Study of the phenolic compounds formed during pretreatment of sugarcane bagasse by wet oxidation and steam explosion

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 483-487 ◽  
Author(s):  
Carlos Martín ◽  
Helene B. Klinke ◽  
Marcelo Marcet ◽  
Luis García ◽  
Ena Hernández ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Sugarcane Bagasse ◽  
Steam Explosion ◽  
Total Content ◽  
Wet Oxidation ◽  
Aldehydes And Ketones ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Ferulic Acids

Abstract The formation of phenolic compounds during pretreatment of sugarcane bagasse was investigated. Bagasse was pretreated by wet oxidation (WO) at 195°C during 15 min under either alkaline or acidic conditions and by steam explosion (STEX) at 205°C during 10 min. The total content of phenolic compounds in the prehydrolysates was determined spectrophotometrically. Under acidic and alkaline WO conditions, 3.8% (w/w) and 3% phenols were found, respectively. STEX gave rise to 1.9% phenols. Individual phenols were identified by GC-MS. Phenylpropanoid derivatives, such as p-coumaric and ferulic acids, accounted for more than 50% of the phenols identified in STEX prehydrolysates. In WO prehydrolysates, on the other hand, phenols lacking the propanoid side chain were predominant. Of the latter, p-hydroxybenzaldehyde was the most abundant phenol, with concentrations of 0.27% (acidic conditions) and 0.15% (alkaline conditions). As expected, high concentrations of oxidised compounds were generally observed in WO prehydrolysates, such as carboxylic acids, aldehydes and ketones. This is a true reflection of the oxidative conditions during WO pretreatment.

High-Added-Value Antioxidants Obtained from the Degradation of Wine Phenolics by Lactobacillus plantarum

2007 ◽  
Vol 70 (11) ◽  
pp. 2670-2675 ◽  
Author(s):  
JOSÉ MARÍA LANDETE ◽  
HÉCTOR RODRÍGUEZ ◽  
BLANCA DE LAS RIVAS ◽  
ROSARIO MUÑOZ
Keyword(s):  
Phenolic Compounds ◽  
Gallic Acid ◽  
Lactobacillus Plantarum ◽  
Antimicrobial Activities ◽  
Added Value ◽  
Methyl Gallate ◽  
Biotechnological Production ◽  
Wine Production ◽  
High Concentrations ◽  
Ferulic Acids

Disposal of the waste from wine production has long been a problem for wineries, mainly because of the presence of phenolic compounds. In this study, we analyzed the antimicrobial activities of 10 wine phenolic compounds against Lactobacillus plantarum strains. Inhibition increased in this order: catechin = gallic acid < epicatechin = salicylic acid < methyl gallate = caffeic acid < ferulic acid = tryptophol < p-coumaric acid. The obtained results indicated that L. plantarum is able to grow in the presence of high concentrations of some wine phenolic compounds. Of the 10 compounds analyzed, only the hydroxycinnamic acids, gallic acid, and methyl gallate were metabolized by the four L. plantarum strains studied. Results also revealed that 4-vinylphenol and 4-vinylguaiacol are originated from p-coumaric and ferulic acids. These phenolic compounds are valuable intermediates in the biotechnological production of new fragrances. In addition, gallic acid and its ester, methyl gallate, are metabolized to produce the powerful antioxidant pyrogallol. Therefore, it might be possible to use L. plantarum strains to obtain high-added-value antioxidants from the degradation of phenolic compounds found in wine wastes.

scholarly journals Photooxidation Contribution Study on the Decomposition of Azo Dyes in Aqueous Solutions by VUV-Based AOPs

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Chih-Ming Ma ◽  
Gui-Bing Hong ◽  
Hua-Wei Chen ◽  
Nguyen-Thi Hang ◽  
Yung-Shuen Shen
Keyword(s):  
Azo Dyes ◽  
Ph Value ◽  
Reaction Rates ◽  
Degradation Of Dyes ◽  
Degradation Rates ◽  
Effects Of Ph ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Acid Blue

The effects of pH value, VUV intensity, initial dye concentration, initial H2O2concentration, and TiO2loading dose on the degradation of three azo dyes: acid Orange 8, acid Blue 29, and acid Blue 113 were studied to explore and compare the treatment efficiencies among the adopted AOPs. It was found that pH played an important role in the degradation of dyes using VUV irradiation. For VUV/H2O2, VUV/TiO2, and VUV/TiO2/H2O2processes, the decoloration rates of the three azo dyes were more efficient under acidic conditions relative to alkaline conditions. The degradation rates of dyes increased with increasing concentrations of H2O2, but reaction rates were retarded at high concentrations of H2O2because the H2O2compound acted as a scavenger of the hydroxyl radical. In this paper, three azo dyes were decomposed efficiently by VUV irradiation only demonstrating the effectiveness of VUV direct photolysis.

scholarly journals Bioaccessibility and Gut Metabolism of Free and Melanoidin-Bound Phenolic Compounds From Coffee and Bread

2021 ◽  
Vol 8 ◽  
Author(s):  
Genilton Alves ◽  
Leandro Araújo Lobo ◽  
Regina Maria Cavalcanti Pilotto Domingues ◽  
Mariana Monteiro ◽  
Daniel Perrone
Keyword(s):  
Phenolic Compounds ◽  
Chlorogenic Acids ◽  
Simulated Digestion ◽  
Intestinal Fluids ◽  
Acidic Conditions ◽  
Free Phenolics ◽  
Ferulic Acids ◽  
Bound Phenolics ◽  
Gut Metabolism ◽  
Gut Fermentation

The aim of this study is to investigate the bioaccessibility and gut metabolism of free and melanoidin-bound phenolic compounds from coffee and bread. Phenolics from coffee were predominantly found in free forms (68%, mainly chlorogenic acids), whereas those from bread were mostly bound to melanoidins (61%, mainly ferulic acid). Bioacessibility of coffee total free phenolics slightly decreased during simulated digestion (87, 86, and 82% after the oral, gastric, and intestinal steps, respectively), with caffeoylquinic acids being isomerized and chlorogenic acids being partially hydrolyzed to the corresponding hydroxycinnamic acids. Bioacessibility of bread total free phenolics decreased during simulated digestion (91, 85, and 67% after the oral, gastric, and intestinal steps, respectively), probably related to complexation with the proteins in simulated gastric and intestinal fluids. Upon gut fermentation, the bioaccessibility of total free phenolics from both coffee and bread decreased, mainly after the first 4 h (56 and 50%, respectively). Caffeic and ferulic acids were the predominant metabolites found during coffee and bread gut fermentation, respectively. Melanoidin-bound phenolics from coffee and bread were progressively released after the gastric and intestinal steps, probably due to hydrolysis caused by the acidic conditions of the stomach and the action of pancreatin from the intestinal fluid. The bioaccessibilities of all phenolics from coffee and bread melanoidins after the gastric and intestinal steps were, on average, 11 and 26%, respectively. During gut fermentation, phenolics bound to both coffee and bread melanoidins were further released by the gut microbiota, whereas those from coffee were also metabolized. This difference could be related to the action of proteases on melanoproteins during gastrointestinal digestion, probably anticipating phenolics release. Nevertheless, bioaccessibilities of melanoidin-bound phenolics reached maximum values after gut fermentation for 24 h (50% for coffee and 51% for bread). In conclusion, the bioaccessibilities of coffee and bread free phenolics during simulated digestion and gut fermentation were remarkably similar, and so were the bioaccessibilities of coffee and bread melanoidin-bound phenolics.

scholarly journals Relationships Between the Content of Phenolic Compounds and the Antioxidant Activity of Polish Honey Varieties as a Tool for Botanical Discrimination

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1810
Author(s):  
Monika Kędzierska-Matysek ◽  
Małgorzata Stryjecka ◽  
Anna Teter ◽  
Piotr Skałecki ◽  
Piotr Domaradzki ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Caffeic Acid ◽  
Principal Component ◽  
Total Content ◽  
Component Analysis ◽  
Total Phenolic ◽  
Hydroxybenzoic Acid ◽  
Coumaric Acid

The study compared the content of eight phenolic acids and four flavonoids and the antioxidant activity of six Polish varietal honeys. An attempt was also made to determine the correlations between the antioxidant parameters of the honeys and their polyphenol profile using principal component analysis. Total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (ABTS) and reduction capacity (FRAP) were determined spectrophotometrically, and the phenolic compounds were determined using high-performance liquid chromatography (HPLC). The buckwheat honeys showed the strongest antioxidant activity, most likely because they had the highest concentrations of total phenols, total flavonoids, p-hydroxybenzoic acid, caffeic acid, p-coumaric acid, vanillic acid and chrysin. The principal component analysis (PCA) of the data showed significant relationships between the botanic origin of the honey, the total content of phenolic compounds and flavonoids and the antioxidant activity of the six Polish varietal honeys. The strongest, significant correlations were shown for parameters of antioxidant activity and TPC, TFC, p-hydroxybenzoic acid, caffeic acid and p-coumaric acid. Analysis of four principal components (explaining 86.9% of the total variance), as a classification tool, confirmed the distinctiveness of the Polish honeys in terms of their antioxidant activity and content of phenolic compounds.

scholarly journals Phenolic Compounds from Leaves and Flowers of Hibiscus roseus: Potential Skin Cosmetic Applications of an Under-Investigated Species

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 522
Author(s):  
Luana Beatriz dos Santos Nascimento ◽  
Antonella Gori ◽  
Andrea Raffaelli ◽  
Francesco Ferrini ◽  
Cecilia Brunetti
Keyword(s):  
Phenolic Compounds ◽  
Total Phenolics ◽  
Biological Activities ◽  
Skin Care ◽  
Modern Trend ◽  
Perennial Species ◽  
Collagenase Activity ◽  
Protection Factor ◽  
Hydroxycinnamic Acid Derivatives ◽  
Ferulic Acids

The use of plant extracts in skin-care cosmetics is a modern trend due to their richness in polyphenols that act as anti-aging molecules. Hibiscus roseus is a perennial species naturalized in Italy, with beautiful soft pink flowers; its phenolic composition and biological activities have not been studied yet. The aim of this study was to characterize and quantify the phenolics and to evaluate the antioxidant, sun protection factor (SPF), and anti-collagenase activities of the ethanolic extracts of H. roseus leaves (HL) and flowers (HF). p-Coumaric, chlorogenic, and trans-ferulic acids derivatives as well as quercetin and kaempferol flavonoids were the main phenolic compounds detected. Catechin, epicatechin, kaempferol-3-O-rutinoside, kaempferol-3-O-glucoside, kaempferol-7-O-glucoside, tiliroside, oenin, and peonidin-3-O-glucoside were detected only in HF, while phloridzin was exclusive from HL, which also showed greater amounts of hydroxycinnamic acid derivatives. HF was richer in flavonoids and total phenolics, also exhibiting greater antioxidant capacity. The SPF and anti-collagenase activity of both extracts were similar and comparable to those of synthetic standards. The overall results demonstrate that H. roseus extracts are promising sources of bioactive phenolic compounds that could be potentially applied as anti-aging agents in skin-care cosmetics.

Aktywność przeciwutleniająca i przeciwbakteryjna miodu, propolisu oraz pyłku kwiatowego

2020 ◽  
Vol 21 (3) ◽  
Author(s):  
Magdalena Woźniak ◽  
Lucyna Mrówczyńska ◽  
Anna Sip ◽  
Marta Babicka ◽  
Tomasz Rogoziński ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Pathogenic Bacteria ◽  
Radical Scavenging Activity ◽  
Colorimetric Method ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Total Content ◽  
Diffusion Method ◽  
Bacterial Strains

Introduction. Honey, propolis and pollen belong to bee products that have beneficial biological properties. These products exhibit e.g. antibacterial, antifungal and antioxidant properties. Due to biological activity and natural origin, bee products are used, e.g. in the food industry, cosmetology and pharmacy. Aim. The aim of the study was to compare the antioxidant and antibacterial activity of honey, propolis and pollen from an apiary located in Wielkopolska Province. Material and methods. Honey, propolis and pollen used in this study came from the same apiary located in Wielkopolska Province. The antioxidant potential of bee products was evaluated applying DPPH· free radical scavenging activity assay. The antimicrobial activity of the tested bee products was determined by the point-diffusion method against 13 strains of pathogenic and potentially pathogenic bacteria. In addition, the total content of phenolic compounds in honey, propolis and pollen was determined by the colorimetric method. Results. Propolis exhibited higher antioxidant activity, in comparison to honey and pollen. The antiradical activity of propolis was equal to 80% approx. activity of Trolox, the standard antioxidant. Among tested bee products, propolis was characterized by the highest total phenols content. In addition, honey, propolis and pollen showed antagonistic activity against tested bacterial strains. Conclusions. The obtained results indicate that among the tested bee products of native origin, i.e. honey, propolis and pollen, propolis characterized by the highest antioxidant activity and the total content of phenolic compounds. In addition, all bee products showed bactericidal activity against the tested bacterial strains.

Quality improvement of biosolids by ferrate(VI) oxidation of offensive odour compounds

1996 ◽  
Vol 33 (3) ◽  
pp. 119-130 ◽  
Author(s):  
Allen C. Chao ◽  
Sergio J. de Luca ◽  
Carlos N. Idle
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Potassium Ferrate ◽  
Sulphur Compounds ◽  
Environmental Recovery ◽  
Oxidizing Power ◽  
Aldehydes And Ketones ◽  
High Concentrations ◽  
By Products

Studies concerning the treatment, stabilization and final disposal of biosolids, one of the by-products of wastewater treatment, in environmental recovery, have been intensified by the sanitary and environmental effects of land disposal. The careful assessment of biosolid quality shows that, when appropriately managed, the environmental risks of their uses can be minimized by chemical stabilization, and biosolids could even be used as fertilizer and soil conditioner. A research study of biosolid stabilization was performed using lime as a standard process compared to potassium ferrate (VI). The chances of leaching and solubilization of metals were tested, simulating conditions for disposal in the environment. The sanitary effectiveness in terms of pathogens (bacteria, fungi and helminth eggs) were also evaluated. Experiments were performed on the lime and ferrate(VI) treatment of compounds such as ammonia, nitrate, soluble sulphides, and total sulphates, indicators of odouriferous offensive compounds which might occasionally prevent some uses of the solids, and the results are presented in this paper. Wastewater Treatment Plants emit offensive odours generated during the sewage treatment process, as well as during the treatment and the management of biosolids. This occurs in the drying beds and the spreading of biosolids on land, due to the high concentrations of sulphur compounds, nitrogen compounds, acids and organic compounds (aldehydes and ketones). The potassium ferrate(VI) utilized in the research is a powerful oxidizing agent throughout the pH scale, with the advantage of not generating by-products which will cause toxicity or mutagenicity (DE LUCA, 1981). The ion ferrate(VI) has greater oxidizing power than permanganate, e.g., it oxidizes reduced sulfur forms to sulphate, ammonia to nitrate, hypochlorite to chlorite and chlorite to chlorate(DE LUCA et al., 1992; CHAO et al., 1992). This paper shows that, as expected, the potassium ferrate (VI) treatment replaces several chemical products utilized for odour control of sludges, mainly aggressive odours caused by ammonia and sulphides, through the formation of precipitates with iron compounds. Ferrate (VI) has often been shown to destroy soluble sulphides, transforming them into sulphate. The generation of oxygen in the decomposition of ferrate(VI) increases its oxidizing power. Ferrate(VI) applied to sludges also has the double effect of transforming ammonia into nitrates, such that this product takes the place of sulphates, acting as an electron acceptor, thus preventing the development of further odours when biosolids are utilized.

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