Potravinarstvo Slovak Journal of Food Sciences
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Study of chemical structure, antimicrobial, cytotoxic and mechanism of action of Syzygium aromaticum essential oil on foodborne pathogens
Get PDFIn this study, chemical composition (gas chromatography-mass spectroscopy), chemical structure (fourier transform infrared spectroscopy) and antioxidant potential (β-carotene bleaching assay and DPPH/ABTS-radical scavenging activity tests) of Syzygium aromaticum essential oil (SAEO) were evaluated. Eugenol (75.11%) was found to be the major compound of SAEO. Eugenol, as the main chemical constituent of SAEO, showed its signature peaks in the wavenumber range of 720 – 1250 cm-1, ascribing to the C=C region. The antimicrobial activity of SAEO on Escherichia coli, Staphylococcus aureus, Listeria innocua and Pseudomonas aeruginosa were evaluated. The scanning electron microscopy (SEM) was then applied to unravel the antibacterial mechanism of SAEO on E. coli as the most resistant strain and L. innocua as the most sensitive strain. The MTT assay was also used to investigate the cytotoxicity effect of SAEO on human colonic cancer cell lines (HT29 cell line) and the highest cytotoxic effect was observed at 200 mg.mL-1 concentration of SAEO. The SEM micrographs revealed that the SAEO treatment was able to manifestly increase the cell permeabilization and membrane integrity disruption. This means that the entirety of the cell membranes was remarkably affected by the essential oil, which could lead to cytoplasm secretion and subsequent cell death. The data strongly suggest that SAEO had a potential antioxidant, antimicrobial and cytotoxicity activity
Ecotoxicological studies of Akmola region lakes
Get PDFThe research object is water, bottom sediments in Akmola region lakes located in the intensive agriculture area. The territory of Akmola region is subjected to intensive human impacts, including the inevitable pollution with agricultural pesticides, which are ecotoxicants. The work has carried out hydrochemical studies in technogenic polluted lakes: general hydrochemical indicators, persistent organic pollutant content. The POPs in the samples were determined on the gas chromatograph Clarus 580 (PerkinElmer) with a mass spectrometer detector Clarus-SQ 8. According to the analysis results, the general hydrochemical pollution is classified as an average. The MPC excess indicators in the Akmola region lakes are observed for salt ammonium (up to 0.002 MPC), magnesium (up to 1.15 MPC), nitrites (up to 1.12 MPC), petroleum products (up to 1.98 MPC), iron (up to 2.0 MPC), SSAS (up to 3.8 MPC). High concentration indicators for the sulphate (3.5 MPC), copper (4.3 MPC), magnesium (1.125 MPC). Mainly the lakes are dominated by sulfates, ion chloride. But in general among 21 investigated POPs 8 substances are accumulated in bottom sediments of the investigated Zhalauly, Tastykol lakes, Unnamed Lake to the south of Akkol village, Itemgen lake, Zhalanash lake near Malinovka village (near Astana city), Kokay, Yesey, Bolshoe Chebachie
Microbiota of different wine grape berries
Get PDFThe wine grape berries share a complex microbial ecology including filamentous fungi, yeasts and bacteria. The microbiota reveals different physiological characteristics and depends on the grape ripening stage and the availability of nutrients with different effect on wine production. The microbiota of grape berries (n = 12) was isolated and identified in the present study. The samples were collected in September 2018. Grape berries were obtained from Vrbovo vineyard located in Slovakia. The grape berries investigated belonged to Blue Frankish, Cabernet Sauvignon, Chardonnay, Dornfelder, Feteasca regala, Green Veltliner, Irsai Oliver, Mūller Thurgau, Pálava, Pinot Blanc, Rhinriesling and Welschriesling varieties. The microorganisms were cultivated on Malt extract agar (MEA) at 25 °C for five days in aerobically for microscopic filamentous fungi and Tryptone Soya agar (TSA) at 37 °C for 24 – 48 h aerobically for bacteria and yeasts. Total bacterial counts on different wine grape berries ranged from 2.57 ±0.09 in Chardonnay to 4.39 ±0.21 log CFU.g-1 in Pálava. Microscopic filamentous fungi count ranged from 1.18 ±0.03 in Blue Frankish to 2.60 ±0.17 log CFU.g-1 in Welschriesling. MALDI-TOF MS Biotyper mass spectrometry was used for identification of microorganisms (bacteria and yeasts) and microscopic filamentous fungi with manuals. The most identified microscopic fungal species was Alternaria sp., for yeasts Issatchenkia orientalis and Leuconostoc mesenteroides subsp. mesenteroides for bacteria
Hygienic quality and composition of raw sheep's bulk milk samples on selected Slovak farms during year 2018
Get PDFAt the control of raw ewe's milk (REM) quality is a major microbiological criterion to the total bacterial count (TBC). The aim of our work was to determine the incidence of technologically important species of microorganisms in REM in Slovak Republic. At the monitored 28 ewe´s farms, we took bulk milk samples from evening or morning milking in spring, summer and autumn during year 2018. We analyzed nutrients (fat, protein, lactose and urea) and somatic cell count (SCC). We established technologically important microorganisms (MO) of psychotrophic MO, coliform MO, thermoresistant MO, spore-forming anaerobic MO. We have found a gradual increase in milk components, except for lactose, which is apparently related to the increasing cont of somatic cells during the milking period. We found that the TBC in raw sheep's milk complied an average of 132 x 103 CFU.mL-1 per spring (min 34 x 103 CFU.mL-1, max 501 x 103 CFU.mL-1), 300 x 103 CFU.mL-1 in summer (min. 31 x 103 CFU.mL-1, max 640 x 103 CFU.mL-1) and in autumn with an average value of 147 x 103 CFU.mL-1 (min 52 x 103 CFU.mL-1, max 276 x 103 CFU.mL-1). The enormous occurrence of psychrotrophic bacteria was found in one farm in northern Slovakia during spring and summer, in the summer we increased our number to 3 farms, in the autumn of 2 farms. At the other farms we evaluated the average value of 12 x 103 CFU.mL-1 per spring and 28 x 103 CFU.mL-1 in summer, 130.5 x 103 CFU.mL-1 in the autumn. The count of thermoresistent MO achieved 57 CFU.mL-1 per spring, 15 CFU.mL-1 in summer and 33 CFU.mL-1 in the autumn. The presence of spore-forming anaerobic MO in raw ewe´s milk was found during spring at six farms out of 15, but in the summer at just one in 9, in the autumn two farms
Adhesion effect on environment process injection
Get PDFТhe analytical analysis of roller impact on the medium and its behavior at deformation influences are carried out, ways of choosing an optimal variant of the process for providing the maximum or minimum value of parameters (criterion) are proposed. The physical essence of the equation of energy flows of the intensity of deformation of the mass of the medium, which depends on the method of applying mechanical forces, the degree of its previous dispersion (recipe) and its physical and mechanical properties, is considered. To reveal the essence and understanding of the general research execution, a number of hypotheses for the determination of adhesion are given and a generalized approach to the definition of adhesion is given. The proposed scheme of causal relationships between the medium and roll, divided into three groups, and determine the change in the process of injection dough. The nature of the maximum increase of the forces of interaction of the dough with the high contact of the roller working body in the injection nozzle of the fuming machine is established. Violation of these mutual relations leads to the production of low-quality products and a decrease in the efficiency of the machine. These phenomena are little studied today, and the nature of adhesion requires research. It is noted that the determination of deformation processes during the passage of the process of injection of the medium by roller working bodies plays an important role in calculating the design of molding, roll-over equipment. The deformation in the knot of the injection dough by rolls and the dependence of the work performed on the influence of adhesion on the flow process in the molding machine are revealed. The contact area of the adhesive and the component forming work for overcoming the adhesion and deformation of the environment in determining the criteria that influence the process, according to each particular period of the deformation stage, are substantiated. The obtained data provide an answer to a number of questions about the possibility of regulating the process of the work of agents on the environment
Evaluation of the content of pigments and total sugars in ground sweet paprika
Get PDFThe aim of this research was to evaluate and compare the content of pigments and total sugars in raw materials of both the domestic as well as foreign origin that are used in the production of sweet ground pepper. The tests included two samples exported from abroad, specifically from Serbia and China and the following domestic varietes of Capsicum annum L.: Kolora, Žitava, Dvorská (varieties that form the base of the final product called Paprika Žitava/Žitavská paprika and a mix of a number of domestic varieties called Slovenský polotovar. The tests were conducted in 2015 and 2016. The highest content of pigments in both years was contained in Dvorská and Kolora – 6.81 and 6.11 g.kg⁻¹. The largest amount of total sugars was recorded within Žitava in 2015 (20.5%) and in 2016 Slovenský polotovar with 24.5%. Both the exported as well as domestic products fulfilled the parameters of quality required in the production of sweet pepper
Multiple linear regression model of Golden apple's failure characteristics under repeated compressive load
Get PDFIn this paper, the multiple linear regression model of mechanical properties related to the failure mechanism of apple tissue under repeated compressive load was investigated. More refined failure characteristics may lead to improved processing and logistics aspects of the given fruits. For our study, the following failure-related factors are considered during the cyclic measurements of Golden Delicious apples: the viscoelastic parameters, the dissipated energy, and the rupture point of the cell-structure, which is described with the time to failure parameter (TTF). For the determination of viscoelastic components, the three element Poynting-Thomson body was applied, and a closed-loop control system is identified with the measured creep data. From the hysteresis loop - in each cycle of the force-deformation parametric curve - the dissipated energy can be calculated with a numeric integration method. The rupture point of the fruit tissue - where the measuring pin is breaking through the peel and the cortex - is observed with a high-framerate video analysis, so that the time index of the failure point can be evaluated. The focus is to define the influence of the mentioned factors to the TTF parameter of the examined fruit material. During the statistical evaluation of the resulted data, the failure of time can be successfully determined with a multiple lienar regression model of the determined viscoelastic and dissipated energy variables. With the resulted equation, the failure time of Golden Delicious apples can be predicted based on the measured failure-related parameters obtained during the compressive load tests
Oryctes rhinoceros larva oil supplementation improves tissue antioxidant status in cholesterol-fed rats
Get PDFExperimental evidence from previous study has demonstrated the hypolipidemic effects of Oryctes rhinoceros oil (ORO) when fed as a supplement to a cholesterol-based diet. Due to renew interest in the consumption of insect derived oil, the present study was designed to elucidate the effect of Oryctes rhinoceros oil (ORO) supplementation in comparison to vitamin E on oxidative status in some tissues of rats fed a cholesterol-based diet. Forty (40) Swiss albino rats were divided into 4 groups (n = 10) and maintained on a basal diet (cholesterol free as control), a cholesterol-based diet (5% cholesterol as cholesterol), a cholesterol-based diet supplemented with ORO (cholesterol + ORO) and a cholesterol-based diet supplemented with vitamin E (Cholesterol + vit E) for 10 weeks. Animals in the cholesterol group had a significantly(p <0.05) higher malondialdehyde (MDA), conjugated diene and nitric oxide concentrations in the serum, liver, heart, kidney and lung compared to control, cholesterol + ORO and cholesterol + vit E groups. Tissue glutathione (GSH) concentration was significantly (p <0.05) higher in rats fed cholesterol-based diet supplemented with ORO and vitamin E compared to those fed cholesterol-based diet alone. Xanthine oxidase activity was significantly (p <0.05) reduced in tissues of rats fed ORO and vitamin E supplemented diets compared to cholesterol rat group. In addition, catalase and superoxide dismutase activities in the various tissues examined were significantly (p <0.05) higher in both ORO and vitamin E supplemented groups compared to the cholesterol group. No significant difference was observed between animals fed ORO and vitamin E supplemented diets. These results showed that Oryctes rhinoceros larva oil exhibited similar protective effects to vitamin E against diet-induced oxidative stress in rats. In addition, data from this study showed that Oryctes rhinoceros larva oil possessed antioxidant property. Overall, the potential nutritional benefit of Oryctes rhincoceros larva oil consumption on cardiovascular health could possibly involve its ability to upregulation of cellular antioxidant defense mechanisms
The influence of the moisture content of raw materials on the structuring of the extrudates
Get PDFThe article presents the results of studies on the model systems of extrudates conducted with a view to determining the function of moisture during the process of forming the structure of starch pastes. There was studied the influence of the moisture content of raw materials on a starch gelatinization point. Studies showed that 15% moisture content in raw materials is sufficient for its constituent phase - starch gelatinization, as well as for the transition of the whole mass to a fluid-viscous state. Further increase in the moisture content is accompanied by a decrease in a gelatinization point. In order to study the influence of moisture on the formation of a porous structure of extrudates, we studied the relationship between the different-type starch pastes and the degree of its transparency and its embrittlement temperature. It has been found that during the process of thermal and mechanical impacts, there occurs the process of the formation of a structure of starch pastes, in particular, samples with the different moisture contents can have an amorphous or crystalline structure. There has been established the relationship between the moisture content of raw materials on the modulus of elasticity of starch pastes based on them. The modulus of elasticity of samples was determined one hour (cooling time to room temperature) and one week after obtaining the starch paste. The above studies showed that minimal physico-chemical and mechanical transformations occur in starch pastes, which are in an amorphous state, that is, in the conditions of a low moisture content. We have established that the moisture content of raw materials, on the one hand, ensures the transition of a high-dispersive phase to a fluid state, or implementing the ex process of extrusion, and on the other hand, influences on the formation of a porous structure in the extrudates
Determination of HMW - GS in wheat using SDS - PAGE and Lab-on-chip methods
Get PDFSDS-PAGE is widely used to determine the amounts of the different gluten protein types. However, this method is time-consuming, especially at early stages of wheat breeding, when large number of samples needs to be analyzed. On the other hand, LoC (Lab-on-Chip) technique has the potential for a fast, reliable, and automatable analysis of proteins. Benefits and limitations of Lab-on-Chip method over SDS-PAGE method in gluten proteins evaluation were explored in order to determine in which way LoC method should be improved in order to make its results more compliant with the results of SDS-PAGE. Chip electrophoresis provides a very good reproducibility of HMW-GS patterns. Moreover this approach is much faster than the conventional SDS-PAGE methods requiring several hours for an analysis. Another advantage over traditional gel electrophoresis is lower sample and reagent volume requirements, as well as specialized protein standards for accurate reproducibility and quantification. In the present study, we identified novel complex allele located at the locus Glu-1B