalents, MDAE/Kg oil), but high p-anisidine value (23–32). The results indicated that both Prunus avium L. and Prunus spinosa L. kernel oils exhibited unique chemical compositions. Full article

In a circular economy, significant emphasis is given to the energetic valorization of agricultural byproducts. Cotton stalks are suitable as a feedstock for the production of bioenergy due to their high energy content. This study’s main focal areas are the economic viability and environmental implications of a system that can gasify or pyrolyze 25,500 tons of cotton stalk annually. To learn more about how gasification and pyrolysis affect the environment, a life cycle assessment (LCA) was conducted. This analysis evaluates the whole value chain and covers all stages of the cotton supply chain from cradle to gate, including production, harvest, transportation, and utilization. According to the findings, both systems exhibit economic viability, generating sizable profits and having quick payback times. However, despite its larger initial expenditure of EUR 2.74 million, the pyrolysis unit ends up being the better option because it has a payback period of 1.58 years, a return on investment (ROI) of 58% and a net present value (NPV) of EUR 21.5 million. Gasification is still an economically attractive alternative with a lower initial investment (EUR 1.81 million), despite having a lower ROI (36%) and NPV (EUR 10.52 million), as well as a longer payback period (2.41 years). However, the environmental implications of the gasification option are generally higher than those of pyrolysis. The impacts of gasification on fossil depletion (FDP) were estimated to be 5.7 million kg oil eq., compared to 5.3 million kg oil eq. for pyrolysis. Similarly, gasification resulted in 41.55 million kg U235 eq. and pyrolysis in 41.5 million kg U235 eq. related to impacts on ionizing radiation (IRP_HE). Other impact categories that emerge as the most important are freshwater eutrophication (FEP) and marine eutrophication (MEP). Full article

Large quantities of wine lees are produced annually by the wine industry. The high phenolic content makes them unsuitable for disposal in the environment or animal feed without a suitable treatment. In this study, wine lees were treated by Pleurotus ostreatus in submerged cultivation, producing a high-value biomass and elevated levels of laccase, an important industrial enzyme. Biomass and laccase production reached 21 g/L and 74,000 Units/L, respectively, at the optimal conditions of initial pH 6.0, 20% v/v wine lees, 30 g/L glucose, and 20 g/L yeast extract, while decolorization and dephenolization rates of the waste were over 90%. The mycelial biomass was rich in proteins and essential amino acids reaching up to 43% and 16% per dry weight, respectively. Carbohydrates and lipids were the second richest bioactive compound in biomass, with values of 29.4 ± 2.7% and 29.5 ± 2.7%, respectively. The crude laccase in the culture supernatant was purified via a simple two-step purification procedure by 4.4-fold with a recovery of 44%. The molecular weight of the enzyme was determined to be 62 kDa via SDS electrophoresis. Enzyme activity was optimal at pH 5.0 and 70 °C. The activation energy of the enzyme was calculated at a value of 20.0 ± 0.2 kJ/mol. The pH stability and thermostability of the purified laccase were studied. The enzyme was remarkably stable at pH 8.0 and at temperatures up to 40 °C. The thermal inactivation energy of the enzyme was determined to be 76.0 ± 1.2 kJ/mol. The thermodynamic parameters (ΔH*, ΔG*, and ΔS*) for the thermal deactivation of the purified laccase at a temperature range of 20–60 °C were: 73.8 ≤ ΔH* ≤ 74.3 kJ·mol⁻¹, 98.7 ≤ ΔG* ≤ 101.9 kJ·mol⁻¹, and −90.5 ≤ ΔS* ≤ −84.3 J·mol⁻¹·K⁻¹. Wine lees could be ideal substrates of fungal cultivation for laccase production and biomass with a high protein content in an eco-friendlier way. Full article

The persimmon fruit (Diospyros kaki Thunb.) is renowned for its exceptional health benefits, which can be attributed to its abundance of bioactive compounds. This study aimed to optimize the extraction of bioactive compounds from persimmon peel, an underexplored waste biomass, within the frame of sustainability and a circular economy. For this reason, a comprehensive multi-factor extraction approach was employed. Specifically, diverse methods including a pulsed electric field and ultrasonication combined with simple stirring were explored. Through this systematic approach, the most efficient extraction process was determined, resulting in elevated yields of bioactive compounds, including polyphenols, ascorbic acid, and total carotenoids. Among the identified phenolic compounds, rutin emerged as the most abundant, with concentrations reaching up to 172.86 μg/g. Utilizing partial least squares analysis, the maximum predicted values for the bioactive compounds were determined, with total polyphenols reaching 7.17 mg GAE/g, ascorbic acid at 4.93 mg/g, and total carotenoids at 386.47 μg CtE/g. The antioxidant activity of the extracts was evaluated with the ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, and H₂O₂ scavenging assays. The recorded antioxidant performance underscored the substantial potential of persimmon peels as a source of cost-effective extracts with high antioxidant activity. This study not only contributes to optimizing the bioactive compounds’ extraction from persimmon peel but also highlights the process’s viability by producing valuable extracts with antioxidant properties at low cost. Full article

Expanding markets for renewable energy feedstocks have increased demand for woody biomass. Concerns associated with forest biomass harvesting include increased erosion, the applicability of conventional forestry Best Management Practices (BMPs) for protecting water quality, and reduced woody debris retention for soil nutrients and cover. We regionally compared the data and results from three prior independent studies that estimated erosion, BMP implementation, and residual woody debris following biomass and conventional forest harvests in the Mountains, Piedmont, and Coastal Plain of Virginia. Estimated erosion was higher in the Mountains due to steep slopes and operational challenges. Mountain skid trails were particularly concerning, comprising only 8.47% of the total area but from 37.9 to 81.1% of the total site-wide estimated erosion. BMP implementation varied by region and harvest type, with biomass sites having better implementation than conventional sites, and conventional Mountain sites having lower implementation than other regions. Sufficient woody debris remained for BMPs on both harvest types in all regions, with conventional Mountain sites retaining twice that of Coastal Plain sites. BMPs reduced the estimated erosion on both site types suggesting increased implementation could reduce potential erosion in problematic areas. Therefore, proper BMP implementation should be ensured, particularly in Mountainous terrain, regardless of harvest type. Full article

The food processing industry is a continuously developing sector that uses innovative technologies to efficiently process food products. During processing, food industries generate substantial amounts of by-products in the form of waste materials. This food waste consists of organic matter rich in bioactive compounds, such as polyphenols, carotenoids, and flavonoids. Improper management of food waste can adversely affect both the environment and human health, leading to environmental pollution and the release of greenhouse gas emissions. Thus, proper food waste management has become an urgent global issue. The presence of bioactive compounds (mainly polyphenols, flavonoids, and anthocyanins, but also carotenoids, alkaloids, proteins, lipids, and carbohydrates) in food waste holds the potential to transform them into valuable resources. Several sectors, including food and energy, have recognized food waste as an innovative source. Recently, much emphasis has been placed on optimizing the extraction yield of such bioactive compounds through the utilization of environmentally friendly and sustainable methodologies and solvents. Pulsed electric field (PEF)-assisted extraction is an emerging technique that holds promise for the utilization of waste materials. PEF technology can efficiently optimize the extraction of valuable compounds within a shorter time while minimizing solvent and energy consumption. In this review, we provide a comprehensive overview of the current state of PEF technology and its implications for recovering bioactive compounds from food waste. The integration of innovative technologies like PEF in the food processing industry can play a crucial role in managing food waste sustainably, reducing environmental impact, and harnessing the full potential of bioactive compounds contained in these waste materials. The objective of this critical review is to provide an overview of the utilization of PEF pretreatment for food by-products and to conduct a comparative analysis with other extraction techniques. Full article

A methodology was developed to assess the allocation of different types of endogenous waste biomass to eight technologies for producing electricity, heat, biogas and advanced biofuels. It was based on the identification of key physicochemical parameters for each conversion process and the definition of limit values for each parameter, applied to two different matrices of waste biomass. This enabled the creation of one Admissibility Grid with target values per type of waste biomass and conversion technology, applicable to a decision process in the routing to energy production. The construction of the grid was based on the evaluation of 24 types of waste biomass, corresponding to 48 sets of samples tested, for which a detailed physicochemical characterization and an admissibility assessment were made. The samples were collected from Municipal Solid Waste treatment facilities, sewage sludges, agro-industrial companies, poultry farms, and pulp and paper industries. The conversion technologies and energy products considered were (trans)esterification to fatty acid methyl esters, anaerobic digestion to methane, fermentation to bioethanol, dark fermentation to biohydrogen, combustion to electricity and heat, gasification to syngas, and pyrolysis and hydrothermal liquefaction to bio-oils. The validation of the Admissibility Grid was based on the determination of conversion rates and product yields over 23 case studies that were selected according to the best combinations of waste biomass type versus technological solution and energy product. Full article

Sustainable and renewable sources of liquid and solid fuels are essential to prevent fossil fuel use from damaging the environment. Secondary agricultural residues, which are already transported to food processing centers, have great potential to be converted into biofuels. The wastes from coffee roasting, sugar production, and rice milling have been investigated using hydrothermal carbonization (HTC) to produce aqueous products containing monosaccharides alongside solid biofuels. These sugar-laden liquid products were characterized after pretreating coffee silverskins, sugarcane bagasse, and rice husks with HTC. They were then concentrated using direct contact membrane distillation (DCMD), a low-energy process that can use waste heat from other biorefinery processes. The higher heating value of the solid products was also characterized by bomb calorimetry. The liquid products from HTC of these wastes from food production were found to contain varying concentrations of glucose, xylose, galactose, and arabinose. DCMD was capable of concentrating the liquid products up to three times their original concentrations. Little difference was found among the higher heating values of the solid products after 180 °C HTC pretreatment compared to 200 °C pretreatment. HTC of waste from food processing can provide solid biofuels and liquid products containing sugars that can be concentrated using DCMD. Full article

In recent years, the production of food biomass waste has been increasing rapidly. This necessitates urgent measures to be taken so as to utilize them. Since most food biomass waste contains useful bioactive substances, cloud-point extraction (CPE) has emerged as a promising solution to valorize waste. CPE is an extraction method employed for the extraction and preconcentration of various chemical compounds, including polyphenols and flavonoids. As with any other extraction procedure, CPE isolates the target compound(s) from the sample, resulting in increased recovery. One major advantage of CPE is that the extraction is carried out without special equipment or harmful reagents. Moreover, other significant advantages are its effectiveness, simplicity, safety, and rapidity. This review focuses on the extraction of bioactive compounds from food-based waste using CPE and highlights the important parameters that can be tuned to improve the performance of CPE. Furthermore, the potential in promoting environmentally friendly practices within the food industry is also discussed. Full article

This study aimed to assess the feasibility of employing cloud point extraction (CPE) as an efficient way of extracting polyphenols from peach waste (PW). Four distinct food-grade surfactants (Genapol X-080, PEG 8000, Tween 80, and lecithin) were evaluated at concentrations ranging from 2–10% w/v to determine the efficiency of the technique in two separate PW streams [i.e., lye peeling waste stream (LPWS) and total wastewater stream (TWS)]. Low amounts (2% w/v) of surfactants in a single-step CPE were found to result in less than ~61% polyphenol recovery in LPWS and less than ~69% polyphenol recovery in the TWS, necessitating additional extraction steps. In both PW streams, the single-step polyphenol recovery was improved by 25–67% utilizing a higher amount of surfactants (5–10% w/w), leading to a statistically significant figure (p < 0.05). The CPE procedure was conducted under optimal conditions, including a temperature of 65 °C, a sodium chloride concentration of 3% w/v, a pH level of 3.5, and a surfactant concentration of 5% w/v. The polyphenol recovery was efficient when the CPE procedure was conducted twice. Tween 80 proved to be the most efficient surfactant among the four tested surfactants, achieving recoveries above 98% in both PW streams. Under optimum extraction conditions, the total polyphenol content and antiradical activity of PW extracts were evaluated. The results showed statistically significant differences (p < 0.05) between the two PW streams, with the LPWS having approximately 12 times higher polyphenol content and being more potent, achieving ~64% antiradical activity. Using the LPWS instead of the TWS is a more cost-effective and feasible option for the industry. In addition, the considerable volume of the TWS makes it challenging to handle and demands a correspondingly major amount of surfactant. Considering that Tween 80 is a low-toxicity surfactant and that the CPE method is simple, fast, cost-effective, highly accurate, and selective, the extracted polyphenols from two PW streams could be exploited as natural antioxidants to be used directly in the food industry. These findings could have major implications for the manufacturing of sustainable and naturally-derived food additives. Full article

Catalytic pyrolysis is an attractive alternative for converting biomass into energy and chemicals, replacing fossil sources. Efficient catalysts can be used to remove compounds containing oxygen during pyrolysis, improving the bio-oil properties and thus being an important route towards sustainability. Catalytic pyrolysis of medium-density fiberboard (MDF) residues over platinum (1%) supported on beta zeolite was carried out using a biomass/catalyst ratio of 1.0/0.2. The catalysts were characterized via Fourier transform infrared spectroscopy, flame atomic absorption spectrometry, X-ray diffraction, nuclear magnetic resonance, temperature-programmed reduction, and temperature-programmed desorption of ammonia. The thermokinetic and thermodynamic parameters were determined using the isoconversional and non-isothermal methods of Friedman, Flynn-Wall-Ozawa (FWO), and Kissinger-Ahakira-Sunose (KAS). The Friedman method was the most adequate to describe the reaction and thermodynamic parameters. The results show that the catalysts promote the reduction in activation energy compared to non-catalytic pyrolysis. Non-impregnated and impregnated catalysts showed different activation energies and thus different reactions. The addition of platinum slightly increased the activation energy due to the promotion of reactions that require more energy, for example, cracking and coke deposition. Full article

AlCl₃·6H₂O was used as a catalyst in the esterification reaction of levulinic acid with 1-hexanol for producing hexyl levulinate, a compound that finds applications in several industrial sectors and represents an excellent candidate to be used in diesel fuel blends. A kinetic and thermodynamic study of the esterification reaction was performed, considering four different temperatures (338, 348, 358, and 368 K), an acid: alcohol: catalyst 1:1:0.01 molar ratio, and a reaction time of 72 h. An optimization study was then carried out, evaluating the effect of alcohol and catalyst amounts, and, in the best reaction conditions (acid:alcohol:catalyst 1:2:0.1), a very high levulinic acid conversion (92.5%) was achieved. By using AlCl₃·6H₂O, alongside the high reaction yield, the product purification was also simplified, being such a catalyst able to trap most of the water in a different phase than hexyl levulinate, and, furthermore, it was found to be completely recoverable and reusable for several reaction cycles, without losing its catalytic effectiveness. The use of AlCl₃·6H₂O, therefore, represents a promising effective green route for obtaining hexyl levulinate. Full article

The influence of microaeration, pH, and substrate during dark fermentation of sour cabbage, gelatin, and wheat straw was investigated, and the results of dark fermentation of these three substrates and their mixtures are presented in this research. The fermentation of cabbage, gelatin, and wheat straw was investigated under varying pH and aeration conditions. We investigated concentrations of volatile suspended solids (VSS) of 20 g VSS/L of a substrate at a stable pH of 6.0 and a not aligned pH value. Sour cabbage resulted in the highest volume of hydrogen for 450 mL/g VSS with a pH of 6.0. The mixing of substrates caused lower hydrogen production than sour cabbage or wheat straw alone. Full article

This study evaluated the feasibility of producing solid recovered fuel (SRF) from rejected waste from waste picker cooperatives (WPC). Three scenarios using different SRF and petroleum coke proportions in cement kilns were assessed. The samples of rejected waste from WPC were obtained in the city of Florianópolis, Brazil, and their physical and chemical characteristics were determined. Furthermore, the avoided atmospheric emissions by replacing conventional cement fuel with SRF and the costs to implement a SRF facility were estimated. According to the results, 60.29% of the waste from WPC could be used for energy recovery. Out of the materials eligible to produce SRF, 75.26% are made up of plastic packaging and paper. Concerning atmospheric emissions, replacing petroleum coke with SRF for direct feeding into the clinker kiln contributed to a reduction of 4.83%, 14.73%, and 13.37% in the atmospheric emissions for Scenario 1, Scenario 2, and Scenario 3, respectively. Furthermore, considering two hypothetical SRF industrial plants with capacities of 522 and 720 t/day, each ton of SRF produced would cost about USD 6.00, representing a decrease of 35 times in the costs when compared to petroleum coke. Therefore, SRF from the rejected fraction of WPC could be an alternative waste-to-energy approach. Full article