Chemical composition of seed oil from red grape varieties obtained by supercritical CO2 extraction

This study aimed to investigate the potential of the most abundant red grape variety from the central part of Serbia (the region of three Morava rivers) for grape oil manufacturing, using supercritical CO2 extraction. The content of the main constituents of grape seed oils from the indigenous variety Prokupac was determined and the results of the analysis were compared with selected, most commonly grown, international varieties (Cabernet Sauvignon, Pinot Noir, Merlot, and Gamay). Fatty acid profile and the content of biologically active compounds (total phenolic compounds and ?- tocopherol) were determined. Oxidative stability of the oils was estimated using a DSC (differential scanning calorimetry) method, by determining the oxidation onset temperature. The fatty acid composition was in accordance with literature data. In terms of ?-tocopherol content, its low relative amount was measured in the oils from all grape seed varieties.

Phenethyl angelate - a new ester from immortelle essential oil?

Esters of angelic, senecioic and tiglic acids with various saturated/ unsaturated/aromatic alcohols contribute to the aroma of many essential oils. However, mass spectrometry with electron-impact ionization sometimes fails to distinguish these regio-/geometric isomers and this was the case with the minor constituent of Helichrysum italicum (immortelle) essential oil that was tentatively identified as the ester of 2- phenyl-1-ethanol with one of the mentioned acids. Our efforts to identify this phenethyl ester were also hampered by the inconsistency or by the lack of appropriate RI data in the literature. Therefore, we prepared and fully spectrally characterized (1D- and 2DNMR, IR, MS) synthetic samples of all three isomeric esters. Subsequent GC analyses of immortelle oil samples with spiked synthetic phenethyl esters unambiguously confirmed that the compound in question was phenethyl angelate. This rare plant secondary metabolite has been previously reported only twice as a constituent of samples of natural origin. However, the outcomes of our study strongly imply that this molecule was misidentified in these earlier studies with the corresponding senecioate/tiglate. Thus, the existing libraries of RI/MS data for tiglates and angelates have to be upgraded with appropriate data for senecioates to avoid these kinds of errors in the future.

Chemical remediation technologies

Environmental pollution remains one of the most serious world problems. Great efforts are made to limit the release of harmful compounds into the environment, and a variety of methods for remediation of soil, surface water, and groundwater have been developed over the years. Chemical remediation technologies are of great interest since they can remove and degrade pollutants in contaminated sites. This paper focuses on several chemical remediation technologies, such as precipitation, flocculation, adsorption and ion exchange, chemical oxidation, soil washing and flushing, and electrokinetic remediation. Remediation technologies are almost always combined one with another, although they can be used separately. Choosing an appropriate technology will depend on the type of the pollutants and site conditions, and it should be done in such a manner so that the most cost-effective and efficient technology is chosen. Even though some of the technologies are used full-scale, research should be focused on enhancing the existing, and developing new remediation technologies.

Determination of content and antioxidant capacity of natural food colors E160a and E160d in ketchup

After potato, tomato (Solanum lycopersicum) is the world?s second-largest vegetable crop. More than 80% of tomato consumption comes from processed products such as ketchup, tomato juice, pickled tomatoes, sauces, paste, pur?e. Samples of mild ketchup from two different manufacturers (A and B) were selected for the analysis of the content of natural food colors E160a and E160d. Using a UV-Vis spectrophotometric method and Lambert-Beer law, a system of two linear equations with two unknowns was set up, which was used to determine the concentrations of colors E160a and E160d. The antioxidant capacity of the two selected samples was determined using the DPPH assay. The obtained results indicated that the content of colors E160a and E160d was higher in the sample of ketchup B. Also, the DPPH assay showed that the sample of ketchup B had a higher antioxidant capacity.

Supercritical CO2 extraction of oils from red grape varieties: Yields and extraction parameters

In this work, the extraction by supercritical carbon dioxide of grapeseed oil from five red grape varieties was investigated. Apart from an indigenous variety Prokupac, as the domestic, and Merlot and Cabernet Sauvignon, as international grape varieties the most represented in the Republic of Serbia, Pinot Noir and Gamay were studied as well. Extraction conditions were: temperature of 50?C, 250 bar pressure, and 0.3 kg/h flow rate of CO2. It was shown that the extraction kinetics of international grape varieties, mutually similar differ significantly from the domestic one. The obtained oil yields were in the range of 8.3% w/w (Gamay) to 10.4% w/w (Pinot Noir) for the international varieties and 5.0% w/w for the domestic variety. The mathematical model ?Sovova? was applied to define transport parameters regulating the oil mass transfer inside the seed particles and determine the agreement between experimental and model curves. The interpretation of results took into account the differences of grade seed morphologies (outer surfaces and inner layers) which was investigated by SEM analysis.

Lithium aluminum hydride reduction of 1-phenylbutane-1,3-dione, and acetylation of the products: NMR and GC-MS analysis

Reduction of ?-diketones with lithium aluminum hydride (LiAlH4, LAH) can lead to different products, depending on the tautomeric equilibrium: the reduction of diketo forms gives the corresponding diols and the reduction of ketoenol forms yields elimination products, saturated and unsaturated ketones and alcohols. Here, we report on the results of LAH reduction of 1-phenylbutane-1,3-dione. The products of reduction were further acetylated and separated by dry flash chromatography. The obtained products, phenylbut(en)ols, phenylbut(en)ones and phenylbut(en)yl acetates, were characterized by spectral (1H and 13C NMR, MS) and retention index (RI) data. It can be concluded that LAH preferentially reduces the carbonyl group more distant from the phenyl group of 1-phenylbutane-1,3-dione. The structure-retention index relationships between isomers were discussed. Proton splitting patterns were resolved by proton NMR simulations.

Physico-chemical characteristics of geothermal water in Tulare near Medvedja

The paper presents general characteristics and legal regulations for the use of thermomineral waters in Serbia, provides information on the regional position and geological characteristics of Tulare near Medvedja, the springs of water in Tulare and the methods of testing the physical and chemical characteristics of water in Tulare are described. In addition, the results of measuring the temperature, hardness, acidity, and chemical composition of water in Tulare are given. The results of the measurements showed that the water in Tulare belongs to homeothermal waters, that is soft to very soft, slightly acidic, and has an increased amount of Na, Ca, K and Mg, and also Sr, B, Li, P, As and Hg in small quantities. The water from the spring in Tulare is not suitable for drinking. To determine the balneological utility of the water in Tulare it is necessary to carry out appropriate drilling and further examine the physical, chemical, and balneological properties of this water.

Assignment of 1H and 13C NMR spectral data of diastereomeric acetals directly from their mixture by spectral simulation

Herein, an NMR spectral analysis was performed of a mixture of diastereomeric acetals synthesized from 2-fluorobenzaldehyde and a racemic mixture of 4-methylpentan-2-ol. The simulated 1H- and 13C-NMR spectra of individual diastereomers, as well as their superimposed and summed spectra, were compared with the obtained experimental spectra. Spin simulation of proton signals was particularly useful for the assignment of the aromatic part of the molecules and of the diastereotopic protons of the methylene groups. The isomer NMR spectral data - chemical shifts, coupling constants, HMBC and NOESY interactions were systematized in appropriate tables and schemes.

Organic thiocyanates - glucosinolate enzymatic degradation products or artefacts of the isolation procedure?

Glucosinolates are abundant in plants of the order Brassicales, and they are degraded by myrosinases into various organic breakdown products: isothiocyanates, thiocyanates, nitriles, etc., depending on their structure, conditions of hydrolysis, the presence of certain protein cofactors. Their most common hydrolysis products are isothiocyanates, while simple nitriles, epithionitriles, and thiocyanates are produced occasionally. Organic thiocyanates are described from a very limited number of Brassicales taxa. Up to now benzyl, (4-hydroxyphenyl)methyl, (4-methoxyphenyl)methyl, 4- methylthiobutyl, and allyl thiocyanates were reported as products of glucosinolates autolysis. The present review summarizes the knowledge on the mechanism of organic thiocyanate formation from the corresponding thioglucosides. The enzymatic formation of organic thiocyanates is believed to be enabled by thiocyanate-forming protein (TFP), but they could be formed via metabolic routes that do not involve TFP. All of the reported thiocyanates are produced from stable (carbo)cationic species that allow an isomerization of an isothiocyanate to thiocyanate, and vice versa. Although the possibility that thiocyanates can be biosynthesized in plats under certain conditions cannot be dismissed, allyl thiocyanate can be a thermal isomerization artefact of the original isothiocyanate that is formed in the heated zones of the gas chromatograph, while other thiocyanates could form in an aqueous medium via heterolytic dissociation to ambident nucleophilic SCN- and its recapture. One should always be aware of this analytical shortcoming when concluding on the presence and quantity of these specific (iso)thiocyanantes in the analyzed sample.

Attractor behaviour of holographic inflation model for inverse cosine hyperbolic potential

We study a model of tachyon inflation and its attractor solution in the framework of holographic cosmology. The model is based on a holographic braneworld scenario with a D3-brane located at the holographic boundary of an asymptotic ADS5 bulk. The tachyon field that drives inflation is represented by a Dirac-Born-Infeld (DBI) action on the brane. We examine the attractor trajectory in the phase space of the tachyon field for the case of inverse cosine hyperbolic tachyon potential.