Advances in the extraction of natural ingredients by high pressure extraction technology

Antimicrobial Activity of Pomegranate Peel and Its Applications on Food Preservation

Pomegranate (Punica granatum L.) fruit is being cultivated since the civilization is known, and its production and consumption have been increased since the last century due to the scientific confirmation of its health benefits. Pomegranate fruits, fruit juice, its seeds, and peels are known to have higher contents of bioactive compounds, viz., phenolic acids, flavonoids, and hydrolysable tannins. The peels of pomegranate fruits are the major by-products produced during food processing of pomegranate enriched in antioxidants and broad-spectrum antimicrobial agents and can prevent food deterioration even. This health potential of pomegranate is known to vary significantly upon the varieties, growing conditions, cultivation practices, stages of the development, and the extraction methods. Herein, the biochemical composition of the pomegranate peel extract (PPE), its efficacy in food preservation, and antimicrobial activities are discussed to provide a comprehensive guide for farmers, food processing, and storage sectors and academia.

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%.

Comparison of Different Extraction Methods for the Recovery of Olive Leaves Polyphenols

In the present study, advanced extraction techniques, microwave (MAE), ultrasound (UAE), and high pressure (HPAE)-assisted extraction, were applied to improve extraction efficiency of olive (Olea europaea L.) leaves polyphenols. The effect of sample mass (1.5 and 3 g), MAE—time (2, 8.5, and 15 min) and temperature (45 and 80 °C), UAE—time (7, 14, and 21 min) and amplitude (50 and 100%) and HPAE—time (1, 5.5, and 10 min) and pressure (300 and 500 MPa) on the concentration of each analyzed polyphenol compound was examined. Identified polyphenols were oleuropein, hydroxytyrosol, chlorogenic acid, caffeic acid, verbascoside, and rutin. All three advanced extraction techniques yielded higher content of total polyphenols when compared to the conventional heat-reflux extraction (CE) along with a significant reduction of extraction time from 60 (CE) to 2, 21, and 5.5 min in MAE, UAE, and HPAE, respectively. The most intensive values of tested parameters in each technique were the ones that promoted cell wall disruption, e.g., temperature of 80 °C in MAE, 100% amplitude in UAE and 500 MPa in HPAE. MAE and UAE were more efficient in total polyphenols’ recovery than HPAE.

Optimising anthocyanin extraction from strawberry fruits using response surface methodology and application in yoghurt as natural colorants and antioxidants

The aim of the present study was to optimise the extraction conditions of anthocyanins from strawberry fruits and incorporate them in yoghurt to achieve a natural coloration as well as enrich the product with antioxidants. The response surface methodology (RSM) based on Box-Behnken design was studied to assess the influence of the three factors being agitation speed (400-800 rpm), sample to solvent ratio (0.5-2 g/40 mL), and extraction time (1-15 min) on total anthocyanin content and antioxidant activity of strawberries. According to the results, the linear, quadratic and interaction effects of the studied factors on total anthocyanin content and antioxidant activity were determined by the response surface methodology, and the optimal conditions for anthocyanin extraction were 586 rpm for agitation speed, 1.26 g/40 mL for sample to solvent ratio, and 9.36 min for extraction time. Under these extraction conditions, the total anthocyanin content and antioxidant activity recorded by the two validated models were 38.04 mg C3GE/100 g FW and 21.38 mg AAE/100 g FW, respectively. The enriched natural yoghurt contains anthocyanins with a content of 36.50 µg C3GE/100 g and an antioxidant activity of 21.22 µg AAE/100 g. The anthocyanin enriched yoghurt developed in this study may be considered as a functional food with an interesting source of natural antioxidants, and these anthocyanins can substitute synthetic (industrial) colorants.

Extraction of chitosan from squid pen waste by high hydrostatic pressure: Effects on physicochemical properties and antioxidant activities of chitosan

Squid pen sample was treated by high hydrostatic pressure (HHP) prior to the extraction of chitosan. The physicochemical and antioxidant activities of the chitosan obtained with HHP (HHP-CS) were compared with chitosan of untreated squid pen sample (UT-CS). The chitosan extraction yield was optimized using response surface methodology, and the optimum condition was achieved at pressure of 500 MPa, extraction time of 10 min, and 1% (w/w) acetate concentration. The maximum yield of chitosan sample from the chitin of squid pens treated by HHP reached 81.9%. Among the process variables, the combined effects of pressure and acetate concentration significantly enhanced the extraction of chitosan from squid pens. The HHP-CS was found to be significantly effective in enhancing the fat binding capacity, water binding capacity, and water solubility index. SEM image analysis suggested that the HHP-CS had a rough surface with high porosity, while UT-CS exhibited a smooth surface. In vitro antioxidant assay suggested that HHP-CS had significantly higher DPPH radical scavenging activity, greater reducing power, and a stronger ferrous ion chelating effect than did UT-CS. Therefore, HHP can be an excellent alternative method for improving the physicochemical properties and antioxidant activities of chitosan from squid pens.

Pomegranate as a source of bioactive constituents: a review on their characterization, properties and applications

Increasing awareness about the use of compounds obtained from natural sources exerting health-beneficial properties, including antimicrobial and antioxidant effects, led to increased number of research papers focusing on the study of functional properties of target compounds to be used as functional foods or in preventive medicine. Pomegranate has shown positive health properties due to the presence of bioactive constituents such as polyphenols, tannins, and anthocyanins. Punicalagin is the major antioxidant, abundantly found in pomegranate's peel. Research has shown that pomegranate polyphenols not only have a strong antioxidant capacity but they also inhibit the growth of pathogenic bacteria like V. cholera, P. aeruginosa and S. aureus, B. cereus, E. coli, and S. virulence factor, and inhibits fungi such as A. Ochraceus, and P. citrinum. Compounds of natural origin inhibit the growth of various pathogens by extending the shelf life of foodstuffs and assuring their safety. Therefore, the need to find compounds to be used in combination with antibiotics or as new antimicrobial sources, such as plant extracts. On the basis of the above discussion, this review focuses on the health benefits of pomegranate, by summarizing the current body of research focusing on pomegranate bioactive constituents and their therapeutic potential against some pathogenic microbes.

Extraction of bioactive compounds from purple corn using emerging technologies: A review

The increase in the use of bioactive compounds from purple corn in the food and pharmaceutical industries has led to the investigation of nonconventional extraction technologies that allow one to obtain more of these compounds. In this context, nonconventional techniques, known as emerging technologies, use more efficient processes that are safe for the environment, in addition to obtaining products with better functional characteristics as compared to those obtained by conventional technologies. This review aims to provide information on different nonconventional techniques used in the extraction of bioactive compounds from purple corn.

Effect of high hydrostatic pressure extraction on biological activities of stinging nettle extracts

Ethanolic extracts obtained at 200 MPa presented higher phenolic compound concentration and better results concerning all biological activities and also showed potential for DNA protection with no pro-oxidant activity and no cytotoxicity.

High pressure extraction of bioactive diterpenes from the macroalgae Bifurcaria bifurcata: an efficient and environmentally friendly approach

The brown macroalgae Bifurcaria bifurcata have gained special attention due to their ability to biosynthesize linear diterpenes (rarely found in other species). However, the conventional extraction methods normally used to extract these compounds involve organic solvents and often high temperatures, leading to the degradation of thermo-labile compounds. In this context, the main objective of this work was to study and optimize for the first time the extraction of diterpenes from B. bifurcata through an environmentally friendly methodology, namely, high pressure extraction (HPE) using ethanol : water. This was compared with conventional Soxhlet extraction, using dichloromethane. Box–Behnken design was employed to evaluate the linear, quadratic, and interaction effects of 3 independent variables (pressure (X₁), ethanol percentage (X₂), and time of extraction (X₃)) on response variables (extraction yield and diterpenes content (mg g⁻¹ of extract and mg kg⁻¹ of dry weight)) and the optimal extraction conditions (X₁: 600 MPa; X₂: 80%; X₃: 5 min) were estimated by response surface methodology (RSM). B. bifurcata extract obtained under HPE optimal conditions showed a diterpenes content (612.2 mg g⁻¹ of extract) 12.2 fold higher than that obtained by conventional extraction (50.1 mg g⁻¹ of extract). The HPE extract, obtained under optimal conditions, showed antioxidant and antibacterial (against Staphylococcus aureus) activities considerably higher than the Soxhlet extract, and also presented a promising synergic effect with antibiotics, improving the antibiotic efficacy against S. aureus. In conclusion, these results indicate that HPE is a promising methodology, compared to conventional methodologies to obtain linear diterpene rich extracts from B. bifurcata with great potential to be exploited in pharmaceutical or biomedical applications.

Bioactive linear diterpenes were selectively extracted from the macroalga Bifurcaria bifurcata through optimized high-pressure extraction.

Current Research on the Bioprospection of Linear Diterpenes from Bifurcaria bifurcata: From Extraction Methodologies to Possible Applications

Marine resources are considered as a very promising source of bioactive molecules, and macroalgae in particular have gained special attention, due to their structurally diverse composition. Particular interest has been devoted to the brown macroalga Bifurcaria bifurcata, due to their abundance in bioactive linear diterpenes. In this appraisal, a thorough review concerning the methodologies used in the extraction, fractionation, and identification of diterpenes from B. bifurcata is provided and discussed in detail. An exhaustive compilation of the mass spectra and nuclear magnetic resonance (NMR) data are also provided. The in vitro and in chemico assays already performed to assess different biological activities attributed to B. bifurcata diterpenes are also reviewed, emphasizing the use of isolated components, enriched fractions, or crude extracts. The associated major strengths and challenges for the exploitation of B. bifurcata diterpenes for high-value applications are critically discussed.

Extraction of bioactive ingredients from fruiting bodies of Antrodia cinnamomea assisted by high hydrostatic pressure

The aim of this study was to use high hydrostatic pressure treatment to enhance the extraction efficiency of the active components from the fruiting bodies of Antrodia cinnamomea, and compare with those obtained by shake and ultrasonic extraction methods. The conditions of high pressure extraction (HPE) at 600 MPa, a liquid/solid ratio of 40:1, and 3 min of treatment yielded triterpenoids and adenosine concentrations of 410.41 mg/100 mL and 0.47 mg/100 mL, respectively, which did not differ significantly from those with the two other treatments-shake extraction at 180 rpm for 8 h and ultrasonic extraction at 50 Hz for 60 min. The HPE extracts significantly attenuated reactive oxygen species, nitric oxide and prostaglandin E₂ production in lipopolysaccharide-stimulated RAW 264.7 cells than shake extracts did. SEM micrographs revealed that high-pressure caused physical morphological damage to the mycelium of fruiting bodies, such as distortion and disruption of mycelial cells, and increased the mass-transfer effectiveness of the solvent and solute. HPE can be employed as an efficient extraction technique for production of bioactive ingredients that might have a potential application in food and related industries.

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 600 MPa/5 min of HPE resulted in higher total phenolic (567-642 mg GAE/g) and flavonoid (47.2-57.2 mg QU/g) concentrations; gallic acid (44.5-53.2 μg/g) and rutin (26.8-34.2 μg/g) were the main phenolic and flavonoid compounds. When the extraction pressure was greater than 450 MPa, 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.

Identification and Antioxidant Activity of Flavonoids Extracted from Xinjiang Jujube (Ziziphus jujube Mill.) Leaves with Ultra-High Pressure Extraction Technology

In this study, the ultra-high pressure extraction (UHPE) conditions for obtaining the maximum flavonoid yield from Xinjiang jujube (Ziziphus jujuba Mill.) leaves (XJL) were optimized by response surface methodology (RSM). Box–Behnken design (BBD) was applied to evaluate the effects of four variables (extraction temperature, pressure, time and liquid-to-solid ratio) on flavonoid yield. The results showed that the optimal flavonoid yield (25.45 ± 0.21 mg/g) was derived at 50.0 °C, 342.39 MPa, 11.56 min, and a liquid-to-solid ratio of 43.95 mL/g. Eight compounds were tentatively identified and quantified as kaempferol and quercetin glycosides with UPLC-ESI-MS. Compared to ultrasound-assisted extraction (UAE), UHPE can obtain higher concentrations of total flavonoids and stronger DPPH and ABTS radical-scavenging activities in a much shorter time. Therefore, UHPE is an alternative to UAE for obtaining flavonoids from XJL, which may be an optional method for large-scale industrial flavonoid extraction from XJL.

Enhancement of Bioactivity of Natural Extracts by Non-Thermal High Hydrostatic Pressure Extraction

Natural extracts, like those obtained from medicinal herbs, dietary plants and fruits are being recognized as important sources of bioactive compounds with several functionalities including antioxidant, anticancer, and antimicrobial activities. Plant extracts rich in phenolic antioxidants are currently being successfully used for several pharmaceutical applications and in the development of new foods (i.e., functional foods), in order to enhance the bioactivity of the products and to replace synthetic antioxidants. The extraction method applied in the recovery of the bioactive compounds from natural materials is a key factor to enhance the bioactivity of the extracts. However, most of the extraction techniques have to employ heat, which can easily lead to heat-sensitive compounds losing their biological activity, due to changes caused by temperature. Presently, high hydrostatic pressure (HHP) is being increasingly explored as a cold extraction method of bioactive compounds from natural sources. This non-thermal high hydrostatic pressure extraction (HHPE) technique allows one to reduce the extraction time and increase the extraction of natural beneficial ingredients, in terms of nutritional value and biological activities and thus enhance the bioactivity of the extracts. This review provides an updated and comprehensive overview on the extraction efficiency of HHPE for the production of natural extracts with enhanced bioactivity, based on the extraction yield, total content and individual composition of bioactive compounds, extraction selectivity, and biological activities of the different plant extracts, so far studied by extraction with this technique.

Effect of emergent non-thermal extraction technologies on bioactive individual compounds profile from different plant materials

Extraction is the first step for isolation and purification of interesting bioactive compounds, by mixing of the plant material with an adequate solvent. Those bioactive compounds are, usually, secondary metabolites, such as phenolic acids and flavonoids which are present in closed insoluble structures, making its extraction a challenge. There are many different traditional extraction methods, such as Soxhlet, heat reflux, and maceration. Nevertheless, due to several disadvantages, they are being replaced by new methods, using emergent technologies, such as high hydrostatic pressure, ultrasounds, pulsed electric fields, and supercritical fluids. The use of novel technologies allows enhancing mass transfer rates, increasing cell permeability as well as increasing secondary metabolite diffusion, leading to higher extraction yields, fewer impurities on the final extract, extractions at room temperature with thermo-sensitive structures preservation, use of different non-organic solvents, low energy consumption, short operation time, and have no significant or lower effect on the structure of bioactive compounds. This paper aims to review the effect of the main emergent extraction technologies (high hydrostatic pressure, pulsed electric fields, ultrasounds, and supercritical fluid assisted) on the individual profile of bioactive compounds from plant material.

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.

Extraction of bioactive compounds and essential oils from mediterranean herbs by conventional and green innovative techniques: A review

Market interest in aromatic plants from the Mediterranean is continuously growing mainly due to their medicinal and bioactive compounds (BACs) with other valuable constituents from essential oils (EOs). From ancient times, these plants have been important condiments for traditional Mediterranean cuisine and remedies in folk medicine. Nowadays, they are considered as important factors for food quality and safety, due to prevention of various deteriorative factors like oxidations and microbial spoilage. EOs have different therapeutic benefits (e.g. antioxidant, anti-inflammatory, antimicrobial, and antifungal), while BACs mostly affect nutritive, chemical, microbiological, and sensory quality of foods. Currently, many plant extracts are used for functional (healthy) foods, which additionally fuels consumer and industrial interest in sustainable and non-toxic routes for their production. EO yields from dried plants are below 5%. Their extraction is strongly dependent on the hydrophobic or lipophilic character of target molecules, hence the common use of organic solvents. Similarly, BACs encompass a wide range of substances with varying structures as reflected by their different physical/chemical qualities. Thus, there is a need to identify optimal non-toxic extraction method(s) for isolation/separation of EO/BCs from plants. Various innovative non-thermal extractions (e.g. ultrasound-, high-pressure-, pulsed electric fields assisted extraction, etc.) have been proposed to overcome the above mentioned limitations. These techniques are "green" in concept, as they are shorter, avoid toxic chemicals, and are able to improve extract yields and quality with reduced consumption of energy and solvents. This research provides an overview of such extractions of both BAC and EOs from Mediterranean herbs, sustained by innovative and non-conventional energy sources.

Optimized ultra-high-pressure-assisted extraction of procyanidins from lychee pericarp improves the antioxidant activity of extracts

To establish optimal ultra-high-pressure (UHP)-assisted extraction conditions for procyanidins from lychee pericarp, a response surface analysis method with four factors and three levels was adopted. The optimum conditions were as follows: 295 MPa pressure, 13 min pressure holding time, 16.0 mL/g liquid-to-solid ratio, and 70% ethanol concentration. Compared with conventional ethanol extraction and ultrasonic-assisted extraction methods, the yields of the total procyanidins, flavonoids, and phenolics extracted using the UHP process were significantly increased; consequently, the oxygen radical absorbance capacity and cellular antioxidant activity of UHP-assisted lychee pericarp extracts were substantially enhanced. LC-MS/MS and high-performance liquid chromatography quantification results for individual phenolic compounds revealed that the yield of procyanidin compounds, including epicatechin, procyanidin A2, and procyanidin B2, from lychee pericarp could be significantly improved by the UHP-assisted extraction process. This UHP-assisted extraction process is thus a practical method for the extraction of procyanidins from lychee pericarp.

High-pressure assisted extraction of bioactive compounds from industrial fermented fig by-product

High-pressure assisted extraction was employed to obtain fig by-product derived extracts and its impact was evaluated on antioxidant activity and total phenolic, tannin, and flavonoid. A Box-Behnken design was applied to evaluate the effects of pressure, extraction time and ethanol concentration on extractions and optimal conditions were estimated by response surface methodology. The correlation analysis of the mathematical-regression model indicated that a quadratic polynomial model could be employed to optimize the high pressure extraction of compounds. Only the models developed for total antioxidant activity by DPPH ^· and for total flavonoids presented coefficient determinations lower than 0.95. From response surface plots, pressure, extraction time and ethanol concentration showed independent and interactive effects. The optimal conditions included 600 MPa, an extraction time between 18 and 29 min, depending on the parameter analyzed and a low ethanol concentration (<15%) except for flavonoids (48%). High pressure led to an increase of 8-13% of antioxidant activity and an increase of 8-11% of total phenolics, flavonoids and tannins content when compared to extracts performed at 0.1 MPa. Analysis of variance indicated a high goodness of fit of the models used and the adequacy of response surface methodology for optimizing high pressure extraction.