Analysis of Antioxidant Capacity and Antimicrobial Properties of Selected Polish Grape Vinegars Obtained by Spontaneous Fermentation

Nowadays, products of natural origin with health-promoting properties are increasingly more common. Research shows that fruit vinegars can be a source of compounds with antioxidant activity. Research on the total antioxidant capacity, total phenolic content, and antimicrobial properties against Staphylococcus aureus, Escherichia coli, and Candida albicans of grape vinegars were conducted. Moreover, gas chromatography was used to measure acetic acid content in the vinegars. The research material consisted of vinegars produced from five different grape varieties. For each variety, two variants were prepared: with and without the addition of sugar in the fermentation process. The highest antimicrobial activity against all micro-organisms was observed in vinegar produced from Solaris grapes with added sugar. The highest polyphenol content was observed in vinegar produced from the Prior grape variety with added sugar and the highest total antioxidant capacity is the Johanniter grape variety with added sugar. The vinegars examined in this study differed, depending on grape variety, in terms of antimicrobial properties, antioxidant capacity, total phenolic content, as well as acetic acid content. Sugar addition caused significant differences in the antioxidant capacity of vinegar samples.     

Low temperature one-step synthesis of cobalt nanowires encapsulated in carbon

The one-step method of carbon nanotubes filled with continuous cobalt nanowires (CoF-CNT) synthesis is presented. Co/ZSM-5 (8 wt% Co) was used as catalyst for CoF-CNT production by methane decomposition at the temperature of 400 °C and 800 °C at atmospheric pressure in a conventional gas-flow system. The average diameter of the CoF-CNT is about 25 and 40 nm for products obtained at 400 °C and at 800 °C, respectively. The average size of coherently scattering domains along the normal to graphite layers L _c , the interlayer spacing d ₀₀₂, the graphitization degree of carbon, and the relative intensities of the G and D bands in Raman spectroscopy were determined to characterize the quality of carbon. It was proved that cobalt-filled carbon nanotubes can be produced by a simple method. The results of XRD, FE-SEM, and TEM show that CoF-CNT can be obtained even at 400 °C by catalytic decomposition of methane. On the basis of XRD, TEM, Raman spectroscopy was found that at a temperature of 800 °C, a better quality of carbon was produced.     

Evaluation of quality changes of beetroot juice after high hydrostatic pressure processing

ABSTRACT

Freshly squeezed commercially available beetroot juice, a popular beverage in Poland, is a good source of betalains, but as a root vegetable can contain undesirable microflora from the soil. The objective of this study was to investigate the effect of new preservation technique, high hydrostatic pressure, on the beetroot juice quality. Samples of beetroot juice were treated with pressure 300, 400 and 500?MPa/20°C/up to 10 min. Reduction in the total count of spoilage microorganisms reached 3.8, 4.1 and 4.5 log cfu/mL, depending on the pressure. After this treatment beetroot juice showed a 11.3–12.2% decrease in betacyanins content and 7.7–8.9% in betaxanthins content. A significant reduction of the number of spoilage microorganisms with a slight degradation of pigments indicates the possibility of industrial application of high pressure to the preservation of beetroot juice.     

Surface properties of UV-irradiated poly(vinyl alcohol) films containing small amount of collagen

The surface properties of poly(vinyl alcohol) (PVA) films in the presence of 1%, 3% and 5% of collagen before and after UV-irradiation have been studied by atomic force microscopy (AFM) and by contact angle measurements. PVA films have been obtained by solvent evaporation from water solution of PVA and PVA containing small amount of collagen. After drying, the samples were irradiated with UV light wavelength λ = 254 nm in air. Surface properties before and after UV-irradiation were observed using AFM. Contact angles of two liquids: diiodomethane (D) and glycerol (G) on polymeric films were measured at constant temperature using goniometer.The results have shown that the contact angle and the surface free energy for PVA films were altered by UV-irradiation. These alterations indicate photooxidation and an increase of polarity of the surface. The comparison of surface properties of PVA films and PVA containing collagen points out that collagen is more sensitive to photooxidation than PVA and PVA/collagen blends. PVA films containing collagen easier undergo photooxidation process with formation of new polar groups than pure PVA films.     

Existence and continuation of periodic solutions of autonomous Newtonian systems

In this article, we study the existence and the continuation of periodic solutions of autonomous Newtonian systems. To prove the results we apply the infinite-dimensional version of the degree for SO(2)-equivariant gradient operators defined by the third author in Nonlinear Anal. Theory Methods Appl. 23(1) (1994) 83-102 and developed in Topol. Meth. Nonlinear Anal. 9(2) (1997) 383-417. Using the results due to Rabier [Symmetries, Topological degree and a Theorem of Z.Q. Wang, J. Math. 24(3) (1994) 1087-1115] and Wang [Symmetries and calculation of the degree, Chinese Ann. Math. 10 (1989) 520-536] we show that the Leray-Schauder degree is not applicable in the proofs of our theorems, because it vanishes.     

Deactivation of the S2 and Two Lowest Triplet States of 4H-1-Benzopyran-4-thione and Its Alkyl Derivatives in Methanol Solution

Spectral and photochemical properties of three aromatic thioketones, 4H-1-benzopyran-4-thione and its two alkyl derivatives, in their second excited singlet and two lowest triplet states have been a subject of stationary and time-resolved studies. Quantum yields of emissions from the above-mentioned states as well as lifetimes of these states have been measured. The results indicate an important role of intermolecular solvent-induced processes in deactivation of the excited states of the thioketones studied. The possible mechanism of these processes involves hydrogen atom abstraction and/or formation of exciplex. For relatively high thione concentrations, the contribution of self-quenching in deactivation of the triplet states becomes significant. The effect of the alkyl chain in a thione molecule on deactivation parameters is discussed.     

Effect of Processing Treatment and Modified Atmosphere Packing on Carrot’s Microbial Community Structure by Illumina MiSeq Sequencing

The aim of this study was to analyze the microbiome of carrot (Daucus carota subsp. sativus) subjected to minimal pre-treatment (rinsing in organic acid solution) and packaging in a high-oxygen modified atmosphere, and then stored for 17 days under refrigeration conditions (4 °C). The highest levels of bacteria in the carrot microbiome were characterized, at almost 78%, by bacteria belonging to the Enterobacteriaceae and Pseudomonadaceae families. Rinsing in a solution of ascorbic and citric acids resulted in the improvement of microbiological quality in the first day of storage. However, the use of a high-oxygen modified atmosphere extended the shelf life of the minimally processed product. Compared to carrots stored in air, those stored in high oxygen concentration were characterized by a greater ratio of bacteria belonging to the Serratia and Enterobacter genera, and a lower ratio belonging to the Pseudomonas and Pantoea genera. Moreover, the β-biodiversity analysis confirmed that the oxygen concentration was the main factor influencing the differentiation of the metabiomes of the stored carrots. The bacterial strains isolated from carrots identified by molecular methods were mostly pathogenic or potentially pathogenic microorganisms. Neither the minimal pre-treatment nor packaging in high-oxygen atmosphere was able to eliminate the threat of pathogenic bacteria emerging in the product.     

Thermodynamics of oxygen in dilute liquid silver–tellurium alloys

Abstract  

The activity coefficient of oxygen in liquid Ag and binary Ag–Te dilute alloys were determined between 1,285 and 1,485 K by coulometric titration using the electrochemical cell (Ir, [O] in liquid metal or alloy | yttria stabilized zirconia | air, Pt). The experimental and evaluation procedures described in the literature were adopted. The oxygen activity coefficient was determined in pure liquid silver to be . Next, the oxygen activity coefficient in dilute Ag–(Te)–O alloys for variable X _Te content (from 0.01 to 0.06) was measured. From the obtained results, Wagner’s interaction parameter as a function of temperature was derived in the form . The electrochemical coulometric titration method seems to be very useful to study the thermodynamics of oxygen interaction in liquid silver and its alloys.     

A convenient two-step synthesis of dialkylphosphate ionic liquids

Dialkylphosphate ionic liquids are useful solvents for cellulose dissolution and catalytic reactions. In this paper, a new methodology for the synthesis of hydrophobic phosphate-based ionic liquids is described. This method involves the oxidation reaction of an easily prepared H-phosphonate precursor by using the environmentally friendly and inexpensive oxidizing agent hydrogen peroxide.     

Spectrophotometric study of colour reaction of vanadium(IV) with Chrome Azurol S in the presence of cationic and non-ionic surfactants

The optimum conditions for the formation of complexes of vanadium(IV) with Chrome Azurol S (CAS) in the presence of cationic (benzyldodecyldimethylammonium bromide (ST)) and non-ionic (Triton X-100, Tween 20 and Brij 35) surfactants have been determined. The complexes are formed in weakly acid solution (optimum pH: 4.6, 4.0 and 3.9) and show the absorption maxima at 603, 600 and 598 nm, respectively. The highest sensitivity was obtained for the method based on quaternary system V(IV)-CAS-ST-Triton X-100 due to the higher CAS: V(IV) molar ratio in this complex than in binary and ternary complexes: V(IV)-CAS) and V(IV)-CAS-ST. The molar absorptivity of this system is 8.08 × 10⁴ L/mol cm. The LOD and LOQ values are: 0.006 and 0.02 μg/mL, respectively. Beer’s law is obeyed in the range: 0.02–0.60 μg/mL of V. The precision (RSD = 0.51%) and accuracy (1.9%) are satisfactory. This method has been applied to the determination of vanadium in plant materials.