Ultrasonication--a complementary 'green chemistry' tool to biocatalysis: a laboratory-scale study of lycopene extraction

Acoustic black hole ultrasonic radiator for high-efficiency radiation

The utilization of conventional longitudinal transducers in the field of ultrasonic liquid processing is constrained by limitations in radiation area and directional characteristics. These limitations can be addressed through the implementation of mode conversion techniques. However, an expanded radiation area may also result in reduced acoustic radiation intensity. To mitigate this issue, this study proposes an Acoustic Black Hole Ultrasonic Radiator (ABHUR) designed to enhance ultrasound intensity and thereby achieve high-efficiency radiation. The proposed ABHUR comprises a Bolted Langevin-type Transducer (BLT) and a Curved Acoustic Black Hole (CABH) ring. A theoretical model, based on the transfer matrix method, is developed to analyze the in-plane vibrational behavior of the CABH ring, and its validity is confirmed through Finite Element Method (FEM) simulations. The underwater vibrational and sound field distribution properties of the ABHUR are investigated using FEM and compared with two alternative radiators employing longitudinal-bending (L-B) and longitudinal-radial (L-R) modes. Owing to the unique properties of the Acoustic Black Hole structure (ABHs), which amplify bending wave amplitudes and concentrate energy, the ABHUR operating in L-B mode demonstrates superior ultrasound intensity. Furthermore, a prototype of the ABHUR is fabricated, and a series of three experiments are conducted to validate the operational feasibility of the proposed system.

How well ultrasonic waves penetrate glass, SS, and plastics?

To effectively utilize ultrasound, it is crucial to identify materials and media that facilitate optimal penetration. Extraction and aluminum foil erosion experiments were performed using beakers made of glass, stainless steel, and various plastics (PE, PFA, and PTFE) under different ultrasonic conditions. Additionally, ultrasound-assisted chromatography was conducted in six solutions with varying surface tensions: water, alcohol, 6% and 17% NaOH, and 20% and 35% sucrose in water. The results of the extraction and erosion experiments indicated that glass demonstrated the highest extraction efficiency and the strongest physical effects, with minimal ultrasound energy attenuation, particularly under sweep mode and low-frequency conditions. In chromatography, the findings showed that ultrasound transmission was more effective in a 6% NaOH aqueous solution compared to water.

The sources, properties, extraction, biosynthesis, pharmacology, and application of lycopene

Lycopene is an important pigment with an alkene skeleton from Lycopersicon esculentum, which is also obtained from some red fruits and vegetables. Lycopene is used in the food field with rich functions and serves in the medical field with multiple clinical values because it has dual functions of both medicine and food. It was found that lycopene was mainly isolated by solvent extraction, ultrasonic-assisted extraction, supercritical fluid extraction, high-intensity pulsed electric field-assisted extraction, enzymatic-assisted extraction, and microwave-assisted extraction. Meanwhile, it was also obtained via 2 synthetic pathways: chemical synthesis and biosynthesis. Pharmacological studies revealed that lycopene has anti-oxidant, hypolipidemic, anti-cancer, immunity-enhancing, hepatoprotective, hypoglycemic, cardiovascular-protective, anti-inflammatory, neuroprotective, and osteoporosis-inhibiting effects. The application of lycopene mainly includes food processing, animal breeding, and medical cosmetology fields. It is hoped that this review will provide some useful information and guidance for future study and exploitation of lycopene.

Comparison between the use of polyether ether ketone and stainless steel columns for ultrasonic-assisted extraction under various ultrasonic conditions

The ultrasound-assisted extraction (UAE) was conducted using the stainless steel (SS) and polyether ether ketone (PEEK) columns and analyzed with high-performance liquid chromatography (HPLC) to understand the mechanism of ultrasound-assisted chromatography (UAC). Empty SS and PEEK columns were used to extract dyes from a fabric under identical conditions with several parameters including the initial ultrasonic bath temperatures (30 °C and 40 °C), ultrasound power intensities (0, 20, 40, 60, 80, and 100 %), ultrasound operation modes (normal and sweep), and ultrasound frequencies (25 kHz, 40 kHz, and 132 kHz) to compare their extraction capabilities. After 30 min of extraction, the amount of extract was determined by HPLC. The PEEK material was significantly affected by ultrasonic radiation compared to the SS material, especially at a higher temperature (40 °C), power intensity (100 %), and frequency (132 kHz) with sweep mode. At a maximum power density of 45 W/L, the extraction effectiveness ratio of PEEK to SS was in the range of 1.8 - 3.9 depending on the specific frequency, initial temperature, and with or without temperature control. The most optimal ultrasound frequencies, in terms of enhancing extraction effectiveness, are in the order of 132 kHz, 40 kHz, and 25 kHz. Unlike the SS material, the PEEK material was more affected by temperature and acoustic effects under identical conditions, especially at 132 kHz ultrasound frequency. In contrast, at lower frequencies of 40 kHz and 25 kHz, no significant differences in the acoustic effects were observed between the PEEK and SS materials. The findings of this study contribute to elucidating the roles of column materials in UAE and UAC.

Valorization of Tomato Residues by Supercritical Fluid Extraction

Tomato processing leads to the production of considerable amounts of residues, mainly in the form of tomato skins, seeds and vascular tissues, which still contain bioactive molecules of interest for food, pharmaceutical and nutraceutical industries. These include carotenoids, such as lycopene and β-carotene, tocopherols and sitosterols, among others. Supercritical fluid extraction is well positioned for the valorization of tomato residues prior to disposal, because it remains an environmentally safe extraction process, especially when using carbon dioxide as the solvent. In this article, we provide an extensive literature overview of the research on the supercritical fluid extraction of tomato residues. We start by identifying the most relevant extractables present in tomatoes (e.g., lycopene) and their main bioactivities. Then, the main aspects affecting the extraction performance are covered, starting with the differences between tomato matrixes (e.g., seeds, skins and pulp) and possible pretreatments to enhance extraction (e.g., milling, drying and enzymatic digestion). Finally, the effects of extraction conditions, such as pressure, temperature, cosolvent, flow rate and time, are discussed.

Improving oxidative stability of foods with apple-derived polyphenols

Consumers demand healthy and natural food products. Thus, naturally derived antioxidants are emerging as a promising alternative to the use of present ingredients. Apples and apple derivative products (e.g., apple juice, apple cider, apple sauce, and others) are widely consumed throughout the world for a variety of different reasons and supply a large quantity of polyphenolic compounds. The extraction of polyphenolic compounds from apples and their incorporation into processed foods as naturally sourced ingredients could be a preferred alternative to commonly used commercial antioxidants that are used in many foods. In addition, they could have a positive impact on the environment and on the economy due to the utilization of byproducts generated during processing of apples, like apple pomace. In terms of the extraction procedures for the antioxidant compounds found in apples, the most efficient processes are methods that use ultrasound as the extraction tool. With this technique, greater yields are achieved, and less extraction time is required when compared with other, more conventional, extraction methods. However, parameters such as the extraction solvent, temperature during extraction, and extraction time must be suitably optimized in order to obtain the best performance and the highest antioxidant capacity. From an application standpoint, the use of apple-derived polyphenol extracts as a naturally derived food additive has documented applications for bread, meat, fish, cookies, and juices and there is evidence of increased antioxidant capacity, reduced rate of lipid oxidation, and increased storage time without compromising on sensory properties.

Integrated strategies for enzyme assisted extraction of bioactive molecules: A review

Conventional methods of extracting bioactive molecules are gradually losing pace due to their numerous disadvantages, such as product degradation, lower efficiency, and toxicity. Thus, in light of the rising demand for these bioactive, enzymes have garnered much attention for their efficiency in extraction. However, enzyme-assisted extraction is also plagued with a high capital cost that cannot justify the extraction yields obtained. In order to mitigate these problems, enzyme-assisted extraction can be consorted with non-conventional methods. This review includes current progress concerning the combined approaches while converging the recent advancements in the field that outperformed conventional extraction processes. It also highlights the design of biocatalyst and key parameters involved in the effective extraction of bioactive molecules. An integrated approach for efficiently extracting polyphenols, essential oils, pigments, and vitamins has been comprehensively reviewed. Furthermore, the different immobilization strategies have been discussed for large-scale implementation of enzymes for extraction. The integration of advanced non-conventional methods with enzyme-assisted extraction will open new avenues to enhance the overall extraction efficiency.

Optimization of chromium(VI) removal by indigenous microalga (Chlamydomonas sp.)-based biosorbent using response surface methodology

Phycoremediation of heavy metals has garnered considerable recent research interest. In this study, an indigenous microalga (Chlamydomonas sp.)-based biosorbent was employed for biosorption of Cr(VI) dissolved solids (Cr(VI)-DS), optimized using response surface methodology (RSM). The effects of microalga concentration, pH, and contact time were studied with 250 mg Cr(VI)-DS L-1 . The biosorption of Cr(VI)-DS was higher at acidic pH (94.17% at pH 4) than at alkaline conditions (68.53% at pH 10). The interaction of pH and microalga concentration exerted significant (p < 0.05) influence on the biosorption. Under the optimized parameters of 1.5 g microalga L-1 , pH 4, and contact time of 30 min, a predicted biosorption of 91.31% and biosorption capacity of 152 mg Cr(VI)-DS g-1 biomass were documented. FTIR analysis attested the electronegative surface functional groups of the microalgae biomass, bracketed together with its high biosorption potency. The study evinced the potential of the indigenous microalga for remediation of hexavalent chromium. PRACTITIONER POINTS: Indigenous Ethiopian microalga (Chlamydomonas sp.) exhibited 94% Cr(VI) abatement with biosorption capacity of 152 mg Cr(VI) g-1 . FTIR analysis of the biosorbent divulged the presence of electronegative functional groups (amino, carboxyl, hydroxyl, and carbonyl groups). Higher biosorption of Cr(VI)-DS under acidic pH (94.17% at pH 4) than alkaline pH (68.53% at pH 10). Significant (p < 0.05) interaction effect of pH and biomass concentration on the biosorption, evinced in RSM optimization 91% Cr(VI) removal achieved under optimal conditions of 1.5 g biosorbent L-1 , 30 min of contact time, and pH 4.

Specific Removal of Nitrite from Lake Urmia Sediments by Biohydrogel Based on Isolated Soy Protein/Tragacanth/Mesoporous Silica Nanoparticles/Lycopene

In this study, a biodegradable biohydrogel based on isolated soy protein/tragacanth containing mesoporous silica nanoparticles and lycopene pigment (ISP/TG/MPS/Lyc) is prepared. The physicochemical characteristics and structure of the biohydrogel are investigated by scanning electron microscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction, and thermal gravimetry analysis (TGA) techniques. Mechanical properties (tensile strength and elongation at break point), antioxidant activity, water solubility, water absorption capacity (WAC), and the humidity content of the biohydrogels are studied. Five optimal biohydrogels including pure ISP, ISP/TG, ISP/MPS, ISP/Lyc, and ISP/TG/MPS/Lyc are used for chemical treatment of Lake Urmia sediments. For this purpose, biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrate, and nitrite of sediments are examined before and after treatment with biohydrogels. According to the FTIR results, there is only physical interaction between lycopene and isolated soy protein. According to the TGA results, adding silica mesoporous to biohydrogel increases its thermal stability. Tragacanth gum and lycopene pigment reduce water solubility and increase the WAC of biohydrogel. The biohydrogel significantly reduces the BOD and COD of the sediments. The biohydrogel reduces nitrite content up to 90%, while reducing nitrate content by almost 30%. The results show that the biohydrogel containing lycopene selectively purifies nitrite from the sediment solution of Lake Urmia.

Phenolic Composition, Antioxidant and Anticancer Potentials of Extracts from Rosa banksiae Ait. Flowers

Rosa banksiae Ait. (R. banksiae) is a traditional Chinese folk medicine and an ornamental plant. Most previous studies have focused on cultivation and utilization while there are few research papers on the pharmacological activity of R. banksiae. This study aimed to get a better understanding of R. banksiae by extracting polyphenols with fractionated extraction technology. The results showed that ethyl acetate phase (EAP) contained the most polyphenols, while water phase (WP) had the least. HPLC analysis indicated that rutin and luteolin-4'-O-glucoside existed in the EAP and butanol phase (BP), but quercetin was only detected in the EAP. Six phenolic compositions were not detected in WB. The antioxidant and anti-tumor abilities of the EAP and BP were excellent. The results revealed that R. banksiae possessed a great antioxidant capacity and was rich in polyphenols, thus indicating R. banksiae was suitable for being a natural antioxidant and an abundant source of polyphenols.

Tomato as Potential Source of Natural Additives for Meat Industry. A Review

Tomato industry produces huge amounts of by-products that represent an environmental and economic problem. However, these by-products contain multiple bioactive compounds, which would make them a renewable source for obtaining natural antioxidants and colourants (carotenoids). This is in line with the preferences of the current consumer who demands more natural and healthy products. However, the lipophilic character of carotenoids means that their extraction must be carried out using toxic organic solvents. To overcome environmental and health problems of organic solvents, the application of supercritical fluid extraction (SFE) for the extraction of lipophilic compounds such as lycopene was used successfully, achieving yields similar to those obtained with conventional techniques. Nonetheless, the extraction conditions must be carefully selected, to obtain high yields and at the same time maintain a high antioxidant capacity. On the other hand, the use of tomato and tomato extracts as natural additives in meat products are reduced in comparison with other natural antioxidant/colourant extracts. However, different researches conclude that the use of tomato improved nutritional quality, reduced lipid oxidation and increased stability during the shelf-life period of meat products, while retaining or increasing sensory properties and overall acceptability, which converts tomato by-products into a promising source of natural additives.

Synergistic effect of ultrasonication and co-immobilized enzymes on tomato peels for lycopene extraction

In the present work, tomato peels were pre-treated using combination of ultrasound and enzyme co-immobilized amino-functionalized magnetic nanoparticles (AMNPs) for the efficient release of lycopene. To achieve maximum activity of enzymes in the co-immobilized form, optimization of several parameters were carried out. Moreover, the influence of ultrasound and enzyme co-immobilized magnetic nanoparticles on lycopene release was studied. Maximum lycopene release was obtained at 3% (w/w) enzyme co-immobilized AMNPs, pH 5.0, temperature of 50 °C, at 10 W ultrasound power and 20 min incubation time. After enzymatic pre-treatment, lycopene from the pre-treated mixture was extracted and separated using tri-solvent extraction method. Maximum recovery of lycopene using solvent extraction was obtained at 50 °C, 90 min of incubation time and agitation speed of 150 rpm. The presence of lycopene in the extract was confirmed by FT-IR, UV-vis spectroscopy and HPLC analysis. The co-immobilized bio-catalyst showed excellent reusability giving more than 50% lycopene yield even after 6th cycles of reuse.

Modeling of the lycopene extraction from tomato pulps

The inputs of this network were the concentration of pectinase and time of incubation, and the outputs were extracted lycopene and the activity of radical scavenging activity. Two different networks were designed for the process under the sonication and without it. For optimal network, networks' transfer functions and different learning algorithms were evaluated and the validity of each one was determined. Consequently, the feedforward neural network with function of logarithmic transfer, Levenberg Marquardt algorithm and 4 neurons in the hidden layer with the correlation coefficient of 0.96 and 0.99 were respectively observed for the treatments under sonication and without it, furthermore, root mean squared error and standard error values were obtained 0.46 and 0.22 respectively for the treatments under sonication and 0.77 and 0.38 without it as respectively optimal networks. The selected networks could determine the chosen responses, individually and in combined effect of both inputs as well (R(2) > 0.98).

The combined use of ultrasound and molecular sieves improves the synthesis of ethyl butyrate catalyzed by immobilized Thermomyces lanuginosus lipase

In this work, the combined use of ultrasound energy and molecular sieves was investigated for the synthesis of ethyl butyrate, ester with mango and banana notes, catalyzed by the immobilized lipase from Thermomyces lanuginosus (Lipozyme TL-IM). Initially, the best concentrations of biocatalysts (35%) and butyric acid (0.7M) were tested using ultrasound as an alternative to mechanical agitation. The amount of acid in the reaction could be increased by 2-fold when compared to previous works where mechanical agitation was used. In the next step, substrate molar ratio and reaction temperature were optimized and the best conditions were at their lowest levels: 1:1 (acid:alcohol), and 30°C, reaching 61% of conversion in 6h. Molecular sieves (3Å) were added to optimized reaction medium in order to remove the formed water and improve the maximum yield. The reaction yield increased 1.5 times, reaching 90% of conversion in 6h, when 60mg of molecular sieves per mmol of butyric acid was used. Finally, the reuse of Lipozyme TL-IM for the ultrasound-assisted synthesis of ethyl butyrate was verified for 10 batches, without any appreciable loss of activity, whereas in systems using mechanical agitation, the biocatalyst was completely inactivated after 5 batches. These results suggest that the combined use of ultrasound and molecular sieves greatly improve esterification reactions by stabilizing the enzyme and increasing yields.

Combined effects of ultrasound and immobilization protocol on butyl acetate synthesis catalyzed by CALB

It is well established that the performance of lipase B from Candidaantarctica (CALB) as catalyst for esterification reactions may be improved by the use of ultrasound technology or by its immobilization on styrene-divinylbenzene beads (MCI-CALB). The present research evaluated the synthesis of butyl acetate using MCI-CALB under ultrasonic energy, comparing the results against those obtained using the commercial preparation, Novozym 435. The optimal conditions were determined using response surface methodology (RSM) evaluating the following parameters: reaction temperature, substrate molar ratio, amount of biocatalyst, and added water. The optimal conditions for butyl acetate synthesis catalyzed by MCI-CALB were: temperature, 48.8 °C; substrate molar ratio, 3.46:1 alcohol:acid; amount of biocatalyst, 7.5%; and added water 0.28%, both as substrate mass. Under these conditions, 90% of conversion was reached in 1.5 h. In terms of operational stability, MCI-CALB was reused in seven cycles while keeping 70% of its initial activity under ultrasonic energy. The support pore size and resistance are key points for the enzyme activity and stability under mechanical stirring. The use of ultrasound improved both activity and stability because of better homogeneity and reduced mechanical stress to the immobilized system.

Bio-based hyperbranched poly(ester amide)-MWCNT nanocomposites: multimodalities at the biointerface

There has been a growing interest in the use of nanomaterials featuring potent biocompatibility and biodegradability together with the added facet of antibacterial activity, particularly against drug-resistant bacterial species. Addressing these three features at the biointerface, we report the fabrication of multimodal bio-based hyperbranched poly(ester amide) (HBPEA)-microwave functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposites by incorporation of various weight percentages (1, 2.5, and 5 wt%) of the f-MWCNTs into HBPEA by using an ex situ polymerization technique. Fourier transform infrared spectroscopy confirmed the structural changes upon interaction of the f-MWCNTs with HBPEA. The formation of thermosetting nanocomposites resulted in an acceptable improvement of the desired properties including their mechanical properties (∼170%), instrumental for providing mechanical integrity in cultured cells. The nanocomposite films were found to be biocompatible substrates for the in vitro adhesion and proliferation of peripheral blood mononuclear cells (PBMC) with enhanced cell viability correlating with the increase of the f-MWCNT content. The antibacterial results, monitored by a CFU count and the protein concentration, demonstrated that the prepared nanocomposites were more toxic towards Gram positive bacteria and Mycobacterium smegmatis than the Gram negative ones. The damage of bacterial cells upon interaction with the nanocomposites was validated by UV-visible spectroscopy and a SEM study. The antibacterial and biocompatibility studies suggested that these microporous nanocomposite films (3D interconnected porous structures with pore diameters of 5-105 μm and a porosity of 39.90%) possess concurrent long-term lethal activity against the bacterial cells and biocompatibility with PBMC. Thus, the prepared nanocomposites may find potential bio-medical applications, particularly as antimicrobial dressing materials for infected burn wounds.

Green Extraction: Enhanced Extraction Yield of Asiatic Acid from Centella asiatica (L.) Nanopowders

Nanopowders of Centella asiatica (L.) were produced using planetary ball mill in order to investigate the differences of water extraction yield of asiatic acid as compared to micropowders of Centella asiatica. Effect of extraction time (20–60 min) on extraction yield of asiatic acid from Centella asiatica was examined. Results showed that water extraction of asiatic acid using Centella asiatica nanopowders exhibits was almost 50% higher extraction yield with 7.09 mg/g as compared to the micropowders of Centella asiatica. It was concluded that nanopowders contributed in enhancing water extraction yield of asiatic acid as compared to micropowders. Thereby utilizing nanopowders in water extraction could improve the extraction of asiatic acid via clean, eco-friendly, and less expensive process.

Ultrasound extraction optimization of Acanthopanax senticosus polysaccharides and its antioxidant activity

In this study, effects of several experimental parameters, including ultrasonic time, ratio of water to material, extraction temperature and ultrasonic power on the extraction yield of polysaccharides from Acanthopanax senticosus stem (ASS) were investigated by single factor experiment and an orthogonal test design (L9(3)(4)) was used to optimize the ultrasound extraction conditions. The polysaccharides from Acanthopanax senticosus stem (ASSP) and fruit (ASFP) were further fractionated by stepwise ethanol precipitation and the anti-oxidation activities of those fractions were evaluated by hydroxyl, superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Under the optimal conditions (ultrasonic time 75min, ratio of water to material 50ml/g, extraction temperature 80°C and ultrasonic power 100W), the yield was 10.9mg/g. All fractions of ASP possessed considerable antioxidant activity. The results indicated that the ultrasound extraction was a very useful method for the extraction of ASP and the polysaccharides could be explored as a potential antioxidant agent for use in medicine or functional food.