Marine macroalgae represent a rich source of bioactive compounds that can be implemented in various food, cosmetic, and pharmaceutical products for health improvement. It has been proven that these ...bioactive compounds, such as polyphenols, polysaccharides, carotenoids, and ω-3 fatty acids possess bioactivity. For the extraction of these compounds, modern methods (Supercritical Fluid Extraction (SFE), Subcritical Water Extraction (SWE), Ultrasound-Assisted Extraction (UAE), and Microwave-Assisted Extraction (MAE)) have been used due to their advantages over the conventional methods. The process parameters of each method must be optimized for obtaining the extracts with the targeted bioactive compounds. In distinction from the existing reviews, the present review provides novelty with respect to: (a) presenting systematically the selected process parameters of SFE (temperature, time, pressure, use of co-solvents), SWE (temperature, time, pressure, solid-solvent ratio), UAE (temperature, time, frequency, power, solid-solvent ratio), and MAE (temperature, time, frequency, power, solvent type) applied for the extractions of marine macroalgae; (b) reporting the major groups or individual compounds extracted with their biological activities (if determined); and,
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•Supercritical CO2 extraction of black poplar buds was optimized (first time report).•The obtained extracts were rich in bioactive phenolics.•The pressure exhibited highest impact on ...the extraction yield.•Pinostrobin extraction was affected only by the operating pressure.
The scope of current study was to apply supercritical CO2 for extraction of black poplar buds (Populus nigra L.) and to optimize the extraction parameters (pressure and temperature) using response surface methodology aimed at maximum extraction yield, total phenolic content (TP), ferric reducing antioxidant power (FRAP) and individual amount of selected bioactive phenolics. The pressure and temperature influenced significantly the extract yield (0.38–10.28 g/100 g), TP content (21.62–31.09 μg GAE/mg), FRAP capacity (0.30–0.48 μmol Fe2+/mg), and the amounts of p-coumaric acid (0.33–1.52 μg/mg), pinocembrin (20.99–47.24 μg/mg) and galangin (4.04–10.25 μg/mg). The extraction of pinostrobin (51.73–79.56 μg/mg), pinobanksin (0.41–1.55 μg/mg), and chrysin (0.97–2.03 μg/mg) was significantly affected only by the operating pressure. Optimized extraction parameters (30 MPa and 60 °C) allow to obtain higher yield and extracts enriched with bioactive phenolics.
Abstract
This work investigated a green approach to obtain and stabilize
Lavandula stoechas
L. volatile organic compounds with sensory aroma characteristics by using alternative solvents, namely ...supercritical carbon dioxide (scCO
2
) and deep eutectic solvents (DES). The CO
2
extracts were dispersed in different DES mixtures (betaine:ethylene glycol (1:3), betaine:glycerol (1:2), and glycerol:glucose (4:1)) and their stability was monitored during 6 months of storage at room temperature by monitoring the headspace (HS) profile. The CO
2
extract was used as the control. It was initially determined that there was a dominant presence of oxygenated monoterpenes (67.33–77.50%) in the extracts. During storage, significant changes occurred in the samples’ HS, such as the decrease in terpene hydrocarbons which also affected the presence of oxygenated terpenes, which increased in certain cases. Moreover, the highest formation of new components was recorded in the control which could be an indicator of decreased stability. The DESs-CO
2
were more stable than the CO
2
control and among them, betaine:ethylene glycol stood out as the most adequate systems for maintaining the stability of
L. stoechas
HS components. For the visual estimation of similarities and dissimilarities among the samples, chemometric pattern recognition approaches were applied including the hierarchical cluster analysis, principal component analysis, and sum of ranking differences.
The Menshutkin reaction represents the alkylation of tertiary amines by alkyl halide where the reactants are neutral and the products, quaternary ammonium salts, are two ions with opposite signs. The ...most commonly used organic solvents in quaternization reactions are volatile organic solvents (VOSs), namely acetone, anhydrous benzene, dry dichloromethane (DCM), dimethylformamide (DMF) and acetonitrile (ACN). The purpose of this work was to examine eutectic solvents as a “greener” alternative to conventional solvents so that quaternization reactions take place in accordance with the principles of green chemistry. Herein, sixteen eutectic solvents were used as replacements for volatile organic ones in quaternization reactions of isonicotinamide with substituted phenacyl bromides. The reactions were carried out at 80 °C by three synthetic approaches: conventional (4–6 h), microwave (20 min) and ultrasound (3 h). Microwave-assisted organic reactions produced the highest yields, where in several reactions, the yield was almost quantitative. The most suitable eutectic solvents were based on choline chloride (ChCl) as the hydrogen bond acceptor (HBA) and glycerol, oxalic or levulinic acid as hydrogen bond donors (HBDs). The benefits of these three deep eutectic solvents (DESs) as a medium for quaternization reactions are the simplicity of their preparation for large-scale production, with inexpensive, available and nontoxic starting materials, as well as their biodegradability.
•Chemical characterization of nectar-to-honey conversion by FTIR-ATR spectroscopy.•First record on IR chemical fingerprints of Citrus unshiu nectar/honey sac content.•Comparative compositional ...changes in Citrus nectar-to-honey transformation pathway.•Preliminary results: >1/3 of the sugar-related conversion occurs in the honey sac.
Samples of Satsuma mandarin (Citrus unshiu Marc.) nectar, honey sac content and honey were analyzed by FTIR-ATR spectroscopy and reference methods. The spectral analysis allowed detection of the major chemical constituents in C. unshiu nectar-to-honey transformation pathway thus providing information on the intensity and location of the compositional changes occurring during this process. The preliminary results showed that in average more than one-third of sugar-related nectar-to-honey conversion takes place directly in the honey sac; the average sugar content (w/w) was 17.93% (nectar), 47.03% (honey sac) and 79.63% (honey). FTIR-ATR results showed great spectral similarity of analyzed honey samples and small degree variations in both sugar and water content in nectar samples. The spectral data revealed distinctive differences in the chemical composition of individual honey sac contents with the most intensive and complex absorption envelope in the spectral region between 1175 and 950cm−1 (glucose, fructose and sucrose absorption bands).
The aim of this study was to develop an innovative sheep cheese enriched with Thymus capitatus L. essential oil (EO) nanoincorporated into small homogeneous liposomes. The latter were prepared using ...two types of lecithin: one commonly used for liposome production, and the other used as dietary supplement. Both EO liposomes, which showed similar physico-chemical characteristics (i.e., size, homogeneity, surface charge), were incorporated into fresh sheep cheese. These enriched sheep cheeses were produced in Sardinia (Italy) and analysed 20, 60 and 180 days after preparation. HS-SPME at 40 and 80 °C coupled with GC-MS/FID method was used to evaluate the volatile fraction and identify the main compounds of both EO and cheese. A validated HPLC-DAD analysis allowed the identification and quantification of thymol and carvacrol, and thymol amount dosed at 20 days was the highest (9.51–10.10 mg/kg). The amount of monoterpenoid phenols and the antiradical and total antioxidant capacity evaluated by FRAP and DPPH• assays, decreased linearly (r ≥ 0.93, p ≤ 0.05) as the cheese maturation increased. Overall results suggested that sheep cheese enriched with T. capitatus EO nanoformulations had an enhanced antioxidant activity compared to cheese without liposomal EO, up to 180 days.
•An innovative enriched sheep cheese was developed.•Thymus capitatus L. essential oil was nanoincorporated in liposomes.•Thymol amount in cheese at 180 days ranged between 2.53 and 3.53 mg/kg.•Antiradical and total antioxidant capacities were enhanced until 180 days.
Two selected brown algae (
and
from the family Dictyotaceae, order Dictyotales) growing in the same area (island Vis, central Adriatic Sea) were collected at the same time. Their phytochemical ...composition of the headspace volatile organic compounds (HS-VOCs; first time report) was determined by headspace solid-phase microextraction (HS-SPME). Hydrodistillation was applied for the isolation of their volatile oils (first report on
volatile oil). The isolates were analyzed by gas chromatography (GC-FID) and mass spectrometry (GC-MS). The headspace and oil composition of
were quite similar (containing germacrene D, epi-bicyclosesquiphellandrene, β-cubebene and gleenol as the major compounds). However,
headspace and oil composition differed significantly (dimethyl sulfide, octan-1-ol and octanal dominated in the headspace, while the oil contained mainly higher aliphatic alcohols,
-phytol and pachydictol A). Performed research contributes to the knowledge of the algae chemical biodiversity and reports an array of different compounds (mainly sesquiterpenes, diterpenes and aliphatic compounds); many of them were identified in both algae for the first time. Identified VOCs with distinctive chemical structures could be useful for taxonomic studies of related algae.
Various mint taxa are widely cultivated and are used not only for medicinal purposes but also in cosmetic and industrial applications. The development of new varieties or cultivars of mint generates ...difficulties in their correct identification and safe use. Volatile organic compounds (VOCs) from the leaves of seven different taxa of the genus Mentha obtained by hydrodistillation (HD) and headspace solid-phase microextraction (HS-SPME) were analyzed using gas chromatography–mass spectrometry (GC-MS). Principal component analysis (PCA) was also performed. Comparative GC-MS analysis of the obtained extracts showed similarity in the major compounds. PCA data allowed the separation of two groups of chemotypes among the analyzed mints, characterized by the abundance of piperitenone oxide and carvone. Two out of seven analyzed taxa were not previously examined for VOC profile, one was examined only for patent application purposes, and six out of seven were investigated for the first time using the HS-SPME technique. The presented analysis provides new data on the abundance and qualitative characterization of VOCs in the studied mint plants and on the safety of their use, related to the possibility of the presence of potentially toxic components. HS-SPME is a valuable method to extend the characterization of the VOC profile obtained by hydrodistillation.
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