Search Results (89)

Black chokeberry (Aronia melanocarpa L.) pomace (BCP), a major by-product of juice production, is an underutilized source of polyphenols and anthocyanins with strong antioxidant properties. This study aimed to optimize and compare three green extraction techniques—pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), and ultrasound-assisted extraction (UAE)—for recovering total polyphenols (TP) and total monomeric anthocyanins (TMA) from BCP, with reflux extraction as a benchmark. The effects of temperature, extraction time, and solid–solvent ratio were evaluated, and cryogrinding was assessed as a pre-treatment. PLE achieved the highest TP yields at elevated temperatures but reduced anthocyanin recovery, while MAE offered a balance of high TP and TMA, with strong antioxidant capacity. Cryogrinding enhanced TP extraction, with only 1 min of cryogrinding maximizing yield. UPLC-MS/MS analysis of optimized MAE extract confirmed cyanidin-3-glucoside and cyanidin-3-galactoside as dominant anthocyanins, alongside notable flavonols and phenolic acids, validating the rich phenolic profile. Overall, MAE combined with 1 min of cryogrinding proved to be the most effective approach for preserving heat-sensitive compounds while achieving high yields. These findings demonstrate that optimized green extraction can efficiently valorize BCP, supporting sustainable food processing and waste reduction in line with circular economy principles. Full article

Pine nut oil (PNO) is highly valued by consumers for its rich content of unsaturated fatty acids, which confer unique nutritional benefits. However, PNO is highly susceptible to lipid oxidation during storage and extraction. This chemical degradation compromises product quality and poses potential risks to food safety. To address this challenge, the food industry is developing antioxidant strategies, including optimizing pretreatment conditions to improve flavor and storage stability. Green extraction technologies such as microwave-assisted extraction (MAE) and ultrasonic-assisted extraction (UAE) have been introduced to enhance extraction efficiency and promote environmental sustainability. Light-proof packaging, reduced oxygen environments, and temperature control have also been employed to significantly extend the shelf life of PNO. Furthermore, to maintain the nutritional integrity and safety of PNO while expanding its functional applications in the food industry, several innovative approaches have been employed. These include the incorporation of natural antioxidants, the development of Pickering emulsions, the use of microencapsulation, and the formulation of oleogels. Full article

Rising industrial demands emphasize the need for exploring other non-traditional sources for obtaining pectin. As efforts to enhance circular economy practices and reduce reliance on primary resources intensify; the focus has shifted towards utilizing various types of agricultural and food industry waste; including tomato pomace waste (TPW). In this work; the microwave-assisted extraction (MAE) and TPW pretreatment methods were optimized to improve pectin yields and decrease the environmental impact of the extraction process; compared to conventional solvent extraction (CSE). The response surface methodology was used to model the optimization process. The physico-chemical properties of pectin were determined using titrimetric methods and FTIR spectroscopy. A life cycle assessment (LCA) was applied to assess the environmental impact of MAE and CSE. Optimal microwave conditions (11.66 min/600 W/pH 1) yielded two times more pectin than CSE (2 h/85 °C/pH 1.5). Pre-processing treatments (mechanical ball milling and defatting) showed marginal effects on pectin yields and properties; and; therefore; can be omitted in order to reduce the energy consumption of the process. The LCA showed that single conventional extraction treatment had two times higher values of the ecological footprint compared to MAE; for all indicators. The results suggest that MAE can be used as an efficient green method for pectin extraction from TPW Full article

The revalorization of artichoke (Cynara scolymus L.) by-products is a promising strategy to obtain bioactive compounds with antioxidant properties, supporting a circular economy approach. This study compares the efficiency of an enzymatic pretreatment followed by microwave-assisted extraction (EMAE), ultrasound-assisted extraction (EUAE), and ultrasound-microwave-assisted extraction (EUMAE) at a pilot scale for recovering antioxidant compounds. Extracts were purified using Diaion^® HP20 resin to obtain phenolic-rich fractions with enhanced antioxidant activity. The results showed that EUAE was the most effective technique, achieving a total phenolic content (TPC) of 210.76 ± 1.40 µmol GAE/g d.w. with an extraction yield of 21.38%. HPLC-MS analysis identified 14 major phenolic compounds, including chlorogenic acid isomers (60.73 mg/g d.e.), caffeic acid (34.29 mg/g d.e.), and luteolin rutinoside (103.27 mg/g d.e.), among others, which contribute to the extracts’ high bioactivity. The antioxidant potential of the extracts was assessed using Folin–Ciocalteu (F-C), ABTS, DPPH, and FRAP assays. EUAE extracts exhibited the highest antioxidant activity values, with F-C: 985.33 ± 4.46 µmol GAE/g d.e., ABTS: 80.46 ± 2.39 µmol TE/g d.e., DPPH: 87.03 ± 1.11 µmol TE/g d.e., and FRAP: 184.99 ± 2.52 µmol TE/g d.e. The purification process using Diaion^® HP20 resin further enhanced TPC and antioxidant activity, with the enzyme–ultrasound-assisted extraction—purified extract (EUAE-PE) reaching a phenolic purity of 50.71% and an F-C value of 2981.35 ± 12.16 µmol GAE/g d.e. Full article

The aim of this study is to establish a rapid and convenient microwave-assisted digestion method for sample pretreatment to evaluate amino acids in Chebulae fructus (CF). The microwave digestion method was optimized to extract amino acids from CF, and the differences in amino acids in CF from different origins and different processing states were analyzed and evaluated. The influences of digestion temperature, digestion time, and liquid–material ratio on extraction effect were investigated by sing factor test and response surface method (RSM), and the extraction conditions were optimized. The contents of 17 amino acids were determined by an automatic amino acid analyzer. The optimal digestion conditions were a digestion temperature of 150 °C, a digestion time of 18 min, and a liquid–material ratio of 65:1 (mL:g). Under these conditions, the total amino acid content of CF could reach 19.72 mg/g. CF from Lincang city of Yunnan province and unprocessed CF were considered to have higher nutritional value. The results of chemometric analysis showed that there were significant differences in the amino acid content in CF between Guangxi province, Dehong prefecture of Yunnan province, and Lincang city of Yunnan province, and six differential amino acids between the three origins were screened out. This study can provide references for the quality evaluation of the producing area, the extraction, and content research of amino acids of CF. Full article

This article provides an overview of various microwave-assisted techniques, such as microwave-assisted extraction (MAE), microwave-assisted organic synthesis (MAOS), microwave-assisted pyrolysis (MAP), microwave-assisted hydrothermal treatment (MAHT), microwave-assisted acid hydrolysis (MAAH), microwave-assisted organosolv (MAO), microwave-assisted alkaline hydrolysis (MAA), microwave-assisted enzymatic hydrolysis (MAEH), and microwave-assisted fermentation (MAF). Microwave-assisted biomass pretreatment has emerged as a promising method to improve the efficiency of biomass conversion processes, in particular microwave-assisted pyrolysis (MAP). The focus is on microwave-assisted pyrolysis, detailing its key components, including microwave sources, applicators, feedstock characteristics, absorbers, collection systems, and reactor designs. Based on different studies reported in the literature and a mathematical model, a mechanical design of a microwave oven adapted for pyrolysis is proposed together with a computer-aided design and a finite element analysis. The semi-continuous system is designed for a 40 L capacity and a power of 800 W. The material with which the vessel was designed is suitable for the proposed process. The challenges, opportunities, and future directions of microwave-assisted technologies for the sustainable use of biomass resources are presented. Full article

In the present work, brewer’s spent grain, BSG, the main by-product of beer production, was applied for the recovery of total polyphenols (TPs). Whole and ground BSG (wBSG and gBSG), derived from a Pilsen beer, was subjected to a solvent extraction using ethanol/water (50:50 v/v), and then, to improve TP recovery, microwave, ultrasound bath or probe pre-treatments were applied. The highest total phenolic content (TPC) (5.8 mg GAE/g_DW) was obtained with gBSG pre-treated with the ultrasound (US) probe for 15 min at 250 W. Solid-state fermentation (SSF) with Phanerochaete chrysosporium, in microcosms was investigated to improve the release of TPs. Microcosms were monitored by means of CO₂ production, the total proteins, and laccase activity. Fungal growth on gBSG, after only 10 days of fermentation, resulted in a 30% increase in the TPC compared to the unfermented substrate. Applying US probe-assisted extraction to fermented, ground BSG resulted in a 51% improvement compared to the untreated sample. Full article

The ultrasound-assisted extraction process with microwave pretreatment was modeled and optimized to maximize the yield of antioxidants from green walnut husks using a response surface methodology with Box–Behnken design. In this design, the ultrasound-assisted extraction time (10–40 min), ultrasound-assisted extraction temperature (40–60 °C), and microwave pretreatment time (20–60 s) were selected as the factors, while the total antioxidant content was defined as the response. The solvent of choice for extracting antioxidants was 50% (v/v) ethanol. After optimization using the desirability function, an ultrasound-assisted extraction time of 23 min, ultrasound-assisted extraction temperature of 60 °C, and microwave pretreatment time of 60 s were proposed as the optimal conditions and their validity was verified. Under these conditions, the experimentally determined total antioxidant content was 3.69 g of gallic acid equivalent per 100 g of dry matter. In addition to phenolics, UHPLC–ESI–MS/MS analysis indicated the presence of lipids, quinones, terpenoids, and organic acids in the extract. After the antioxidant extraction, the solid residue was further processed to isolate cellulose in line with the concept of sustainable manufacturing. The structural characterization and hydration properties of cellulose were analyzed to identify its key features and assess its potential for value-added applications. The results demonstrate that green walnut husks are a valuable and cost-effective agro-industrial byproduct for extracting antioxidants and isolating cellulose. This aligns with the principles of a circular economy and the sustainable production of natural compounds. Full article

Eugenol is the key bioactive compound in clove oil, which has a variety of biological functions and is extensively employed in the medicinal and food industries. Nowadays, deep eutectic solvents (DESs) have received considerable attention as green solvents that enhance extraction efficiency. The present study investigated the effects of DESs on the eugenol composition in clove essential oils (CEOs) extracted from clove buds using ultrasonic- and microwave-assisted hydrodistillation techniques. The study revealed that both DES-based microwave-assisted hydrodistillation (DES-MHD) and ultrasonic-assisted DES pretreatment followed by microwave-assisted hydrodistillation (U-DES-MHD) significantly enhanced the eugenol purity in CEOs compared to the MHD method without the use of DESs. The great CEOs with a high amount of eugenol obtained via choline chloride–oxalic acid (ChCl-OA) at a 1:2 molar ratio were used as DESs. Their oils had a eugenol content of 82.90% and 83.34%, respectively, corresponding to the extraction by DES-MHD and U-DES-MHD methods, which were raised from the oil’s extraction without DES by MHD 7.42% and 8.36%, respectively. Corresponding to a strong antioxidant agent of eugenol, the oils extracted by ChCl-OA-based MHD and ultrasonic-assisted ChCl-OA-based MHD methods had significantly stronger DPPH radical scavenging activity with an IC₅₀ level of 2.16 ± 0.11 and 2.19 ± 0.05 μg/mL, respectively, than the oils extracted without DESs. Hence, these innovative processes offer a promising approach to improving the bioactivity of clove oils, while providing straightforward operation and environmentally friendly extraction methods. Additionally, these novel processes may find application in other edible essential oil extractions for the food and pharmaceutical industries. Full article

Lavender is one of the most appreciated aromatic plants, with high economic value in food, cosmetics, perfumery, and pharmaceutical industries. Lavender essential oil (LEO) is known to have demonstrative antimicrobial, antioxidant, therapeutic, flavor and fragrance properties. Conventional extraction methods, e.g., steam distillation (SD) and hydro-distillation (HD), have been traditionally employed to extract LEO. However, the low yield, high energy consumption, and long extraction time of conventional methods have prompted the introduction of novel extraction technologies. Some of these innovative approaches, such as ohmic-assisted, microwave-assisted, supercritical fluid, and subcritical water extraction approaches, are used as substitutes to conventional extraction methods. While other methods, e.g., sonication, pulsed electric field, and cold plasma, can be used as a pre-treatment that is preceded by conventional or emerging extraction technologies. These innovative approaches have a great significance in reducing the energy consumption, shortening the extraction time, and increasing the extraction yield and the quality of EOs. Therefore, they can be considered as sustainable extraction technologies. However, the scale-up of emerging technologies to an industrial level should also be investigated from the techno-economic points of view in future studies. Full article

Microalgae have been described as a potential alternative source of a wide range of bioactive compounds, including polar lipids and carotenoids. Specifically, Nannochloropsis gaditana is described as producing large amounts of polar lipids, such as glycolipids and phospholipids. These natural active compounds serve as key ingredients for food, cosmetic, or nutraceutical applications. However, microalgae usually possess a rigid cell wall that complicates the extraction of these compounds. Thus, an ultrasound-assisted enzymatic pretreatment is necessary to efficiently extract bioactives from microalgae, and it was studied in this article. Pretreated biomass was extracted using different advanced and green methodologies and compared to traditional extraction. Furthermore, the analysis, characterization, and identification of valuable compounds using GC-MS and LC-MS analytical methods were also investigated. Interestingly, major results demonstrated the efficiency of the pretreatment, enriching polar lipids’ distribution in all extracts produced no matter the extraction technique, although they presented differences in their concentration. Pressurized liquid extraction and microwave-assisted extraction were found to be the techniques with the highest yields, whereas ultrasound-assisted extraction achieved the highest percentage of glycolipids. In summary, green extraction techniques showed their effectiveness compared to traditional extraction. Full article

For the first time, rutin-rich extracts from black elderberry waste (BEW) were encapsulated using the particles from gas-saturated solutions (PGSS) method to improve the preservation of rutin. The extracts used in this study were obtained using five different extraction techniques under optimal conditions, as follows: conventional solid–liquid extraction (SLE) and four non-conventional techniques—ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), enhanced solvent extraction (ESE), and supercritical CO₂ pretreatment—followed by ESE (SFE-CO₂ + ESE). The PGSS process of the obtained extracts was performed using two amphiphilic carriers, glycerol monostearate (GlyMS) and gelucire (Gel), in a mass ratio of 1:6, in favor of the carrier. The efficiency of the PGSS process was evaluated based on the encapsulation yield (EnY), encapsulation efficiency (EE), and physical properties of the encapsulated extracts. The results showed that the SLE extract encapsulated with GlyMS had the highest EnY (92.47%). The Gel only in combination with the ESE extract exceeded the 50% efficacy threshold, with an EnY of 55.18%. The encapsulated SLE extract with Gel showed excellent flow properties and the highest EE (98.91%). These results emphasize the advantages of the PGSS process, including its efficiency and adaptability to produce encapsulated rutin-enriched BEW extracts for pharmaceutical, nutraceutical, and cosmetic applications. Full article

Research studies for cellulose recovery from lignocellulosic materials are essential in order to propose sustainable alternatives to harness residual biomasses, solving problems caused by their abundance and inadequate use. In this study, olive-tree pruning biomass has been subjected to different pretreatments with different organosolvents (acetone, ethanol, and $\gamma$-valerolactone) with microwave radiation assistance. The effect of operating parameters has been studied, considering specific ranges of variables values according to each experimental design but, in any case, located in the ranges of 33–67% (chemical compound concentration), 130–170 °C (temperature), 5–30 min (reaction time), and 1/20–1/5 (solid/liquid ratio, s/L). Based on the R² and R²_adj values (mostly above 0.97), the experimental data were adequately adjusted to four selected response variables: post-solids cellulose and lignin content apart from removal percentages of both structural components. The optimization process resulted in post-treatment solids with meaningful cellulose yields (higher than 84.7%) and reduced lignin content (lower than 4.2%). The best results were obtained using 66.5% acetone (155 °C, 8.4 min and s/L = 1/19), involving greater material deconstruction, a high percentage of delignification (96.7%), not very significant cellulose loss (29.4%), and a post-treatment solid consisting almost exclusively of cellulose (≈99%). Full article

Growing awareness of resource sustainability and waste management has driven the search for circular-economy solutions. Lignocellulosic biomass waste, the most abundant renewable carbon resource, offers green potential as an alternative to declining non-renewable fuels. However, due to its recalcitrant nature, it requires pre-processing to convert it into valuable products like energy and chemicals. Biorefineries play a key role in this process by promoting the integral use of biomass, by finding ways to utilize lignin, previously treated as waste. Common pretreatment methods are unsustainable, prompting research into eco-friendly solvents and advanced techniques like ultrasound- and microwave-assisted methods. Recent approaches have also explored the use of eutectic solvents, which, when combined with these intensification techniques, offer promising results. These green technologies improve delignification efficiency, which in turn improves the saccharification process, reduces solvent use, and minimizes environmental impact. Despite progress, challenges remain in making these methods economically viable and adaptable to diverse biomass types. This review article highlights recent advances in sustainable treatment technologies, including the combined use of eutectic solvents and process-intensification techniques, and the potential of the obtained lignin in various industrial applications. It also discusses future prospects for more environmentally friendly processes in biomass utilization. Full article

This study investigates the potential of converting waste biosolids from industrial sources, focusing on economic viability and heavy metal removal efficiency. Traditional management methods like landfilling and incineration are increasingly impractical due to land constraints and environmental concerns, prompting a shift towards thermal and biological conversion technologies including anaerobic digestion, pyrolysis, gasification, and hydrothermal liquefaction. Incorporating a pretreatment for heavy metal removal is essential, as industrial wastes are highly subjected to metal contamination. The study screens a range of metal removal processes, including precipitation, adsorption, ion exchange, and microwave induction. Although a techno-economic analysis can help give a perspective on the economic viability and environmental impact of each technology, it does not account for technical limitations and variations in the treated waste stream. A mixed integer linear programming (MILP) optimization model is developed to fill in this gap and assist in waste stream allocation to the most appropriate technology, taking into account both technology capacities and feed characteristics. This study looked into the optimal treatment route at different feed moisture contents and varying flow rates. The results demonstrate that the model distributes the feed across the different technologies on the basis of maximizing the capacity of the optimal technology while ensuring the moisture and heavy metal content limits are satisfied. Thus, it maximizes profitability and ensures heavy metal removal efficiency. By optimizing industrial biosolids treatment pathways, this study promotes sustainable resource recovery aligning with circular economy principles in waste management. The developed model facilitates informed decision-making in biosolids management and industrial waste treatment practices. Full article