Concentration Of Phenolic Substances Research Articles

Synergetic catalysis of ligand connecting MOFs@MOFs composites in electrochemical detection of P-Chlorophenols

P-Chlorophenols (4-CP) are known as persistent toxic compounds for their acute toxicity and poor biodegradability. When the concentration of phenolic substances in water reaches 0.1005 mg/L, it becomes undrinkable. As a result, the detection of this human-toxic compound was indispensable. Hence, the high sensitivity and absorption ability of MOFs@MOFs composites (HP-UIO66@Ni-BDC) was applied to detect the 4-CP, which was constructed by using the ligand defect NH2-UIO-66 and Ni-BDC via a ligand linking approach. The improved performance of the materials compared to bare MOFs was attributable to the enhanced catalytic ability by the interaction of the MOFs and the high affinity between the 4-CP and the MOFs@MOFs composites (the electron donor-acceptor interaction and π-π stacking interaction). The electrochemical results illustrated the satisfactory electrochemical performances of modified GCEs toward 4-CP, such as the low limit of detection (LOD = 0.328 μM), wider linear detection range from 10 to 160 μM, and good stability and selectivity. Besides, the recovery experiments’ results have shown that the electrochemical sensor could be used in the actual sample detecting. All the results suggested that the prepared HP-UIO66@Ni-BDC composites could serve as a prospective sensor for the real-time detection of 4-CP.

Antioxidant and Photoprotective Potentials and Chemical Comparison of Three Species of Ocimum

Several species of the genus Ocimum are traditionally known and consumed by the population, but studies on aqueous extract composition are restricted to preparations by infusion. The aim of this study was to compare three different aqueous extractive methods (decoction, infusion, and maceration) of the leaves from Ocimum basilicum, O. gratissimum, and O. kilimandscharicum, using their chemical composition, and antioxidant and photoprotective potentials. Using the data from LC-DAD-ESI-MS/MS, we identified two organic acids and ten flavonoids in the extracts. Comparing the three studied species, O. gratissimum showed the greatest antioxidant and photoprotective potentials and the highest concentration of phenolic substances, followed by the species O. basilicum and O. kilimandscharicum. Considering the extraction methods, decoction showed the greatest antioxidant and photoprotective potentials and the highest content of phenolic substances regardless of the species.

Concentrations of Phenolic Acids Are Differently Genetically Determined in Leaves, Flowers, and Grain of Common Buckwheat (Fagopyrum esculentum Moench).

Common buckwheat (Fagopyrum esculentum Moench) is a valuable source of proteins, B vitamins, manganese, tryptophan, phytochemicals with an antioxidant effect, and the natural flavonoid rutin. Due to its composition, buckwheat supports the human immune system, regulates blood cholesterol, and is suitable for patients with diabetes or celiac disease. The study aimed to compare the allocation of selected phenolic acids (neochlorogenic acid, chlorogenic acid, trans-caffeic acid, trans-p-coumaric acid, trans-sinapic acid, trans-ferulic acid) and flavonoids (rutin, vitexin, quercetin, kaempferol) in the leaves, flowers, and grain of buckwheat cultivars of different origin. The content of individual phenolics was determined by the HPLC-DAD method. The results confirmed the determining role of cultivar on the relative content of chlorogenic acid, trans-caffeic acid, trans-sinapic acid, vitexin, and kaempferol in buckwheat plants. A significantly negative correlation among concentrations of phenolic acids in different common buckwheat plant parts shows that there are different mechanisms of genetic influences on the concentration of phenolic substances in common buckwheat flowers, leaves, and grain. These differences should be taken into account when breeding buckwheat for a high concentration of selected phenolic substances.

Aeration ofVitis viniferaShiraz fermentation and its effect on wine chemical composition and sensory attributes

Background and Aims Aeration during fermentation of red wines has the potential to enhance positive red fruit attributes and suppress less desirable reductive characteristics. The implementation of aeration in commercial winemaking, however, is impeded by the lack of a clear understanding of both the major benefits of its use and the nature of the aeration regimes required to modify the finished product. This work aimed to evaluate the impact of different modes of aeration, varying in their timing, duration and intensity, on fermentation duration, chemical composition and sensory properties of Shiraz wine. Methods and Results Forty-eight pilot-scale fermentations (450 kg) were treated with different aeration modalities and compared to non-aerated fermentations across four vintages. This work demonstrated the reproducible effects of aeration, resulting in an enhancement of fruit-related attributes, decreases in colour intensity and a lowering of astringent mouthfeel and bitterness. The development of attributes describing possible oxidation or undesirable volatility were not observed in this work. These effects on wine sensory attributes were correlated with an increase in the concentration of relevant short and branched-chain esters and acetates, and a decrease in the concentration of phenolic substances. No enhancement of fermentation performance was observed in any of the trials. Overall, this work revealed the robustness of red wine fermentations to aeration. Conclusions This work provides strong evidence that aeration does not alter the duration of either alcoholic or malolactic fermentation of red musts. Although there was no impact on fermentation performance, aeration did result in the production of wines with increased red fruit characters, and decreased astringency and reductive off-odours. Significance of the Study This work demonstrates aeration to be a useful oenological tool for the production of red wine and indicates that stylistic impact, rather than fermentation performance, is likely to be more pertinent to the adoption of red wine aeration.

Concentrates of polyphenols from grape raw materials and their functional properties

The work presents the possibility of obtaining polyphenol concentrates from raw materials (pomace, seeds, cane, vines, leaves) of Crimean grapes of white varieties Aligote, Rhine Riesling, Rkatsiteli and grapes of red varieties Muscat Hamburg, Cabernet-Sauvignon, by vacuum concentration of alcoholic extracts of grape raw materials. An experimental assessment on the qualitative and quantitative structure of polyphenols, the basic functional ingredients of biological activity of grapes has been given. It has been established that by concentration of phenolic substances, the concentrates are distributed in the following sequence: seeds of grapes of white and red varieties, stalks of grapes of white and red varieties, pomace of grapes of red varieties, leaves of grapes, vine of grapes, pomace of grapes of white varieties. In grape concentrates, anthocyanins, flavones, flavan-3-ols, oligomeric and polymeric procyanidins, oxycinnamic and oxybenzoic acids and stilbenoids have been identified. The maximum quantitative evaluation of stilbenoid concentration obtained in grape concentrates was up to 5.0 g/L, which is by order of magnitude greater than in red wines. The antioxidant activity indicator (AOA), estimated in vitro in grape seed concentrate, ranged from 180.0 to 250.0 g/l, which is by order of magnitude greater than in red grape wines.

Biologization of grape growing technologies to obtain safe and high-quality products

Viticulture is impossible without the use of chemical plant protection agents. Their use follows to ecological destabilization of ampelocenoses and constitutes real danger to human health. Last years there is a tendency to biologize the protection technologies that the relevance of studies of the influence of biopreparations on the quality of graps and wines. The article presents the results studies of fungicide action of the preparations Biocomposite-correct and Biocomposite-protect. Their high anti-mycotic activity (97-100%) against Trichothecium roseum and Botrytis cinerea has been established. The high efficiency in the control of grey rot on grapes cultivar Merlot showed a two-fold application of the Biocomposite-protect– the damage to grapes decreased by 2 times in comparison with the control and amounted to 0.3%. Using of biofungicides did not affect the of mush/must fermentation. The test wines were distinguished by a higher (by 13-28%) concentration of phenolic substances. The use of Biocomposite-protect followed to an increase of anthocyanins concentration (by 1.5 times) and the total dry extract (by 12%) in wines; decrease – of titratable acids; Biocomposite-correct – decrease the total dry extract (by 10%). Using of biological preparations for grape protection did not influence the organoleptic quality of wines.

Effect of national chelated micronutrient fertilizers on the productivity of grape plants and quality indicators of wine

The article presents the results of studies, carried out in 2018-2020 in soil and climatic conditions of viticultural zone of the South Coast of Crimea on wine grape variety ‘Cabernet-Sauvignon’. It was established that double application of national chelated micronutrient fertilizers Tiaton and Chelaton Extra for foliar dressing of grapes contributed to an increase in the average bunch weight by 9.3-15.3 g (10.3-16.9%), shoot productivity by 10.4-17.1% and cropping power by 0.6-1 t/ha (10-16.7%) in comparison with the control. It was experimentally determined that test treatments with Chelaton Extra preparation led to a significant increase in the average length of annual shoots by 13.3 cm (9.3%) and a gain in the green matter of bushes by 265.9 cm3 (12%). Using of the studied micronutrient fertilizers against the background of increased grape productivity positively influenced the process of sugar accumulation and ensured the value component at the control level. The studies have proven that double treatment with Chelaton Extra fertilizer contributed to an increase in the mass concentration of phenolic substances in wine by 10.7%.

IMPROVEMENT OF THE TECHNOLOGICAL MODES OF PRODUCING DRY WHITE TABLE WINES

By using the classical technology of making dry white wines, which does not involve maceration of the pomace, we can produce standard table wines, light and delicate. This minimises such an objectionable factor as saturation of the wine with extra nitrogenous and phenolic substances and oxidative enzymes. On the other hand, this scheme gives a specific varietal aroma no chance to reveal itself more expressively. The paper overviews briefly the scientific works considering the modes of pomace maceration before fermentation and the use of enzyme preparations in the technology of white table wines. The physicochemical and sensory characteristics of wine materials from Rkatsiteli grapes grown in the south of the Mykolaiv Region have been analysed. This analysis has proved that standard white table wine materials can be obtained both by the traditional method (the so called ‘white’ method) and with the use of short-term maceration of the pomace. Macerating the pomace resulted in obtaining fuller, richer wine materials with a bright aroma and good body. It has been shown that to obtain bright and not too blunt wine materials, the most essential parameter of the maceration process is its low temperature. A pectolytic enzyme preparation used during maceration increased, to some extent, the mass concentration of phenolic substances, the reduced extract, the optical density, and the concentration of terpene alcohols. Besides, it allowed fuller revealing a wine’s aromatic profile. The research has resulted in establishing that there is regularity in how the concentration of terpene alcohols changes with different temperature conditions of steeping the pomace. It has been shown that the maximum concentration of terpenes responsible for the varietal aroma is best retained in wine materials when the maceration temperature is 5°C. A rise in the pomace maceration temperature to 20°C led to a decrease in the concentration of labile terpene alcohols, so it should be avoided in producing quality wines. Studying different maceration modes has allowed recommending a certain method to manufacture full-bodied, well-structured white table wines with a pronounced varietal aroma. This method involves adding the enzyme preparation Depectil CLARIFICATION to the pomace and macerating it for 12 hours at 5°C.

In Vitro Assessment of Antioxidant Enzymes, Phenolic Contents and Antioxidant Capacity of the Verdolaga (Portulacaceae)

In this study, the antioxidants and photosynthetic compounds of Verdolaga were examined. Compounds were extracted from distinctive segments of the verdolaga using various solvents such as methanol (40, 60, 80%), ethanol (40, 60, 80%), acetone (40, 60, 80%), and deionized water. The use of 80% methanol led to the highest extracted concentration of phenolic substances and flavonoids. The extracted products (Leaves, Stem strips, and Root strips) were evaluated for their radical scavenging capabilities with DPPH (IC50= 22.26, 20.56, and 32.10), and ABTS (IC50= 2.86, 3.70, and 5.24), reducing power (EC50= 15.70, 16.39, and 21.69), and peroxide scavenging activity (1C50= 1.717, 2.937, and 3.255), respectively. The extracted products were analyzed by a gas chromatography-mass spectrometer. Peroxidase, catalase, and polyphenol oxidase assays were completed for the crude extract of verdolaga’s leave, stem strips, and root strips. As indicated by these tests, extracts of the verdolaga’s roots, stems and leaves using 80% methanol yielded high antioxidant activity. The most elevated concentrations of extracted chlorophyll, lycopene, and carotenoids were from the leaves and the highest concentration of extracted tannin was noted from strips of stems. The highest measures of peroxidase and polyphenol oxidase were identified in root strips and the highest units of catalase was identified in leaves.

Phenolic Compounds and Antioxidant Potential of Wild-Growing Plant Materials of the North Caucasus Region

The article presents the results of studying the qualitative composition and quantitative content of some groups of phenolic compounds in 11 types of medicinal plants growing in the foothills of the North Caucasus, and provides the estimates of the antioxidant activity of extracts from these plants. The qualitative and quantitative content of phenolic compounds was determined using a Kapel-105M capillary electrophoresis system, and the total antioxidant activity of the extracts was measured on a Tsvet Yauza-01-AA device with an amperometric detector. In the studied plant samples, the total content of tannins was determined, eight phenolcarbonic acids were identified and quantified, as well as quercetin and rutin — two of the most important flavonols. The highest total content of phenolcarbonic acids (11,776.2 mg/kg), as well as the highest antioxidant activity were noted in the aqueous extract obtained from Echinacea purpurea (lat. Echinacea angustifolia). The direct relationship between the antioxidant activity of the studied medicinal raw material and the content of phenolic compounds has been experimentally established as follows: the higher is the concentration of phenolic substances, the higher is the antioxidant activity. The results of this study provide new information on the composition and content of phenolic compounds in some types of wild-growing plant raw materials of the North Caucasus and the antioxidant activity of extracts based thereon that will facilitate the use of the studied plants as a potential source of natural antioxidants in the production of functional materials.

Dynamics of phenolic compounds content in <i>Olea europaea</i> L. leaves during the cold period on the Southern Coast of the Crimea

Dynamics of total phenolic compounds content in the leaves of four cultivars and one subspecies of Olea europaea L. were studied during the cold periods of 2016-2019 years on the Southern Coast of the Crimea. The concentration of phenolic substances ranged from 642 to 1332 mg/100 g of fresh biomass. It was found out that the content of phenolic compounds depended on weather conditions during a particular cold period and it did not almost depend of the degree of frost resistance of the studied genotypes.

Delaying winter pruning, after pre-pruning, alters budburst, leaf area, photosynthesis, yield and berry composition in Sangiovese (Vitis viniferaL.)

Background and Aims Earlier ripening of grapes due to global warming could be mitigated by delaying hand pruning on pre-pruned canes. Hand pruning on pre-pruned vines was delayed until after distal buds on canes had burst for Sangiovese (Vitis vinifera L.) vines, and the effect on phenology, canopy development, leaf gas exchange, yield and berry development and composition was assessed. Methods and Results Pre-pruned vines, which were subsequently hand-pruned during winter, were compared to vines where hand pruning was delayed (DP) until shoots from distal nodes of canes had burst and developed 3–4 (DP3) or 7–8 (DP7) expanded leaves. Delayed pruning delayed budburst by about 30 days in DP3 vines and 37–47 days in DP7 vines, which led to a slowing of canopy development and berry growth. Veraison was delayed by between 10 and 20 days. Yield was substantially reduced by delaying hand pruning but the concentration of phenolic substances and the acidity of berries was increased. Conclusions Delaying hand pruning on vines that had already been pre-pruned delayed budburst, anthesis and veraison, reduced yield and significantly affected berry composition. The magnitude of these effects increased with the length of the pruning delay. Significance of the Study Delaying hand pruning on pre-pruned grapevines may represent a promising technique to mitigate against some of the deleterious effects of global warming in vineyards.

Use of gaseous ozone for reduction of ochratoxin A and fungal populations on sultanas

Background and Aims Contaminated dried vine fruits including sultanas are regarded as an important source of ochratoxin A (OTA), a fungal secondary toxic metabolite, in human diets. Management of fungal contamination and OTA in the dried vine fruit industry includes prevention, regulation and decontamination. The purpose of this study was to evaluate the efficacy of gaseous ozone on the degradation of OTA on spiked sultanas. The effect of ozonation on indigenous fungal populations and the concentration of phenolic substances was also evaluated on non‐spiked portions of the sultana sample. Methods and Results Sultanas were exposed to a continuous stream of gaseous ozone at 12.8 mg/L for up to 240 min in a treatment chamber at ambient laboratory conditions. The initial OTA level on spiked sultanas, determined as 16.7 μg/kg, was reduced by 60.2 and 82.5% after 120 and 240 min of ozone exposure, respectively. Exposure to gaseous ozone for 120 min yielded more than 2.2 log reduction in the fungal population naturally present on sultanas. Ozonation for up to 120 min did not cause a significant (P > 0.05) change in the concentration of phenolic substances of sultanas. Conclusions Greater than the 60% reduction in the concentration of OTA on superficially contaminated sultanas can be achieved by gaseous ozone treatment without causing a significant decrease in the concentration of phenolic substances. Significance of the Study Gaseous ozone has potential to degrade OTA and reduce fungal viability on sultanas

Grape seed extract: the first protein-based fining agent endogenous to grapes

Background and Aims There is a growing interest in finding alternative wine fining agents to replace potentially allergenic animal-derived and plant-derived proteins. In this context, the potential use of grape-derived fining agents would be beneficial as they would not introduce additional, potentially allergenic products to the finished wine. In this project, grape seed flour, a by-product of the grape oil seed industry, has been used to prepare a grape seed extract (GSE) for testing as a novel wine fining agent. Methods and Results The fining performance of GSE was compared with that of patatin, pea proteins, polyvinylpolypyrrolidone and potassium caseinate in a white and in a rose wine, and of ovalbumin and gelatin in a red wine. Reduction of turbidity, effect on wine colour, the concentration of phenolic substances, browning potential and wine sensory attributes were determined. Grape seed extract was effective in decreasing white wine turbidity when compared to potassium caseinate. In red wine, GSE removed some anthocyanin and proanthocyanins, while wine colour was only slightly affected. The greatest GSE effect was observed on the sensory properties of the treated wines, as it strongly reduced the vegetal notes in the rose wine and improved the overall taste of the red wine as a result of the reduction in both acidity and astringency. Conclusions Grape seed extract can be considered a valid allergen-free alternative to the most common wine fining agents. Significance of the Study Grape seed extract is the first effective fining agent endogenous to grapes, thus not attracting the legal restrictions concerning the presence of foreign substances.

Ultraviolet spectroscopy study of phenolic substances and other major compounds in red wines: relationship between astringency and the concentration of phenolic substances

Background and Aim In a previous study, based on statistical considerations, absorbance values at 230 nm provided a good prediction of wine astringency. The present paper seeks spectroscopic arguments to support such a prediction. Methods and Results Ultraviolet spectra were acquired for several families of phenolic substances, and for the main wine compounds. Wine absorbance at 230 nm is mainly because of tannins which are the major compounds responsible for astringency in wines. Conclusion A good relationship was observed between astringency threshold and absorbance at 230 nm for most of the compounds analysed, confirming the previous results. Moreover, absorbance at 230 nm appeared to balance better the contributions of the different phenolic substances than absorbance at 280 nm. Significance of the Study The spectroscopic observations are in agreement with the statistical considerations. Both studies confirm the value of the absorbance at 230 nm for characterisation of red wine phenolic substances and astringency evaluation.

Overcoming the bottlenecks of anaerobic digestion of olive mill solid waste by two-stage fermentation

ABSTRACTTwo-stage anaerobic digestion (AD) of two-phase olive mill solid waste (OMSW) was applied for reducing the inhibiting factors by optimizing the acidification stage. Single-stage AD and co-fermentation with chicken manure were conducted coinstantaneous for direct comparison. Degradation of the polyphenols up to 61% was observed during the methanogenic stage. Nevertheless the concentration of phenolic substances was still high; the two-stage fermentation remained stable at OLR 1.5 kgVS/m³day. The buffer capacity of the system was twice as high, compared to the one-stage fermentation, without additives. The two-stage AD was a combined process – thermophilic first stage and mesophilic second stage, which pointed out to be the most profitable for AD of OMSW for the reduced hydraulic retention time (HRT) from 230 to 150 days, and three times faster than the single-stage and the co-fermentation start-up of the fermentation. The optimal HRT and incubation temperature for the first stage were determined to four days and 55°C. The performance of the two-stage AD concerning the stability of the process was followed by the co-digestion of OMSW with chicken manure as a nitrogen-rich co-substrate, which makes them viable options for waste disposal with concomitant energy recovery.

Antioxidant profile of commercial oenological tannins determined by multiple chemical assays

Background and Aims The addition of oenological tannins during winemaking is a longstanding technological practice. To assist such a practice, knowledge of their antioxidant properties is an asset for understanding their role in redox processes occurring in wine. Hence, the aim of this work was to assess the antioxidant profile of oenological tannins from several botanical sources, which are usually applied at different winemaking steps. Methods and Results Several antioxidant assays, including the ability to reduce copper(II) assay (CUPRAC), the scavenging capacity against 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH), and the peroxyl radical scavenging capacity (oxygen radical absorbance capacity assay, ORAC) were applied. The concentration of phenolic substances and the ability to chelate iron(II) (ICA) were also determined. A significant correlation was obtained between the concentration of phenolic substances and the copper(II) reducing antioxidant capacity (R = 0.89), and the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (R = 0.86) and 2,2-diphenyl-1-picrylhydrazyl (R = 0.86) assays. No such correlation was observed (R = 0.15) with the oxygen radical absorbance capacity assay. Conclusions The highest radical scavenging capacity was attained for oenological tannins composed of gallotannins, while those containing ellagic acid were able to chelate iron(II) strongly, preventing the oxidative damage mediated by Fenton-based reactions. Condensed tannins demonstrated a significant ability to scavenge peroxyl radicals, which represents a powerful antioxidant mechanism to prevent lipid peroxidation. Significance of the Study The chemical antioxidant profile of oenological tannins displayed in radar charts provides valuable information for winemakers and manufacturers of oenological tannins.

Kinetics Of Competitive Ozonation Of Some Phenolic Compounds Present In Wastewater From Food Processing Industries

Ozonation of four phenolic compounds found in wastewater effluents from food manufacturing processes: Gallic (G-Ac) and p-hydroxybenzoic (pHB-Ac) acids, (+)-catechin ((+)-Cat) and tyrosol (Ty), has been carried out in ultrapure water. The results showed that the direct reaction between ozone and the organic compound seems to be the exclusive way of phenolic compounds elimination. A kinetic study of these reactions was completed by using a high concentration of phenolic substances (up to 3 g L−1 total phenolic content) to simulate typical amounts of these compounds found in real wastewater. By means of a competitive method, rate constants of the direct reaction with ozone were determined at different pH. The following reactivity was found depending on pH: pHB-Ac < Ty < G-Ac < (+)-Cat in acidic conditions, pHB-Ac < Ty < G-Ac < (+)-Cat in neutral conditions and pHB-Ac < Ty for basic conditions. Finally, validation of the calculated rate constants was completed by checking the kinetic regime in which competitive reactions were developed.

SEM observations on cyanobacteria-infected cycad coralloid roots

In Nostoc -infected coralloid roots of the cycads Encephalartos transvenosus Stapf & Burtt Davy and E. paucidentatus Stapf & Burtt Davy the intercellular cyanobacteria are present in a narrow circular band between the outer and the inner cortex only. When the cyanobacterial density is very great, some intracellular infection is present. In uninfected coralloid roots, cells with a high concentration of phenolic substances are evenly distributed throughout the outer and inner cortical layers, but in infected roots, such cells are restricted largely to the outer cortex. Cyanobionts newly isolated from cycad coralloid roots consist of cells arranged in filaments. Some large spherical structures, similar to those which each leads to the development of a new filament during the late heterocystous phase of the nostocacean life cycle, are found in the roots. On some cyanobacterial cells other micro-organisms are visible. These bacteria-like micro-organisms are probably the heterotrophic bacteria that usually occur in cultures of coralloid root endophytes.

Degradation of Phenolic Compounds Downstream from a Petroleum Refinery Complex

Measurements downstream from refinery outfalls in the region of Montreal East have shown that, under favorable temperature conditions, the concentration of phenolic substances in the river water rapidly diminishes with distance from the refineries. Mass balance calculations at different transverse sections show that this decrease in concentration cannot be attributed to dilution only. Laboratory experiments performed on river water samples demonstrate the effects of water temperature and sterilization on the rate of phenol breakdown. Results support the idea that biodegradation is responsible for the self-purification of phenolics in the St. Lawrence River.