Design and applications of a neural networks assisted portable liquid surface tensiometer

In this paper, a portable instrument for surface tension measurements, characterization and applications is described. The instrumentation is operated wirelessly, and samples can be measured in situ. The instrument has changeable different size probes; therefore, it is possible to measure samples from 1 ml up to 10 ml. The response of the measured retraction force and the concentrations of measured surfactant is complex. Therefore, two calibration methods were proposed: (i) the conditional calibration using polynomial and logarithmic fitting and (ii) the neural network trained model prediction of the surfactant concentration in samples. Calibrating the instrument, the neural network trained model showed a superior coefficient of determination (0.999), comparing it to the conditional calibration using polynomial (0.992) and logarithmic (0.991) fit equations

Volatile Compounds in Honey: A Review on Their Involvement in Aroma, Botanical Origin Determination and Potential Biomedical Activities

Volatile organic compounds (VOCs) in honey are obtained from diverse biosynthetic pathways and extracted by using various methods associated with varying degrees of selectivity and effectiveness. These compounds are grouped into chemical categories such as aldehyde, ketone, acid, alcohol, hydrocarbon, norisoprenoids, terpenes and benzene compounds and their derivatives, furan and pyran derivatives. They represent a fingerprint of a specific honey and therefore could be used to differentiate between monofloral honeys from different floral sources, thus providing valuable information concerning the honey’s botanical and geographical origin. However, only plant derived compounds and their metabolites (terpenes, norisoprenoids and benzene compounds and their derivatives) must be employed to discriminate among floral origins of honey. Notwithstanding, many authors have reported different floral markers for honey of the same floral origin, consequently sensory analysis, in conjunction with analysis of VOCs could help to clear this ambiguity. Furthermore, VOCs influence honey’s aroma described as sweet, citrus, floral, almond, rancid, etc. Clearly, the contribution of a volatile compound to honey aroma is determined by its odor activity value. Elucidation of the aroma compounds along with floral origins of a particular honey can help to standardize its quality and avoid fraudulent labeling of the product. Although only present in low concentrations, VOCS could contribute to biomedical activities of honey, especially the antioxidant effect due to their natural radical scavenging potential

High catechin concentrations detected in Withania somnifera (ashwagandha) by high performance liquid chromatography analysis

<p>Abstract</p> <p>Background</p> <p><it>Withania somnifera </it>is an important medicinal plant traditionally used in the treatment of many diseases. The present study was carried out to characterize the phenolic acids, flavonoids and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activities in methanolic extracts of <it>W. somnifera </it>fruits, roots and leaves (WSFEt, WSREt and WSLEt).</p> <p>Methods</p> <p>WSFEt, WSREt and WSLEt was prepared by using 80% aqueous methanol and total polyphenols, flavonoids as well as DPPH radical scavenging activities were determined by spectrophotometric methods and phenolic acid profiles were determined by HPLC methods.</p> <p>Results</p> <p>High concentrations of both phenolics and flavonoids were detected in all parts of the plant with the former ranging between 17.80 ± 5.80 and 32.58 ± 3.16 mg/g (dry weight) and the latter ranging between 15.49 ± 1.02 and 31.58 ± 5.07 mg/g. All of the three different plant parts showed strong DPPH radical scavenging activities (59.16 ± 1.20 to 91.84 ± 0.38%). Eight polyphenols (gallic, syringic, benzoic, p-coumaric and vanillic acids as well as catechin, kaempferol and naringenin) have been identified by HPLC in parts of the plant as well. Among all the polyphenols, catechin was detected in the highest concentration (13.01 ± 8.93 to 30.61 ± 11.41 mg/g).</p> <p>Conclusion</p> <p>The results indicating that <it>W. somnifera </it>is a plant with strong therapeutic properties thus further supporting its traditional claims. All major parts of <it>W. somnifera </it>such as the roots, fruits and leaves provide potential benefits for human health because of its high content of polyphenols and antioxidant activities with the leaves containing the highest amounts of polyphenols specially catechin with strong antioxidant properties.</p

Melissopalynological, physicochemical and antioxidant properties of honey from West Coast of Malaysia

Stingless bees are native to tropical region and produce honey which are high in moisture content. Compared to honey from honeybees, there are limited studies on honey derived from stingless bees. Hence, the aim of this study was to evaluate the chemical composition and antioxidant activities of stingless bee honey. Fifteen types of honey were collected from six states in West Coast of Malaysia and pollen analyses were carried out. Four types of unifloral honey samples produced by stingless bees were selected to determine their physicochemical and antioxidant activities including total phenolic, total flavonoid and ascorbic acid contents. Melissopalynological study of 15 honey samples collected from different states showed presence of both unifloral and multifloral origins. Honey samples collected from Apis mellifera (honeybee) combs had lower number of total pollen compared to samples collected from Heterotrigona itama and Geniotrigona thoracica (stingless bees). Jambul Merak honey contains the highest phenolic and flavonoid contents with greatest color intensity and has the highest antioxidant potential. This study highlights the chemical composition and biological activity of honey from stingless bees which may increase its commercial value or to be utilised as potential functional food ingredient

Assessment of the best available techniques for surface sewage management of stormwaters potentiol in Lithuania

Magistratūros baigiamajame darbe analizuojamas geriausiai prieinamų gamybos būdų (toliau – GPGB) paviršinėms nuotekoms tvarkyti taikymo Lietuvoje galimybių įvertinimas. Darbo apimtis 65 puslapiai kompiuteriu spausdinto teksto, įskaitant 28 paveikslus ir 19 lentelių. Naudotos literatūros sąrašą sudaro 27 literatūros šaltiniai. Darbo tikslas – apžvelgti paviršinių nuotekų tvarkymo būdus užsienio šalyse ir Lietuvoje bei parinkti paviršinių nuotekų tinkamiausius tvarkymo būdus Lietuvos gyvenvietėse. Šiame darbe apžvelgtos problemos, susijusios su paviršinių nuotekų tvarkymu Lietuvoje – kokios yra esminės problemos bei tinkamiausios priemonės paviršinėms nuotekoms tvarkyti. Analizuojamas užsienio šalių požiūris į paviršinių nuotekų tvarkymo problemas bei kokias pagrindines priemones paviršinių nuotekų tvarkymui taiko užsienio šalys. Paviršinių nuotekų bendras ilgis 2626 km. Daugiausia paviršinių nuotekų tinklų yra Vilniaus apskrityje – 744 km. Pagrindinės problemos, susijusios su paviršinių nuotekų tvarkymu Lietuvoje, yra tai, kad praktiškai miestuose ir miesteliuose paviršinės nuotekos nevalomos. Tik nuo kai kurių pramonės įmonių, degalinių, autoservisų ir kitų smarkiai užterštų naftos produktais teritorijų paviršinės nuotekos surenkamos ir išvalomos. Dauguma paviršinių nuotekų tinklų yra susidėvėję, reikalingas remontas arba rekonstrukcija, kurie užtikrintų tolesnį tinklų funkcionalumą, o esami paviršinių nuotekų valymo įrenginiai yra fiziškai pasenę ir nebeatlieka valymo funkcijų, tarša kaupiasi valymo įrenginiuose, o susikaupę paviršinėse nuotekose esantys teršalai liūčių metu su didele koncentracija išplaunami į vandens telkinius. Lietuvoje paviršinių nuotekų tvarkymui naudojami šie įrenginiai: purvo ir naftos atskirtuvai; paviršinių nuotekų sulaikymo tvenkiniai (nusodintuvai ir akumuliuojančios talpos); paviršinių nuotekų išlaikymo tvenkiniai ir įvairios filtravimo priemonės.In this final job of master studies is analysed the state of assessment for the best available techniques of surface sewage management of stormwaters Lithuania potential. The job consists of 65 pages of printed text, including 28 pictures and 19 tables. The list of literature is composed of 27 references. The aim of this job is to review surface sewage management methods in foreign countries and in Lithuania, and to choose the best appropriate surface water management methods for Lithuanian areas. First, it will also be reviewed and analysed the essential negative aspects for surface sewage managament in Lithuania: what are the best measures for the management. Second, we will analyse foreign countries approach to the problems of surface sewage management: what are the main ways which foreign countries use in their practice. The total length of the stormwaters is 2626 km in our country. The biggest network of the stormwaters is in Vilnius district – 744 km. The essential problems are associated with surface water management in Lithuania: the practice in cities and towns cleaned stormwaters. Only from certain industries, gas stations, service centers and other heavily polluted areas of surface oil wastewater collected and cleaned. Most stormwaters networks are worn out, need repairs or reconstruction to ensure the continued functioning of networks and the existing stormwaters treatment plants are physically obsolete and no longer provides a cleaning function, accumulation of pollution treatment facilities, and the accumulated stormwaters contaminants during heavy rainfall with a high concentration of the eluted water bodiesThe most appropriate means of stormwaters management in Lithuania are the following: dirt and oil separators, stormwaters retention ponds (settlers and accumulation capacity) of stormwaters retention ponds and a variety of filtering tools.Žemės ūkio akademijaVytauto Didžiojo universiteta

Bee products for food and human health

OP23The diversity of the products produced by the bees are unique. Apis mellifera are the most popular domesticated bee species used among beekeepers. Probably there are not animal or insect species in the nature producing such a variety of products suitable for human consumption. Honey, bee pollen, bee bread, propolis, royal jelly, wax and bee venom are the whole family of the products produced by the bees. However, some products are more suitable for food (such as honey), others - for health. Because of possible allergic reactions, bee venom is not recommended to use for self-treatment. The diversity of the bee products' biological activities are described in the literature: antioxidant, antibacterial, antifungal, antiviral, anti-inflammatory, antitumor, antiproliferative, antimetastatic, immunomodulatory, antiseptic, antistress, antiulcer, antihyperlipidemic, antidiabetic, anticancer and etc. The activities list is not final, as various bee products or their mixtures are highly investigated nowadays. It is difficult to distinguish what has the highest impact to their biological activity. Probably the activity depends on a complex set of factors, such as botanical origin, related to phytochemicals in the bee products, secretion of the honey bees, containing proteins, amino acids, fatty acids, enzymes, pheromones, vitamins and minerals, which are secreted from different glands of the bees, varying the proportions of these compounds among the different bee products, or interaction of these factorsInstrumentinės analizės APCVytauto Didžiojo universiteta

The application of chemometric techniques for the classification of bee products : a review

The chemometric techniques are used for the classification of the samples to the groups. The classification may be unpredictable (when samples are grouped according to some specific parameters) and predictable (when the dependence of the sample to some specific (already known) group is tested). The hierarchical cluster analysis, principal component analysis, linear discriminant analysis are the most popular in classification of food samples, including bee products. However other tests, like artificial neural networks, partial least squares or partial least squares discriminant analysis, canonical variate analysis, soft independent modelling class analogy, and etc., are applied. As composition of bee products is enough rich in diversity of chemical compounds, the various factors are used for the classification of the samples: carbohydrates composition, amino acids content and composition, volatile compounds composition, phenolic compounds and flavonoids content and composition, mineral composition. Chemometric classification of bee products can be based not only chemical composition, but also on other characteristics, like antiradical activity, DNR composition, electrical conductivity, optical rotation, antibacterial activity, and etcBiochemijos katedraVytauto Didžiojo universiteta

Analysis of bee products using chromatographic techniques : a review

Bee products are very valuable for consumers due to their unique properties, which cover the “power” of plants and bees itself. Bee products are used as food or are introduced in the folk medicine from the ancient times. Honey is the most favourable out of all bee products due to it sweet taste and characteristic aroma. Bee bread, bee pollen, propolis, bee wax, royal jelly and bee venom are also very valuable bee products with a wide spectrum of biological activity. The latter two are not so easily available for the consumers and mainly are used in pharmacy products. However the use of bee products as food or as medicine, requires determination of their composition, evaluation of quality and biological activities or verifying the authenticity. The variety of chromatographic techniques allows to evaluate many parameters concerning to the bee products composition or impurities. Sugar composition can be determined by different methods, e.g. HPLC with refractometric detection, HPLC with pulsed amperometric detection, ion exchange chromatography with pulsed amperometric detection. GC-FID and GC-MS also can be applied for sugar analysis; just in this case the derivatization of carbohydrates must be performed to make them volatile. Aroma of bee product can be analyzed by GC with various detectors, after different sample preparation techniques, i.e. direct headspace analysis, solid phase microextraction (SPME), solvent extraction (SE), Likens-Nickerson, purge-and-trap or hydrodistillation. The residues of pesticides, fungicides and antibiotics in bee products can be determined using HPLC or GC after a proper sample preparation. [...]Biochemijos katedraVytauto Didžiojo universiteta

Skirtingos botaninės kilmės medaus sudėties ypatumai ir savybės

Bibliogr.: p. 105-113Kauno technologijos universiteta

Vaistinių augalų antrinių metabolitų analizė panaudojant dujų ir skysčių chromatografijos metodus su masių spektrometrija

The research on bioactive compounds of natural origin has gained much interest in the last two decades. The aim of the present study was the analysis of secondary metabolites of three medicinal plants (Bidens tripartita L., Calendula officinalis L. and Silybum marianum L.) cultivated in Lithuania and collected at different phenological stages. Supercritical CO2 extraction was applied for the extraction of essential oils from B. tripartita and C. officinalis. Identification of volatile compounds was produced using gas chromatographic-mass spectrometric analysis. Non-volatile compounds from all plants were extracted with methanol/water solution. The total content of phenolic compounds was tested by the Folin–Ciocalteu method, and the total content of flavonoids was also determined by AlCl3 colorimetric method. Radical scavenging activity was determined in model system with DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical. The qualitative analysis of phenolic compounds was performed by high performance liquid chromatography (HPLC). The study showed that both qualitative and quantitative composition of volatile and non-volatile compounds were strongly dependent on the plant phenological stageBiochemijos katedraVytauto Didžiojo universiteta