Valorization of Sour Cherry Kernels: Extraction of Polyphenols Using Natural Deep Eutectic Solvents (NADESs).

The objective of this research was to optimize the natural deep eutectic solvent (NADES) extraction process from sour cherry kernels (Prunus cerasus L.). For polyphenol isolation, conventional solid-liquid extraction was employed using different concentrations of ethanol (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 96%), as well as the innovative NADES extraction technique. In the initial phase of the research, a screening of 10 different NADESs was conducted, while extraction was carried out under constant parameters (50 °C, 1:20 w/w, 60 min). NADES 4, composed of lactic acid and glucose in a molar ratio of 5:1, exhibited the highest efficiency in the polyphenol isolation. In the subsequent phase of the research, response surface methodology (RSM) was utilized to optimize the extraction process. Three independent variables, namely temperature, extraction time, and solid-liquid (S/L) ratio, were examined at three different levels. The extracted samples were analyzed for total phenol (TP) and antioxidant activity using the DPPH, ABTS, and FRAP assays. ANOVA and descriptive statistics (R2 and CV) were performed to fit the applied model. According to RSM, the optimal extraction conditions were determined as follows: temperature of 70 °C, extraction time of 161 min, and S/L ratio of 1:25 w/w.

Green Extraction Approach for Isolation of Bioactive Compounds in Wild Thyme (Thymus serpyllum L.) Herbal Dust-Chemical Profile, Antioxidant and Antimicrobial Activity and Comparison with Conventional Techniques.

The aim of this study was to provide a chemical profile and determine the antioxidant and antimicrobial activity of the essential oil (EO) and lipid extracts of Thymus serpyllum L. herbal dust obtained via conventional (hydrodistillation (HD) and Soxhlet extraction (SOX)) and novel extraction techniques (supercritical fluid extraction (SFE)). In addition, a comparative analysis of the chemical profiles of the obtained EO and extracts was carried out, as well as the determination of antioxidant, antibacterial and antifungal activity of the lipid extracts. According to the aforementioned antioxidant and antimicrobial activities and the monoterpene yield and selectivity, SFE provided significant advantages compared to the traditional techniques. In addition, SFE extracts could be considered to have great potential in terms of their utilization in the pharmaceutical and cosmetic industries, as well as appropriate replacements for synthetic additives in the food industry.

Recovery of Polyphenolic Compounds and Vitamins from the Stinging Nettle Leaves: Thermal and Behavior and Biological Activity of Obtained Extracts.

Stinging nettle (SN) is an extraordinary plant from the Urticaceae botanical family. It is well-known and widely used in food and folk medicine to treat different disorders and diseases. This article aimed to study the chemical composition of SN leaves extracts, i.e., polyphenolic compounds and vitamins B and C, because many studies ascribed high biological potency to these compounds and their significance in the human diet. Besides the chemical profile, the thermal properties of the extracts were studied. The results confirmed presence of many polyphenolic compounds and vitamins B and C. It also showed that the chemical profile closely correlated with the applied extraction technique. The thermal analysis showed that analyzed samples were thermally stable up to about 160 °C. Thermal degradation of samples UAE, MAE, and MAC took place in four steps, and sample SE in three steps. Altogether, results confirmed the presence of health-beneficial compounds in stinging nettle leaves and indicated the possible application of its extract in pharmaceutical and food industries as both a medicinal and food additive.

Isolation, Bioactive Potential, and Application of Essential Oils and Terpenoid-Rich Extracts as Effective Antioxidant and Antimicrobial Agents in Meat and Meat Products.

Using food additives (e.g., preservatives, antioxidants) is one of the main methods for preserving meat and meat product quality (edible, sensory, and technological) during processing and storage. Conversely, they show negative health implications, so meat technology scientists are focusing on finding alternatives for these compounds. Terpenoid-rich extracts, including essential oils (EOs), are remarkable since they are generally marked as GRAS (generally recognized as safe) and have a wide ranging acceptance from consumers. EOs obtained by conventional or non-conventional methods possess different preservative potentials. Hence, the first goal of this review is to summarize the technical-technology characteristics of different procedures for terpenoid-rich extract recovery and their effects on the environment in order to obtain safe, highly valuable extracts for further application in the meat industry. Isolation and purification of terpenoids, as the main constituents of EOs, are essential due to their wide range of bioactivity and potential for utilization as natural food additives. Therefore, the second goal of this review is to summarize the antioxidant and antimicrobial potential of EOs and terpenoid-rich extracts obtained from different plant materials in meat and various meat products. The results of these investigations suggest that terpenoid-rich extracts, including EOs obtained from several spices and medicinal herbs (black pepper, caraway, Coreopsis tinctoria Nutt., coriander, garlic, oregano, sage, sweet basil, thyme, and winter savory) can be successfully used as natural antioxidants and antimicrobials in order to prolong the shelf-life of meat and processed meat products. These results could be encouraged for higher exploitation of EOs and terpenoid-rich extracts in the meat industry.

Kinetics of Microwave-Assisted Extraction Process Applied on Recovery of Peppermint Polyphenols: Experiments and Modeling.

The aim of this work was to investigate the microwave-assisted extraction (MAE) kinetics of polyphenolic compounds from organic peppermint leaves. The phytochemicals of peppermint (Mentha piperita L.) are increasingly used in food technology due to their numerous biological activities. The processing of various plant materials by MAE and the production of high-quality extracts is becoming increasingly important. Therefore, the influence of microwave irradiation power (90, 180, 360, 600, and 800 W) on total extraction yield (Y), total polyphenols yield (TP), and flavonoid yield (TF) were investigated. Common empirical models (first-order, Peleg's hyperbolic, Elovich's logarithmic, and power-law model) were applied to the extraction process. The first-order kinetics model provided the best agreement with the experimental results in terms of statistical parameters (SSer, R2, and AARD). Therefore, the influences of irradiation power on the adjustable model parameters (k and Ceq) were investigated. It was found that irradiation power exerted a significant influence on k, while its influence on the asymptotic value of the response was negligible. The highest experimentally determined k (2.28 min-1) was obtained at an irradiation power of 600 W, while the optimal irradiation power determined by the maximum fitting curve determination predicted the highest k (2.36 min-1) at 665 W.

Recovery of Biologically Active Compounds from Stinging Nettle Leaves Part II: Processing of Exhausted Plant Material after Supercritical Fluid Extraction.

Stinging nettle (Urtica dioica L.) is one fantastic plant widely used in folk medicine, pharmacy, cosmetics, and food. This plant's popularity may be explained by its chemical composition, containing a wide range of compounds significant for human health and diet. This study aimed to investigate extracts of exhausted stinging nettle leaves after supercritical fluid extraction obtained using ultrasound and microwave techniques. Extracts were analyzed to obtain insight into the chemical composition and biological activity. These extracts were shown to be more potent than those of previously untreated leaves. The principal component analysis was applied as a pattern recognition tool to visualize the antioxidant capacity and cytotoxic activity of extract obtained from exhausted stinging nettle leaves. An artificial neural network model is presented for the prediction of the antioxidant activity of samples according to polyphenolic profile data, showing a suitable anticipation property (the r2 value during the training cycle for output variables was 0.999).

Isolation of Garlic Bioactives by Pressurized Liquid and Subcritical Water Extraction.

Garlic (Allium sativum L.) is widely used in various food products and traditional medicine. Besides unique taste and flavour, it is well known for its chemical profile and bioactive potential. The aim of this study was to apply subcritical water extraction (SWE) and pressurized liquid extraction (PLE) for the extraction of bioactive compounds from the Ranco genotype of garlic. Moreover, PLE process was optimized using response surface methodology (RSM) in order to determine effects and optimize ethanol concentration (45-75%), number of cycles (1-3), extraction time (1-3 min) and temperature (70-110 °C) for maximized total phenols content (TP) and antioxidant activity evaluated by various in vitro assays. Furthermore, temperature effect in SWE process on all responses was evaluated, while allicin content (AC), as a major organosulphur compound, was determined in all samples. Results indicated that PLE provided tremendous advantage over SWE in terms of improved yield and antioxidant activity of garlic extracts. Therefore, high-pressure processes could be used as clean and green procedures for the isolation of garlic bioactives.

Polyphenols Recovery from Thymus serpyllum Industrial Waste Using Microwave-Assisted Extraction-Comparative RSM and ANN Approach for Process Optimization.

The aim of this study was to valorize Thymus serpyllum L. herbal dust, the particular fraction distinguished as industrial waste from filter-tea production. This work demonstrated comparable analysis considering model fitting, influence analysis and optimization of microwave-assisted extraction (MAE) of bioactive compounds from the aforementioned herbal dust using face-centered central composite experimental design within the response surface methodology (RSM), as well as artificial neural networks (ANN). In order to increase yield and amount of compounds of interest and minimize solvent, time and energy consumption, the ethanol concentration (45, 60 and 75%), extraction time (5, 12.5 and 20 min), liquid-solid ratio (10, 20 and 30 mL/g) and irradiation power (400, 600 and 800 W) were used as independent variables. Total extraction yield (Y), total phenols yield (TP), as well as antioxidant activity parameters obtained by DPPH and ABTS assays, were selected as responses. It could be concluded that the MAE technique is an efficient approach for the extraction of biologically active compounds from T. serpyllum herbal dust, which represents a high-value source of natural antioxidants with great potential for further use in various forms within different branches of industry.

Isolation of Cherry Seed Oil Using Conventional Techniques and Supercritical Fluid Extraction.

This study aims to compare the suitability of three extraction techniques (cold pressing, Soxhlet and supercritical fluid extraction (SFE)) to isolate oil from cherry seeds. Oils were examined in terms of extraction yield, fatty acids profile, tocopherols yield and antioxidant activity. Additionally, influence of SFE parameters was evaluated using one-factor-at-a-time design with pressure (200−350 bar), temperature (40−70 °C), flow rate (0.2−0.4 kg/h) and particle size (<800 µm and >800 µm). Oil yields ranged from 2.50% to 13.02%, whereas the highest yield was achieved with SFE. Samples were rich in polyunsaturated fatty acids, regardless of the applied extraction technique. The main fatty acids were linoleic (46.32−47.29%), oleic (40.89−41.65%), palmitic (6.56−8.00%) and stearic (2.21−2.30%) acid. Total tocopherols yield was between 16.63 mg/100 g oil and 60.61 mg/100 g oil, and highest yield was achieved with SFE. Among the tocopherols, γ-tocopherol was the most abundant, followed by α-, δ- and ß-tocopherol. Antioxidant activity was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic) cation (ABTS) assays, and the results indicated that SFE extracts exhibited better or comparable antioxidant potential compared to traditional techniques. The comparison between modern and conventional extractions for oil recovery demonstrates pros and cons for the possibility of industrial application.

Supercritical Fluid Extraction Kinetics of Cherry Seed Oil: Kinetics Modeling and ANN Optimization.

This study was primarily focused on the supercritical fluid extraction (SFE) of cherry seed oil and the optimization of the process using sequential extraction kinetics modeling and artificial neural networks (ANN). The SFE study was organized according to Box-Behnken design of experiment, with additional runs. Pressure, temperature and flow rate were chosen as independent variables. Five well known empirical kinetic models and three mass-transfer kinetics models based on the Sovová's solution of SFE equations were successfully applied for kinetics modeling. The developed mass-transfer models exhibited better fit of experimental data, according to the calculated statistical tests (R2, SSE and AARD). The initial slope of the SFE curve was evaluated as an output variable in the ANN optimization. The obtained results suggested that it is advisable to lead SFE process at an increased pressure and CO2 flow rate with lower temperature and particle size values to reach a maximal initial slope.

Pressurized-Liquid Extraction as an Efficient Method for Valorization of Thymus serpyllum Herbal Dust towards Sustainable Production of Antioxidants.

The aim of this study was to valorize Thymus serpyllum herbal dust, a particular fraction distinguished as an industrial waste from filter-tea production. Pressurized liquid extraction (PLE) was used with the aim of overcoming certain obstacles of conventional extraction techniques in terms of shortening extraction time, reducing solvent consumption and energy costs, using "green" solvents and obtaining high yield and quality products. In order to optimize PLE of T. serpyllum herbal dust, the preliminary screening of the independent variables in order to define the most influential parameters and their domain was done first. After the screening, the optimization study using the face-centered central composite experimental design (CCD) with response surface methodology (RSM) was implemented. Additionally, taking into account the high awareness of the positive influence of antioxidants on the human health and associating it with high content of polyphenolic compounds in various members of Lamiaceae family, PLE has proven to be a great approach for antioxidants recovery from T. serpyllum herbal dust.

Chemical composition and antimicrobial activity of Osage orange (Maclura pomifera) leaf extracts.

The main goal of this study was to establish the chemical profile of Osage orange (Maclura pomifera) leaf extracts, obtained by conventional maceration technique, and to examine its antimicrobial activity. The identification and quantification of the extract compounds were done using ultra-high-performance liquid chromatography, with a diode array detector coupled with triple-quadrupole mass spectrometer and gas chromatography-mass spectrometry techniques. Thirty-one polyphenolic compounds were detected and identified in the ethanolic extracts, whereby 5-O-caffeoylquinic acid was found to be the dominant compound. Among other compounds, pentacosane and palmitic acid were the most abundant compounds in the dichloromethane extract. The preliminary antimicrobial activity screening shows that Gram-positive bacteria tend to be more sensitive to the investigated extracts. The highest antimicrobial activity was determined against Enterococcus faecalis ATCC 19433 and Listeria monocytogenes ATCC 35152. From these results, Osage orange leaves can be considered as plant material with significant antimicrobial properties.

Antioxidant and enzyme-inhibitory activity of peppermint extracts and essential oils obtained by conventional and emerging extraction techniques.

Peppermint is widely used medicinal plant with distinguished bioactive potential, therefore, the aim of present work was to develop novel peppermint extracts with high activity by application of traditional and emerging separation techniques. Conventional hydrodistillation and microwave-assisted hydrodistillation (MWHD) were applied for recovery of essential oil (EO), while organic solvent extraction using Soxhlet apparatus, microwave-assisted and ultrasound-assisted process and supercritical fluid extraction (SFE) were applied for non-selective recovery of peppermint lipophilic extracts. Extracts were characterized in terms of terpenoids profile with special emphasis on content of major compounds (mentol, menthone, isomenthol and eucalyptol). Antioxidant activity (DPPH, ABTS, CUPRAC, FRAP, chelating and phosphomolybdenum assay) and enzyme-inhibitory assays (acetylcholinesterase, butyrylcholinesterase, tyrosinase, amylase and glucosidase inhibition) were used for screening of peppermint bioactivity. MWHD was recognized as alternative for traditional process in EO recovery, while SFE extracts were useful for green production of solvent-free peppermint extracts rich in terpenoids and other lipophilic bioactives.

Tomato pomace extract and organic peppermint essential oil as effective sodium nitrite replacement in cooked pork sausages.

The effect of supercritical fluid extract of tomato pomace (TP) and essential oil of organic peppermint (PM) on pH, color, residual nitrite content, lipid oxidation (TBARS value) and total plate count (TPC) of cooked pork sausages produced with 50 mg/kg of sodium nitrite was investigated. Five batches were produced: T1: 100 mg/kg of sodium nitrite; T2: 50 mg of sodium nitrite; T3: 50 mg of sodium nitrite and 0.150 µL/g TP; T4: 50 mg of sodium nitrite, 0.075 µL/g TP and 0.075 µL/g PM; T5: 50 mg of sodium nitrite and 0.150 µL/g PM. The lowest residual nitrite content and TBARS value were observed in treatment T4. The inclusion of TP increased redness of cooked pork sausages. TPC was the lowest in treatment T5. The results of this study showed that the addition of TP and PM enhanced quality of cooked sausages produced with reduced level of sodium nitrite.

Coriander essential oil as natural food additive improves quality and safety of cooked pork sausages with different nitrite levels.

The effect of coriander essential oil (CEO) at concentrations of 0.075-0.150 µL/g on pH, color, lipid oxidation (TBARS), residual nitrite concentration and microbial growth of cooked pork sausages produced with different levels of sodium nitrite (0, 50 and 100 mg/kg) was investigated. Artificial neural networks modeling and the multi-response optimization were used to determine the optimal combinations of process parameters and storage time. Reduced concentration of sodium nitrite (60 mg/kg) in combination with 0.12 µL/g of CEO resulted in satisfying redness (a* approx. 11.1) and improved oxidative (TBARS approx. 0.12 mg MDA/kg) and microbial stability (total plate count - TPC approx. 2.50 Log CFU/g) of cooked pork sausages during refrigerated storage. Therefore, the results of this paper revealed significant antioxidative and antimicrobial activity of CEO, and consequently its high potential of utilization in processing of cooked pork sausages with enhanced quality and shelf-life.

Essential oil versus supercritical fluid extracts of winter savory (Satureja montana L.) - Assessment of the oxidative, microbiological and sensory quality of fresh pork sausages.

The effect of winter savory (Satureja montana L.) essential oil (SEO) and supercritical extracts (SE1; SE2) at concentrations of 0.075 and 0.150 µL/g on pH, lipid oxidation (TBARS), microbial growth and sensory quality of fresh pork sausages during storage were investigated. SEO, SE1 and SE2 improved oxidative and microbial stability of fresh pork sausages. The addition of SEO and SE1 at concentration of 0.150 µL/g affected the reduction of total Enterobacteriaeceae count to under 3 log cfu/g. Sausages produced with SE1 and SE2 had a higher scores for odor, flavor and overall acceptance compared to sausages treated with SEO and control sample. Therefore, the results of this paper revealed significant antioxidative and antimicrobial activity of SE1 and SE2, and consequently its high potential of utilization in processing of fresh pork sausages.

The influence of the extraction temperature on polyphenolic profiles and bioactivity of chamomile (Matricaria chamomilla L.) subcritical water extracts.

The main goal of this research was to determine the relationship among chemical structure, bioactivity and temperature of chamomile during subcritical water extraction in isobaric conditions (45 bar) at seven different temperatures (65-210 °C). The influence of temperature on phenolic profiles was defined by UHPLC-HESI-MS/MS. The overall results indicate that the presence of conjugated double bonds, side chains, glucose moiety or ether moiety in molecules influence the efficiency of polyphenols' extraction in subcritical water. In terms of antioxidant activity, the extracts were the most active towards ABTS radicals (IC50 = 7.3-16.8 µg/mL), whereby temperature of 150 °C was optimal. On the other hand, the extracts obtained at 115 °C showed highest cytotoxicity. Inhibition of α-amylase and α-glucosidase was the highest at 65 and 85 °C, i.e. 0.51 and 4.13 mmolAE/g, respectively. Activity against tyrosinase was the highest at 210 °C (17.92 mgKAE/g). The data showed that different non-phenolic compounds may also participate in bio-activities of the extracts.

Autofermentation of Chamomile Ligulate Flowers Promote Antitumor Effects in vitro.

In the frame of this paper, the enzyme-assisted hydrolysis coupled with ultrasound and Soxhlet extraction was applied in order to get extracts of chamomile ligulate flowers (CLF). Obtained extracts were characterized in terms to their apigenin and apigenin glucoside composition, as well as antiproliferative potential against tumour cells. Antioxidant activity was determined by two different assays based on different mechanisms showing that autofermented extracts have higher reduction potential. Autofermented extracts prepared by ultrasound and Soxhlet extraction had a stronger impact on the treated carcinoma (HeLa and NCI-H358) and leukemia (K562) cells' growth reduction in comparison to the native extracts, 30-35% greater inhibition at the lowest concentration (0.01 mg/mL), in two observed time points (48 and 72 h). Leukemia cells are more sensitive to all tested extracts. The autofermented CLF extracts with highest antiproliferative efficacy induced morphological changes and apoptosis in the HeLa cells. Obtained results clearly showed that the combination of enzymatic hydrolysis with cavitation phenomenon results in extracts with higher apigenin content and increased biological potential.

Subcritical water extraction as a cutting edge technology for the extraction of bioactive compounds from chamomile: Influence of pressure on chemical composition and bioactivity of extracts.

The study was designed to determine the relationship between chemical structure, bioactivity and pressure during the subcritical water extraction (SCW) of chamomile. Extraction was carried out at isothermal conditions (100 °C) at five different pressures (10, 30, 45, 60 and 90 bar). Twenty three polyphenolic compounds were identified in the extracts, whereby apigenin was found to be the dominant compound (61.53-1344.99 mg/kg). Results suggest that the lowest applied pressure has negligible effect on phenolic recovery from chamomile, but also the use of pressures above than 45 bar was proven as needlessly. By using in vitro assays, influence of pressure on antioxidant, cytotoxic and enzyme-inhibitory activities of the extracts was evaluated. Extracts obtained at 30, 45 and 60 bar exhibited stronger bioactivities than at 10 and 90 bar. It was concluded that pressure exert a significant influence on chemical composition of extracts, and thus on biological activity of chamomile extracts.

Comparative in vitro studies of the biological potential and chemical composition of stems, leaves and berries Aronia melanocarpa's extracts obtained by subcritical water extraction.

Preparation of functional products as well as natural-based products requires non-toxic but effective extraction techniques. In this study, subcritical water extraction was used for the extraction of different aronia parts in order to explore their potential. Stems, leaves and berries of Aronia melanocarpa were extracted under the following conditions: temperature 130 °C; pressure 35 bar; time 20 min. The total phenols and flavonoid contents of the produced extracts were evaluated by conventional spectrophotometric methods. Additionally, the main phenolic compounds were also identified and quantified by high performance liquid chromatography with diode array detection (HPLC-DAD). The biological potential of the extracts was evaluated by determining their antioxidant (DPPH, ABTS and lipid peroxidation assays), antimicrobial, enzyme inhibitory (cholinesterase and elastase) and cytotoxic effects (HeLa, A-549, LS-174T, MRC-5 cell lines). The results indicate that leaves and berries extracts exhibited stronger antioxidant action when compared with stems. The strongest cholinesterase and elastase inhibitory activity was also found in berries extract. Similarly, the extracts obtained from leaves and berries showed considerable cytotoxic effects against tested cell lines. A moderate antimicrobial effects was observed too. Demonstrated biological potential of all three aronia parts can trace a new road map for developing newly designed functional products.