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Keywords = ultrasonic-thermal assisted extraction

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22 pages, 4525 KiB  
Article
Comparison of Ultrasound-Microwave-Assisted and Hot Reflux Extractions of Polysaccharides from Alpinia officinarum Hance: Optimization, Characterization, and Antioxidant Activity
by Haibao Tang, Baogang Zhou, Mengge Sun, Yihan Wang, Ran Cheng, Tao Tan and Dongsheng Yang
Molecules 2025, 30(14), 3031; https://doi.org/10.3390/molecules30143031 - 19 Jul 2025
Viewed by 337
Abstract
Alpinia officinarum Hance exhibits various bioactivities, with polysaccharides being one of its key bioactive components. However, the relationship between the structural characteristics of these polysaccharides and their bioactivities remains unclear and underexplored. In this study, to optimize the extraction process, a Response Surface [...] Read more.
Alpinia officinarum Hance exhibits various bioactivities, with polysaccharides being one of its key bioactive components. However, the relationship between the structural characteristics of these polysaccharides and their bioactivities remains unclear and underexplored. In this study, to optimize the extraction process, a Response Surface Methodology-based design combined with single-factor experiments was applied to determine the optimal conditions for the ultrasonic-microwave-assisted extraction of polysaccharides from A. officinarum. The primary structural characteristics and antioxidant activities of two polysaccharide fractions, PAOR-1 extracted by ultrasonic-microwave-assisted extraction and PAOR-2 extracted by hot reflux extraction (HRE), were systematically compared. The optimal extraction conditions, including a liquid–solid ratio of 1:50, extraction time of 19 mins, and ultrasonic power of 410 W, yielded a maximum polysaccharide extraction rate of 18.28% ± 2.23%. The extracted polysaccharides were characterized as acidic polysaccharides with a three-dimensional structure. PAOR-1 and PAOR-2 have different monosaccharide compositions, surface morphologies, and thermal stabilities. The antioxidant activity in vitro studies suggest that PAOR-1 may have higher antioxidant activity than PAOR-2 due to its higher content of uronic acids, lower relative molecular mass, and a more closely packed spatial configuration. These findings provide a theoretical basis for the development and utilization of AOR. Full article
(This article belongs to the Collection Advances in Food Chemistry)
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14 pages, 2084 KiB  
Article
Optimized High-Pressure Ultrasonic-Microwave-Assisted Extraction of Gingerol from Ginger: Process Design and Performance Evaluation
by Yang Zhang, Siyi Yang, Wensi Li, Xiaoyan Li, Xiangqin Lai, Xiang Li, Wuwan Xiong and Bo Zhang
Processes 2025, 13(7), 2149; https://doi.org/10.3390/pr13072149 - 6 Jul 2025
Viewed by 425
Abstract
This study employed high-pressure ultrasonic-microwave-assisted extraction (HP-UMAE) to extract gingerols from ginger. The extraction yield and total polyphenol content of the extracts were determined. Their antioxidant activity was assessed by DPPH and ABTS radical scavenging assays, and compared with extracts obtained by leaching [...] Read more.
This study employed high-pressure ultrasonic-microwave-assisted extraction (HP-UMAE) to extract gingerols from ginger. The extraction yield and total polyphenol content of the extracts were determined. Their antioxidant activity was assessed by DPPH and ABTS radical scavenging assays, and compared with extracts obtained by leaching extraction, reflux extraction, ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE), and ultrasonic-microwave-assisted extraction (UMAE). The results demonstrated that HP-UMAE achieved the highest extraction yield and the strongest ABTS radical scavenging activity among the evaluated methods. Furthermore, HP-UMAE extracts exhibited the highest concentrations of key gingerol constituents: 6-gingerol (14.29 mg/L), 8-gingerol (0.38 mg/L), 10-gingerol (1.95 mg/L), and 6-shogaol (4.32 mg/L). This enhanced efficacy is attributed to the synergistic combination of ultrasonic cavitation and microwave-induced thermal effects under elevated pressure. This synergy creates conditions promoting cellular wall disruption, facilitating the release of intracellular components, while concurrently enhancing solvent penetration and gingerol solubility. Scanning electron microscopy (SEM) analysis confirmed the significant structural damage inflicted on ginger cell walls following HP-UMAE treatment. The process parameters for HP-UMAE were optimized using single-factor experiments. The optimal extraction conditions were determined as follows: microwave power 800 W, ultrasonic power 1000 W, liquid-to-solid ratio 55:1, and temperature 100 °C (corresponding pressure 2 MPa). Under these optimized parameters, the extraction yield and ABTS radical scavenging rate reached their peak performance, yielding values of 4.52% and 43.23%, respectively. Full article
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23 pages, 23181 KiB  
Article
Ultrasound-Assisted Ferritin Extraction from Northern Pike Liver: An Innovative Approach for Chlorogenic Acid Encapsulation with Enhanced Thermal Stability
by Zhikun Xing, Yi Wang, Yabo Wei, Xin Guo, Xiaoyue Liang, Xiaorong Deng, Lianfu Zhang and Jian Zhang
Molecules 2025, 30(9), 2080; https://doi.org/10.3390/molecules30092080 - 7 May 2025
Cited by 1 | Viewed by 534
Abstract
Ferritin, an emerging protein resource, has garnered significant attention in scientific research due to its biocompatibility and unique cavity structure capable of encapsulating bioactive compounds. This study aimed to optimize ultrasound-assisted extraction (UAE) for enhancing ferritin yield from northern pike liver byproducts and [...] Read more.
Ferritin, an emerging protein resource, has garnered significant attention in scientific research due to its biocompatibility and unique cavity structure capable of encapsulating bioactive compounds. This study aimed to optimize ultrasound-assisted extraction (UAE) for enhancing ferritin yield from northern pike liver byproducts and evaluate its potential as a nanocarrier for chlorogenic acid (CA). Through response surface methodology (RSM), the optimal UAE parameters were established as 200 W ultrasonic power, 1:3 solid–liquid ratio, and 25 min extraction time. Under these conditions, the ferritin extraction yield reached 139.46 mg/kg, representing a 4.02-fold increase compared to conventional methods (34.65 mg/mL). Electrophoretic analysis confirmed the electrophoretic purity of the extracted liver ferritin. Comprehensive characterization using UV-vis spectroscopy, FTIR, and fluorescence spectroscopy revealed preserved structural integrity of UAE-extracted ferritin. Homology modeling provided molecular insights into the ferritin architecture. Successful encapsulation of CA was achieved with an encapsulation efficiency of 13.25%, as quantified by HPLC. Analysis by DLS and ζ potential as well as TG and DSC showed that not only the thermal stability of CA was enhanced after ferritin encapsulation, but also that the ferritin remained stable with a cage-like structure. This investigation establishes UAE as an effective strategy for valorizing fish processing byproducts through high-yield ferritin extraction while demonstrating the protein’s functional capacity as a nanocarrier for bioactive compound delivery. The findings highlight the dual advantage of sustainable resource utilization and advanced delivery system development through this biotechnological approach. Full article
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19 pages, 752 KiB  
Systematic Review
Enhancing Root Canal Disinfection with Er:YAG Laser: A Systematic Review
by Jakub Fiegler-Rudol, Zuzanna Grzech-Leśniak, Marcin Tkaczyk, Kinga Grzech-Leśniak, Anna Zawilska and Rafał Wiench
Dent. J. 2025, 13(3), 101; https://doi.org/10.3390/dj13030101 - 26 Feb 2025
Cited by 3 | Viewed by 1925
Abstract
Background: The quest for minimally invasive disinfection in endodontics has led to using Erbium:Yttrium-Aluminum-Garnet (Er:YAG) lasers. Conventional approaches may leave bacterial reservoirs in complex canal anatomies. Er:YAG’s strong water absorption generates photoacoustic streaming, improving smear layer removal with lower thermal risk than other [...] Read more.
Background: The quest for minimally invasive disinfection in endodontics has led to using Erbium:Yttrium-Aluminum-Garnet (Er:YAG) lasers. Conventional approaches may leave bacterial reservoirs in complex canal anatomies. Er:YAG’s strong water absorption generates photoacoustic streaming, improving smear layer removal with lower thermal risk than other laser systems. Methods: This systematic review followed PRISMA 2020 guidelines. Database searches (PubMed/MEDLINE, Embase, Scopus, Cochrane Library) identified studies (2015–2025) on Er:YAG laser-assisted root canal disinfection. Fifteen articles met the inclusion criteria: antibacterial efficacy, biofilm disruption, or smear layer removal. Data on laser settings, irrigants, and outcomes were extracted. The risk of bias was assessed using a ten-item checklist, based on guidelines from the Cochrane Handbook for Systematic Reviews of Interventions. Results: All studies found Er:YAG laser activation significantly improved root canal disinfection over conventional or ultrasonic methods. Photon-induced photoacoustic streaming (PIPS) and shock wave–enhanced emission photoacoustic streaming (SWEEPS) yielded superior bacterial reduction, especially apically, and enabled lower sodium hypochlorite concentrations without sacrificing efficacy. Some research indicated reduced post-operative discomfort. However, protocols, laser parameters, and outcome measures varied, limiting direct comparisons and emphasizing the need for more standardized, long-term clinical trials. Conclusions: Er:YAG laser-assisted irrigation appears highly effective in biofilm disruption and smear layer removal, supporting deeper irrigant penetration. While findings are promising, further standardized research is needed to solidify guidelines and confirm Er:YAG lasers’ long-term clinical benefits. Full article
(This article belongs to the Special Issue Laser Dentistry: The Current Status and Developments)
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30 pages, 6583 KiB  
Article
A Comprehensive Analysis of Non-Thermal Ultrasonic-Assisted Extraction of Bioactive Compounds from Citrus Peel Waste Through a One-Factor-at-a-Time Approach
by Matthew A. Xuereb, Georgios Psakis, Karen Attard, Frederick Lia and Ruben Gatt
Molecules 2025, 30(3), 648; https://doi.org/10.3390/molecules30030648 - 1 Feb 2025
Viewed by 1457
Abstract
Food waste presents a critical environmental and economic challenge across Europe. In the Mediterranean region, the agricultural industry generates considerable quantities of citrus fruits, leading to significant byproduct waste, which remains underutilized. To help address this, this study explored the valorization of orange [...] Read more.
Food waste presents a critical environmental and economic challenge across Europe. In the Mediterranean region, the agricultural industry generates considerable quantities of citrus fruits, leading to significant byproduct waste, which remains underutilized. To help address this, this study explored the valorization of orange peel waste using non-thermal ultrasonic-assisted extraction (UAE) and a one-factor-at-a-time experimental design to investigate the effects of nine chemical and physical UAE parameters. The goal was to identify ideal operational ranges for each parameter using several responses (bioactive compound recovery, antioxidant activity, and radical scavenging activity), thus elucidating the most influential UAE factors and their role in co-extracting various classes of natural compounds. The key findings revealed that the polarity and ionic potential of the extraction medium, tuned through ethanol:water or pH, significantly influenced both the chemical profile and bioactivity of the extracts. Notably, citric acid and citrates appeared to stabilize co-extracted compounds. Lower solid-to-liquid ratios increased yields, while particle sizes between 1400 and 710 µm enhanced phenolic recovery by approximately 150 mg/L GAE. In contrast, increases in pulse, probe diameter, immersion depth, and extraction time led to degradation of bioactive compounds, whereas the maximal amplitude improved phenolic acid recovery by up to 2-fold. Collectively, these insights provide a foundation for optimizing non-thermal UAE to valorize orange peel waste. Full article
(This article belongs to the Special Issue Chemical Analysis of Functional Foods)
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15 pages, 2518 KiB  
Article
Complexation of Olive Protein with Soluble Dietary Fibers: A Way to Improve the Functional Properties of Proteins and Efficiently Utilize Olives
by Yan Xiang, Yumin Chi, Qiang He, Lirong Jia, Wenxue Zhang and Yi Dong
Foods 2024, 13(16), 2563; https://doi.org/10.3390/foods13162563 - 16 Aug 2024
Viewed by 1357
Abstract
High-value resources beyond oil extraction for the olive industry need to be developed due to increased olive production. Soluble dietary fibers (SDFs) and olive proteins (OPIs) are important components of olives. However, the commercial production process partially damages OPIs’ emulsifying and foaming properties. [...] Read more.
High-value resources beyond oil extraction for the olive industry need to be developed due to increased olive production. Soluble dietary fibers (SDFs) and olive proteins (OPIs) are important components of olives. However, the commercial production process partially damages OPIs’ emulsifying and foaming properties. Thus, the preparation of SDF-OPI complexes would help protect and even improve the emulsifying and foaming properties. The effects of pH and thermal–ultrasonic treatment on the complexation were explored, which showed that the SDF-OPI complexes prepared at pH 5 exhibited superior solubility (p < 0.05). SDF addition noticeably improved OPI thermal stability, emulsifying properties, and foaming properties. Moreover, the complexes prepared by thermal–ultrasonic treatment exhibited higher emulsion stability and lower emulsification activity than those prepared without thermal–ultrasonic treatment. In the acidic system, the electrostatic interaction was considered the main driving factor, assisted by the hydrophobic interaction. Additionally, after thermal–ultrasonic treatment, the covalent binding was observed by infrared spectroscopy. These results revealed the interaction mechanism between SDF and OPI, and the complexes significantly enhanced the functional properties of OPI. This study provides a reference for the high-value utilization of olives, thus broadening their potential uses in the food sector and beyond. Full article
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17 pages, 3272 KiB  
Article
Recovery of Rare Earth Elements from Coal Fly and Bottom Ashes by Ultrasonic Roasting Followed by Microwave Leaching
by Milica Stojković, Mirjana Ristić, Maja Đolić, Aleksandra Perić Grujić and Antonije Onjia
Metals 2024, 14(4), 371; https://doi.org/10.3390/met14040371 - 22 Mar 2024
Cited by 8 | Viewed by 3127
Abstract
Considering the rising demand for rare earth elements (REEs), researchers are looking for new sources for their extraction, thereby fostering economic and environmentally justified processing solutions. Among potential industrial sources, coal fly ash emerges as one of the most promising. The recovery of [...] Read more.
Considering the rising demand for rare earth elements (REEs), researchers are looking for new sources for their extraction, thereby fostering economic and environmentally justified processing solutions. Among potential industrial sources, coal fly ash emerges as one of the most promising. The recovery of REEs from coal fly and bottom ashes derived from different thermal power plants was the main focus of this study. A dual-step methodology was conducted on ash samples, which involved an ultrasonic roasting process to disintegrate the silica matrix, followed by a microwave-assisted acid leaching step to extract REEs. The roasting procedure was studied using the Plackett–Burman design, and the Box–Behnken design was subsequently implemented to optimize the leaching procedure. The optimized ultrasonic roasting procedure was set up at 95 °C for 10 min with an ash-to-roasting agent (3M NaOH) ratio of 0.5:1 (m/V). For acid leaching, the optimal conditions were obtained at 174 °C for 30 min with an HCl ÷ HNO3 mixture (1:1 V/V). The standard reference material (NIST 1633c) was used in the conclusive experiments to estimate the average recovery (80%) of REEs. The green aspects of this methodology were evaluated using several metrics (atom economy, E-factor, and energy consumption). The proposed process outperforms high-temperature roasting procedures in terms of greenness; however, the REE recovery rate is lower. Full article
(This article belongs to the Special Issue New Technologies in Leaching and Recovery of Valuable Metals)
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21 pages, 1751 KiB  
Review
Advancing Sustainable Innovations in Mulberry Vinegar Production: A Critical Review on Non-Thermal Pre-Processing Technologies
by Turkson Antwi Boasiako, Isaac Duah Boateng, John-Nelson Ekumah, Nana Adwoa Nkuma Johnson, Jeffrey Appiagyei, Mian Shamas Murtaza, Bismillah Mubeen and Yongkun Ma
Sustainability 2024, 16(3), 1185; https://doi.org/10.3390/su16031185 - 31 Jan 2024
Cited by 7 | Viewed by 3318
Abstract
Mulberry is renowned for its medicinal properties and bioactive compounds, yet its high moisture content renders it highly perishable and challenging to transport over long distances. This inherent limitation to its shelf life poses sustainability challenges due to potential food waste and the [...] Read more.
Mulberry is renowned for its medicinal properties and bioactive compounds, yet its high moisture content renders it highly perishable and challenging to transport over long distances. This inherent limitation to its shelf life poses sustainability challenges due to potential food waste and the increased carbon footprint associated with transportation. To address this issue sustainably, mulberry vinegar emerges as a biotechnological solution. Utilizing a fermented mixture of crushed mulberries, sugar, and mixed acid, transforms the highly perishable raw material into a more stable product. However, conventional methods of mulberry vinegar production often involve heat-intensive processing, which poses environmental concerns and energy inefficiencies. Recognizing the need for sustainable practices, this review delves into alternative non-thermal technologies (NTTs) that can revolutionize mulberry vinegar production. These technologies, such as ultrasonication, ultra-high-pressure homogenization, pulsed light treatments, enzyme-assisted pretreatment, and membrane filtration, offer eco-friendly alternatives by eliminating the need for excessive heat. NTTs enhance energy efficiency and sustainability in mulberry vinegar production by deactivating the microbes and extending the shelf life, thereby enhancing product stability and quality without using thermal methods. Ultrasonication, for example, plays a pivotal role in improving bioactive compound extraction, contributing to the overall quality enhancement of mulberry juice. Enzyme-assisted pretreatment, specifically with Pectinex Ultra SP-L and Viscozyme L, not only enhances juice quality, but also holds promise for sustainable vinegar production. Furthermore, ultra-high-pressure homogenization and pulsed light treatments positively influence mulberry processing, offering additional sustainable alternatives. Membrane filtration, especially ultrafiltration, not only enhances the phenolic content, but also contributes to stability in mulberry juice, showcasing potential benefits for vinegar production. In conclusion, exploring these NTTs represents a transformative shift from traditional heat treatment methods in mulberry food processing. By providing energy efficient, environmentally friendly, and high-quality alternatives, this review offers valuable insights into sustainable practices, particularly in mulberry vinegar production, thereby contributing to a more sustainable future for the mulberry food industry. Full article
(This article belongs to the Section Sustainable Food)
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14 pages, 7276 KiB  
Article
Characterization and Function Analysis of Soluble Dietary Fiber Obtained from Radish Pomace by Different Extraction Methods
by Xiqian Tan, Xiaoxiao Cheng, Bingyu Ma, Fangchao Cui, Dangfeng Wang, Ronghu Shen, Xuepeng Li and Jianrong Li
Molecules 2024, 29(2), 500; https://doi.org/10.3390/molecules29020500 - 19 Jan 2024
Cited by 9 | Viewed by 2577
Abstract
Soluble dietary fiber (SDF) benefits human health, and different extraction methods might modify the structure and functions of the SDFs. Radish is rich in dietary fiber. To assess the impact of various extraction techniques on the properties and functions of radish SDF, the [...] Read more.
Soluble dietary fiber (SDF) benefits human health, and different extraction methods might modify the structure and functions of the SDFs. Radish is rich in dietary fiber. To assess the impact of various extraction techniques on the properties and functions of radish SDF, the SDFs were obtained from white radish pomace using alkaline, ultrasonic-assisted, and fermentation-assisted extraction methods. Analysis was conducted on the structure, physicochemical characteristics, thermal properties, and functional attributes of the SDFs. The study revealed that various extraction techniques can impact the monosaccharides composition and functionality of the SDFs. Compared with the other two extraction methods, the surface structures of SDFs obtained by fermentation-assisted extraction were looser and more porous, and the SDF had better water solubility and water/oil holding capacity. The adsorption capacities of glucose and cholesterol of the SDFs obtained from fermentation-assisted extraction were also improved. Wickerhamomyces anomalus YFJ252 seems the most appropriate strain to ferment white radish pomace to acquire SDF; the water holding, oil holding, glucose absorption capacity, and cholesterol absorption capacity at pH 2 and pH 7 have a 3.06, 1.65, 3.19, 1.27, and 1.83 fold increase than the SDF extracted through alkaline extraction method. Full article
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22 pages, 6377 KiB  
Article
Anti-Aging Effect of Hemerocallis citrina Baroni Polysaccharide-Rich Extract on Caenorhabditis elegans
by Yunxia Zou, Xiyue Qin, Wenli Wang, Qingyong Meng and Yali Zhang
Int. J. Mol. Sci. 2024, 25(1), 655; https://doi.org/10.3390/ijms25010655 - 4 Jan 2024
Cited by 11 | Viewed by 2745
Abstract
Plant polysaccharides are important for anti-aging research. Polysaccharides from Hemerocallis citrina Baroni (H. citrina) have been reported to have antioxidant activity; however, their anti-aging roles and mechanisms are not clear. In this study, we extracted polysaccharides from H. citrina by an [...] Read more.
Plant polysaccharides are important for anti-aging research. Polysaccharides from Hemerocallis citrina Baroni (H. citrina) have been reported to have antioxidant activity; however, their anti-aging roles and mechanisms are not clear. In this study, we extracted polysaccharides from H. citrina by an ultrasonic-assisted water extraction–alcohol precipitation method and chemically determined the physicochemical properties such as extraction yield, content, and in vitro antioxidant properties of H. citrina polysaccharide-rich extract (HCPRE). Using Caenorhabditis elegans (C. elegans) as a model animal, the anti-aging effect of HCPRE was investigated, and the mechanism of action of HCPRE was explored by the in vivo antioxidant level assay of C. elegans and the related gene expression assay. The extraction yield of HCPRE was 11.26%, the total polysaccharide content was 77.96%, and the main monosaccharide components were glucose and galactose. In addition, HCPRE exhibited good antioxidant activity both in vitro and in vivo. Under normal thermal stress and oxidative stress conditions, being fed 1200 µg/mL of HCPRE significantly prolonged the life span of C. elegans by 32.65%, 17.71%, and 32.59%, respectively. Our study showed that HCPRE exerted an anti-aging effect on C. elegans, and its mechanism involves increasing the activities of catalase (CAT) and superoxide dismutase (SOD), reducing the level of reactive oxygen species (ROS) and regulating the expression of related genes. Full article
(This article belongs to the Section Molecular Plant Sciences)
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27 pages, 1370 KiB  
Review
Ultrasound-Assisted Enzymatic Protein Hydrolysis in Food Processing: Mechanism and Parameters
by Jingya Qian, Di Chen, Yizhong Zhang, Xianli Gao, Ling Xu, Guoqiang Guan and Feng Wang
Foods 2023, 12(21), 4027; https://doi.org/10.3390/foods12214027 - 4 Nov 2023
Cited by 48 | Viewed by 6242
Abstract
Ultrasound has been widely used as a green and efficient non-thermal processing technique to assist with enzymatic hydrolysis. Compared with traditional enzymatic hydrolysis, ultrasonic-pretreatment-assisted enzymatic hydrolysis can significantly improve the efficiency of enzymatic hydrolysis and enhance the biological activity of substrates. At present, [...] Read more.
Ultrasound has been widely used as a green and efficient non-thermal processing technique to assist with enzymatic hydrolysis. Compared with traditional enzymatic hydrolysis, ultrasonic-pretreatment-assisted enzymatic hydrolysis can significantly improve the efficiency of enzymatic hydrolysis and enhance the biological activity of substrates. At present, this technology is mainly used for the extraction of bioactive substances and the degradation of biological macromolecules. This review is focused on the mechanism of enzymatic hydrolysis assisted by ultrasonic pretreatment, including the effects of ultrasonic pretreatment on the enzyme structure, substrate structure, enzymatic hydrolysis kinetics, and thermodynamics and the effects of the ultrasonic conditions on the enzymatic hydrolysis results. The development status of ultrasonic devices and the application of ultrasonic-assisted enzymatic hydrolysis in the food industry are briefly described in this study. In the future, more attention should be paid to research on ultrasound-assisted enzymatic hydrolysis devices to promote the expansion of production and improve production efficiency. Full article
(This article belongs to the Section Food Engineering and Technology)
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13 pages, 2606 KiB  
Article
Extraction and Surface Functionalization of Cellulose Nanocrystals from Sugarcane Bagasse
by Sen Tang, Zhipeng Chen, Feifan Chen, Xuanren Lai, Qiaoyan Wei, Xianling Chen and Caiyun Jiang
Molecules 2023, 28(14), 5444; https://doi.org/10.3390/molecules28145444 - 16 Jul 2023
Cited by 9 | Viewed by 2831
Abstract
The present study aimed to optimize the process for extracting cellulose nanocrystals (CNCs) from sugarcane bagasse through ultrasonic-assisted sulfuric acid hydrolysis and its subsequent modification with L-malic acid and silane coupling agent KH-550. The effects of the different modification methods and the order [...] Read more.
The present study aimed to optimize the process for extracting cellulose nanocrystals (CNCs) from sugarcane bagasse through ultrasonic-assisted sulfuric acid hydrolysis and its subsequent modification with L-malic acid and silane coupling agent KH-550. The effects of the different modification methods and the order of modification on the structures and properties of bagasse CNCs were explored. The results indicated that the optimal process conditions were achieved at an acid-digestion temperature of 50 °C, a reaction time of 70 min, an ultrasonic power of 250 W, and a volume fraction of 55%. The modified CNCs were analyzed using infrared spectral, X-ray diffraction, and thermogravimetric techniques, which revealed that L-malic acid was attached to the hydroxyl group on the CNCs via ester bond formations, and the silane coupling agent KH-550 was adsorbed effectively on the CNCs’ surfaces. Moreover, it was observed that the modification of the CNCs by L-malic acid and the KH-550 silane coupling agent occurred only on the surface, and the esterification–crosslinking modification method provided the best thermal stability. The performance of self-made CNC was found to be superior to that of purchased CNC based on the transmission electron microscopy analysis. Furthermore, the modified esterified-crosslinked CNCs exhibited the best structure and performance, thereby offering a potential avenue for the high-value utilization of sugarcane bagasse, a byproduct of sugarcane sugar production, and the expansion of the comprehensive utilization of sugarcane bagasse. Full article
(This article belongs to the Special Issue Biomass-Derived Nanomaterials: Sustainable Production and Application)
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18 pages, 2726 KiB  
Article
Sustainable Ultrasound Assisted Extractions and Valorization of Coffee Silver Skin (CS)
by Vedran Biondić Fučkar, Marinela Nutrizio, Anamarija Grudenić, Ilija Djekić and Anet Režek Jambrak
Sustainability 2023, 15(10), 8198; https://doi.org/10.3390/su15108198 - 18 May 2023
Cited by 5 | Viewed by 2240
Abstract
The Sustainable Development Goals (SDG) encourage the efficient use of sustainable technologies. Ultrasound-assisted extraction (UAE) is one of the extraction process techniques, which are also directed towards sustainability as a goal. Coffee silver skin (CS), being a healthy raw material as well as [...] Read more.
The Sustainable Development Goals (SDG) encourage the efficient use of sustainable technologies. Ultrasound-assisted extraction (UAE) is one of the extraction process techniques, which are also directed towards sustainability as a goal. Coffee silver skin (CS), being a healthy raw material as well as a waste, could be utilized in the manufacturing process of new dietary products. The goal of this research was to isolate proteins and polyphenols from CS using UAE and to employ spectrophotometry to determine the yields. Three parts of the research were conducted: ultrasonic extraction, the optimization of UAE conditions for the isolation of proteins and polyphenols from CS, and the analysis of the amino acid extract obtained with the optimal use of UAE. According to the results, it was reported that the highest yields of total polyphenols isolated from the CS using UAE were obtained by applying an amplitude of 75% and a time interval of 9 min. The optimal parameters of UAE, when considering the proportions of total polyphenols and proteins, are an amplitude of 100% and a time of 9 min. The most abundant amino acids in isolated proteins (Asp, Glu, Pro, Gly, and Ala) were defined as well. Based on the use of energy, it was obvious that UAE is a promising technology. This concurs with the proposed practice that when non-thermal technologies are analyzed from an environmental point of view, the first common denominator is the use of electricity to run the equipment, in relation to resource depletion. As expected, CS poses a great waste to be recycled, being a nutritionally rich raw material with great potential. Quantitative consideration on the environmentally friendly applicability of CS in mass production should be carried out to validate the entire process of developing a new product from both economic and environmental aspects. Full article
(This article belongs to the Special Issue New Food Waste Horizons)
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12 pages, 1376 KiB  
Article
Anthocyanins and Total Phenolic Compounds from Pigment Extractions of Non-Native Species from the Umia River Basin: Eucalyptus globulus, Tradescantia fluminensis, and Arundo donax
by Antía Iglesias, Ángeles Cancela, Xana Álvarez and Ángel Sánchez
Appl. Sci. 2023, 13(10), 5909; https://doi.org/10.3390/app13105909 - 11 May 2023
Cited by 3 | Viewed by 2446
Abstract
Alien invasive species (AIS) and non-native species are a prominent and extended problem in a wide range of areas in Europe and around the world. Centered in the Umia’s riparian forest, in Galicia, we found at least three main AIS needing to be [...] Read more.
Alien invasive species (AIS) and non-native species are a prominent and extended problem in a wide range of areas in Europe and around the world. Centered in the Umia’s riparian forest, in Galicia, we found at least three main AIS needing to be controlled and harvested to preserve the biodiversity of the area. Previous studies probed that leaves and bark of selected species—Tradescantia fluminensis, Arundo donax, and Eucalyptus globulus—have important antioxidant properties, suitable for use in pharmaceutical and industrial contexts. A comparison of four solid-liquid extraction methods—Soxhlet extraction, ultrasound assisted extraction, thermal agitator, and infusion—was conducted in order to define the most efficient method in correlation within antioxidant (anthocyanins and total phenols) extraction. Water was selected as solvent, providing a sustainable research background without implying any chemical additives. The best extraction yields were obtained with Soxhlet extraction for all raw matter, with best results for Tradescantia fluminensis (41.89%) and Eucalyptus globulus leaves (39.35%); followed by the ultrasonic assisted extraction method, with better yield performed with Eucalyptus leaves (27.07%). On the contrary, Tradescantia fluminensis showed better efficiency with thermal agitator (35.07% compared to 23.19% from ultrasound extraction). After extractions, identification and quantification of total phenolic compounds and anthocyanins were carried out using spectrophotometric determination and acid hydrolysis in butanol method. In general, the best extraction yield in correlation with higher antioxidant content was performed by thermal agitator method, and Eucalyptus globulus leaves were demonstrated to be the better anthocyanins (6.18 ± 0.82 mg CC/g) and total phenols containers (172.40 ± 44.53 mg GAE/g). Studies provided promising possibilities for the residues of the three non-native species analyzed, as a source of antioxidants, favoring circular economy systems, as well as taking care of biodiversity in affected environments. Full article
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13 pages, 7508 KiB  
Article
Preparation of Cellulose Nanocrystals by Synergistic Action of Ionic Liquid and Recyclable Solid Acid under Mild Conditions
by Li Ma, Yongjian Xu, Jian Chen, Cuihua Dong and Zhiqiang Pang
Molecules 2023, 28(7), 3070; https://doi.org/10.3390/molecules28073070 - 30 Mar 2023
Cited by 9 | Viewed by 2273
Abstract
Cellulose nanocrystals (CNCs) are nanoscale particles made from cellulose. They have many unique properties such as being lightweight, stiff, and renewable, making them promising for a variety of applications in a wide range of industries, including materials science, energy storage, and biomedicine. In [...] Read more.
Cellulose nanocrystals (CNCs) are nanoscale particles made from cellulose. They have many unique properties such as being lightweight, stiff, and renewable, making them promising for a variety of applications in a wide range of industries, including materials science, energy storage, and biomedicine. In this paper, a two-stage (swelling-SA-catalyzed) method including IL pretreatment and solid acid hydrolysis process was developed to extract CNCs with high purity and good thermal stability from microcrystalline cellulose (MCC). In the first stage, the swelling of MCC in ionic liquid was studied with the assistance of ultrasonication, and it was found that the amorphous regions became more disordered while the crystalline areas were selectively retained under the conditions of 30 min of reaction time, 45 °C of temperature, 2% of ionic liquid water content and 1:4 mass ratio of cellulose to ionic liquid. CNCs were extracted using solid acid hydrolysis, with a 45 wt% solid acid to cellulose ratio and a 5.0 h hydrolysis process at 45 °C. The morphology, crystallinity, surface characteristics and thermo stability of the sample were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. Results demonstrated the highly thermostable CNCs were successful extracted with rodlike shape of 300 ± 100 nm in length and 20 ± 10 nm in width. Solid acid recovery and reuse were also studied, revealing a promising candidate that can reduce the environmental impact associated with chemical products. Full article
(This article belongs to the Special Issue Carbon Nanomaterials: Design and Applications)
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