High Pressure-assisted Extraction Research Articles

Effects of different extraction methods on the physico-chemical characteristics and biological activities of polysaccharides from Clitocybe squamulosa

This study comparatively evaluated the effects of the commonly used six extraction methods (acidic, alkaline, enzymatic, ultrasonic, high-pressure, and microwave) on the physico-chemical properties, processing characteristics, and biological activities of polysaccharides from Clitocybe squamulosa (CSFPs). The results show that polysaccharides extracted using an enzyme-assisted extraction method has a relatively high extraction yield (4.46 ± 1.62 %) and carbohydrate content (70.79 ± 6.25 %) compared with others. Furthermore, CSFPs were all composed of glucose, galactose, mannose, xylose, and glucosamine hydrochloride. Only ultrasonic-assisted extraction of polysaccharides (CSFP-U) has a triple helix chain conformation. Scanning electron microscopy (SEM) revealed significant differences in the microstructure of polysaccharides prepared using different methods. Besides that, the polysaccharides prepared by alkali extraction (CSFP-B) and high-pressure assisted extraction (CSFP-H) have good water (2.86 ± 0.29 g/g and 3.15 ± 0.29 g/g) and oil (8.13 ± 0.32 g/g and 7.97 ± 0.04 g/g) holding properties. The rheological behavior demonstrated that CSFPs solutions were typical non-Newtonian fluid. Apart from this, the antioxidant capacity (clearing DPPH (IC50 = 0.29) and ABTS free radicals (IC50 = 0.19), total reduction ability (IC50 = 3.02)) of polysaccharides prepared by the microwave-assisted extraction (CSFP-M) method was significantly higher than that of other extraction methods. By contrast, the polysaccharide prepared by acid extraction (CSFP-A) has the optimum binding capacity (bile acid salt (71.30 ± 6.78 %) and cholesterol (57.07 ± 3.26 mg/g)). The antibacterial activity of CSFPs was positively correlated with their concentration. Thus, the research results can provide a theoretical basis for the development and utilization of polysaccharides from C. squamulosa.

High-Pressure-Assisted Extraction of Phenolic Compounds from Olive Leaves: optimization and Comparison with Conventional Extraction

The scope of the study was to optimize high-pressure-assisted extraction (HPAE) conditions for the extraction of phenolic compounds from olive leaves and to compare the optimum HPAE conditions with conventional extraction (CE) (at 50 °C for 30 min). In this regard, different treatment pressure levels (300–500 MPa), time (5–15 min), and solid-to-solvent ratios (0.1–0.3 w/v) were used to optimize the total phenolic content (TPC) and oleuropein content by using the Box–Behnken design. According to the results, optimal HPAE conditions were selected as 433.3 MPa for 15 min with 0.1 w/v solid–solvent ratio to obtain the maximum TPC (57.5 mg GAE/g DW) and oleuropein content (18.45 mg/g DW). Compared to CE, HPAE increased the TPC, antioxidant capacity, and oleuropein content significantly (p ≤ 0.05). Fourier transform infrared spectroscopy results showed no difference between HPAE and CE samples. Based on scanning electron microscopy results, HPAE caused structural changes compared to CE, and this caused to increase the mass transfer rate of phenolic substances.

Optimization and Comparison of High-Pressure-Assisted Extraction of Phenolic Compounds from Olive Pomace

In this study, it was aimed to find the optimum condition for extraction of phenolic compounds from olive pomace by using high-pressure-assisted extraction (HPAE). In this method, different pressure parameters (300–500 MPa), times (5–15 min), and ethanol concentrations (50–90% v/v) were used. According to Box–Behnken design, 15 experimental runs were performed to find the optimum condition of total phenolic and oleuropein contents. Also, the optimum HPAE condition was compared with that of classical solvent extraction (CSE). Based on the results, the optimum HPAE condition was chosen as 409 MPa for 11.16 min with 63.74% v/v ethanol concentration. According to ANOVA results, pressure, time, and ethanol concentration had significant effects on the total phenolic content and oleuropein content (p ≤ 0.05). Compared to CSE, it was found that HPAE increased the total phenolic content, antioxidant capacity, and oleuropein content significantly. According to scanning electron microscopy and Fourier transform infrared spectroscopy results, it was found that the mass-transfer rate of phenolic compounds increased because of morphological changes, but there were no chemical changes in phenolic compounds observed when HPAE treatment was applied. Overall, it can be said that HPAE treatment was an effective method to improve the recovery of phenolic compounds from olive pomace compared to the traditional treatment.

Effects of High Hydrostatic Pressure on Fungal Spores and Plant Bioactive Compounds

Fungi, and their spores, are responsible for the spoilage of several foods and plants and are susceptible to contamination with mycotoxins, which have associated health hazards. In this context, proper methodologies for inactivating such fungi and controlling mycotoxin production are critical. High-pressure processing (HPP) has recently become popular as a nonthermal alternative to conventional thermal pasteurization processes. Even though HPP can effectively eliminate some fungal spores, some species, such as those from the genera Byssochlamys, Talaromyces, and Aspergillus, are quite resistant to this treatment. Additionally, high pressure can also be used as a cold extraction technique for bioactive compounds from medicinal plants and other matrices (termed high pressure-assisted extraction, HPE). With this method, safe use for food, cosmetic, and pharmaceutical applications is guaranteed. This method simultaneously works (depending on the applied pressure level) as an extraction technique and induces the pasteurization effect on the extracts. This encyclopedia entry aims to highlight the effects of nonthermal HPP on fungal spores, the prevalence of mycotoxins in plant materials and how high pressure can be used as an extraction technique to produce high-value cold pasteurized extracts with biological activity.

Effects of High Pressure-Assisted Extraction on Yield, Antioxidant, Antimicrobial, and Anti-diabetic Properties of Chlorogenic Acid and Caffeine Extracted from Green Coffee Beans

The bioactive ingredients of green coffee beans were extracted using high pressure-assisted extraction (HPE) and compared against those derived from the traditional heat reflux (HR) extraction method. The effect of extraction conditions on the extraction efficiency of functional components (chlorogenic acids, caffeine, total phenols, and flavonoids); the free radical-scavenging activity of the extract; and the inhibition of α-glucosidase, α-amylase, and food pathogenic bacteria were measured. Using water as the solvent, the high-pressure extraction rates of chlorogenic acid (CGA) and caffeine were 3.20–5.75 mg/100 g and 4.32–7.95 mg/100 g, respectively, which were significantly higher than the rates obtained using the traditional method (2.92 mg/100 g and 3.54 mg/100 g, respectively). Under optimal extraction conditions of 25 °C and 600 MPa for 2.5 min, inhibition of α-glucosidase and α-amylase by the extract reached rates of 27.8% and 26.7%, respectively, with the highest free radical-scavenging activity of 81.5%. HPE exhibited antibacterial activity against both gram-positive (Staphylococcus aureus and Listeria innocua) and gram-negative (Escherichia coli and Salmonella enterica) bacteria, and the lowest minimum inhibitory concentration (4.69 mg/mL) against S. aureus was achieved. Scanning electron microscopic observations evidenced that high pressure partially damaged the intercellular compartments of coffee beans, increased solvent permeability, and improved the extraction rate of bioactive ingredients. The outcomes of the study demonstrated that HPE can be employed as an efficient extraction technique for production of chlorogenic acids and caffeine that might have a potential application in food and related industries.

Optimization of High-Pressure-Assisted Extraction of Cadmium and Lead from Kelp (Laminaria japonica) Using Response Surface Methodology.

Kelp (Laminaria japonica) is a popular and nutritious sea vegetable, but it has a strong biosorption capacity for heavy metals. The high content of cadmium (Cd) and lead (Pb) is a threat to the quality of kelp. The objective of this study was to investigate the effects of high-pressure-assisted extraction (HPAE) conditions on Cd and Pb removal efficiency from kelp. Pressure intensity (0.1–200 MPa), the number of HPAE cycles (one to five) and acetic acid concentration (0–10%) were optimized using response surface methodology. The pressure intensity had the most significant positive effects on Cd and Pb removal efficiency, while the correlation between acetic acid concentration and removal efficiency was positive for Cd and negative for Pb. The optimum conditions for the removal of Cd and Pb were attained at 188 MPa, with four cycles and with an acetic acid concentration of 0%. At optimum conditions, the experimental values of removal efficiency were 61.14% (Cd) and 70.97% (Pb), and this was consistent with the predicted value, confirming the validity of the predictive model.

Unveiling Biological Activities of Marine Fungi: The Effect of Sea Salt

There is an urgent need for new substances to overcome current challenges in the health sciences. Marine fungi are known producers of numerous compounds, but the manipulation of growth conditions for optimal compound production can be laborious and time-consuming. In Portugal, despite its very long coastline, there are only a few studies on marine fungi. From a collection of Portuguese marine fungi, we screened for antimicrobial, antioxidant, enzymatic, and cytotoxic activities. Mycelia aqueous extracts, obtained by high pressure-assisted extraction, and methanolic extracts of culture media showed high antioxidant, antimicrobial, and cytotoxic activities. The mycelium extracts of Cladosporium rubrum showed higher antioxidant potential compared to extracts from other fungi. Mycelia and culture media extracts of Aspergillus affinis and Penicillium lusitanum inhibited the growth of Staphylococcus aureus, Kocuria rhizophila, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, including multiresistant strains. Penicillium lusitanum and Trichoderma aestuarinum inhibited the growth of clinical strains of Candida albicans, C. glabrata, C. parapsilosis, and C. tropicalis. All extracts from culture media were cytotoxic to Vero cells. Sea salt induced alterations in the mycelium’s chemical composition, leading to different activity profiles.

Red Seaweeds as a Source of Nutrients and Bioactive Compounds: Optimization of the Extraction

The present work aimed to determine the nutritional composition (ash, protein, fat, carbohydrate content and energy value), phenolic compounds, pigments and organic acids content of three typical red algae from the Northwest of Spain: Chondrus crispus, Mastocarpus stellatus, and Gigartina pistillata; as well as their antioxidant and antimicrobial activities. Furthermore, the present work compared two extraction techniques: conventional heat assisted extraction (HAE) and high pressure assisted extraction (HPAE) to maximize the yield and the concentration of target compounds. Different independent variables were considered for the response study. Time (t) and percentage of ethanol of the solvent (S) were chosen for both techniques and temperature (T) and pressure (P) were used for HAE and HPAE, respectively. The experiments were designed following a response surface methodology (RSM) approach. The obtained results showed a similar nutritional composition between algae samples: low-fat content and high content of proteins, carbohydrates and energy. All tested algae showed good antioxidant and antimicrobial properties. Finally, HEA demonstrated to be the most efficient extraction technique. This study confirms the potential of red algae to be part of the human diet as a source of non-animal protein, due to its nutritional content, phenolic profile, pigments concentration and bioactive properties, which proves that HAE is the optimum technique for the extraction maximization.

Enhanced gelling performance of oxhide gelatin prepared from cowhide scrap by high pressure-assisted extraction.

In this study, the feasibility of preparing oxhide gelatin from cowhide scrap by high pressure assisted-liquid extraction was verified. Different processing conditions, including high pressure time (15 to 25 min), pressure (250 to 350 MPa), and liquid-to-solid ratio (1:3 to 1:5), were optimized through response surface methodology. Under the optimum manufacturing conditions, when the high-pressure processing (HPP) time was 22 min, the pressure was 289 MPa, and the liquid-to-solid ratio was 1:4, the highest extraction yield (36%) and gel strength (224 g) were achieved. Based on DSC, XRD, FTIR, SEM, gelling and melting temperatures, HPP led to the structural modification of the gelatinized collagen, which enhanced the rearrangement of the gel structure during the gelation process and made it have better gelling properties. In addition, compared with the commercial sample, they do not differ significantly in the relaxation time and peak area of prepared oxhide gelatin. These findings provide new insights into the practicability of HPP during the preparation of oxhide gelatin, which can noticeably reduce the processing time and be applied to industrial production. PRACTICAL APPLICATION: Compared with traditional processing, a high pressure-assisted extraction process can noticeably reduce the processing time while producing cowhide gelation with similar physicochemical and functional properties. Meanwhile, high pressure processing (HPP) led to the structural destruction of the cowhide and gelatinized collagen, which enhanced the rearrangement of the gelatin structure during the gelation process and made it have better gelling properties. Importantly, high pressure-assisted extraction can facilitate the use of a low-cost raw material and improve the preparation efficiency of oxhide gelatin, which shows great potential in large-scale and efficient industrial production and the quality control of oxhide gelatin.

Optimization of antioxidant activity and bioactive compounds extraction of winter savory leaves by high hydrostatic pressure

ABSTRACT Winter savory is often used in traditional medicine, having several recognized biological properties. This study aimed to evaluate the effect of high pressure-assisted extraction (HPE) and its optimization by response surface methodology to obtain winter savory extracts with a high content of bioactive compounds and high antioxidant activity (the effect of extraction pressure, extraction time, and ethanol concentration were investigated). Results showed that data could be well fitted to second-order polynomial mathematical models for total phenolics, total flavonoids, chlorophylls, carotenoids, and extraction yield, as well as for antioxidant activity. The models predicted optimal conditions ranging 200–500 MPa, extraction time 1–20 min, and ethanol concentration 0–70% (v,v). In comparison with extraction at atmospheric pressure, HPE showed to be more efficient, allowing obtaining an increase of about 40% for all compounds, and an increase of 29, 48, and 70% for antioxidant activity by FRAP, DPPH and ABTS assays, respectively.

Effect of High Hydrostatic Pressure Extraction on Biological Activities and Phenolics Composition of Winter Savory Leaf Extracts.

Satureja montana L. has several biological properties related to its diverse composition of secondary metabolites. Nevertheless, it has been mainly studied for its essential oil, with only a few studies on the profile and bioactivities of the bioactive compounds from its leaf extracts being reported. This work aimed to study the antioxidant activity (by oxygen radical absorbance capacity (ORAC) assay), antimicrobial minimum inhibitory and bactericidal concentrations (MIC and MBC) determination, antibiofilm (by colorimetry), impact upon DNA (anti- and pro-oxidant assay), and cytotoxicity (by cell metabolism viability assays) of S. montana extracts obtained by high-pressure-assisted extraction (HPE). The extract obtained at 348 MPa, 35% (v/v) ethanol presented the highest concentration of individual phenolic compounds, and a minimum bactericidal concentration of 20 mg/mL against Listeria monocytogenes. HPE extracts showed antioxidant activity not only in ORAC but they were also able to prevent/attenuate peroxide-induced damage upon DNA. Moreover, on its own, HPE extract induced less oxidative damage than the control extract. Concerning the cytotoxicity, HPE extracts (at 0.5 and 1.0 mg/mL) were not harmful to HT29 cell lines, while control extracts (obtained at atmospheric pressure) at higher concentrations (>1.0 mg/mL) slightly reduced the metabolism of the cells. Finally, all extracts showed inhibition of the viability of 3 cancerous cell lines (>2.0 mg/mL for Caco-2, HeLa, and TR146) to below 15%.

Optimization of phycobiliprotein pigments extraction from red algae Gracilaria gracilis for substitution of synthetic food colorants

The extraction of phycobiliprotein (PBP) pigments from red algae Gracilaria gracilis was optimized using maceration, ultrasound-assisted extraction (ultrasonic water bath and ultrasonic probe), high pressure-assisted extraction, and freeze-thaw. The experimental conditions, namely homogenization time (t1), buffer concentration (C), treatment time (t2), biomass: buffer ratio (R), and pressure (P), were optimized using Response Surface Methodology (RSM). The yield of phycoerythrin (PE) extracted, determined spectroscopically, was used as the response variable. Maceration was the most efficient extraction method yielding 3.6 mg PE/g biomass under the optimal conditions (t1 = t2 = 10 min; C = 0.1 M; R = 1:50). Scanning Electron Microscopy (SEM) analysis of the biomass before and after the cell disruption treatments revealed a more efficient cell wall rupture with maceration.

Novel oil extraction technologies: Process conditions, quality parameters, and optimization.

Conventional techniques of extracting oil using organic solvents pose health, safety, and environmental concerns. In modern extraction methods, green solvents such as water, ethanol, ethyl acetate, carbon dioxide, ionic liquids, and terpenes are currently gaining prominence. These green solvents present no signs of pollution and remain in liquid form over a temperature range of 0 to 140°C. Other techniques covered in this review include microwave-assisted enzymatic extraction, ultrasound-assisted extraction, supercritical fluid technology, high pressure-assisted extraction, and pulse electric field-assisted extraction. These techniques are considered environmentally friendly because they exhibit less hazardous chemical synthesis, use renewable feedstock, and reduce the chemical load and emissions generated by organic solvents. Aqueous enzymatic extraction is a novel technique that uses enzymes as the medium for extraction of oil. Selection of the enzymes solely depends on the structure of the oilseed and the composition of the cell wall. Studies reveal an enzyme to substrate ratio of 1% to 8%, the temperature of 40 to 55°C, and a pH of 4 to 8 to be typical for enzymatic extraction of oil from different oilseeds. Microwave-assisted extraction has proven to impart significant effects on mass transfer and offers high throughput and extraction efficiency. A microwave power of 275 to 1,000 W and a temperature range of 30 to 60°C are noticed in the different studies. The review presents a comprehensive account of the modern extraction techniques, the parameters responsible for yield and quality, and their industrial applications. Besides, the review highlights the optimized parameters for oil extraction from different oil-bearing materials.

Effects of high pressure extraction on the extraction yield, phenolic compounds, antioxidant and anti-tyrosinase activity of Djulis hull.

The hulls of Djulis (Chenopodium formosanum) are a type of agricultural waste. Using 70% ethanol as the extraction solvent, this study compared the extraction yields of high-pressure-assisted extraction (HPE) and conventional oscillation extraction (CE) for Djulis hulls (DH). The total phenolic and flavonoid contents, and antioxidant, anti-inflammatory and anti-tyrosinase activities were also compared. Our findings indicated that 600MPa/5min of HPE resulted in higher total phenolic (567-642mgGAE/g) and flavonoid (47.2-57.2mgQU/g) concentrations; gallic acid (44.5-53.2μg/g) and rutin (26.8-34.2μg/g) were the main phenolic and flavonoid compounds. When the extraction pressure was greater than 450MPa, HPE extracts showed stronger antioxidant capacity and anti-tyrosinase activity than CE extracts. In a LPS-induced RAW 264.7 cell model of inflammation, HPE extracts had significant inhibitory effects on the cumulative concentrations of nitric oxide and prostaglandin E2. These results indicate that HPE had a better extraction yield, and required a shorter time for the extraction of functional ingredients from DH. Hence, DH could be a potential source for natural antioxidants for the food and biotechnology industries.

Novel Food Processing and Extraction Technologies of High-Added Value Compounds from Plant Materials.

Some functional foods contain biologically active compounds (BAC) that can be derived from various biological sources (fruits, vegetables, medicinal plants, wastes, and by-products). Global food markets demand foods from plant materials that are “safe”, “fresh”, “natural”, and with “nutritional value” while processed in sustainable ways. Functional foods commonly incorporate some plant extract(s) rich with BACs produced by conventional extraction. This approach implies negative thermal influences on extraction yield and quality with a large expenditure of organic solvents and energy. On the other hand, sustainable extractions, such as microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), high-pressure assisted extraction (HPAE), high voltage electric discharges assisted extraction (HVED), pulsed electric fields assisted extraction (PEF), supercritical fluids extraction (SFE), and others are aligned with the “green” concepts and able to provide raw materials on industrial scale with optimal expenditure of energy and chemicals. This review provides an overview of relevant innovative food processing and extraction technologies applied to various plant matrices as raw materials for functional foods production.