Impact of Pressurized Liquid Extraction and pH on Protein Yield, Changes in Molecular Size Distribution and Antioxidant Compounds Recovery from Spirulina

Evaluation of Inulin and Polyphenol Content and the Cytotoxicity of Cichorium intybus L. var. foliosum Root Extracts Obtained by Pectinase- and Pressure-Assisted Extraction

BACKGROUND

Cichorium intybus L., a member of the Asteraceae family, has numerous health-promoting properties that categorize its preparations as functional foods and herbal medicines. Most previous research focused on the root of C. intybus var. sativum (industrial chicory) as a rich source of inulin, while the witloof variety (C. intybus var. foliosum) is less explored.

OBJECTIVES

This study aimed to evaluate the cytotoxicity of C. intybus var. foliosum root extracts obtained with different extraction protocols and to analyze their polysaccharide and polyphenol content.

METHODS

Freeze-dried root extracts were prepared using water and three extraction methods: pectinase-assisted, pressure-assisted, and a combination of both. The contents of inulin, total polyphenols, and total caffeic acid derivatives in the extracts were measured by the Layne-Eynon, Folin-Ciocalteu, and UHPLC-PDA methods, respectively. Cytotoxicity of the extracts and inulin was tested in vitro using the L929 cell line, MTT method, and paracetamol as the reference standard.

RESULTS

Inulin levels in the extracts ranged from 43.88 to 50.95 g/100 g dry matter (dm), total polyphenols were between 816.7 and 906.4 mg/100 g dm, and total phenolic acids ranged from 11.50 to 187.1 mg/100 dm, with pressure-assisted extraction yielding the highest phytochemical recovery. The cytotoxicity tests showed IC50 values from 4.72 to 7.31 mg/mL for the extracts, compared to 3.02 for paracetamol and 19.77 for inulin.

CONCLUSIONS

Given the high content of active compounds and low cytotoxicity, the root extracts of C. intybus var. foliosum merit further research into their functional and medicinal properties. Pressure-assisted extraction is recommended for effective extraction of chicory.

Comparison of Pressurized Water Extraction With Ultrasound Assisted Extraction for Isolation of Phycobiliproteins From Arthrospira platensis (Spirulina)

INTRODUCTION

Cyanobacterium Arthrospira platensis (AP) (Nordstedt) Gomont contains high content of phycobiliproteins (PBP), which are an important source for food industry. Methods effectively extracting proteins contained in AP cells are demanded to provide a supply of the material. Water-based extraction methods are advisable due to the high solubility of the PBP.

OBJECTIVES

Extraction techniques such as ultrasound assisted extraction (UAE) and pressurized water extraction (PWE) are popular due to their environmental friendliness, better extraction efficiency, and faster extraction process. In this paper, efficiency of the two methods is compared.

MATERIALS AND METHODS

PWE along with UAE is utilized for release of PBP from the AP cells. The extraction parameters including time, temperature, pressure, and ultrasound intensity are tested to obtain the most efficient setup. The methods were evaluated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the replicates of PWE extracts were further analyzed by capillary isoelectric focusing with laser-induced fluorescence (cIEF-LIF).

RESULTS

The developed PWE method using higher pressure treatment at lower temperature was significantly faster than UAE methods, and the SDS-PAGE results showed a high content of phycobiliproteins in the extracts. cIEF-LIF analysis showed that the sequential PWE of individual samples was repeatable, and the mild extraction provided a fluorescent profile similar to the commercially available C-phycocyanin standard.

CONCLUSION

Pressurized water extraction was shown to be an efficient, rapid, and well-automated extraction method for AP proteins in general, including bioactive phycobiliproteins. Obtained results encourage the use of PWE in small-scale analytical applications for primary extraction of proteins.

Deep Eutectic Solvents based green approach for bioactive molecules recovery from Spirulina

Spirulina is a unicellular microalga, characterized by blue/green color, that has received significant attention for its interesting nutritional composition. Phenolic compounds and phycocyanin (PC) are responsible for the many biological activities of Spirulina. Spirulina phenolic compounds are usually extracted using organic solvents, while PC is extracted with water or phosphate buffer solution, obtaining an extract characterized by low stability and low purity. Deep Eutectic Solvents (DESs) are green solvents, widely applied for bioactive molecules extraction, composed by two or more molecules which act as hydrogen bond acceptor or hydrogen bond donor to create an eutectic mixture. A Natural Deep Eutectic Solvent (NADES), is a DES composed only by natural compounds. This work aimed to optimize a green extraction procedure based on NADES to obtain an extract rich in phenolic compounds and PC from Spirulina. The application of NADESs as extraction solvents is an important strategy for recovering phenolic compounds and to increase and stabilize the protein PC. The optimized extraction procedure involved to use a betaine-glucose NADES under the following conditions: matrix-to-solvent ratio of 1:20 (w/w), temperature of 50 °C and one hour as extraction time. The developed extraction procedure guaranteed to recover a phenolic compounds and PC quantity of 11.77 ± 1.23 mg GAE (gallic acid equivalents) and 27.56 ± 2.46 g per g of Spirulina powder respectively. PC in the NADES extract degraded more slowly than in an aqueous extract. The extract phenolic compounds profile was determined through high performance liquid chromatography coupled with mass spectrometry analysis.

Sustainable algal proteins, novel extraction techniques and applications in the bakery, dairy and pharmaceutical industries: A comprehensive review

Microalgae have emerged as favorable substitutes for traditional animal-based proteins in the search for sustainable protein sources. Despite being underexplored, microalgae offer the possibility of large-scale protein production via novel extraction techniques. This review synthesizes current knowledge on microalgal proteins, shedding light on their novel extraction techniques and techno-functional properties, which are still in the early stages of exploration. Additionally, it explores the miscellaneous applications of algae proteins across various industrial sectors, including bakery, dairy, pharmaceuticals, and nutrition. By discussing the techno-functional properties of algae proteins and peptides, this review underscores their potential to revolutionize the industrial landscape while addressing sustainability challenges. As research in this field progresses, microalgae are poised to emerge as a viable and environmentally friendly protein source, offering a pathway toward a more sustainable future.

Green and sustainable technologies for extraction of carotenoids from natural sources: a comprehensive review

In recent years, driven by increasing consumer demand for natural and healthy convenient foods, the food industry has been shifting from synthetic to natural products. This shift is also reflected in the growing popularity of non-conventional extraction methods for pigments, which are favored for sustainability and environment-friendliness compared to conventional processes. This review aims to investigate the extraction of carotenoids from a variety of natural sources, including marine sources like fungus, microalgae, and crustaceans, as well as widely studied plants like tomatoes and carrots. Additionally, it delves into the recovery of valuable carotenoids from waste products like pomace and peels, highlighting the nutritional and environmental benefits. The review also emphasizes the role of green solvents such limonene, vegetable oils, ionic liquids, supercritical fluids, and natural deep eutectic solvents in effective and ecologically friendly carotenoid extraction. These technologies support the ideas of a circular and sustainable economy in addition to having a smaller negative impact on the environment. Overall, the present study highlights the crucial importance of green extraction technologies in achieving the dual goals of sustainability and public safety.

Blue food proteins: Novel extraction technologies, properties, bioactivities and applications in foods

With the growing demand for healthy and sustainable food, blue food proteins have emerged as an important way to address resource-intensive production and environmental concerns. This paper systematically reviewed the extraction technologies, properties and bioactivities of blue food proteins and explored their wide range of applications. The novel extraction technologies not only improve the extraction efficiency of the proteins, shorten the production time and have environmental advantages, but also enhance the protein properties and facilitate subsequent applications. The amino acid composition of the blue food proteins is close to the FAO recommended standard and better than most of the livestock proteins, with excellent solubility and water holding capacity. Some of the proteins also have significant bioactivity and show great potential for improving health. Applications include emulsions, protein films, microcapsules, food colorants, dietary supplements, 3D printing materials, and cultured meat. This paper provides theoretical support for further research and application of blue food proteins and promotes their wider application in future food products.

Trends in extracting protein from microalgae Spirulina platensis, using innovative extraction techniques: mechanisms, potentials, and limitations

Microalgal, species are recognized for their high protein content, positioning them as a promising source of this macronutrient. Spirulina platensis, in particular, is noteworthy for its rich protein levels (70 g/100 g dw), which are higher than those of meat and legumes. Incorporating this microalgae into food can provide various benefits to human health due to its diverse chemical composition, encompassing high amount of protein and elevated levels of minerals, phenolics, essential fatty acids, and pigments. Conventional techniques employed for protein extraction from S. platensis have several drawbacks, prompting the exploration of innovative extraction techniques (IETs) to overcome these limitations. Recent advancements in extraction methods include ultrasound-assisted extraction, microwave-assisted extraction, high-pressure-assisted extraction, supercritical fluid extraction, pulse-electric field assisted extraction, ionic liquids assisted extraction, and pressurized liquid extraction. These IETs have demonstrated efficiency in enhancing protein yield of high quality while maximizing biomass utilization. This comprehensive review delves into the mechanisms, applications, and drawbacks associated with implementing IETs in protein extraction from S. platensis. Notably, these innovative methods offer advantages such as increased extractability, minimized protein denaturation, reduced solvent consumption, and lower energy consumption. However, safety considerations and the synergistic effects of combined extraction methods warrant further exploration and investigation of their underlying mechanisms.

Optimization of Pressurized Liquid Extraction (PLE) Parameters for Extraction of Bioactive Compounds from Moringa oleifera Leaves and Bioactivity Assessment

Moringa oleifera leaves are rich sources of bioactive compounds with potential health benefits, including antioxidants and anti-inflammatory agents. Pressurized liquid extraction (PLE) stands out as a promising technique for effectively extracting valuable compounds from natural sources. In this study, we aimed to optimize PLE parameters, such as temperature, extraction duration, and pressure, to maximize bioactive compound (polyphenols, flavonoids, and ascorbic acid) yield from M. oleifera leaves and evaluate their antioxidant and anti-inflammatory activities. According to the outcomes of this research, the maximum achieved total polyphenol content was 24.10 mg gallic acid equivalents (GAE)/g of dry weight (dw), and the total flavonoid content was increased up to 19.89 mg rutin equivalents (RtE)/g dw. Moreover, after HPLC-DAD analysis, neochlorogenic and chlorogenic acids, catechin and epicatechin, rutin, and narirutin were identified and quantified. As far as the optimum ascorbic acid content is concerned, it was found to be 4.77 mg/g dw. The antioxidant activity was evaluated by three different methods: ferric reducing antioxidant power (FRAP), the DPPH method, and the anti-hydrogen peroxide activity (AHPA) method, resulting in 124.29 μmol ascorbic acid equivalent (AAE)/g dw, 131.28 μmol AAE/g dw, and 229.38 μmol AAE/g dw values, respectively. Lastly, the albumin denaturation inhibition was found to be 37.54%. These findings underscore the potential of PLE as an efficient extraction method for preparing extracts from M. oleifera leaves with the maximum content of bioactive compounds.

Enhancing Nutrient Recovery and Bioactive Compound Extraction from Spirulina through Supercritical Fluid Extraction: Implications for SH-SY5Y Cell Viability

This work explores the efficiency of supercritical fluid extraction (SFE) to recover minerals, pigments, and antioxidant compounds from the spirulina microalgae. Moreover, the fatty acids and phenolic profiles of the extracts obtained were also investigated, and the effect of the extracts on SH-SY5Y cell viability was tested. The extraction of phycocyanin was improved by SFE compared to conventional extraction, from 2.838 ± 0.081 mg/g dry matter (DM) (control) to 6.438 ± 0.411 mg/g DM (SFE). SFE treatment also improved chlorophyll a and carotenoid recoveries increasing from 5.612 ± 0.547 to 8.645 ± 0.857 mg/g DM and from 0.447 ± 0.096 to 0.651 ± 0.120 mg/g DM, respectively. Regarding minerals, the SFE improved Mg recovery with 77% more than the control extraction. Moreover, palmitoleic, stearic, γ-linolenic, eicosadienoic and eicosatrienoic acids recovery was improved by SFE. Phenolic profiles were identified via triple-TOF-LC-MS-MS. Considering heavy metals, a higher rate of Pb extraction was observed for the SFE extract, while no significant differences were observed for Hg between both extractions. Finally, SFE extract improved cell viability compared to the control extract. Thus, SFE constitutes an interesting tool to sustainably extract high-added-value compounds; however, potential contaminants such as Pb need to be controlled in the resulting extracts.

Role of secondary metabolites in distressed microalgae

Proficient photosynthetic microalgae/cyanobacteria produce a remarkable amount of various biomolecules. Secondary metabolites (SM) represent high value products for global biotrend application. Production improvement can be achieved by nutritional, environmental, and physiological stress as a first line tools for their stimulation. In recent decade, an increasing interest in algal stress biology and omics techniques have deepened knowledge in this area. However, deep understanding and connection of specific stress elucidator are missing. Hence, the present review summarizes recent evidence with an emphasis on the carotenoids, phenolic, and less-discussed compounds (glycerol, proline, mycosporins-like amino acids). Even when they are synthesized at very low concentrations, it highlights the need to expand knowledge in this area using genome-editing tools and omics approaches.

Comparative study of factors affecting the recovery of proteins from malt rootlets using pressurized liquids and ultrasounds

Malt rootlets (MR) are a waste from brewing with high protein content. This work proposes to study the impact of extracting parameters on the recovery of proteins and the characteristics of extracts from MR using ultrasound-assisted extraction (UAE) and pressurized liquid extraction (PLE). A Box-Behnken experimental design was employed to study the effect of extracting parameters on the protein yield, while characterization comprised the study of antioxidant properties, the identification of extracted proteins using high-resolution tandem mass spectrometry, and the evaluation of the co-extraction of phenolic compounds. Protein extraction was promoted at an ultrasounds amplitude of 68%, for 20 min at 52 °C in UAE, while adding 33% ethanol resulted in the highest yield in PLE. While UAE extracted 53 ± 5% of MR proteins, PLE reached a 73 ± 7%, using more sustainable conditions. Significant antioxidant activities were observed in the PLE extract, although undermined by gastrointestinal digestion. Proteomic analysis detected 68 proteins from Hordeum vulgare in the UAE extract and 9 in the PLE extract. Proteins in MR are very different to that from barley grains or brewer's spent grains. PLE also co-extracted phenolic compounds while this was not significant by UAE.

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PLE and UAE can extract proteins from malt rootlets, a waste from brewing.

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The use of PLE with low amounts of EtOH promoted the extraction of protein.

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PLE extracted 73% of the proteins in malt rootlets, which is 38% more than the UAE using a shorter time.

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PLE extract showed high antioxidant capacity likely due to the co-extraction of phenolic compounds.

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Extracted proteins were involved in metabolic processes and defence/stress responses.

High-Pressure Technologies for the Recovery of Bioactive Molecules from Agro-Industrial Waste

Large amounts of food waste are produced each year. These residues require appropriate management to reduce their environmental impact and, at the same time, economic loss. However, this waste is still rich in compounds (e.g., colorants, antioxidants, polyphenols, fatty acids, vitamins, and proteins) that can find potential applications in food, pharmaceutical, and cosmetic industries. Conventional extraction techniques suffer some drawbacks when applied to the exploitation of food residues, including large amounts of polluting solvents, increased time of extraction, possible degradation of the active molecules during extraction, low yields, and reduced extraction selectivity. For these reasons, advanced extraction techniques have emerged in order to obtain efficient residue exploitation using more sustainable processes. In particular, performing extraction under high-pressure conditions, such as supercritical fluids and pressurized liquid extraction, offers several advantages for the extraction of bioactive molecules. These include the reduced use of toxic solvents, reduced extraction time, high selectivity, and the possibility of being applied in combination in a cascade of progressive extractions. In this review, an overview of high-pressure extraction techniques related to the recovery of high added value compounds from waste generated in food industries is presented and a critical discussion of the advantages and disadvantages of each process is reported. Furthermore, the possibility of combined multi-stage extractions, as well as economic and environmental aspects, are discussed in order to provide a complete overview of the topic.