Search Results (282)

Hot water extraction (HE), enzyme-assisted hot water extraction (EAHE), ultrasonic-assisted extraction with NADES (UAE-NADES) and ultrasonic-assisted extraction with NADES and enzyme pretreatment (UAE-NADES-E) were employed to extract polysaccharides from Peucedani Decursivi Radix (PDR) and their structures were characterized for the first time. UAE-NADES-E was found to be the most effective extraction method, and the extraction process was optimized by Box–Behnken design (BBD)-response surface methodology (RSM) experiments. The optimal extraction process was determined by using a NADES system with a molar ratio of betaine to 1,3-butanediol of 1:3, a water content of 30%, a liquid/solid ratio of 40:1 mL/g, an ultrasound time of 30 min, an ultrasound temperature of 45 °C and an alcohol precipitation time of 6 h; the polysaccharide extraction yield reached 19.93%. Further, the structures of polysaccharides from PDR extracted by the above four methods were characterized by FT-IR, SEM, gel and anion-exchange chromatography. Eight monosaccharides were detected in the PDR polysaccharides extracted by the four methods. The PDR polysaccharides extracted by the UAE-NADES-E method had lower molecular weights compared with those extracted by the other methods. Moreover, the PDR polysaccharides exhibited obvious antioxidant activity, as revealed by DPPH, ABTS+ and hydroxyl radical scavenging experiments, meaning they have the potential to be developed as natural antioxidants. Full article

Parkinson’s disease (PD) is the second most prevalent neurodegenerative disease. It is characterized by mitochondrial dysfunction, increased reactive oxygen species (ROS), α-synuclein (α-syn) and phosphorylated-tau protein (p-tau) aggregation, and dopaminergic neuron cell death. Current drug therapies only provide temporary symptomatic relief and fail to stop or reverse disease progression due to the severe side effects or the blood–brain barrier. This study aimed to investigate the neuroprotective effects of an intermittent heating approach, thermal cycling-hyperthermia (TC-HT), in an in vitro PD model using rotenone (ROT)-induced human neural SH-SY5Y cells. Our results revealed that TC-HT pretreatment conferred neuroprotective effects in the ROT-induced in vitro PD model using human SH-SY5Y neuronal cells, including reducing ROT-induced mitochondrial apoptosis and ROS accumulation in SH-SY5Y cells. In addition, TC-HT also inhibited the expression of α-syn and p-tau through heat-activated pathways associated with sirtuin 1 (SIRT1) and heat-shock protein 70 (Hsp70), involved in protein chaperoning, and resulted in the phosphorylation of Akt and glycogen synthase kinase-3β (GSK-3β), which inhibit p-tau formation. These findings underscore the potential of TC-HT as an effective treatment for PD in vitro, supporting its further investigation in in vivo models with focused ultrasound (FUS) as a feasible heat-delivery approach. Full article

Following the debate on food processing, resulting in a negative definition of ultra-processed products, the improvement of the food system could be pursued through the co-creation of new food solutions aimed at enhancing human health and increasing safety and sustainability, in particular by using neglected foodstuff, crops or by-products, and applying mild processing technologies. The proper management of mild/non-thermal processing technologies, such as dynamic and hydrostatic high-pressure, vacuum impregnation, ultrasound, pulsed electric field and cold plasma applications, can result in a less negative effect with respect to the traditional thermal treatments, and, in some cases, the overall functionality can be improved. In many cases, these treatments can induce structural changes that improve the bioaccessibility and/or the bioavailability of bioactive compounds such as probiotic microorganisms. Moreover, non-thermal pretreatments, also combined with mild thermal drying technology, could lead to a significant reduction in the total request of energy, even when considering the energy input for their application. A selected review of results published in the last few years on those strategies is presented, considering studies carried out within the frame of different national and EU projects. Full article

Regulating the dissolution and interfacial behavior of minerals via external force fields is considered a promising strategy for enhancing the flotation of soluble minerals. This study explored the potential of ultrasound-assisted pulp conditioning in improving ultrafine smithsonite flotation. Specifically, we systematically evaluated the effects of ultrasonic pretreatment (UP) on the physicochemical properties of smithsonite suspensions (focusing on surface erosion behavior) and assessed subsequent flotation performance using flotation tests and modern analytical techniques. It has been found that UP can significantly modify smithsonite suspension characteristics, including particle morphology, ionic composition, electrokinetic properties, and pulp pH. Flotation results demonstrate that UP yields higher recovery compared to traditional stirring (TS) conditioning, especially at medium-to-high sodium oleate (NaOL) concentrations. Comparative analysis reveals that ultrasonic-assisted dissolution and ion-selective migration are the main factors driving improved flotation performance. Unlike TS, UP promotes greater zinc ion release, facilitates the dissolution–hydrolysis–precipitation equilibrium, generates more and finer nanoparticles in the bulk phase, and induces the deposition of hydrozincite on smithsonite surfaces. These changes increase active zinc sites for more stable NaOL adsorption, thereby enhancing the flotation of ultrafine smithsonite particles. Full article

Walnut (Juglans regia L.) shells are valuable agro-industrial by-products rich in polyphenols. This study investigated traditional (maceration) and advanced extraction techniques—ultrasound-assisted extraction (UAE), enzyme-assisted extraction (EAE), pressurized liquid extraction (PLE), and combined ultrasound–enzyme extraction (US-EAE)—to recover bioactive compounds from walnut shells. Extraction efficiency, total phenolic content (TPC), antioxidant capacity (ABTS^•+, DPPH•), and polyphenol composition were evaluated. UPLC-ESI-MS/MS identified key polyphenols including ellagic acid, 4-hydroxybenzoic acid, vanillin, taxifolin, and quercitrin. The highest TPC (5625 mg GAE/100 g dw) was found in extracts subjected to US-EAE, in which ultrasound pretreatment (200 W, 10 min) was followed by enzymatic extraction using 0.06 mL/g Viscozyme^® L at pH 3.5 and 45 °C. Under the same extraction conditions, UAE alone yielded the second highest TPC (4129 mg GAE/100 g dw). The highest ABTS^•+ scavenging activity (14,478 mg TE/100 g dw) and enhanced DPPH• activity (45.38 mg TE/100 g dw) were also observed in US-EAE extracts. Chemometric techniques (PCA and HCA) revealed meaningful clustering and variation patterns among methods. These findings highlight the potential of walnut shells as a sustainable source of polyphenols and demonstrate the effectiveness of innovative extraction technologies in maximizing bioactive compound recovery for potential functional applications. Full article

The growing demand for natural preservatives in the food industry has highlighted the importance of essential oils (EOs), despite their limitations related to volatility and oxidative instability. This study addresses these challenges by developing pectin-based microcapsules for encapsulating lemon essential oil (LEO) using ultrasound-assisted ionotropic gelation. The EO, extracted from Citrus limon (Eureka variety), exhibited a high limonene content (56.18%) and demonstrated significant antioxidant (DPPH IC50: 28.43 ± 0.14 µg/mL; ABTS IC50: 35.01 ± 0.11 µg/mL) and antifungal activities, particularly against A. niger and Botrytis spp. Encapsulation efficiency improved to 82.3% with ultrasound pretreatment, and SEM imaging confirmed spherical, uniform capsules. When applied to fresh-cut apples, LEO-loaded capsules significantly reduced browning (browning score: 1.2 ± 0.3 vs. 2.8 ± 0.2 in control), microbial load (4.9 ± 0.2 vs. 6.5 ± 0.4 log CFU/g), and weight loss (4.2% vs. 6.4%) after 10 days of storage at 4 °C. These results underscore the potential of ultrasound-enhanced pectin encapsulation for improving EO stability and efficacy in food preservation systems. Full article

Although algae possess a high capacity for carbon sequestration, the recalcitrant multilayered cell wall structure and residual microcystin toxicity associated with Microcystis aeruginosa significantly hinder the efficient recovery of algal biomass resources. This study developed a synergistic ozone-ultrasonication (O₃-US) pretreatment strategy, systematically comparing its cell-disruption efficacy with standalone O₃ or US, using harvested algal biomass from natural aquatic systems dominated by Microcystis aeruginosa. The synergistic effects revealed were: (1) O₃-mediated oxidation of extracellular polymeric substances and cell wall matrices, (2) the release of ultrasound-induced cavitation-enhancing intracellular components, and (3) an improvement in the O₃ mass transfer by hydrodynamic shear forces. Through response surface methodology optimization, the O₃-US process achieved maximal performance at 0.14 gO₃/gTSS, with a 4 W/mL ultrasonic intensity, and a 20 min duration. Remarkably, the released protein was 289.2 mg/gTSS, which was 4.3-fold and 1.9-fold, respectively, more than that released in O₃ pretreatment and US pretreatment, while the polysaccharide was 87.5 mg/gTSS, increased by 2.4-fold and 3.1-fold respectively, compared to O₃ alone and US alone. The released solubilized chemical oxygen demand (SCOD) was 1037.1 mg/gTSS, increased by 43.3% and 216.1%, respectively, relative to O₃ alone and US alone. DNA quantification further validated the synergistic cell disruption caused by O₃-US. Fluorescence excitation-emission matrix (EEM) spectroscopy identified biodegradable aromatic proteins (Regions I-II) and soluble microbial byproducts (Region IV) as dominant organic fractions, demonstrating enhanced bioavailability. The hybrid process reduced energy consumption by 33.3% in ultrasonic intensity and 60% in duration versus US alone, while achieving 94.5% microcystin-LR (MC-LR) degradation, which showed a 96.6% risk reduction compared to ultrasonic treatment. This work establishes an efficient, low-energy, and safe pretreatment technology for algal resource recovery, synergistically enhancing intracellular resource release while mitigating cyanotoxin hazards in algal biomass valorization. Full article

In the present study, the effects of varying ultrasound treatment durations (5, 15, 30, and 45 min) applied prior to osmotic dehydration in xylitol solutions on apple tissues were investigated. The efficiency of the osmotic dehydration process was assessed by analyzing its kinetic parameters. In selected samples of osmotically dehydrated fruits, physicochemical properties were evaluated, including dry matter content, total acidity, pH, sugar profile, color attributes, total phenolic content, antioxidant activity (measured by DPPH and ABTS assays), and vitamin C content. Additionally, principal component analysis (PCA) was conducted to explore the relationships among the measured variables and to identify underlying patterns within the dataset. Osmotic dehydration in xylitol significantly modified the physicochemical and antioxidant properties of apples, promoting substantial water loss and partial replacement of natural sugars with xylitol. The results showed that ultrasound pretreatment markedly influenced these effects, with treatment duration playing a critical role. Shorter ultrasound applications (15–30 min) enhanced xylitol uptake while better preserving antioxidant activity and color, whereas longer ultrasound treatments (45 min) achieved greater mass transfer but led to higher losses of bioactive compounds compared to untreated samples. Full article

This study aimed to investigate the impact of ultrasonic pretreatment vacuum drying (UAVD) and temperature on drying kinetics and qualitative attributes of blood oranges in comparison to several drying methods: hot air drying (HAD), vacuum drying (VD), and freeze drying (FD). The drying kinetics and modeling, total phenolic content (TPC), antioxidant capability (assessed using DPPH and ABTS tests), individual phenolic profiles, vitamin C concentration, and color factors were meticulously examined. Drying times were recorded as 22.5 h, 12.5 h, and 9 h for HAD; 11.5 h, 9.5 h, and 8.5 h for VD; and 10 h, 8.5 h, and 7.5 h for UAVD at 50, 60, and 70 °C, respectively. The HAD, VD, and UAVD procedures were conducted at 50, 60, and 70 °C, resulting in reduced drying periods with increasing temperature. The integration of ultrasound markedly lowered drying durations. Eleven thin-layer drying models were utilized to recreate the drying process precisely. The D_eff values of the HAD, VD, and UAVD dried samples varied from 9.08 × 10⁻⁶ to 2.82 × 10⁻⁵ m²/s, from 2.60 × 10⁻⁵ to 2.96 × 10⁻⁵ m²/s, and from 2.20 × 10⁻⁵ to 2.99 × 10⁻⁵, respectively. Among the desiccated blood orange slices, the greatest total phenolic content (TPC) was observed in freeze-dried samples (131.27 mg GAE/100 g), followed by those dried using ultrasonic-assisted vacuum drying (UAVD) at 50 °C (128.77 mg GAE/g DM). Dried blood orange slices had a vitamin C content of 29.79 to 49.01 mg/100. The drying process substantially impacted the color parameters L*, a*, and b*. These findings highlight the efficacy of ultrasound-assisted drying in decreasing drying duration while improving the retention of bioactive components in blood orange slices. Full article

Spent hops from the supercritical extraction process represent a valuable source of xanthohumol (XN), a prenylated flavonoid with demonstrated anticancer, antidiabetic, antibacterial, and anti-inflammatory properties. However, XN is thermally sensitive and readily isomerizes into the less bioactive iso-XN at elevated temperatures, necessitating mild extraction conditions. Previous studies have shown that the pretreatment of plant biomass can enhance the extraction efficiency of bioactive compounds. In this study, various pretreatment methods—including physical (freeze–thaw, ultrasound, and microwave), chemical (acid and base hydrolysis), and enzymatic approaches—were applied to spent hops prior to extraction, and XN yields were compared to those obtained from untreated samples. The experiments, performed in triplicate, yielded meaningful results which helped understand the raw material’s behavior in applied conditions. Due to the compound’s high thermal sensitivity, ultrasound and microwave pretreatments require precise control to prevent excessive temperature increases, making low-temperature methods more suitable. Additionally, exposure to elevated pH adversely affected XN extraction efficiency, limiting the applicability of strong alkaline pretreatments. Among the evaluated methods, freeze–thaw pretreatment proved to be a simple and effective strategy, enhancing XN extraction yields by up to 10.7 ± 0.7% through the optimization of soaking time, the solid-to-liquid ratio, and the thawing temperature. Identifying an inexpensive and efficient pretreatment method could reduce extraction time while improving yield, contributing to the sustainable utilization of spent hops as an XN source. Full article

This study evaluates the feasibility of using banana peels as a substrate for cultivating fodder yeast biomass. Banana peels (BPs), representing approximately 38% of the total fruit weight, are rich in cellulose and hemicellulose, thus presenting a significant opportunity for valorisation. The study investigates the effects of microwave and ultrasound treatments on the hydrolysis efficiency of banana peels and the subsequent cultivation of yeast. Two yeast strains, Scheffersomyces stipitis and Meyerozyma guilliermondii, were cultivated in hydrolysates prepared using various methods, including acid–thermal, enzymatic, microwave, and ultrasound treatments. The results demonstrate that enzymatic hydrolysis following microwave or ultrasound pretreatment significantly enhances sugar release, supporting higher biomass yields. The maximum biomass concentration achieved was 7.68 g DM/L, with crude protein content reaching up to 45.46% DM. These results indicate that banana peels can be effectively utilised for single-cell protein production, providing a sustainable alternative for animal feed. The study underscores the potential of integrating microwave and ultrasound technologies in bioprocessing to enhance the efficiency and environmental sustainability of yeast cultivation. Full article

There is a growing interest in studying the bioactive compounds of invasive green macroalga Caulerpa cylindracea due to their potential biotechnological applications. Algal samples were collected from two sites and seasons. Elemental analysis showed the abundance of carbon in the raw material as a source of carbohydrates. The total protein content in different samples ranged from 8.17 to 9.98%. Total lipids in different samples were around 2%. Fatty acid (FA) results revealed the presence of various types, including omega-3 and omega-6 PUFA. Furthermore, an alkaline hydrolysis optimization using response surface methodology was investigated to extract soluble compounds. It showed that the best combination for polyphenols and ABTS was 12.5% sodium carbonate (SC) at 100 °C for 8 h; however, the best combination for proteins and carbohydrates was 7.5% SC at 100 °C for 5 h. A combination of ultrasound pretreatments was carried out to assess the enhancement of the contents. Thus, an increasing amount was recorded for polyphenols and antioxidant capacity. Ultrasound pretreatment results in decreasing extraction time for all compounds. Results showed that the invasive seaweeds, causing environmental impacts in the Mediterranean Sea, represent an interesting source of bioactive compounds. Full article

Ultrasound (US) is a non-thermal food processing method that can be used as a pre-treatment or integrated during drying to enhance mass transfer by inducing cavitation and forming microchannels in plant tissue. Thus, this study investigated the combined effect of ultrasound pre-treatment (21 kHz; 180 W; 10 min, 20 min, 30 min) and the subsequent hybrid drying process—ultrasound-assisted hot-air drying (temperature of 70 °C, frequency of 36 kHz; ultrasound power of 120 W, 160 W, 200 W)—on the drying kinetics and quality attributes of dried Gloster apples. The experimental design was optimized using the response surface methodology (RSM). The effects of ultrasound parameters on drying time, dry matter content, water activity, rehydration and hygroscopic properties, color change, textural properties, content of vitamin C, polyphenols and flavonoids, and antioxidant activity were evaluated. Among the analyzed variants, the most effective combinations were longer US duration (30 min) with lower US power (120 W) or shorter US duration (10 min) with higher US power (200 W). To obtain dried material with the most desirable rehydration and hygroscopic properties, a US power in the range of 120–160 W, preceded by a US pre-treatment lasting 20 min, should be selected. Conversely, optimizing the content of bioactive components would involve choosing the longest US treatment time and medium to high ultrasonic power during drying. These results provide actionable insights for the industry to tailor drying parameters based on the desired product attributes. Full article

Ultrasound-assisted extraction (UAE) using water as a green solvent is a promising non-thermal technique for the extraction of total dietary fiber (TDF) and betaine from red beetroot (Beta vulgaris L.) peel. Compared to conventional thermal extraction (CE), UAE has proven to be a more efficient alternative method for the extraction of TDF and betaine. The pretreatment of beet was carried out using pulsed electric field (PEF) technology, with the specific energy of the PEF treatment set at 1.6 kJ/kg. To achieve the maximum betaine concentration of 24.80 µg/mL, the optimum UAE parameters were 50% amplitude with an extraction time of 3 min using distilled water as extraction solvent. The optimum TDF yield of 44.07% was achieved at 75% amplitude, 6 min treatment time and 50% ethanol solution as extraction solvent. These conditions can effectively supplement UAE, especially in the extraction of bioactive compounds from red beetroot peel. However, the TDF obtained in the residue must be evaporated for further use, which increases energy consumption. Ethanol concentration had no statistically significant effect (p > 0.05) on the TDF results, suggesting that distilled water could replace ethanol as a solvent in UAE. This substitution offers environmental and economic advantages, as water is more environmentally friendly and less expensive than ethanol. In addition, the use of distilled water eliminates the need to evaporate ethanol, which is particularly advantageous when the extracted material is intended for fortification or improvement of the technological and functional properties of food products. Full article

The current work investigates the intensification process of the biological oxidation (BO) of a pharmaceutical effluent using ultrasound (US)-based pretreatment methods. US, in combination with chemical oxidants, like hydrogen peroxide (H₂O₂), Fenton, potassium persulphate (KPS), and peroxone, was used as a pretreatment technique to enhance the efficacy of BO, as BO alone could only bring about 16.67% COD reduction. The application of US under the optimized conditions of a 70% duty cycle, 120W of power, pH 2, and at a 30 °C temperature resulted in 12.3% COD reduction after 60 min, whereas its combination with oxidants at optimized loadings resulted in a higher COD reduction of 20% for H₂O₂ (2000 ppm), 23.08% for Fenton (1:1 Fe:H₂O₂), and 30.77% for the US + peroxone approach (400 mg/h of ozone with 2000 ppm H₂O₂). The pretreated samples did not produce any toxic by-products, as confirmed by a toxicity analysis using the agar well diffusion method. A cow-dung-based sludge was acclimatised specifically for use in BO. The treatment time for BO was set to 8 h, and the US + peroxone-pretreated samples showed a maximum overall COD reduction of 60%, which is about three times that observed with only BO. This work clearly demonstrates the enhancement of the biodegradation of a complex recalcitrant pharmaceutical effluent using a US-based pretreatment. Full article