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Application of ultrasound for green extraction of proteins from spirulina. Mechanism, optimization, modeling, and industrial prospects

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... Another researcher also agreed that ultrasound is relatively easy to use, versatile, flexible, and requires low investment compared to other novel extraction techniques, such as supercritical fluid extraction (Vernes et al. 2019, Gonzalez-Balderas et al. 2020. Furthermore, UAE is an efficient extraction technique that dramatically reduces working times, increasing yields and quality. ...
... It comprises mechanical waves that need an elastic medium to spread, creating regions of alternating compression and rarefaction waves induced on the medmedium's molecules. Ultrasound appears as a nondestructive and efficient technique since the protein extracted still contained essential amino acids of the initial biomass (Vernes et al. 2019). In addition, Mahali and G (2019) revealed that the functional properties of the protein isolates determined at various pH levels obtained in ultrasound extraction had a high protein yield of 84% in A. plantesis. ...
... Consequently, the cost-efficacy of a cell disruption method does not only depend on the energy consumption of the cell disruption process itself but also the results of the overall energy demand, supplementary chemicals, labor, operational, and capital expenditures (Soto-Sierra, Stoykova, and Nikolov 2018; Vernes et al. 2019). The massive difference between the energy needed to directly disrupt cells on an analytical and preparative scale demonstrates the influence of energy transfer. ...
Article
There is an emergent demand for sustainable and alternative protein sources such as insects and microorganisms that meet the nutritional requirements. Microalgae possess valuable substances that could satisfy the population’s dietary requirement, medicinal purpose, and energy, aligned with effective processing techniques. Several disruption techniques were applied to microalgae species for protein recovery and other compounds. The thick microalgae cell wall makes it difficult to recover all the valuable biomolecules through several downstream processes. Thus, forethought key factors need to be considered when choosing a cell lysis method. The most challenging and crucial issue is selecting a technique that requires consideration of their ability to disrupt all cell types, easy to use, purity degree, reproducible, scalable, and energy efficient. This review aims to provide useful information specifically on mechanical and non-mechanical disruption methods, the status and potential in protein extraction capacities, and constraints. Therefore, further attention in the future on potential technologies, namely explosive decompression, microfluidization, pulsed arc technology, is required to supplement the discussed techniques. This article summarizes recent advances in cell disruption methods and demonstrates insights on new directions of the techniques and future developments.
... This approach has the advantage of straightforward scalability due to its ability to generate increasingly strong areas of cavitation and therefore is suitable for process scaling [33]. Cavitation bubbles in an aqueous suspension of algae produce severe and localized short-term pressure increases as well as microstreaming effects and shock waves that promote the rupture of algae cells [34,35]. The ability of US to cause cavitations depends on its frequency and intensity, medium properties, and ambient conditions [36]. ...
... A feasibility and cost estimate study, in addition to an environmental footprint estimation, of a large-scale ultrasound extraction plan to recover proteins from Spirulina was performed and concluded that the process could be applied in industrial production as an environmentally friendly method. Therefore, depending on the processing volumes, it could be economically feasible to implement an US-assisted C-PC extraction method for industrial applications, considering the low environmental impact of this technique and its high added value [35]. Content courtesy of Springer Nature, terms of use apply. ...
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Spirulina platensis is a cyanobacterium with biological activities. This characteristic is mainly due to its blue pigment C-phycocyanin (C-PC), which is an important commercially available blue food colorant. To take maximum advantage of the benefits of C-PC, a comparative study of four different pretreatment techniques, namely, freeze-thaw (F/T), enzymatic (EE), ultrasound (US), and pulsed electric field (PEF) pretreatment, for C-PC extraction from S. platensis dry biomass was performed to select the method providing the highest yield and desired purity. The extraction of C-PC was conducted using 100 mM phosphate buffer, pH 6.8, which is a green solvent. The highest C-PC yield of 129.5 ± 7.78 mg/g was obtained with US pretreatment after 30 min of sonication at 40 kHz frequency. The next highest yield of 84.00 ± 2.13 mg/g was recorded after 240 μs of PEF pretreatment with a voltage of V = 24 kV/cm and 44 pulses (average pulse width of 5.36 μs). The highest purity of 2.47 ± 0.21 was obtained with F/T pretreatment, followed by US (2.15 ± 0.12) and PEF (2.13 ± 0.39).
... Fresh Spirulina, in its natural state, is made of regularly wrapped spiral multicellular filaments, which are well compartmentalized with a lot of proteins partitioned within the cells. However, the cell wall is made of multiple layers, the first of which containing β-1,2-glucan (Vernès et al., 2019;Chen et al., 2020), that might limit the bioaccessibility of such acclaimed components. ...
... Moreover, the decrease of protein (10-20%) during drying was previously reported (Oliveira et al., 2009) with losses directly proportional to the process temperature (Desmorieux and Hernandez, 2004). Overall, drying treatments are also responsible for an alteration of the biomass, filaments unfold, and begin to fragment; nevertheless, the cells remain intact (Vernès et al., 2019). ...
Article
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This study aimed at investigating the effect of fermentation and enzymatic treatment on the degree of proteolysis of wet (WB), dried at low temperature (DB), and freeze-dried Spirulina (LB) proteins that affect the nutritional (e.g., amino acid content and profiles, and protein digestibility) and functional (e.g., antioxidant and antimicrobial activities) properties. The desiccation treatments influenced the unprocessed Spirulina characteristics because, compared with that in WB, peptides and free amino acids content was 73% lower in DB and 34% higher in LB. An integrated approach, including chromatographic and electrophoresis analyses, was used to evaluate the effect of the different bioprocessing options on protein profiles, release of peptides and amino acids, and the overall protein digestibility. Compared with the application of fermentation with the selected Lactiplantibacillus plantarum T0A10, the treatment with the endopeptidase Alcalase®, alone or combined, determined the most intense proteolysis. Moreover, the treatment with Alcalase® of LB allowed the release of potentially bioactive compounds that are able to inhibit Penicillium roqueforti growth, whereas the combination of fermentation with L. plantarum T0A10 and Alcalase® treatment increased Spirulina antioxidant properties, as determined by the scavenging activity toward ABTS radical (up to 60%) and antimicrobial activity against food pathogen Escherichia coli.
... Vernèsa et al. [52] suggested a new method for the extraction of proteins from Arthrospira platensis, based on the combined effect of three parameters: pressure, temperature and ultrasound. Using the developed method, the authors were able to increase the protein yield by 229% compared with the usual method of ultrasonic treatment. ...
... Advantages and disadvantages of various methods for protein isolation from microalgae biomass (table built using combined data from previous studies[48][49][50][51][52][53][54][55][56][57][58]). ...
Article
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Microalgae are a group of autotrophic microorganisms that live in marine, freshwater and soil ecosystems and produce organic substances in the process of photosynthesis. Due to their high metabolic flexibility, adaptation to various cultivation conditions as well as the possibility of rapid growth, the number of studies on their use as a source of biologically valuable products is growing rapidly. Currently, integrated technologies for the cultivation of microalgae aiming to isolate various biologically active substances from biomass to increase the profitability of algae production are being sought. To implement this kind of development, the high productivity of industrial cultivation systems must be accompanied by the ability to control the biosynthesis of biologically valuable compounds in conditions of intensive culture growth. The review considers the main factors (temperature, pH, component composition, etc.) that affect the biomass growth process and the biologically active substance synthesis in microalgae. The advantages and disadvantages of existing cultivation methods are outlined. An analysis of various methods for the isolation and overproduction of the main biologically active substances of microalgae (proteins, lipids, polysaccharides, pigments and vitamins) is presented and new technologies and approaches aimed at using microalgae as promising ingredients in value-added products are considered.
... Ultrasonication is a non-destructive and efficient pre-treatment method in which high frequency of ultrasound waves is used to agitate and lyse the microalgal cells [147,209]. Cell disintegration is performed by cavitation which is generation, development, and collapse of bubbles in a solution resulting in rise of viscosity and shockwaves and electrical signals which are converted into physical vibration to rupture the elements apart of the microalgal cells [42, 138,217]. The mechanism for greater recovery of proteins with ultrasonic extraction treatment is acoustic cavitation which is an event occurring in the liquid medium under the influence of ultrasound waves, responsible for tissue disruption [123]. ...
... the maximum concentration of proteins obtained using the ultrasound technique, studies supported that this method is environment friendly [97]. As reported by Skorupskaite et al. [186], it is an uncomplicated method to capably break down the cells, easily scalable, versatile, flexible, decrease extensive energy demand, reduces working time, safety measures associated with use of method and can be operated continuously for long run compared to other novel extraction techniques like supercritical fluid extraction [66,186,209]. More noteworthy improvements in VAB recovery from this method employing several algal species are Chlorella, Scenedesmus, Nannochloropsis, and Neochlorisoleo abundans and to a little extent in Botryococcus species also. ...
Article
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Cell disruption is very important for the value-added biocompounds (VAB) to come out from microalgae. Among the most demanding microalgae at industrial level, diatoms and Haematococcus pluvialis have hooked the race. However, they at the same time face difficulty in their cell wall disruption for the VAB to come out as it is very rigid and thick. This is among the major barrier in construction of diatom solar panels for biofuel production. Different diatom walls experience different shear forces for harvesting its biomass. This results in raising the overall cost of photobioreactors controlling their growth and recovery of biomass and VAB. In order to lower the cost, the cell wall of microalgae needs to milk the metabolites without itself getting sacrificed. The current review in depth discusses the techniques to break the cell wall of microalgae especially diatoms and Haematococcus using nanotechnological approaches without lysing the cell. The research gaps, commercial applications, and future research directions have been identified and discussed to strengthen the environmental and economical sustainability. Graphical abstract
... In addition, it is also enriched by various essential acids including histidine, threonine, methionine, valine, lysine, cysteine, and other non-essential amino acids [5]. This has drawn huge attention for researchers to study the application of the protein from Spp into many such as biofuel feedstock, human food supplement, medication, and also anti-oxidation activity [4,[6][7][8]. Furthermore, Spp has been applied as a dietary supplement to provide insufficient nourishment of poor children in developing countries [9]. ...
... Yields of extraction in UAE are affected by particle sizes, types of solvent, temperature, solvent to biomass ratios, and time of extraction are critical parameters in the UAE method to obtain high yields [14]. Different types have been employed to extraction the protein, include methanol, mixture of methanol and ethanol [5], distilled water [6,10], and sodium phosphate buffer [7]. In this paper, we aimed to study the effect on different solvent types, ratios of solvent to biomass, and extraction time with the UAE of Spp to determine the relatively best condition for protein recovery. ...
Article
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Protein is a substantial nutrition that essentially required by human. Spirulina platensis ( Spp ), well known as protein source could be a significant source to be used for many industrial applications. This study was investigated the effectiveness of ultrasound assisted extraction (UAE) method for protein extraction from Spp at various composition of solvent mixture and extraction time. Ethanol and mixture of methanol-ethanol were used as solvent. Extraction was conducted by varying ratios of solvent to biomass at 10:1, 12.5:1, and 15:1 (v/w), and extraction time (20, 35, and 50 min). Optimum protein recovery from dry Spp was 42.55 ± 0.43% obtained by using 20 ml of the mixture of methanol and ethanol at 50 min of extraction time. This study also conducted that mixture of methanol and ethanol was a better solvent on improving the ultrasound assisted extraction, as indicated by high protein recovery with less amount of solvent volume used.
... Nowadays, innovative alternative technologies, such as supercritical fluid extraction (SFE), pressurized liquid extraction (PLE), ultrasound-assisted extraction (UAE), pulsed electric field-assisted extraction (PEF) and microwave-assisted extraction (MAE), are being studied to extract interesting compounds from microalgae [11][12][13][14][15]. These techniques produce a low environmental impact, since no organic solvents are used and there is less volume consumption. ...
... Adam et al. [18] reported the effective extraction of lipids from Nannochloropsis oculata under USN treatment. On the other hand, Vernès et al. [11] and Hildebrand et al. [19] proposed USN technology as an effective tool for the rapid extraction of proteins from Spirulina and Chlorella vulgaris microalgae, respectively. In general, all these authors obtained better results employing ultrasound than those obtained with conventional extraction. ...
Article
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In recent years, a growing interest has been shown in the use of microalgae due to their interesting nutritional and bioactive profiles. Green innovative processing technologies such as ultrasound-assisted extraction (UAE) avoid the use of toxic solvents and high temperatures, being a sustainable alternative in comparison with traditional extraction methods. The present study aims to evaluate the recovery of high added-value compounds from Phaedoactylum tricornutum assisted by ultrasound. To optimize the UAE of proteins, carbohydrates, pigments and antioxidant compounds, a response surface methodology was used. Carbohydrate extraction was positively affected by the temperature. However, for the extraction of carotenoids, the most influential factor was the extraction time. The total polyphenols were only significantly affected by the extraction time. Finally, the antioxidant capacity, measured by 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), was strongly modulated by the extraction time, while for the oxygen radical antioxidant capacity (ORAC) assay, the most important parameter was the temperature, followed by the extraction time. The optimal conditions for the maximum extraction of nutrients, bioactive compounds and antioxidant capacity were 30 min, 50 ºC and a pH of 8.5. Finally, it has been seen that with these conditions, the extraction of fucoxanthin is allowed, although no differences were found between an ultrasound-assisted extraction and a shaking extraction (control).
... The authors ascribed this enhancement to improved cavitation through manosonication, i.e., a combination of ultrasound and pressure. In another study, MS enhanced protein extraction from spirulina, a 6% improvement with respect to standard ultrasound treatment (Vernès et al., 2019). Tchabo et al. (2017) found that among other non-thermal technologies, MS increased the phenolic compounds in aged mulberry wines. ...
... Tchabo et al. (2017) found that among other non-thermal technologies, MS increased the phenolic compounds in aged mulberry wines. These studies clearly show the positive effects of ultrasound when combined with an optimal pressure value adjusted by means of a suitable valve (manual valve in Meullemiestre et al., 2017;Vernès et al., 2019). ...
Article
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Recent research has demonstrated how ultrasound can benefit the industrial processing of olive paste before oil extraction. However, the absence of a device for controlling pressure inside the sonication cell is a major hindrance to its application. To address this problem, a pneumatic device with a programmable logic controller was implemented to automatically adjust pressure in the sonication cell according to a preset value: its functionality was tested in industrial oil extraction. An experiment was conducted to compare device performance when applied to olive batches with different solid/liquid ratios and differing rheology. The control system adjusted the flow section of the valve at the outlet of the sonication cell and the mass flow rate of the feed pump in order to maintain the pressure preset by the operator. Results indicate that the pressure was 3.0 ± 0.2 bar, 3.5 ± 0.2 bar, and 4.0 ± 0.2 bar when the set point was 3.0 bar, 3.5 bar, and 4.0 bar, respectively: there was thus no significant difference between controlled and set values. This indicates that the device is able to control pressure inside the sonication cell with a maximum deviation of 0.2 bar. In this case, the sonication intensity was stabilized at 135 W/cm ² , 150 W/cm ² , and 165 W/cm ² at 3.0 bar, 3.5 bar, and 4.0 bar, respectively. This study presents an advancement in ultrasound applications for industrial olive oil extraction: optimal pressure control in the sonication cell.
... Gelatin UB 45 [31] 150 W [125] Fish (bone) Gelatin UB 300 [14] 700 W [126] Soft-shelled turtle Collagen UP 5 [13] 200 W, 24 kHz, 2s pulls on-3 s off mode [127] Fish (skin) Collagen UP 480 [4] 20 kHZ, 80% amlitude, 20s pulls off 20 s off mode [128] Micro algae Fucoxanthin UB 30 70 kHz [129] Seaweed Carrageenan UB 40 [14] 40 kHz [130] ,, Carrageenan UP 10 [26] 100 W, 20 kHz, 100% amplitude [131] ,, Carrageenan, alginate UB 30 [89] 150 W, 25 kHz [132] Micro algae Astaxanthin UP 15 [28] 200 W, 20 kHz, 10% amplitude [133] Prawns (shells) Chitin UP 240 [36] _ [134] Seaweed Agar UP 30 [89] 400 W, 24 kHz [135] ,, Polysaccharides UB 30 [63] 60 W [136] ,, Polysaccharides UB 15 [24] 150 W, 35 kHz [137] Green algae Polysaccharides UB 40 [68] 180 W, 53 kHz [138] Seaweeds Polysaccharides (fucoidan) UB 59 [14] 196 W [139] ,, Polysaccharides (fucoidan) UB 25 [28] 150 W, 40 kHz [137] ,, Polysaccharides (fucoidan) UB 54 [11] 400 W, 24 kHz [140] ,, Bio-active compounds UB 60 [31] 400 W, 10 min on, 2 min off mode [141] Brown algae Bio-active compounds UB 60 [34] 150 W, 60% amplitudes [142] Brown seaweed Bio-active compounds UP 15 750 W, 20 kHz, 80% amplitude [143] ,, Bio-active compounds UP 25 750 W, 20 kHz [144] Microalgae Bio-active compounds UP 5 400 W, 4 kHz [145] Red seaweed Bio-active compounds UB 58 [45.3] 250 W, 40 kHz [146] Seaweeds Bio-active compounds UB 35 [58] _ [147] Microalgae Bio-active compounds UP 30 [<45] 400 W [148] ,, Lutein UB 30 [36] 35 kHz [149] ,, Pigments UB 79 [64] 200 W, 40 kHz [150] Squid Pigments UB 9 _ [151] Fish Protein UP 3 [<5] 900 W, 20 kHz, 75% amplitiude, 3s pulse on, 2 s off mode [152] ,, Protein UP 10 [4] 750 W, 20 kHz [153] Squid Protein UP 90 [<3] 20 kHz, 40% amplitude [154] Microalgae Protein _ 20 37 kHz [155] ,, Protein UP 15 200 W, 20% amplitude, 5s pulse on, 5s off mode [156] Cyanobacteria Protein UP 20 [<40] 1000 W, 20 kHz [157] Macroalgae Phycobiliproteins UP 10 [34] 1s pulse on, 1s off mode [158] Red algae Amino acid (taurine) UP 38.3 [40.5] 300 W, 20 s pulls on, 2 s off mode [159] Fish Oil UP 15 20 kHz, 40% amplitude, 3s pulse on, 2s off mode [160] Microalgae Oil UB 30 750 W, 20 kHz [161] ,, Lipid UB 20 [28] 40 kHz [162] ,, Lipid UB 180 [63] _ [163] ,, Lipid UP 30 1000 W, 20 kHz [164] ,, Lipid UP 30 1000 W, 20 kHz [165] (Continued) was successfully extracted from dried Arthrospira platensis (spirulina) cyanobacteria after optimizing a green and innovative method referred to as manothermosonication (MTS) UAE. MTS has yielded 229% more protein than the conventional extraction. ...
... MTS has yielded 229% more protein than the conventional extraction. [157] UAE has offered higher extraction yields for simple sulfur-containing amino acid (taurine) from red algae (Porphyra yezoensis) [159] ; whereas, phycobiliproteins (R-phycoerythrin, R-PE and R-phycocyanin, R-PC) were also efficiently isolated from the macroalgae Gelidium pusillum. [158] Synergetic effects were found when combining UAE and homogenization (9.3% extraction enhancement) and UAE and maceration (31% extraction enhancement). ...
Article
Ultrasound-Assisted Extraction (UAE) has attracted much attention in recent years due to its rapid extraction capability, high extraction efficiency, and being an environmentally friendly and low-cost methodology. This review gives a general overview of UAE and specifically its recent applications on fish and aquatic living resources. Moreover, the extraction efficiency of UAE is compared with those offered by other extraction methods. The UAE technique is a hopeful tool for compounds extraction, and it is possible to combine it with other sample pre-treatment techniques such as solid-phase and liquid-phase microextraction techniques.
... Ultrasonic-assisted extraction has received broad attention due to high protein recovery from algae biomass [9]. This technology has the advantage of being able to disrupt algae cell walls based on the cavitation phenomena, thus improving the extraction yield compared to conventional methods, with a significant reduction in solvent consumption, temperature, extraction time and cost [3,10]. ...
Article
Spirulina platensis has been referred as a potential source of high-value added compounds. The objective of this work was to investigate ultrasound-assisted food-grade solvent extraction of valuable compounds from microalgae Spirulina platensis. Besides the ultrasound-assisted solvent extraction, conventional extraction methods such as pre-soaking and homogenization were implemented for effective disruption of cells. Individual food-grade solvents (water (W), ethanol (E)) and their mixture (70% water +30% ethanol (WE30), 50% water +50% ethanol (WE50), 30% water +70% ethanol (WE70)) were used for the extraction procedures. The optimum C-phycocyanin concentration was obtained for the W extraction with 20 min of sonication. The optimal extraction condition for chlorophyll a was found at 10 min of sonication when ethanol was used as the solvent. Moreover, the optimal extraction condition for chlorophyll b was obtained at 30 min of sonication and the highest yield of carotenoids extraction was found at 20 min of sonication when ethanol was used as the solvent. In case of polyphenols, the highest yield was found at 30 min of sonication when WE70 was used as the solvent. The use of ultrasound-assisted food-grade solvent extraction increased the extraction of the high-value added compounds and therefore resulted in higher antioxidant and antibacterial activities.
... Nowadays, there are many studies aimed at CP extraction from Spirulina with different methods of cell disruption, such as thawing and homogenizing [10], freezing and thawing [11], supercritical CO 2 extraction followed by the electrocoagulation method [12], high-pressure cell disruption [13], and ultrasound-assisted extraction [14]. Chittapun, Jonjaroen, and Charoenrat [15] indicated that the freezing and thawing technique showed better performance in terms of CP concentration than the pulsed electric field technique, while CP obtained from the pulsed electric field technique showed a higher purity. ...
Article
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The effect of four different extraction methods on physicochemical characteristics and functionalities of chloro-phycocyanin (CP) was investigated. Swelling (S-CP), freezing and thawing (4FT-CP), ultrasonication with freezing and thawing (4FT+U-CP), and the high-pressure cell disruption (HPCD-CP) process affected CP differently, thus resulting in different levels of solubility, DPPH scavenging activity, ABTS scavenging activity, and reducing power. Among the four CPs, HPCD-CP had the highest CP content (15.3%), purity (1.66 ± 0.16), and ∆E value but the lowest ∆b value. The ζ potential of HPCD-CP (−38.8 mV) was the highest, but the average particle size of 4FT+U-CP (719.1 nm) was the highest. UV-Vis absorption spectra and fluorescence spectra illustrated that high-pressure cell disruption-assisted extraction had more profound impacts on the microenvironment of tetrapyrrole chromophores, the environment of aromatic amino acids, and the phycocyanobilin of CP. Furthermore, HPCD-CP and 4FT-CP showed higher solubility and antioxidant activities than S-CP, especially 4FT+U-CP. The results obtained in this study demonstrate that HPCD technology could obtain a food-grade C-phycocyanin product with higher CP concentration, purity, solubility, and antioxidant activity.
... For example, UAE, conducted at room T for 60 min and using water as solvent, promoted the highest recovery of proteins (84%) from algal sources, comparing with other four applied techniques, such as alkali, enzymatic, thermal, and microwave-assisted extraction (MAE) [73]. A study developed on A. platensis concluded that UAE, performed using sodium phosphate buffer and a frequency of 20 kHz, increased the extraction of proteins by 229% [104]. In addition, protein extraction can be improved through the combination of various techniques with UAE. ...
Article
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The increase in life expectancy has led to the appearance of chronic diseases and interest in healthy aging, in turn promoting a growing interest in bioactive compounds (BCs) and functional ingredients. There are certain foods or products rich in functional ingredients, and algae are one of them. Algae consumption has been nominal in Europe until now. However, in recent years, it has grown significantly, partly due to globalization and the adoption of new food trends. With the aim of obtaining BCs from foods, multiple methods have been proposed, ranging from conventional ones, such as maceration or Soxhlet extraction, to more innovative methods, e.g., ultrasound-assisted extraction (UAE). UAE constitutes a novel method, belonging to so-called green chemistry, that enables the extraction of BCs requiring lower amounts of solvent and energy costs, preserving the integrity of such molecules. In recent years, this method has been often used for the extraction of different BCs from a wide range of algae, especially polysaccharides, such as carrageenans and alginate; pigments, including fucoxanthin, chlorophylls, or β-carotene; and phenolic compounds, among others. In this way, the application of UAE to marine algae is an efficient and sustainable strategy to pursue their deep characterization as a new source of BCs, especially suitable for vegetarian and vegan diets.
... For example, the use of UAE with a subsequent alkaline treatment allowed the extraction of 57% of the total proteins from Ascophyllum nodosum [24]. Moreover, the use of ultrasounds enabled 2.29-fold higher yields of protein extraction compared to conventional methods from the microalga A. platensis [25]. ...
Article
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Over the last decade, algae have been explored as alternative and sustainable protein sources for a balanced diet and more recently, as a potential source of algal-derived bioactive peptides with potential health benefits. This review will focus on the emerging processes for the generation and isolation of bioactive peptides or cryptides from algae, including: (1) pre-treatments of algae for the extraction of protein by physical and biochemical methods; and (2) methods for the generation of bioactive including enzymatic hydrolysis and other emerging methods. To date, the main biological properties of the peptides identified from algae, including anti-hypertensive, antioxidant and anti-proliferative/cytotoxic effects (for this review, anti-proliferative/cytotoxic will be referred to by the term anti-cancer), assayed in vitro and/or in vivo, will also be summarized emphasizing the structure–function relationship and mechanism of action of these peptides. Moreover, the use of in silico methods, such as quantitative structural activity relationships (QSAR) and molecular docking for the identification of specific peptides of bioactive interest from hydrolysates will be described in detail together with the main challenges and opportunities to exploit algae as a source of bioactive peptides.
... Cavitation is considered the fundamental mechanism for UAE, where micro-bubbles form and collapse near the cells, creating cellular disruption. Furthermore, UAE has the benefits of higher efficiency, reduced amount of solvent and extraction time, moderate cost, and simple handling [14,15]. Additionally, ultrasonication can usually be carried out at a low temperature, which reduces potential thermal damage to bioactive ingredients or the loss of volatile components during extraction or pretreatment. ...
Article
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Microalgal biomass is a sustainable source of bioactive lipids with omega-3 fatty acids. The efficient extraction of neutral and polar lipids from microalgae requires alternative extraction methods, frequently combined with biomass pretreatment. In this work, a combined ultrasound and enzymatic process using commercial enzymes Viscozyme, Celluclast, and Alcalase was optimized as a pretreatment method for Nannochloropsis gaditana, where the Folch method was used for lipid extraction. Significant differences were observed among the used enzymatic pretreatments, combined with ultrasound bath or probe-type sonication. To further optimize this method, ranges of temperatures (35, 45, and 55 °C) and pH (4, 5, and 8) were tested, and enzymes were combined at the best conditions. Subsequently, simultaneous use of three hydrolytic enzymes rendered oil yields of nearly 29%, showing a synergic effect. To compare enzymatic pretreatments, neutral and polar lipids distribution of Nannochloropsis was determined by HPLC–ELSD. The highest polar lipids content was achieved employing ultrasound-assisted enzymatic pretreatment (55 °C and 6 h), whereas the highest glycolipid (44.54%) and PE (2.91%) contents were achieved using Viscozyme versus other enzymes. The method was applied to other microalgae showing the potential of the optimized process as a practical alternative to produce valuable lipids for nutraceutical applications.
... The effect of static pressure during sonication is often disregarded. Single studies have demonstrated that a slight increase of the static pressure by a few bars improves the treatment of Arthrospira cells (Vernès et al., 2019), biological sludge (Delmas, Le, Barthe, & Julcour-Lebigue, 2015), or nanoparticle emulsions (Sauter, Emin, Schuchmann, & Tavman, 2008). It is believed that the elevated static pressure affects the nucleation of vapor bubbles as well as their oscillation dynamics and collapse in response to the acoustic pressure field, thus, the rate and amount of acoustic energy being radiated into the suspension (Yasui, Towata, Tuziuti, Kozuka, & Kato, 2011). ...
Article
The microalga C. vulgaris is a potential source for sustainable food ingredients and particularly food protein. Ultrasonication can enhance the extraction of proteins from Chlorella, but a comprehensive comparison to other cell disintegration technologies is not possible since knowledge about the energy requirements is missing. In this article, the effects of an elevated static pressure up to 5 bar, sound amplitude, and treatment duration on energy consumption and protein extraction yield were explored. Elevating the static pressure affects the oscillation dynamics and collapses of cavitating bubbles and leads to more destructive collapses and higher energy. By employing numerical simulations of bubble oscillations, it was shown that the protein yield is mostly affected by the energy being radiated during the collapse of single bubbles and the total number of collapses during the treatment. Increasing the biomass concentration before sonication offers a way to further reduce the mass-specific energy input.
... The ionic interaction between the cells, the protein molecules, intracellular oil, and polysaccharides all affect protein extraction [19]. Therefore, plant cell wall destruction and inclusion of specific reagents during the extraction process have become the key steps to improve the protein extraction efficiency [11,[20][21][22]. In order to obtain the protein in the cells, ultrasound-assisted enzymatic extraction method was used in this study. ...
Article
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To enhance the extraction yield of pecan protein and modify its functional properties, this study investigated whether both ultrasound and enzyme have a synergistic impact on the extraction of pecan (Carya illinoinensis (Wangenh.) K. Koch) protein. The highest protein extraction rate (25.51%) was obtained under the conditions of 1415.43 W.cm⁻², 15 min, pH 10.0, 50°C, and 1% (w/w) alkaline proteinase. Owing to its high shear, mechanical energy and cavitation, the ultrasound process increased the solubility of the substrate making it readily accessible to the enzyme, thereby accelerating the chemical reaction and improving the yield of the protein. The optimized ultrasound-assisted enzymatic method (400W, 20kHz, 5s/3s) effectively changed the secondary and tertiary structure of the pecan protein. The results of surface hydrophobicity, intrinsic fluorescence spectra, sulfhydryl content and scanning electron microscopy all indicated the unfolding of protein and exposure of hydrophobic groups and sulfhydryl groups. Moreover, the protein obtained by this method showed higher solubility (70.77%), higher emulsifying activity (120.56 m²/g), smaller particle size (326.7 nm), and better dispersion (0.305) than single ultrasound and non-ultrasound methods (p < 0.05). To conclude, ultrasound-assisted enzymatic method could be an appropriate technique to improve the yield and quality of the pecan protein. The study also provides a theoretical basis for the application of pecan protein in food processing.
... The number of studies on methods of processing microalgae and using them as a source of protein has rapidly increased in recent years [7]. Vernèsa et al. [8] proposed a new method of protein extraction from Arthrospira platensis based on the combined effect of three parameters: pressure, temperature, and ultrasound. When using the developed method, the authors managed to increase the protein yield by 229% as compared with the conventional method of ultrasonic exposure. ...
Article
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Microalgae are known to be rich in protein. In this study, we aim to investigate methods of producing and purifying proteins of 98 microalgae including Chlorella vulgaris, Arthrospira platensis, Nostoc sp., Dunaliella salina, and Pleurochrysis carterae (Baltic Sea). Therefore, we studied their amino acid composition and developed a two-stage protein concentrate purification method from the microalgae biomass. After an additional stage of purification, the mass fraction of protein substances with a molecular weight greater than 50 kDa in the protein concentrate isolated from the biomass of the microalga Dunaliella salina increased by 2.58 times as compared with the mass fraction before filtration. In the protein concentrate isolated from the biomass of the microalga Pleurochrysis cartera, the relative content of the fraction with a molecular weight greater than 50.0 kDa reached 82.4%, which was 2.43 times higher than the relative content of the same fractions in the protein concentrate isolated from this culture before the two-stage purification. The possibilities of large-scale industrial production of microalgae biomass and an expanded range of uses determine the need to search for highly productive protein strains of microalgae and to optimize the conditions for isolating amino acids from them.
... However, the German Hielscher Ultrasound Company manufactories industrial ultrasonic devices for continuous operations, with powers ranging from 500 to 16,000 W. Moreover, Vernès et al. (2019) conducted a feasibility and cost estimate study, in addition to an environmental footprint estimation, of a large-scale ultrasound-assisted extraction plant to recover proteins from Spirulina and concluded that the process could be applied in industrial production as an environmentally friendly method. Therefore, depending on the processing volumes, it could be economically feasible to implement UAE as a C-PC extraction method industrially, considering the low environmental impact of this technique and its high added value. ...
Article
Background C-phycocyanin (C-PC), a blue-colored natural pigment, is Spirulina's most crucial photosynthetic protein, and it is associated with this cyanobacteria's bioactivity. Many recent studies aimed at optimizing C-PC extraction from Spirulina using different protocols; however, the correlation between the extraction method (both lab scale experimental methods and industrial methods) and the antioxidant activity of the extract has not been explored yet. Scope and approach This review aimed to gather information regarding the most used C-PC extraction techniques from Spirulina in the last decade (2010–2020) and compare these biomolecules' antioxidant capacity with the extraction methodology applied. A density map was created by searching keywords related to C-PC extraction on Scopus, which guided the discussion on the C-PC extraction methods used and their impact on its bioactivity. Key findings and conclusions The density map showed that the lowest density words represented factors that can influence, describe, or determine the success of C-PC extraction. In contrast, the most cited expressions were related to the methods. The compilation of literature on the influence of C-PC extraction on its antioxidant activity showed that ultrasound-assisted extraction (UAE) and solvent extraction using water or buffer were the most used methods to extract C-PC from Spirulina in the last decade. However, the UAE does not seem to protect C-PC's bioactivity. Additionally, most studies of the previous ten years used a single method to determine C-PC's antioxidant activity. We concluded that C-PC's antioxidant activity needs to be appraised by more than one method using assays of different mechanisms to evaluate the extraction influence in its bioactivity in a panoramic way.
... The kind of solvent used and frequency, temperature, and time of sonication are the main factors determining the efficiency of the ultrasound process [11,14,17]. Ultrasound-assisted extraction has been applied for extraction of such various compounds as polysaccharides [18][19][20][21], lipids and oils [22], polyphenols [19,23], carotenoids [24], anthocyanin [25], colorant [26] and protein [27,28]. ...
Article
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The present study adopted electrohydrodynamic (EHD) and ultrasonic (US) pretreatments to enhance the extraction of phenolic compounds from Melissa officinalis. The effects of pretreatment time (EHD: 0–20 min and US: 0–60 min) and diffusion conditions (including ethanol/water ratios of 0.4, 0.8 and 1.2 (w/w), time of 30, 45, 60 min, and the temperature of 30, 50 and 70 °C) on the total phenolic content (TPC) and antioxidant activity of the extracts were investigated using Folin-Ciocalteu and DPPH assay, respectively. The results showed that EHD and US pretreatments could enhance the process of the extraction of phenolic compounds and also improve the extracts’ antioxidant activity. The highest extraction occurred at EHD time of 10 and 20 min, ethanol/water ratio of 1.2 and diffusion temperature of 70 °C. The Fourier transform infrared (FTIR) spectra also revealed that the structure of the extracted compounds was not altered as a result of EHD pretreatment. No changes, however, occurred in the functional groups of the extracts by increasing the EHD duration, diffusion temperature, and ethanol/water ratio.
... ± 1.15 g/100 g DW). Under the microscope, the perforation and fragmentation of the ultrasonic treatment samples were observed, which promoted the extraction of biologically active compounds in spirulina [35]. Another study also showed that compared to the Soxhlet extraction (80 • C and 8 h), the more efficient extraction process for extracting biomolecules from spirulina is to perform ultrasonic-assisted extraction in ethanol-chloroform-water-Na 2 SO 4 and ethanol after 20 s of water extraction in a microwave oven. ...
Article
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The research aims to extract nutrients and bioactive compounds from spirulina using a non-toxic, environmentally friendly and efficient method—Pressurized Liquid Extraction (PLE). In this work, Response Surface Methodology (RSM)–Central Composite Design (CCD) was used to evaluate and optimize the extraction time (5–15 min), temperature (20–60 °C) and pH (4–10) during PLE extraction (103.4 bars). The multi-factor optimization results of the RSM-CCD showed that under the pressure of 103.4 bars, the optimal conditions to recover the highest content of bioactive compounds were 10 min, 40 °C and pH 4. Furthermore, the compounds and antioxidant capacity of PLE and non-pressurized extraction extracts were compared. The results showed that under the optimal extraction conditions (10 min, 40 °C and pH 4), PLE significantly improved the antioxidant capacity (2870.5 ± 153.6 µM TE), protein yield (46.8 ± 3.1%), chlorophyll a (1.46 ± 0.04 mg/g), carotenoids (0.12 ± 0.01 mg/g), total polyphenols (11.49 ± 0.04 mg/g) and carbohydrates content (78.42 ± 1.40 mg/g) of the extracts compared with non-pressurized extraction (p < 0.05). The protein molecular distribution of the extracts was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the results showed that there were more small-molecule proteins in PLE extracts. Moreover, Liquid Chromatography Triple Time of Flight Mass Spectrometry (TOF–LC–MS–MS) was used to analyze the phenolic profile of the extracts, and the results showed the extracts were rich on phenolic compounds, such as p-coumaric acid and cinnamic acid being the predominant phenolic compounds in the PLE extract. This indicates that PLE can promote the extraction of bioactive compounds from Spirulina, which is of great significance for the application of PLE technology to obtain active substances from marine algae resources.
... US can reduce the size of protein aggregates-e.g., pea protein isolate, soy protein isolate-due to cavitation effect and its hydrodynamic shear forces, resulting in different emulsifying properties [44]. This technology was investigated for the extraction of proteins from several sources such as microalgae and insects, using US action alone or in combination with other strategies such as solvent phase partitioning [45][46][47]. ...
Article
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The increased pressure over soils imposed by the need for agricultural expansion and food production requires development of sustainable and smart strategies for the efficient use of resources and food nutrients. In accordance with worldwide transformative polices, it is crucial to design sustainable systems for food production aimed at reducing environmental impact, contributing to biodiversity preservation, and leveraging a bioeconomy that supports circular byproduct management. Research on the use of emergent protein sources to develop value-added foods and biomaterials is in its infancy. This review intends to summarize recent research dealing with technological functionality of underused protein fractions, recovered from microbial biomass and food waste sources, addressing their potential applications but also bottlenecks. Protein-based materials from dairy byproducts and microalgae biomass gather promising prospects of use related to their techno-functional properties. However, a balance between yield and functionality is needed to turn this approach profitable on an industrial scale basis. In this context, downstream processing should be strategically used and properly integrated. Food solutions based on microbial proteins will expand in forthcoming years, bringing the opportunity to finetune development of novel protein-based biomaterials.
... Reference Extraction [1,[15][16][17][18][19] Hydrolysis [20][21][22][23] Emulsification [24][25][26][27] Encapsulation [28][29][30][31] Adsorption/Desorption [32][33][34][35] Detachment [36][37][38][39] Freezing [38][39][40][41] Crystallization [42][43][44][45] Homogenization [46][47][48][49] Drying [50,51] Sterilization & Pasteurization [52][53][54][55] ...
Article
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Ultrasound technology is an emerging food processing technology that helps food processing/preservation shifting away from conventional thermal technologies due to their detrimental effects on food quality, composition, and sensory attributes. This review highlights the applications of ultrasound technology in food processing, and its prospects for eliminating microbial spores, important agents of food spoilage and foodborne intoxication/infection. Ultrasound (sound waves between 20–100 kHz and 2–10 MHz), when applied to foods, inhibits the proliferation of micro-organisms, extends shelf-life, and sustain food quality/sensory attributes. The generated sound waves induce intermolecular forces within the food medium and microbial cells, leading to cell wall rupture and cell lysis, and consequently inactivation. It has found application in the processing of various food items, including beef muscles, juices, oils, etc. The mode of microbial or bacterial spores’ inactivation includes cell wall and membrane disruption, inhibiting enzymatic activities and damaging DNA materials. As a tool for eliminating spores in foods, the technology is commonly used in combination with other treatments such as high temperature (thermosonication), high pressure (manosonication), and UV radiations. These combinations have been shown to improve foods’ physicochemical attributes while increasing spore permeability and sensitivity to other treatments, although through unclear mechanisms.
... Moreover, the biomolecules recovered by PEF + PLE from Spirulina in this study was also higher than other extraction techniques. For example, Vernès et al. used ultrasound technology (probe,20 kHz) to obtain 229% higher protein content (28.42 ± 1.15 g/100 g dw) from Spirulina than the traditional extraction method (8.63 ± 1.15 g/100 g dw) (Vernès et al., 2019), which was still relatively lower to the content of 400 mg/g dw protein in the PEF + PLE Spirulina extract. ...
Article
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This study aims at evaluating the impact of different processes-pulsed electric fields (PEF), pressurized liquid extraction (PLE) and a multistep process combining PEF + PLE on the yield of antioxidant compounds (protein, polyphenols, chlorophyll a, chlorophyll b, and carotenoids) from Spirulina. Firstly, the effects of PEF or PLE treatment on the extraction yield of Spirulina biomolecules were evaluated. To further increase the extraction yield, PEF + PLE was used, as an innovative extraction approach. The results showed that PEF + PLE greatly improved the extraction yield compared with the PEF or PLE treatments alone. Compared with Folch extraction (conventional control technique), PEF + PLE significantly (P < 0.05) shortened the extraction time (−165 min) and increased the protein, polyphenol, chlorophyll a and antioxidant capacity values of Spirulina extracts by 1328%, 979%, 11% and 47% respectively. Furthermore, Triple TOF-LC-MS-MS results showed that PEF + PLE increased both the type and content of phenolic compounds. The above results were attributed to PEF-induced damage on Spirulina helical structure, which was verified by fluorescence and scanning electron microscopy.
... In this process, the first specimen was warmed over for 15 min at 80 C, later treated with ultrasound for 10 min at 600 W power level (Jiang, Wang, et al., 2019). In spirulina, 20 minutes of ultrasound treatment has led to a maximal protein extraction yield of 229% (Vernes et al., 2019). Also, extraction of collagen from seafood byproducts (Kadam, Tiwari, Alvarez, & O'Donnell, 2015) and fatty acid from pacific shrimp cephalothorax (Gulzar & Benjakul, 2019) were done by UAE. ...
Article
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One of the world's promising sectors is food processing. A huge amount of waste is generated during the handling and value addition of agricultural commodities. So researches focus on extracting valuable compounds from organic waste to increase the economical value. On the other hand, the amount of debris is also reduced, which helps sustainable development and carbon footprints. Extractable compounds can be used as an alternative to synthetic compounds in food applications. For this, Ultrasound‐Assisted Extraction (UAE) captures the researcher's attention because of its advantages like less solvent utilization, low‐temperature operation, and eco‐friendly end products. This review recapitulates the mechanism and the factors affecting the extraction and possibility of compounds extracted from waste. The green separation ultrasound‐aided technique has been proven to provide higher extractable compounds. Usage of water as a solvent further reduces environmental and economic problems. By considering all of these advantages, this article discusses the mechanism, elements affecting the extraction, and the effect of combination treatment on properties and the outcome of extraction. It presents the details about the application of the UAE in the valorization of waste compounds. Practical application Food processing is one of the most promising sectors globally; the agricultural organic waste created by this sector plays a significant part in waste generation. Extracting valuable active compounds from this waste can improve the utilization of natural compounds in other foods, help obtain extra income, and help reuse industrial waste. Ultrasound‐assisted extraction is a suitable technology for extracting valuable compounds from organic waste. Optimum process conditions must be identified, which vary based on process conditions and extractable material nature to obtain the maximum extraction.
... The amino acid recovery was between 40% and 50% with water, HCL 0.4 M, and NaOH 0.4 M, with the highest being the alkaline solvent. Vernès et al. (2019b) obtained a protein recovery yield of 26.7% after 20 min of process from 1:20 (g/g) of Arthrospira platensis suspension in the phosphate buffer using an ultrasonic device at low frequency (20 kHz). The value increased by 6% with the application of 2 bar pressure. ...
Chapter
Microalgae are an important source of bioactive compounds, especially due to their high protein content. The production of bioactive compounds depends on multiple factors – from their location within the microalgae to their future uses. Several factors influence the growth of microalgae and the formation of proteins within them, especially the characteristics of the culture medium (pH, salinity, nutrients) and the operating conditions (light, temperature, reactor type). Certain combinations of these parameters favor protein production at the expense of other compounds. Once microalgae with a determined protein content have been cultivated and harvested, it is necessary to extract and separate the proteins by different methods aimed at breaking the cell wall (extraction process) and isolate proteins from other undesired compounds (separation and purification process). Finally, there is a wide range of potential applications for microalgae extracted proteins in the food science field or in products with techno functional properties, especially feeding and nutraceuticals.
... Moreover, 1.5-2 times higher extraction yields and 10-fold lower consumption of acetic acid compared to conventional processes were achieved for ultrasoundintensified production of collagen from skins of flatfish (Paralichthys olivaceus) [342]. Ultrasoundintensified hydrolysis also improved extraction yields, reduced extraction times for collagen extraction from the skin of Japanese sea bass (Lateolabrax japonicus) [391] and microalgae [392]. Ultrasonic extraction yielded relatively intact proteins, suggesting that little protein degradation occurs. ...
Article
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The global demand for dietary proteins and protein-derived products are projected to dramatically increase which cannot be met using traditional protein sources. Seafood processing by-products (SPBs) and microalgae are promising resources that can fill the demand gap for proteins and protein derivatives. Globally, 32 million tonnes of SPBs are estimated to be produced annually which represents an inexpensive resource for protein recovery while technical advantages in microalgal biomass production would yield secure protein supplies with minimal competition for arable land and freshwater resources. Moreover, these biomaterials are a rich source of proteins with high nutritional quality while protein hydrolysates and biopeptides derived from these marine proteins possess several useful bioactivities for commercial applications in multiple industries. Efficient utilisation of these marine biomaterials for protein recovery would not only supplement global demand and save natural bioresources but would also successfully address the financial and environmental burdens of biowaste, paving the way for greener production and a circular economy. This comprehensive review analyses the potential of using SPBs and microalgae for protein recovery and production critically assessing the feasibility of current and emerging technologies used for the process development. Nutritional quality, functionalities, and bioactivities of the extracted proteins and derived products together with their potential applications for commercial product development are also systematically summarised and discussed.
... The ultrasonic device, manufactured by Hielscher Gmbh (Teltow, Germany), consists of an ultrasonic generator (20 kHz), a power supply (4 kW), and cascatrodes placed in a vertical stainless-steel tube (Figure 21a). Vernes et al. 271 have used a continuous ultrasonic reactor with horns (UIP1000hd, Hielscher Ultrasonics, GmbH, Germany) for the ultrasonic extraction of proteins from spirulina. The system consists of an ultrasonic treatment chamber equipped with a sonication horn connected to a stainless-steel cylindrical feed reactor. ...
Chapter
Marine ecology is a reservoir of diverse biomaterials that has extensive applications in various fields such as the food industry, drug delivery, and tissue engineering. Marine resources, that is, algae (microalgae and macroalgae), fish seashells, and marine bacteria, are rich in protein and carbohydrate compounds with quality equivalent to traditional terrestrial resources. One of the challenging tasks for the extraction these compounds is to disrupt the rigid, thick, and complex cell walls of biological matrices of certain marine biomasses, such as algae (macroalgae and microalgae), to release the biocompounds. Ultrasound-assisted extraction is one of the most promising technologies for the efficient recovery of these compounds. Ultrasound induces cavitation in the liquid solvent and a violent collapse of the microbubbles, which damages the tissue and increases the contact area between the liquid and solid. The key benefits of ultrasonic extraction over traditional techniques are the higher rate of extractions and low solvent consumption.
Chapter
A sustainable food supply in order to ensure the extended survival of the growing human population is one of the most significant challenges in the food and agriculture sector. The major environmental concerns associated with current food-processing sectors are high energy but low-production scenario, long-time-consuming food processes, usage of huge volumes of water, and utilization of plenty of carbon resources. This chapter summarized the key concepts of green materials in food processing and novel greener technologies related to food applications. The green food science can be adopted from production to consumption in an energy-efficient way to minimize the carbon footprints and its consequences. Nowadays, the awareness of eco-friendly green technologies through emerging science like nanotechnology is increasing and is widely applied in the food system. These green materials are, therefore, cost-effective, feasible, and most appropriate to the ecological conditions of the country. Hence, green food policies and safety regulations should be designed and encouraged to develop a green sustainable world.
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Microalgae are a known source of proteins, prebiotics, lipids, small molecules, anti-oxidants and bioactives with health benefits that can be harnessed for the development of functional foods, feeds, cosmeceuticals and pharmaceuticals. This review collates information on the supply, processing costs, target markets and value of microalgae, as well as microalgal proteins, lipids, vitamins and minerals. It discusses the potential impact that microalgae could have on global food and feed supply and highlights gaps that exist with regards to the use of microalgal proteins and ingredients as foods and supplements.
Article
The aim of this paper is to present and characterize Polyamidoamine-based hydrogels (PAA) as scaffolds to host photoactive Chlorophyll a (Chl a) from Spirulina (Arthrospira platensis) sea-weed Extract (SE), for potential applications in Photodynamic Therapy (PDT). The pigment extracted from SE was blended inside PAA without further purification, according to Green Chemistry principles. A comprehensive investigation of this hybrid platform, PAA/SE-based, was thus performed in our laboratory and, by means of Visible absorption and emission spectroscopies, the Chl a features, stability and photoactivity were studied. The obtained results evidenced the presence of two main Chl a forms, monomeric and dimeric, interacting with hydrogel polyamidoamines network. To better understand the nature of this interaction, the spectroscopic investigation of this system was performed both before and after the solidification of the hydrogel, that occurred at least in 24 h. Then, focusing the attention on solid scaffold, the ¹Chl a⁎ fluorescence lifetime and FTIR-ATR analyses of PAA/SE were carried out, confirming the findings. The swelling and Point Zero Charge (PZC) measurements of solid PAA and PAA/SE were additionally performed to investigate the hydrogel behavior in water. Chl a molecules blended in PAA were (photo) stable and photoactive, and this latter feature was demonstrated showing that the pigment induced, when swelled in water and under irradiation, the formation of singlet oxygen (¹O2), measured by direct and indirect methods.
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The need of developing a new growth model based on circular economy has led to an increasing interest in the revalorization of urban and industrial wastewaters in order to use the resources efficiently. The most stablished way of valorising these residues implies the energy production in the form of biomethane. However, urban and industrial wastewaters can also be considered promising raw sources for the recovery of valuable chemical compounds. Especially, waste activated sludge from water treatment plants is a fantastic source of biomolecules such as lipids (triglycerides or fatty acids), proteins and enzymes, carbohydrates, and humic and fulvic acids. However, prior to the recovery of these biocompounds, sludge solubilization processes (thermal hydrolysis, sonication and acidification, among others) must be conducted, in order to break the cell walls and release the protoplasmic content into the liquid media, thus obtaining a matrix of high complexity, which condition the possible strategies to be applied. This review gathered and discussed in-depth the studies that deal with the recovery of valuable biocompounds from secondary waste activated sludge. Furthermore, other types of sludge comparable to the activated one, such as cell cultures and food-related sources, have been also discussed here, in order to be used as a starting point for further research on the valorisation of waste activated sludge.
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Citrus limetta is a widely-processed fruit that generates 40 % peel waste involving considerable constraints for waste management. Citrus limetta peel is a rich source of essential oil, especially d-limonene, commonly used as a fragrance and flavor ingredient. This study investigated the application of ultrasonication as a process intensification tool with improved extraction-efficiency. Peleg’s mathematical model was used to study the kinetics of ultrasound-assisted extraction (UAE) of d-limonene. The use of UAE reduces the total extraction time to 20 min compared to 185 min in a conventional process. In UAE, the highest extraction yield of d-limonene (32.9 mg/g, 97 %) was obtained using hexane as food-grade solvent, biomass:solvent ratio of 1:10, 2 mm particle size, agitation speed 300 rpm, temperature 60°C with ultrasonic power 80 W, 50 % duty cycle and frequency 25 kHz. Analysis and characterization of the extract were carried out using HPLC, GC-MS, and FTIR. Also, the surface morphology of raw material after extraction was studied using SEM analysis. The acceptable agreement was seen in the calculated values of Ceq from Peleg’s mathematical model and actual experimental results of extracted d-limonene. UAE stands as a fast, efficient, and economical method for the extraction of d-limonene from the fresh sweet lime peel.
Article
This study aimed to investigate the structural and antimicrobial properties of Maillard reaction products (MRPs) in chicken liver protein (CLP) and its hydrolysate (CLPH) after sonication (SCLPH). The MRPs of CLP (CLPM), CLPH (CLPHM) and SCLPH (SCLPHM) were analyzed by several spectrometric techniques. The molecular weights of the CLPHM and SCLPHM were primarily between 1.35 kDa and 17 kDa. Moreover, the molecular weights in the CLPHM and SCLPHM below 1.35 kDa were increased, which indicated that cross-linking and thermal degradation occurred during the Maillard reaction (MR). The SCLPHM showed an obvious network skeleton, and the surface had many small crystal-shaped particles after ultrasound treatment and MR by scanning electron microscopy. The SCLPHM had more negative charges than the CLPHM, thus effectively inhibiting the growth of S. saprophyticus and E. coli. MR and ultrasound treatment could be a promising technology to expand the application prospects of low-value meat byproducts.
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Adequate nourishment and sustenance of human body rely on the intake and absorption of sufficient dietary nutrients.Proteins derived from plant source are recently gaining popularity due to its increased popularity among vegetarian diet. Moreover, the negative impact of animal protein production on the environment and awareness to produce protein through sustainable means are gaining pace. Plant proteins are mainly serve the purpose of providing good health/nutrition and is recommended in various disease conditions, including heart diseases, diabetes, obesity and cancer. This review aims to delineate the recent developments on the extraction of protein from plant sources using conventional (solvent and alkali-based) and advanced green extraction technologies viz. biochemical extraction (single and concoction of enzymes), and physical extraction (ultrasound-, pulse electric field-, microwave- and high pressure- assisted extraction). It is evident from the findings that novel cell disruptive techniques are proven to be more efficient with respect to protein recovery and posing minimal environmental pollution. Utilizing efficient, cost effective, and eco-friendly techniques for protein extraction can help to decipher the key challenges faced by food processing industries.
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This study aimed to investigate the effect of acoustic cavitation on phenolic compounds recovery from Cucurbita pepo seed using continuous ultrasound-assisted extraction (CUAE) as a green extraction process. A Box–Behnken response surface design was carried out to investigate and optimize the CUAE independent variables, including concentration of hydroethanolic solvent, biomass to solvent ratio, and sonication time on the total extractable phenols (TEP). The optimized conditions were 70.98% v/v concentration of hydroethanolic solvent, 1:26.49 g/mL ratio of biomass to solvent, and 55.38 min sonication time, under which the predicted TEP was 14.01 mg GAE/g. The determination of DPPH and HO free radical scavenging abilities revealed that the extract had a good ability to scavenge these free radicals and polyphenol concentration was positively correlated with antiradical capacity (AC). The gas chromatography–mass spectrophotometer (GC/MS) analysis revealed that C. pepo seed extract is a potential source of essential fatty acids (39% of total fatty acids). From the results, the phenolic compounds and essential fatty acids from C. pepo seeds could be obtained using the cavitation phenomenon during short time extraction. The AC of product was considerably influenced by the CUAE process mode, while the fatty acid composition was almost constant. The microstructure of cells was investigated using scanning electron microscope (SEM), which confirmed the cell disruption by acoustic cavitation technology.
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The present study focused on evaluating the influence of ultrasonic-assisted pasteurization (UAP) on the quality and shelf stability of jambul squash. Squash was analyzed for physicochemical characteristics during a storage period of 4 months. There was a significant effect (p < .05) of storage period on the acidity, DPPH radical scavenging activity, and flavonoids of jambul squash with a significant increase in acidity and DPPH radical scavenging activity and decrease in flavonoids with the corresponding increases in sonication time and pasteurization temperature during storage. The microbial content of jambul squash during storage remained lower than untreated samples. Microstructure evaluation of jambul squash showed de-shaped middle lamella and cell wall after UAP treatment. Outcomes of the current study revealed that squash samples with increased sonication time and pasteurization temperature had less microbial content than untreated samples.
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Mechanochemical-assisted extraction (MCAE) was first applied to extract total protein from watermelon seeds with grinding medium of surfactant instead of alkaline. The optimal conditions of MCAE, that is, sodium bis(2-ethylhexyl)sulfosuccinate (AOT) concentration of 0.10 mol/L, water content of 20, ionic strength of 0.05 mol/L, aqueous phase pH of 7, solid to liquid ratio of 0.2 g/mL, ball milling speed of 523 rpm and ball milling time of 10.5 min were obtained by response surface methodology. The highest yield (489.967±1.214 mg/g) of watermelon seeds protein (WSP) was obtained under the optimal conditions, which corresponds to an increase of 19.7% in comparison with that extracted by conventional alkaline extraction. When considering the secondary structure of protein by FTIR and SEM analysis, the random coil structure of watermelon seeds protein was obviously increased and protein aggregations were apparent by conventional alkaline extraction, suggesting the denaturation of WSP under relatively alkaline environment and no loss of protein activities with surfactant interactions, thus MCAE with surfactant retained the better quality of WSP. The results indicated that MCAE with surfactant could be a protective and effective method for the extraction of natural oil-seeds protein.
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The study is about the watermelon seeds protein extraction using the specific energy per pulse (EPP) (W/g) as the operation parameter for optimization by liquid-phase pulsed discharge (LPD) at various scales, in comparison with the extraction using discharge voltage (kV) as the operation parameter for optimization by LPD. The optimization based on the intrinsic parameters of EPP (W/g), liquid to solid (L/S) ratio (mL/g) and extraction time (min) were firstly implemented. The protein yield of 462.26±1.214 mg/g was obtained under optimal conditions (0.042 W/g EPP, 3.8 min extraction time and 40 mL/g L/S ratio), which was in accordance with the yield of 462.03 ± 1.061 mg/g obtained by traditional optimization based on discharge voltage, extraction time and L/S ratio. Then, the two optimization methods were compared at larger scale of 100–280 mL solvent loading. The protein yields of the EPP optimization were 461.313±0.990, 462.102±1.034, 462.009±0.872 and 460.319±0.981, respectively, which had no significant difference. However, the protein yields of traditional optimization method decreased rapidly. Thus, the results showed that the EPP optimization method had the favorable effect on the reliability and feasibility of the scale-up LPD extraction. These indicated that the EPP accurately reflected the LPD extraction mechanism, and could replace the discharge voltage.
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The paper considers water purification processes from Bacillus bacteria type under the conditions of gases bubbling only (argon, helium, oxygen, and carbon dioxide), cavitation and combined action of gas and cavitation. The synergistic effect was found under conditions of simultaneous action of gas and cavitation (kd(gas/US ) >kd(gas) + kd(US) almost double) and it was shown that kd(gas/US) >kd(gas) by almost an order of magnitude. Relative series of effective destruction of microbial cells was established: Ar/US > О2/US >Не/US > СО2/US. Destruction degree of the cells reaches 70 %at the short-term Ar/US exposure (~8 min), which is 7 times more active than cavitation action and 13.5 times more than bubbling of Aralone.
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Phycocyanin (C-PC) application by the industry is still limited due to extraction methods drawbacks and to the low stability of these compounds after the extraction process. To overcome such limitations, alternative extraction methodologies have been evaluated, and stabilizing agents have been used under different conditions in the past years. Therefore, the aim of this review was to bring the state of the art of C-PC extraction methods, including main parameters that affect the extraction process and cell disruption mechanisms, as well as the physical and chemical parameters that may influence C-PC stability. Stabilizing agents have been used to avoid C-PC content degradation during storage and food processing. A critical analysis of the extraction methods indicated that pulsed electric field (PEF) is a promising technology for C-PC extraction since the extracts present relative high C-PC concentration and purity. Other methods either result in low purity extracts or are time demanding. Regarding stabilizing agents, natural polymers and sugars are potential compounds to be used in food formulations to avoid color and antioxidant activity losses.
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Texas almond cultivar is a crop of significant commercial value in Greece. The present study aimed to develop a new ultrasonic‐assisted extraction method for Texas almond oil based on the Folch method for laboratory use and further evaluate its in vitro antioxidant and antiplatelet, activities as health beneficial bioactivities that further highlight its nutritional value. The results showed that almond oil was quantitatively extracted at ambient temperature and 220 W ultrasonic power by hexane : Isopropanol (3:2, v/v) after 28 min with a solvent to almond ratio equal to 20. Under these conditions, the produced oil exerted antioxidant activities by the DPPH, ABTS, and CUPRAC assays equal to 1.5 ± 0.0, 1.4 ± 0.1, and 2.5 ± 0.0 equivalent nmol of Trolox per mg of almond oil respectively. The IC50 values for antithrombotic and plasma oxidation inhibition activities were 12.80 ± 0.90 and 1.09 ± 0.03 μg almond oil/μL respectively.
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The present-day consumer is not only conscious of the relationship between food consumption and positive health, but also keen on environmental sustainability. Thus, the demand for plant-based proteins, which are associated with nutrition and environmental sustainability. However, the plant-based protein industry still demands urgent innovation due to the low yield and long extraction time linked with traditional extraction methods. Although ultrasound is an eco-innovative technique, there exist limited data regarding its impact with plant-based protein. In this paper, the scientific principles of ultrasonication with regards to its application in plant-based protein research were reviewed. After comparing the cavitational and shearing impacts of different ultrasonic parameters, the paper further reviewed its effects on extracted protein characteristics and techno-functional properties. Additionally, current technological challenges and future perspectives of ultrasonication for the plant-based protein industry were also discussed. In summary, this review does not only present the novelty and environmental sustainability of ultrasound as a plant-based protein assisted-extraction method, but also highlights on the correlation between protein source, structure and subsequent functional properties which are important crucial factors for maximum application of ultrasound in the growing plant-based protein market.
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Background Enzymatic hydrolysates containing peptides with biological activity are being studied as potential novel ingredients in functional foods, cosmetics, and pharmaceuticals. Recently, the microalga Spirulina was suggested as a potential source of bioactive peptides. However, the industrial production of bioactive peptides derived from Spirulina has not yet been achieved mainly caused by high production costs and a limited number of scientific reports with in vivo assessment of bioactivity. Scope and approach In this review, current challenges and needs for reducing the costs of Spirulina production are described. This study emphasises the importance of designing the process based on the end application of the produced biomass, focusing on those requirements needed to improve protein content. Moreover, current methods used to extract proteins and produce bioactive peptides are also summarised and described. Key findings and conclusions Large-scale production of Spirulina using raceway reactors is a reality. Different types of water and nutrients have been studied and their selection will depend largely on the end application of the produced biomass. The performance of large raceway reactors is unknown and more sophisticated systems such as thin-layer cascade reactors have not yet been assessed for the large scale production of Spirulina. Spirulina proteins are a promising source of bioactive peptides, although further in vivo studies are needed to validate the several bioactivities observed in vitro.
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The marine territory is a phenomenal biodiverse constituting nearly half of the total universal biodiversity. Greater species diversity ensures a huge number of distinct natural compounds. Sustainable recovery of bioactive from renewable sources is a need of the hour. Ultrasonic irradiation is an authenticated technology to bolster the efficiency of the extraction of bioactive compounds from marine resources. The technique works on the principle of sonophysical cavitation effect resulting in changes in the physicochemical properties of the molecule, which accelerates the extraction rate and achieves better yield exceptionally at greener conditions. This chapter is dedicated to the more comprehensive discussion about the conditions and protocols for ultrasound application in the extraction of lipids, carotenoids, and other compounds from discrete unique marine sources from the scientific manuscripts accompanying industrial prospects.
Article
Soybean protein extraction was evaluated using conventional (alkaline phosphate buffer) and ultrasonication assisted methods. The impact of the extraction method on protein yield, chemical composition, and structural properties of the protein isolates was assessed. In conventional alkaline extraction, increasing pH values (from 9 to 12) led to an increase in the protein yield, with pH 12 favouring protein extraction, with yields up to 36 % (w/w). Ultrasonication process at the same pH, led to maximum protein extraction yield of 84 % (w/w). Secondary structural changes in ultrasonicated OPI samples were linked to cavitation effects and the duration of the extraction, rather than the intensity of ultrasonication process. Extracted proteins exhibited increased β-sheet content, improved zeta-potential and smaller particle size of ultrasonicated proteins, rendering them suitable ingredients for tailored food applications.
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Traditional extraction techniques have lost their optimum performance because of risingconsumer demand and novel technologies. In this regard, several techniques were developed byhumans for the extraction of plant materials from various indigenous sources, which are no longerin use. Many of the techniques are not efficient enough to extract maximum plant material. By thistime, evolution in extraction has led to development of various techniques including microfiltration,pulsed electric fields, high pressure, microwave assistance, enzyme assistance, supercritical fluid,subcritical fluid and ultrasonication. These innovations in food processing/extraction are known as“Green Food Processing”. These technologies were basically developed by focusing on three universalparameters: simplicity, energy efficiency and economy. These green technologies are practical in anumber of different food sectors, mostly for preservation, inhibition of microorganisms, inactivationof enzymes and extraction of plant material. Like the others, ultrasonication could also be used for thesaid purposes. The primary objective of this review is to confine the potential use of ultrasonicationfor extraction of oils, pectin and phytochemicals by reviewing the literature systematically.
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In order to fill the nutritional needs of a growing world population, countless efforts have been made the search for new and sustainable protein sources. However, these goals may only be met by a multidisciplinary approach, covering the whole food supply chain (from farm to fork), which needs to be addressed and reconsidered. Emerging proteins are now a big trend, but in the future can these alternative protein sources become the most healthy, tasty, and viable option for consumers? Therefore, the issue is not just about the development of functional and nutritionally balanced foods, but it is also crucial to deeply analyze how those alternative protein sources could be produced/obtained sustainably, processed, and delivered to the consumer ensuring a full nutritional and functional potential available. This chapter intends to bring new insights and considerations on the future challenges for researchers in the development of healthy, sustainable, and innovative food protein solutions.
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This is the first report illustrating the extraction of total phenolic compounds (TPC) using the ultrasound-assisted aqueous extraction (USAE) technique from waste Syzygium cumini leaves (WSCL). A kinetic study indicated that Peleg's model was appropriately fitted to the experimental data when the effect of different parameters was checked on extraction with respect to time. Extraction yields of total phenolic contents (TPC) and total flavonoid contents (TFC) were 78.38 mg GAE/g, and 10.15 mg CE/g, respectively, at optimized parameters of 1:25 WSCL: water, 35 °C temperature, 134 W power, 50% duty cycle and in 9 min. of sonication time. Cumulative yields of TPC and TFC obtained by 5 sequential stirred batch extraction were 79.36 mg GAE/g and 10 mg CE/g, respectively. The cost and energy requirement of the USAE process was around 3000 times less than that of the Soxhlet technique. SEM images showed the changes in the morphology of the WSCL surface area before and after ultrasonic extraction. FTIR analysis showed the presence of O-H, N-H, C-H, C=C, and halogenated functional groups. The obtained WSCL extract showed antioxidant potential with an IC50 value of 15.64 μg/mL. IC50 values of extract for α-amylase and α-glucosidase inhibitions were 8.3 and 6.64 μg/mL. Antiproliferation activity against breast, cervical, and lung cancer showed the potential with GI50 values 252.8, 112.5, and 97.8 μg/mL, respectively. Aqueous extract of Syzygium cumini leaves can be used to treat oxidative stress, diabetes, and cancer.
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Consumer interest in protein rich diets are increasing, with more attention being paid to the protein source. Despite the occurrence of animal proteins in the human diet, non-animal proteins are gaining popularity around the world due to their health benefits, environmental sustainability, and ethical merit. These sources of protein qualify for vegan, vegetarian, and flexitarian diets. Non-animal proteins are versatile, derived mainly from cereals, vegetables, pulses, algae (seaweed and microalgae), fungi, and bacteria. This review’s intent is to analyze the current and future direction of research and innovation in non-animal proteins, and to elucidate the extent (limitations and opportunities) of their applications in food and beverage industries. Prior knowledge provided relevant information on protein features (processing, structure, and techno-functionality) with particular focus on those derived from soy and wheat. In the current food landscape, beyond conventionally used plant sources, other plant proteins are gaining traction as alternative ingredients to formulate animal-free foodstuffs (e.g., meat alternatives, beverages, baked products, snack foods, and others). Microbial proteins derived from fungi and algae are also food ingredients of interest due to their high protein quantity and quality, however there is no commercial food application for bacterial protein yet. In the future, key points to consider are the importance of strain/ variety selection, advances in extraction technologies, toxicity assessment, and how this source can be used to create personalized food.
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Background Spirulina is multicellular and filamentous cyanobacteria that have achieved a considerable popularity in the health sector, food industry and aquacultures. It develops and grows in water, can be harvested and processed easily. It has very high content of macro and micronutrients, essential amino acids, proteins, lipids, vitamins, minerals and anti-oxidants. Spirulina is considered as a complete food supplement to fight against malnutritional deficiencies in developing countries. Spirulina is deemed safe for human consumption as evident by its long history of food use and latest scientific findings. In recent years, Spirulina has gathered enormous attention from research fraternity as well as industries as a flourishing source of nutraceutical and pharmaceuticals. Scope and approach The primary objective of this paper is to review the utilization of Spirulina as a dietary supplement in the food industry. In the present work, the three main area of Spirulina research: growth, harvesting and potential application are presented. Key findings and conclusion The important growth parameters have been studied to enhance Spirulina biomass productivity qualitatively and quantitatively. This review provides useful information on commercially viable technology for Spirulina cultivation. Mass cultivation and Innovative formulations are further needed to fortify conventional foods with Spirulina based protein system.
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Population growth combined with increasingly limited resources of arable land and fresh water has resulted in a need for alternative protein sources. Macroalgae (seaweed) and microalgae are examples of under-exploited “crops”. Algae do not compete with traditional food crops for space and resources. This review details the characteristics of commonly consumed algae, as well as their potential for use as a protein source based on their protein quality, amino acid composition, and digestibility. Protein extraction methods applied to algae to date, including enzymatic hydrolysis, physical processes, and chemical extraction and novel methods such as ultrasound-assisted extraction, pulsed electric field, and microwave-assisted extraction are discussed. Moreover, existing protein enrichment methods used in the dairy industry and the potential of these methods to generate high value ingredients from algae, such as bioactive peptides and functional ingredients are discussed. Applications of algae in human nutrition, animal feed, and aquaculture are examined.
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Marine microalgae and seaweeds (microalgae) represent a sustainable source of various bioactive natural carotenoids, including β-carotene, lutein, astaxanthin, zeaxanthin, violaxanthin and fucoxanthin. Recently, the large-scale production of carotenoids from algal sources has gained significant interest with respect to commercial and industrial applications for health, nutrition, and cosmetic applications. Although conventional processing technologies, based on solvent extraction, offer a simple approach to isolating carotenoids, they suffer several, inherent limitations, including low efficiency (extraction yield), selectivity (purity), high solvent consumption, and long treatment times, which have led to advancements in the search for innovative extraction technologies. This comprehensive review summarizes the recent trends in the extraction of carotenoids from microalgae and seaweeds through the assistance of different innovative techniques, such as pulsed electric fields, liquid pressurization, supercritical fluids, subcritical fluids, microwaves, ultrasounds, and high-pressure homogenization. In particular, the review critically analyzes technologies, characteristics, advantages, and shortcomings of the different innovative processes, highlighting the differences in terms of yield, selectivity, and economic and environmental sustainability.
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The successful commercial exploitation of Arthrospira because of its high nutritional value, chemical composition and safety of the biomass has made it one of the most important industrially cultivated microalgae. Knowledge of its biology and physiology, which is essential for understanding the growth requirements of this alkaliphilic organism, has been used in developing suitable technologies for mass cultivation. The relationships between environmental and cultural factors, which govern productivity in outdoor cultures, are discussed in connection with growth yield and efficiency. The response of Arthrospira and its modification under stress are described, together with the strategy of osmotic adjustment and the mechanism of internal pH regulation to alkalinity. The metabolic plasticity of the response to disparate environmental stimuli is demonstrated in the natural environment, but is also well-expressed in the maintenance of high productive monoculture in intensive outdoor cultivation systems. While the confused taxonomy of Arthrospira and its relationship with Spirulina has been resolved by study of the ultrastructural feature of trichomes and 16S rRNA sequence analysis, the problem of species definition is still ongoing. However, molecular methods such as total DNA restriction profile analyses of a wide range of strains are helping to resolve this. © 2012 Springer Science+Business Media B.V. All rights reserved.
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Microalgae are microorganisms that have different morphological, physiological, and genetic traits that confer the ability to produce different biologically active metabolites. Microalgal biotechnology has become a subject of study for various fields, due to the varied bioproducts that can be obtained from these microorganisms. When microalgal cultivation processes are better understood, microalgae can become an environmentally friendly and economically viable source of compounds of interest, because production can be optimized in a controlled culture. The bioactive compounds derived from microalgae have anti-inflammatory, antimicrobial, and antioxidant activities, among others. Furthermore, these microorganisms have the ability to promote health and reduce the risk of the development of degenerative diseases. In this context, the aim of this review is to discuss bioactive metabolites produced by microalgae for possible applications in the life sciences.
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This review presents useful and green techniques of solvent-free extraction used in ancient times, such as extraction of olive oil and citrus essential oil, and innovative techniques, such as pulsed electric field, microwave, instantaneous controlled pressure drop, and extrusion. We discuss the devices, their applications, mechanisms, and parameters influencing sample preparation prior to analysis of natural products.
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The design of green and sustainable extraction methods of natural products is currently a hot research topic in the multidisciplinary area of applied chemistry, biology and technology. Herein we aimed to introduce the six principles of green-extraction, describing a multifaceted strategy to apply this concept at research and industrial level. The mainstay of this working protocol are new and innovative technologies, process intensification, agro-solvents and energy saving. The concept, principles and examples of green extraction here discussed, offer an updated glimpse of the huge technological effort that is being made and the diverse applications that are being developed.
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This paper illustrates the Ultrasound Assisted Extraction (UAE) of β-carotene from Spirulina platensis. Various parameters such as extraction time, solvent type, biomass to solvent ratio, temperature, electrical acoustic intensity, length of the probe tip dipped into the solvent, duty cycle and pre treatment effect were explored for the extraction of β-carotene. From economic point of view, the optimal conditions for the extraction of β-carotene from Spirulina were 1.5g Spirulina (2min pre soaked in methanol) in 50ml n-heptane at 30°C temperature, 167W/cm(2) electrical acoustic intensity and 61.5% duty cycle for 8min with probe tip length of 0.5cm dipped into the extracting solvent from the surface. The maximum extraction achieved under the above mentioned optimum parameters was 47.10%. The pre-treatment time showed a promising effect on the yield as pre-treating the biomass with methanol for 2min before ultrasonication showed 12 times increase in extraction yield of β-carotene.
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Toluidine blue (TB) staining either alone or in association with other methodologies has the potential to answer a variety of biological questions regarding the human, animal and plant tissues or cells. In this brief review, we not only report the primary use of TB to detect the anionic substrates and availability of their binding sites, but also unveil the resulting applications of TB staining in biological research. Among these applications, the uses of TB staining to identify the changes in chromatin DNA-protein complexes, nucleolus location, and extracellular matrix proteoglycan complexes associated with different physiological and pathological events are described. The usefulness of TB staining to monitor the effects elicited by environmental insults on chromatin and intercalation of drugs into the DNA is also included.
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The potential of microalgae as an alternative energy source has been adequately studied. However, exclusive use of microalgae as an energy feedstocks cannot warrant their scalability and economical sustainability due to the high cost involved in their biomass processing. The co-processing of microalgae biomass with other related bio-refinery applications can offset their cost and improve their sustainability. Thus, it triggers up the need of exploring the potential of microalgae biomass beyond their typical use. Microalgae offer interesting features to qualify them as alternative feedstocks for various bio-refinery applications. Microalgae have unique abilities to utilize them for industrial and environmental applications. Thus, this review discusses to expand the scope of integrating microalgae with other biotechnological applications to enhance their sustainability. The use of microalgae as a feed for animal and aquaculture, fertilizers, medicine, cosmetic, environmental and other biotechnological applications is thoroughly reviewed. It also highlights the barriers, opportunities, developments, and prospects of extending the scope of microalgae. This study concludes that sustained research funding, and a shift of microalgae focus from biofuels production to bio-refinery co-products can qualify them as promising feedstocks. Moreover, technology integration is inevitable to off-set the cost of microalgae biomass processing. It is expected that this study would be helpful to determine the future role of microalgae in bio-refinery applications.
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Protein concentrates and isolates were developed from the microalga Spirulina sp. LEB 18 biomass and characterized by functional aspects for food application. Proteins were solubilized at pH 11 and precipitated at pH 4.2 (protein isoelectric point determined by potentiometric titration), with the aid of a high-speed homogenizer. With this procedure, it was possible to obtain a protein concentrate with 83.9 ± 1.7 wt% of protein and a protein isolate with 91.3 ± 1.2 wt%. Protein extraction from this microalga allowed a significant increase in protein solubility and foam stability. Furthermore, proteins from both concentrate and isolate presented higher resistance to thermal denaturation than the original proteins of Spirulina sp. LEB 18 biomass. These results show the application potential of the concentrate and the protein isolate from Spirulina sp. LEB 18 in foods for protein supplementation, since they have >80 and 90% protein, respectively. Industrial relevance text Using proteins from microalgal sources can serve as a sustainable alternative to meet world food demand. The isoelectric precipitation extraction method can be applied on a large scale, achieving high yields. Protein extracts present potential application in specific foods for protein supplementation. Protein extraction can be allied to other biocomposites extraction, such as carbohydrates and lipids for biofuels production.
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Arthrospira platensis is a species of filamentous cyanobacteria whose high protein content renders it suitable as a nutritive supplement for human and animal diets. Furthermore it is easy to grow as it tolerates a broad range of environmental stresses such as extremes of pH, salinity and heavy metals. In this study, changes in the growth, pigments and proteome of A. platensis were analyzed under two major abiotic stresses limiting productivity, salinity and iron. The lower concentrations of stresses showed varied effects on fresh weight, growth rate, pigment constituents and soluble protein of A. platensis. A proteomic analysis was conducted using SDS-PAGE first to obtain an overview of gross changes, followed by 2-DE and mass spectrometry to identify specific proteins whose abundance was affected by these environmental stresses. Eighteen spots were differentially expressed under the stress conditions. Of these, six were found with increased abundance responding only to Fe²⁺ stress, and five as a result of NaCl stress alone. Using LC–MS/MS, 37 proteins were identified within these spots. These proteins were classified into thirteen categories according to their function annotation. The present analysis could provide important data related to stress-tolerance by microalgae.
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There are more than 1300 articles in scientific literature dealing with positive impacts of Ultrasound-Assisted Extraction (UAE) such as reduction of extraction time, diminution of solvent and energy used, enhancement in yield and even selectivity, intensification of diffusion, and eliminating wastes. This present study aims to understand what are the mechanism(s) behind these positive impacts which will help to design a decision tool for UAE of natural products. Different microscopic observations (Scanning Electron Microscopy (SEM), Environmental Scanning Electron Microscopy (e-SEM), Cyto-histochemistry) have been used for spacial and temporal localization of metabolites in rosemary leaves, which is one of the most studied and most important plant for its antioxidant metabolites used in food industry, during conventional and ultrasound extraction. The study permits to highlight that ultrasound impacted rosemary leaves not by a single or different mechanisms in function of ultrasound power, as described by previous studies, but by a chain detexturation mechanism in a special order: local erosion, shear forces, sonoporation, fragmentation, capillary effect, and detexturation. These detexturation impacts followed a special order during ultrasound treatment leading at the end to the total detexturation of rosemary leaves. These mechanisms and detexturation impacts were identified in glandular trichomes, non-glandular-trichomes and the layer adaxial and abaxial cuticle. Modelling metabolites diffusion phenomenon during conventional and ultrasound extraction with the second Fick's law allowed the estimation of diffusivities and solvent penetration into the inner tissues and in meantime to accelerate the release of valuable metabolites.
Article
Biological significance: Arthrospira platensis, widely known as Spirulina, is a type of cyanobacteria which is cultivated at large scale for it great commercial value. It has become a consensus that continually increasing temperature due to global warming is bringing serious threat to agriculture, including the Spirulina cultivation. High temperature not only limits biomass accumulation by Spirulina, but also changes the composition of nutrition. Therefore there is a greater need than ever before to understand how Spirulina tolerates and cope with high temperature. In this study, we for the first time applied the iTRAQ-based quantitative proteomic technology to investigate the thermotolerance of Spirulina. Our results showed that many biological processes were altered by heat stress. Most significantly, we found that heat stress harmed the photosynthesis ability and caused low energy production, and to deal with this situation, energy demanding processes like protein synthesis were down-shifted and the alternative energy metabolism process glycolysis was up-shifted. Our results also show other important proteins, like the classical heat shock proteins and some antioxidant proteins, are also increased. Thus our study sheds light to our understanding of the mechanism underlying the thermotolerance of Spirulina.
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Microalgae are a very interesting and valuable natural source of highly valuable bioactive compounds, such as vitamins, essential amino acids, polyunsaturated fatty acids, minerals, carotenoids, enzymes and fiberfibre. Due to its potential, microalgae have become one of the most promising and innovative sources for new food and functional products., that Moreover, microalgae can be used as functional ingredients in order to enhance the nutritional value of foods and, thus hence, to favourably affecting favourably human health by improving the well-being and quality of life, but also decreasing curtailing diseases and illness risks. This review provides an overview of the current knowledge of the health benefits associated to microalgae consumption, bioactive compounds, functional ingredients, and foods.
Article
The morphology of Spirulina during cultivation is susceptible to external interferences, but the morphogenesis mechanism is still unclear. Here the proteomic changes of linear Spirulina and spiral Spirulina were comparatively investigated via isobaric tag for relative and absolute quantitation (iTRAQ). Totally 165 and 167 differences in proteins expression were screened out from the TJSD2/TJSD3 and TJBC4-1/TJBC4-2 groups, respectively. Gene ontology and metabolic pathway analysis of differences in proteins expression uncovered the metabolic pathways (photosynthesis, carbon fixation, sugar metabolism) that were significantly enriched with the proteins correlated with Spirulina morphogenesis. The results of differences in proteins expression in metabolic pathway were verified by quantitative real-time PCR. We also built a putative model of Spirulina morphogenesis mechanism and thought multiple metabolic pathways interact and take part in Spirulina morphogenesis.
Article
Manothermonication is a recognized and efficient method used for sterilization in food preservation. The synergistic effect of sonication combined with pressure and temperature allows enhancing the cavitation activity. Never employed for extraction, this study is about the transposition of this process as a tool of extraction. In this study, Rhodosporidium toruloides yeast was submitted to extraction by four modes of sonication, with a temperature ranged from 20 to 55 °C and a pressure between 1 to 2 bars. The lipids extraction yields were compared to the conventional maceration. Microbial oils obtained from both processes were analyzed and quantified by HPTLC (High Performance Thin-Layer Chromatography) and GC-FID (Gas Chromatography with flame ionization detector) after transesterification of lipids. Manothermosonication (30 min, 2 bars, 55 °C) permits to enhance of approximately 20% the extraction yield of lipids to compared to conventional maceration. The fatty acid profiles of each pretreatment and extraction by US, MS, TS and MTS do not affect the fatty acid profiles of yeast (majority of oleic acid (C18:1n9), linoleic acid (C18:2n6) and palmitic acid (C16:0)). Manothermosonication technique shows a great potential for lipid extraction from oleaginous microorganisms.
Article
This study was performed to evaluate the responses of Escherichia coli 0157:H7 inoculated in an apple-carrot blended juice to manothermosonication (MTS) treatments. The MTS treatments were conducted in a continuous-flow MTS system. The juice samples were exposed to ultrasound treatment at combinations of three temperatures (60, 50 and 40 °C) and three pressure levels (100, 200, and 300 kPa) for five residence times (15, 30, 45, 60, and 75 s). The results showed that higher treatment temperature (i.e. 60 °C) and hydrostatic pressure in the MTS system significantly enhanced the microbial reduction. A FDA mandated 5-log CFU/ml reduction of E. coli 0157:H7 for juice processing was achieved in 30 s for MTS treatment at 60 °C, in comparison to 60 s at 50 °C. The Weilbull and Log-logistic models provided the best fitting of the inactivation data for the MTS treatments. Extensive damage of E. coli 0157:H7 cells treated with MTS was observed on micro-images of scanning electron microscopy and transmission electron microscopy.
Article
The ethanolic extraction of minor compounds (phospholipids, tocopherols and sugars) present in sunflower collets was studied at 50 and 60 °C in a batch reactor. The extracted material consisted of two phases: a hexane-soluble fraction, comparable to degummed sunflower oils, and a hexane-insoluble fraction high in phospholipids and sugars. Sugars were extracted in large proportion, especially the indigestible raffinose, increasing the nutritional value of the meal. The sugar reduction percentage in the sunflower collets increased over extraction time to up to 60 and 80% at 50 and 60 °C. The effective diffusion coefficient (De) for tocopherols was higher than that for phospholipids (3.950 10⁻⁹ and 2.596 10⁻⁹ m²/s, respectively), both being temperature-independent in the analyzed range. De of sugars was 6.50 10⁻¹⁰ and 1.51 10⁻⁹ m²/s for 50 and 60 °C, respectively. Using ethanol as extraction solvent could improve the oil and meal quality, and help obtain a third phospholipid-rich phase after fractionation.
Chapter
In the past few years, much interest has focused on the applications of ultrasound in food processing and technology. Many reports suggest effective benefits from combining ultrasound with classical techniques. Applications of ultrasound generally involve processes that can enhance rates, improve quality and/or safety, and reduce processing time. Ultrasound assistance has now become of significant importance when scaling up laboratory processes and can play a key role in implementing sustainable “green” technology. Here we look at the concepts of hazard analysis and critical control points (HACCP) and hazard and operability (HAZOP) in the design of an ultrasonic food processing operation. These concepts are currently used as total quality management tools for the improvement of industrial operations. The HACCP program ensures the processing and production of safe foods by analyzing health hazards associated with processing, distribution, and consumption of foods, and in which the critical control points of the process are identified. The HAZOP analysis is used to identify hazardous working conditions in specific steps of a processing operation, taking into account the health effects of both contact and airborne ultrasound exposure.
Article
This study investigate the use of ultrasound assisted extraction (UAE), the present work describes the application of ultrasound to improves the extraction efficiency of the classical solvent extraction techniques such as maceration and soxhelt extraction to extract various bioactive compound from natural source like plant and animals. In this review extraction of various compounds i.e.β carotene, flavonoids, anthraquinones, isoflavones, cepharanthine, melanin, ursolic acid, from various plants i.e. morinda citrifolia, mitragyna speciosa, oscimum sanctum, polygonum cuspidatum, auricularia auricula, stephania rotunda lour,iris tectorum maxim, heterophyllaea pustulata hook, hawthorn seed, spirulina platensisand their therapeutic acivities like antiinflammatory, anti-cancer, anti-oxidant, cardioprotective action, immunomodulatory, anti-diabetic, antirheumatic, anti-bacterial, anthelmintic, anti-depressant, hepatoprotective, radioprotective properties was extracted at different temperature 25°, 45°, 90° C, power setting 3, 6, 9 types of solvent used like ethanol methanol, acetone, acetonitrile in different composition and time 15, 30, 45, 60, 90 minute. The effect of various factors such as extraction solvent, solvent concentration, temperature, solvent to solid ratio, ultrasound power, extraction time, and particle size, on the yield of target components were investigated. Under the optimum conditions the extraction process is carried out and the yield obtained with UAE has been compared with batch and soxhelt extraction the result indicated that UAE was an alternative method for extraction. UAE is based upon acoustic cavitation. Cavitation produces physical effects such as liquid circulation currents and turbulence which results in significant increase in the mass transfer rates and thus increased extraction yield. To achieve the same recovery as that achieved by UAE, soxhelt extraction and maceration extraction required much longer time.
Chapter
In the past few years, much interest has focused on the applications of ultrasound in food processing and technology. Many reports suggest effective benefits from combining ultrasound with classical techniques. Applications of ultrasound generally involve processes that can enhance rates, improve quality and/or safety, and reduce processing time. Ultrasound assistance has now become of significant importance when scaling up laboratory processes and can play a key role in implementing sustainable “green” technology.
Article
Ultrasound-assisted extraction of rapeseed oil was investigated and compared with conventional extraction for energy efficiency, throughput time, extraction yield, cleanness, processing cost and product quality. A multivariate study enabled us to define optimal parameters (7.7 W/cm2 for ultrasonic power intensity, 40 °C for processing temperature, and a solid/liquid ratio of 1/15) for ultrasound-assisted extraction of oil from oilseeds to maximize lipid yield while reducing solvent consumption and extraction time using response surface methodology (RSM) with a three-variable central composite design (CCD). A significant difference in oil quality was noted under the conditions of the initial ultrasound extraction, which was later avoided using ultrasound in the absence of oxygen. Three concepts of multistage cross-current extraction were investigated and compared: conventional multistage maceration, ultrasound-assisted maceration and a combination, to assess the positive impact of using ultrasound on the seed oil extraction process. The study concludes that ultrasound-assisted extraction of oil is likely to reduce both economic and ecological impacts of the process in the fat and oil industry.
Article
In recent decades, microalgae species have focused the attention of several research groups and food industry as they are a great source of nutritionally valuable compounds. The use of environmentally friendly technologies has led to researchers and food industry to develop new alternative processes that can extract nutritionally valuable compounds from different sources, including microalgae. This note describes the potential use of some non-conventional methods including sub- and supercritical fluid extraction, pulsed electric fields, high-voltage electric discharges, high-pressure homogenization, ultrasound- and microwave-assisted extraction, which involve cell disruption to recover nutritionally valuable compounds from microalgae and can help to comply with criteria of green chemistry concepts and sustainability.
Article
Nowadays, there is an increasing trend to develop new extraction methods by using non-conventional technologies as an alternative to classic solid-liquid extraction. Ultrasounds treatment is an alternative cheap, effective and reproducible method for the improved recovery of bioactive compound extracts from plant foods, by-products and algae. The goal of the current article is to revise the impact of ultrasound-assisted extraction on the recovery of polyphenols, carotenoids and chlorophylls from plant and algae materials. At this stage of development, there is a need to optimize ultrasound treatment conditions based on ultrasonic power, the temperature and the sonication duration in order to maximize the antioxidant capacity of the obtained extract, mainly attributed to bioactive compounds. Thereby, the modeling attempts of this technology were also discussed.
Article
The enhancement of release of oak-related compounds from oak chips during wine aging with oak chips may interest the winemaking industry. In this study, the 25-kHz ultrasound waves were used to intensify the mass transfer of phenolics from oak chips into a model wine. The influences of acoustic energy density (6.3-25.8W/L) and temperature (15-25°C) on the release kinetics of total phenolics were investigated systematically. The results exhibited that the total phenolic yield released was not affected by acoustic energy density significantly whereas it increased with the increase of temperature during sonication. Furthermore, to describe the mechanism of mass transfer of phenolics in model wine under ultrasonic field, the release kinetics of total phenolics was simulated by both a second-order kinetic model and a diffusion model. The modeling results revealed that the equilibrium concentration of total phenolics in model wine, the initial release rate and effective diffusivity of total phenolics generally increased with acoustic energy density and temperature. In addition, temperature had a negative effect on the second-order release rate constant whereas acoustic energy density had an opposite effect.
Article
To effectively extract value-added phycocyanin from Spirulina platensis, the effects of processing parameters (pH and temperature) on extraction performance and global kinetics were systematically studied. The extraction kinetics was investigated by varying pH levels (5–8) and temperatures (30–60 °C). An empirical kinetic model incorporating the aforementioned factors was developed. A good agreement between the experimental and fitted data was obtained, which indicated that the extraction process followed second-order kinetics. Furthermore, the model parameters (equilibrium concentration, extraction rate constants, and initial rates of extraction) were calculated and formulated as a function of the operating factors. The activation energy of the extraction was 67.1 kJ mol−1, indicating that the process was endothermic. The predictions obtained from the developed model were compared with the experimental data under the same operating conditions. The predicted and experimental data were consistent, indicating the reliability of the model.
Article
We have adapted the Lowry method to the determination of algal proteins collected on membrane filters. When cells of Euglena gracilis were analyzed the yield of protein was linear with cell amounts to 400 μg. The error of repeatability was 3 μg, and the recovery > 98%.