Relevant bibliographies by topics / Phenolic acids

Journal articles
Dissertations / Theses
Books
Book chapters
Conference papers
Reports

Academic literature on the topic 'Phenolic acids'

Author: Grafiati

Published: 4 June 2021

Last updated: 18 October 2024

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Phenolic acids.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Phenolic acids"

Zilic, Sladjana, Vesna Hadzi-Taskovic-Sukalovic, Dejan Dodig, Vuk Maksimovic, and Vesna Kandic. "Soluble free phenolic compound contents and antioxidant capacity of bread and durum wheat genotypes." Genetika 45, no. 1 (2013): 87–100. http://dx.doi.org/10.2298/gensr1301087z.

Full text

Abstract:

The objective of this study was to determine phenolic compounds and the total antioxidant capacity in the grain of ten bread (T. aestivum L.) and ten durum (T. durum Desf.) wheat genotypes. Soluble free forms of total phenolics, flavonoids, PVPP (polyvinylpolypyrrolidone) bound phenolics, proanthocyanidins and phenolic acids were investigated. In addition, the correlation coefficients between total antioxidant capacities and the concentration of different soluble free phenolic compounds, as well as between soluble free total phenolics and phenolic acids, flavonoids and PVPP bound phenolics were determined. Significant differences in the content of aceton/water extractable total phenolics, PVPP bound phenolics and phenolic acids between and within two wheat species were found. On the average, durum wheat samples had about 1.19-fold higher total phenolic compounds and about 1.5-fold higher PVPP bound phenolics than bread wheat samples. Three phenolic acids, ferulic, caffeic and chlorogenic, were detected in wholemeal bread wheat. Caffeic acid was not found in durum wheat samples whilst ferulic acid was the most abundant. Proanthocyanidins in bread and durum wheat genotypes were not detected. The antioxidant capacity measured as the DPPH radical scavenging activity was similar in wholemeal of bread and durum wheat, however, significant differences were observed among genotypes within species.

APA, Harvard, Vancouver, ISO, and other styles

Roowi, Suri, Z. Hussin, R. Othman, S. A. Muhammad, and Arif Zaidi Jusoh. "Phenolic Acids in Selected Tropical Citrus." Asian Journal of Plant Biology 1, no. 1 (December 26, 2013): 1–5. http://dx.doi.org/10.54987/ajpb.v1i1.13.

Full text

Abstract:

In spite of wide research on plant phenolics, limited data are available on the phenolic acid content in selected tropical citrus. Phenolic acids are known to contribute health benefits to humans. In this study, free and ester conjugated phenolic acid in selected tropical citrus was successfully identified and quantified using Gas Chromatography Mass Spectrometry (GCMS). Citrus microcarpa, Citrus medica, Citrus hystrix and Citrus suhuiensis were among the tropical citrus analysed for their free and ester conjugated phenolic acids. C. microcarpa contains high amount of free and ester conjugated phenolic acid, which may suitable to be applied in health food products.

APA, Harvard, Vancouver, ISO, and other styles

Ye, Lingxu, Sumei Zhou, Liya Liu, Lei Liu, Daniel L. E. Waters, Kui Zhong, Xianrong Zhou, Xiaojun Ma, and Xingxun Liu. "Phenolic Compounds and Antioxidant Capacity of Brown Rice in China." International Journal of Food Engineering 12, no. 6 (August 1, 2016): 537–46. http://dx.doi.org/10.1515/ijfe-2015-0346.

Full text

Abstract:

Abstract The phenolic compounds and antioxidant activity of brown rice are well known but the extent to which phenolics and antioxidant activity varies within rice (Oryza sativa) is not known. This study evaluated the natural variation of phenolic compounds in brown rice of the major cultivars currently grown in China. Free phenolics were extracted with chilled methanol, while bound phenolics were released and extracted by alkaline hydrolysis. There were significant differences in phenolic and flavonoid content between these cultivars and significant differences in bound and total phenolics between japonica and indica samples. Ferulic and p-coumaric acids were the major phenolic acids and existed in both free and bound forms, with the bound form of ferulic acid being a dominant phenolic compound in brown rice. Phenolic compounds were the major contributor to the antioxidant capacity of brown rice and bound phenolics contributed more than free phenolics as estimated using ABTS+ radical scavenging method. This study provides additional information on brown rice from japonica and indica subspecies and may assist in retaining or increasing phenolics and antioxidant activity in rice.

APA, Harvard, Vancouver, ISO, and other styles

Rebiai, Abdelkrim, Bachir Ben Seghir, Hadia Hemmami, Soumeia Zeghoud, Mohamed Lakhder Belfar, and Imane Kouadri. "Determination of some phenolic acids in Algerian propolis." Ovidius University Annals of Chemistry 32, no. 2 (July 1, 2021): 120–24. http://dx.doi.org/10.2478/auoc-2021-0018.

Full text

Abstract:

Abstract Propolis is a resinous material collected by bees from various plant exudates, rich in well-known phenolic compounds, such as phenolic acids, that are important to health. Extracts of propolis are very complex matrices that are hard to test. The purpose of this study was to characterize some of the propolis phenolics that were collected from five different districts in Algeria. The High-Performance Liquid Chromatography (HPLC), a modern quantitative method, has been adopted to identify the phenolic acids. Moreover, total phenolic content of four different phenolic acids were identified, with the most abundant being chlorogenic acid, followed by caffeic acid, gallic acid, and p-coumaric acid, the obtained ratios from phenolic acids being in the range of 52.193 to 148.151 μg/g, 0.043 to 7.128 mg/g, 0.328 to 0.440 mg/g and 0.328 to 0.440 mg/g, respectively. Overall, our analysis indicates that all the samples of propolis tested are healthy sources of phenolic acids and the significant differences in the concentrations of the acids were observed for propolis samples from north and south of Algeria. It is probably the effect of different conditions of the collection of the resin and secrets by bees.

APA, Harvard, Vancouver, ISO, and other styles

Butsat, S., and S. Siriamornpun. "Phenolic Acids and Antioxidant Activities in Husk of Different Thai Rice Varieties." Food Science and Technology International 16, no. 4 (August 2010): 329–36. http://dx.doi.org/10.1177/1082013210366966.

Full text

Abstract:

This study was designed to investigate the free and bound phenolic acids as well as their antioxidant activities in husk of 12 Thai rice varieties consisting of pigmented rice and normal rice. The pigmented rice husk gave higher free total phenolic contents than normal rice husk. However, there was no significant difference in bound total phenolic contents between pigmented rice and normal rice husks. Ferulic and p-coumaric acids were the major phenolic acids in the free fraction of pigmented rice husks, whereas vanillic acid was the dominant phenolic acid in the free fraction of normal rice husks. On the other hand, p-coumaric acid was highly found in bound form of both pigmented and normal rice husks. The antioxidant activity of husk extracts was positively correlated with the total free phenolics content and individual of phenolic acids especially ferulic acid. On the basis of this study, it is suggested that the rice husk could be a potential phenolic acid source and may therefore offer an effective source of natural antioxidant. Our findings provide valuable information on phenolic acids composition and antioxidant activity of husk for further food application.

APA, Harvard, Vancouver, ISO, and other styles

Liu, Yihan, Sanaa Ragaee, Massimo F. Marcone, and El-Sayed M. Abdel-Aal. "Composition of Phenolic Acids and Antioxidant Properties of Selected Pulses Cooked with Different Heating Conditions." Foods 9, no. 7 (July 10, 2020): 908. http://dx.doi.org/10.3390/foods9070908.

Full text

Abstract:

Pulses are recommended for healthy eating due to their high content of nutrients and bioactive compounds that can undergo changes during cooking. This study investigated the effects of four cooking methods (boiling, pressure, microwave, slow) and three heating solutions (water, salt, sugar) on the phenolic acids and antioxidant properties of three pulses (faba beans, lentils, peas). The composition of phenolic acids differed among the three pulses with p-coumaric and ferulic being the dominant acids. Cooking increased free phenolic acids and lessened bound phenolic acids in faba beans and peas, while decreased both free and bound phenolic acids in lentils. Cooking resulted in reductions in total phenol content (TPC) in faba bean methanol and bound extracts. Pressure and microwave cooking increased TPC in lentil methanol extracts, while pot boiling and slow cooking reduced TPC. Microwave cooking resulted in increases in TPC in bound phenolic extracts from lentils. For peas, cooking increased TPC in both methanol and bound phenolic extracts. Significant changes were also observed in the antioxidant capacity of cooked pulses based on the scavenging ability of DPPH, ABTS and peroxyl radicals subject to the type of pulse, polyphenol and antioxidant assay. Despite the significant reduction in antioxidants, high amounts of phenolics with potent antioxidant activities are still found in cooked pulses.

APA, Harvard, Vancouver, ISO, and other styles

Tuyen, Phung Thi, Do Tan Khang, Pham Thi Thu Ha, Tran Ngoc Hai, Abdelnaser Abdelghany Elzaawely, and Tran Dang Xuan. "Antioxidant Capacity and Phenolic Contents of Three Quercus Species." International Letters of Natural Sciences 54 (May 2016): 85–99. http://dx.doi.org/10.18052/www.scipress.com/ilns.54.85.

Full text

Abstract:

The antioxidant capability and phenolic contents of ethanol extracts (free phenolics) and ethyl acetate extracts (bound phenolics) of three Quercus species were estimated in this work. The antioxidant activities were examined by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical, reducing power and b-carotene bleaching methods. HPLC was employed to detect major phenolic acids. The leaf extract of Q. salicina contained maximum total phenolics while the highest total flavonoid content was found in the leaf extract of Q. serrata. The antioxidant activities varied among three species. Bark extract of Q. salicina was the most potential and it was closed to levels of the standard antioxidative dibutyl hydroxytoluene (BHT). The bark extract of Q. serrata also showed promising antioxidant activities despite their eminence was negligibly lower than Q. salicina. Stronger antioxidant activities of free phenolics than those of the bound phenolics may be attributed to higher quantities of free phenolics in the barks of Quercus species, however total flavonoids may not contribute a critical role. By HPLC analysis, thirteen phenolic acids were detected in the leaf and bark extracts. Of them, Q. salicina showed maximum in number (ten compounds) and quantities of detected phenolic acids. Ellagic, chlorogenic and benzoic acids were dominant in Quercus species. Findings of this study revealed that leaves and barks of three Quercus species are rich source of antioxidants, and Q.salicina is the most promising and should be elaborated to exploit its pharmaceutical properties.

APA, Harvard, Vancouver, ISO, and other styles

Tuyen, Phung Thi, Do Tan Khang, Pham Thi Thu Ha, Tran Ngoc Hai, Abdelnaser Abdelghany Elzaawely, and Tran Dang Xuan. "Antioxidant Capacity and Phenolic Contents of Three <i>Quercus</i> Species." International Letters of Natural Sciences 54 (May 11, 2016): 85–99. http://dx.doi.org/10.56431/p-u66fhw.

Full text

Abstract:

APA, Harvard, Vancouver, ISO, and other styles

Suprun, Andrey R., Alexandra S. Dubrovina, Alexey P. Tyunin, and Konstantin V. Kiselev. "Profile of Stilbenes and Other Phenolics in Fanagoria White and Red Russian Wines." Metabolites 11, no. 4 (April 9, 2021): 231. http://dx.doi.org/10.3390/metabo11040231.

Full text

Abstract:

Grapes and wines represent the most important source of edible stilbenes and other phenolic metabolites, which demonstrate a wide range of valuable biological activities. However, there is no information about the profile and content of phenolic compounds in Russian wines. We firstly analyzed phenolics (stilbenes, phenolic acids, and flavonols) in some representatives of Russian wines, including eleven red and seven white Russian wines from Fanagoria, Krasnodarsky Territory. The Russian red wines contained six stilbenes (trans-resveratrol, cis-resveratrol, trans-, cis-piceid, trans-piceatannol, δ-viniferin), while the white wines contained only five stilbenes (cis-resveratrol, trans-, cis-piceid, trans-piceatannol, trans-resveratrol). More than a half of the total stilbenes in the wines (65% of all stilbenes) were presented by trans-piceid and cis-piceid, while trans-resveratrol reached 16% of all the stilbenes. The red wines also contained six phenolic acids and six flavonols, while the white wines contained six phenolic acids and only three flavonols. Myrecitin-3-O-glucoside, quercetin-3-O-glucoside, and myricetin were the major flavonols in the red wines, while dihydroquercetin-3-O-rhamnoside was the major flavonol in the white wines. The red wines contained markedly higher amounts of stilbenes, phenolic acids, and flavonols than the white wines. Thus, the data showed that young red Russian Fanagoria wines represent a rich source of phenolic compounds. The study also revealed that younger wines were more abundant in phenolics, and wine storage for six months in the dark at +10 °C led to a decrease in the total content of phenolics, primarily monomeric stilbenes and quercetin-3-O-glucoside and quercetin flavonols.

APA, Harvard, Vancouver, ISO, and other styles

Sun, Wenli, and Mohamad Hesam Shahrajabian. "Therapeutic Potential of Phenolic Compounds in Medicinal Plants—Natural Health Products for Human Health." Molecules 28, no. 4 (February 15, 2023): 1845. http://dx.doi.org/10.3390/molecules28041845.

Full text

Abstract:

Phenolic compounds and flavonoids are potential substitutes for bioactive agents in pharmaceutical and medicinal sections to promote human health and prevent and cure different diseases. The most common flavonoids found in nature are anthocyanins, flavones, flavanones, flavonols, flavanonols, isoflavones, and other sub-classes. The impacts of plant flavonoids and other phenolics on human health promoting and diseases curing and preventing are antioxidant effects, antibacterial impacts, cardioprotective effects, anticancer impacts, immune system promoting, anti-inflammatory effects, and skin protective effects from UV radiation. This work aims to provide an overview of phenolic compounds and flavonoids as potential and important sources of pharmaceutical and medical application according to recently published studies, as well as some interesting directions for future research. The keyword searches for flavonoids, phenolics, isoflavones, tannins, coumarins, lignans, quinones, xanthones, curcuminoids, stilbenes, cucurmin, phenylethanoids, and secoiridoids medicinal plant were performed by using Web of Science, Scopus, Google scholar, and PubMed. Phenolic acids contain a carboxylic acid group in addition to the basic phenolic structure and are mainly divided into hydroxybenzoic and hydroxycinnamic acids. Hydroxybenzoic acids are based on a C6-C1 skeleton and are often found bound to small organic acids, glycosyl moieties, or cell structural components. Common hydroxybenzoic acids include gallic, syringic, protocatechuic, p-hydroxybenzoic, vanillic, gentistic, and salicylic acids. Hydroxycinnamic acids are based on a C6-C3 skeleton and are also often bound to other molecules such as quinic acid and glucose. The main hydroxycinnamic acids are caffeic, p-coumaric, ferulic, and sinapic acids.

APA, Harvard, Vancouver, ISO, and other styles

More sources

Dissertations / Theses on the topic "Phenolic acids"

Amombo, Noa Francoise Mystere. "Crystal engineering of selected phenolic acids." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/734.

Full text

Abstract:

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Chemistry in the Faculty of Applied Science at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2014
Crystal engineering based upon acid: base compounds have been studied in this thesis. Selected phenolic acids such as: vanillic acid (VA), phenylacetic acid (PAA), 4-hydroxyphenylacetic acid (HPAA), 3-chloro-4-hydroxyphenylacetic acid (CHPAA), caffeic acid (CFA), p-coumaric acid (pCA), trans-ferulic acid (tFER), 2-phenylpropionic acid (PPA) and 2-phenylbutyric acid (PBA) were the main compounds investigated. These phenolic acids have formed co-crystals/co-crystal hydrates, salts/salt hydrates and hybrid salt-co-crystals with acridine (ACRI), caffeine (CAF), cinchonidine (CIND), isonicotinamide (INM), isonicotinic acid (INA), nicotinamide (NAM), quinidine (QUID), quinine (QUIN), theobromine (THBR), theophylline (THPH) and urea (U). The two racemic compounds 2-phenylpropionic acid (PPA) and 2-phenylbutyric acid (PBA) were used to study chiral discrimination leading to the understanding of separation enantiomers. Compounds were prepared in different solvents (alcohols, ketone and distilled water) to investigate the relationship between solvents used and the crystalline product obtained. (If there is any effect on the crystalline compound obtained by changing the solvent). The structures were elucidated using single crystal X-ray diffraction. Ground products of obtained compounds were characterized by powder X-ray diffraction (PXRD). Thermal analyses like thermogravimetry (TG), differential scanning calorimetry (DSC) and hot stage microscopy (HSM) were used for the determination of thermal character of the new compounds. IR was also performed to characterize the new compounds. Non-isothermal TG was utilised to obtain kinetic parameters for the water and the methanol release in (pCA−)(QUIN+)•pCA•MeOH•H2O. A selective experiment was done in which quinidine and quinine were used to compete between selected phenolic acids (PAA and HPAA). viii The comparison of the crystal structures determined showed that, changing the phenolic acid while using the same co-crystal former has a significant effect on the type of compounds obtained. The obtained crystal structures were either co-crystal/co-crystal hydrates, salts/salt hydrates or hybrid salt-co-crystals which formed network via means of supramolecular interactions.

APA, Harvard, Vancouver, ISO, and other styles

Poquet, Laure. "Metabolism and effects of dietary phenolic acids." Thesis, University of Surrey, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504944.

Full text

Abstract:

Ferulic acid is a secondary metabolite usually found as esters in plants and dihydrocaffeic acid results from the microbial metabolism of flavonoids and of caffeic acid, both widely distributed in food. Even though ferulic acid and flavonoids have been proposed to exert several beneficial effects on health, their in vivo activities could partly result from their microbial metabolites and strongly depend on their bioavailability. The absorption and metabolism of phenolic acids were studied in vitro with a model for the colonic epithelium composed of absorptive and mucus secreting cells, ex vivo with everted colonic sacs and liver slices, and in vivo with rats. The photoprotective effect of phenolic acids was tested in vitro on the keratinocytes HaCaT.The ferulic acid permeation was mainly by transcellular diffusion and also by a facilitated transport (S-MCT and MCTI). Intestinal cells conjugated ferulic acid with sulphate or glucuronide and reduced its unsaturated side chain. In rats, intestinal cells were more potent for glucuronidation of dihydrocaffeic acid, whereas the liver favoured sulphation, the methylation being regio-selective.

APA, Harvard, Vancouver, ISO, and other styles

Lal, Priya Kumari. "Maternal prenatal consumption of bioflavonoids and phenolic acids and risk of childhood brain cancer." Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1080569687.

Full text

Abstract:

Thesis (Ph. D.)--Ohio State University, 2004.
Title from first page of PDF file. Document formatted into pages; contains xvii, 274 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: J. Schwartzbaum, School of Public Health. Includes bibliographical references (p. 171-203).

APA, Harvard, Vancouver, ISO, and other styles

Yeung, Shing Joseph. "Role of mycophenolic acid in kidney transplantation." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B31981860.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Sorour, Noha. "Lipase-catalyzed synthesis of phenolic lipids in solvent-free medium using selected edible oils and phenolic acids." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97003.

Full text

Abstract:

The enzymatic synthesis of phenolic lipids (PLs) in solvent-free medium (SFM), by transesterification of flaxseed and fish liver oils with selected phenolic acids was investigated, using Candida antarctica lipase as the biocatalyst. The enzymatic synthesis of phenolic lipids from flaxseed oil was optimized in terms of water activity, agitation speed, enzyme and phenolic acid concentrations. Increasing the water activity of the flaxseed oil reaction mixture from 0.18 to 0.38 resulted in a significant increase in the bioconversion yield from 62 to 77%. The highest enzymatic activity (178 nmol of PLs/g solid enzyme/min) was obtained with the use of 40 mg of solid enzyme (400 PLU)/mL reaction volume at 150 rpm. Under the optimized conditions there was a significant increase in the proportion of linolenic acid (C18:3 n-3), which increased from 57% in the flaxseed oil to 75 and 64% in the produced phenolic mono- and diacylglycerols, respectively. The volumetric productivity (Pv) of the transesterification of flaxseed oil and 3,4-dihydroxyphenyl acetic acid (DHPA) in SFM was increased 11-fold as compared to that in organic solvent medium. On the other hand, a bioconversion yield of 61% was obtained for the transesterification of fish liver oil with dihydrocaffeic acid (DHCA). Optimization of the enzymatic synthesis of phenolic lipids in SFM from fish liver oil was carried out, using response surface methodology (RSM), based on a four-factor-five-level central composite rotatable design (CCRD). The optimal conditions for the enzymatic reaction were obtained at 50.0ºC, 20.9 mM phenolic acid, 51.2 mg of solid enzyme (512 PLU)/mL, 160 rpm agitation speed, water activity of 0.5 and 3.45 mg Silica gel/mL. The bioconversion yield obtained under these optimized conditions was 86.5%, which is very close to the predicted value of 84.5%. Hence, the predicted values showed good validation with the experimental ones. The overall results demonstrated that RSM can be applied effectively to optimize lipase-catalyzed synthesis of phenolic lipids in SFM, from fish liver oil and DHCA. Under the optimized conditions, there was a significant increase in the relative proportions of the two highly desirable essential fatty acids, where (EPA, C20:5 n-3) was increased from 11.5% in the unmodified fish liver oil to 21.2, 20.7, 20.8, 20.1 and 19.8% in dihydrocaffeoylated, 3,4-dihydroxyphenyl acetoylated, caffeoylated, feruloylated and sinapoylated lipids, respectively, whereas (DHA, C22:6 n-3) increased from 12.0% to 21.4, 19.4, 27.5, 22.1 and 22.0%, respectively. Atmospheric pressure chemical ionization-mass spectrophotometry (APCI-MS) analyses confirmed the formation of six 3,4-dihydroxyphenyl acetoylated and six dihydrocaffeoylated lipids from the transesterification of flaxseed and fish liver oils in SFM using DHPA and DHCA, respectively, as substrates. Although the synthesized phenolic lipids demonstrated radical scavenging activity, expressed as IC50 from 1.6 to 3.7-fold higher than that of its corresponding phenolic acid, it was compared to that of α-tocopherol.
La biosynthèse des lipides phénoliques sans solvent, par la transésterification de l'huile de graines de lin (HGL) et l'huile de foie de poisson (HFP) en utilisant comme substrats les acides phénoliques, a été étudiée en utilisant la lipase Candida antarctica comme biocatalyseur. L'optimisation de la biosynthèse des lipides phénoliques à partir de l'HGL a été investiguée en considérant l'activité thermodynamique de l'eau, la vitesse d'agitation, la concentration de l'enzyme et l'acide phénolique. Le rendement de la bioconversion a augmenté de 62 à 77% lorsque l'activité thermodynamique de l'eau du mélange réactionnel de l'HGL a augmenté de 0.18 à 0.38. L'activité enzymatique maximale (178 nmol de PLs/g solide enzyme/min) a été obtenue lors de l'utilisation de 40 mg d'enzyme solide (400 PLU/mL de volume réactionnel) à 150 rpm. En utilisant les conditions réactionnelles optimales, la proportion de l'acide linolénique (C18:3 n-3) a augmenté significativement de 57% dans l'HGL à 75 et 64% dans les produit mono- et diacylglycerols phénoliques, respectivement. La production volumétrique (Pv) de la transésterification de l'HGL et de l'acide dihydroxyphényl acétique (ADHP) en milieu non organique a été 11 fois supérieure à celle obtenue dans le milieu organique. Par ailleurs, le rendement de la bioconversion de 61% a été obtenu lors de la transésterification de l'HFP et de l'acide dihydrocafféique (ADHC). L'optimisation de la synthèse enzymatique des lipides phénoliques a été étudiée en utilisant la méthodologie des surfaces de réponse (MSR), basée sur le factorielle quatre à cinq niveaux sur un plan composite centrale rotatif. Les conditions optimales de la réaction enzymatique ont été déterminées comme suit: 50.0ºC, 20.9 mM d'acide phénolique, 51.2 mg d'enzyme solide (512 PLU)/mL, vitesse de l'agitation 160 rpm, 0.5 de l'activité thermodynamique de l'eau et 3.45 mg de gel Silicate/mL. Le rendement de bioconversion maximum obtenu expérimentalement de 86.5% est très proche de la valeur prédite de 84.5%. Ceci démontre une bonne validation du model. Les résultats, en général, démontrent que la MSR peut être appliquée effectivement pour l'optimisation de la biosynthèse des phénols lipidiques en l'absence de solvant à partir de l'HFP et l'ADHC en utilisant la lipase comme biocatalyseur. Dans les conditions optimales, il y a eu une augmentation significative des proportions relatives des deux acides gras essentiels désirés. L'EPA (C20:5 n-3) dans l'HFP modifié a augmenté de 11.5% à 21.2, 20.7, 20.8, 20.1 et 19.8% dans les lipides dihydrocaffeoylates, 3,4-dihydroxyphenyl acetoylates, caffeoylates, feruloylates et sinapoylates, respectivement, alors que (DHA, C22:6 n-3) a augmenté de 12.0% à 21.4, 19.4, 27.5, 22.1 et 22.0%, respectivement. Les analyses de l'ionisation chimique à pression atmosphérique-spectroscopie de masse (APCI-MS) confirment la formation de six 3,4-dihydroxyphényl acetoylates et de six lipides dihydrocaffeoylates, à partir de la transésterification de l'HGL et de l'HFP avec l'ADHP et l'ADHC, respectivement. Les lipides phenoliques synthetisés ont demontré un pouvoir radicalaire, exprimé par le IC50, de 1.6 à 3.7-fois supérieure à celui des acides phénoliques correspondants, mais il était comparable à celui de α-tocophérol.

APA, Harvard, Vancouver, ISO, and other styles

Al-Hadhrami, Mohamed N. (Mohamed Nasser). "Degradation of Phenolic Acids by Azotobacter Species Isolated from Sorghum Fields." Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc501189/.

Full text

Abstract:

Sorghum plants excrete phenolic acids which reduce subsequent crop yields. These acids accumulate in field soil by combining with soil and clay particles to form stable complexes which remain until degraded by bacterial metabolism. The amount of phenolic acids in soil samples were obtained by gas chromatography measurements, while Azotobacter populations were obtained by plate counts in 40 sorghum field samples from Denton County, Texas. One can conclude that increasing the Azotobacter population in the soil increased the degradation rate of phenolic acids proportionally. It is proposed that seed inoculation will introduce selected strains of Azotobacter into the soil. The presence of Azotobacter should increase crop size in subsequent plantings.

APA, Harvard, Vancouver, ISO, and other styles

Patel, Chirag G. "The pharmacokinetics and pharmacodynamics of mycophenolic acid in kidney transplant recipients /." View online ; access limited to URI, 2006. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/fullcit/3239911.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Mothapo, Mmaphefo Patricia. "Comparative evaluation of three fundamentally different analytical methods antioxidant activity determination with reference to bush tea (anthrixia phylicoides." Thesis, University of Limpopo, 2016. http://hdl.handle.net/10386/1517.

Full text

Abstract:

Thesis (M.Sc. (Chemistry)) -- University of Limpopo, 2016
In this study, antioxidant activity methodologies were evaluated in terms of analytical performances. The total antioxidant activity from Athrixia phylicoides leaves (Bush tea) determined using 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH•) method, cupric ion reducing power (CUPRAC) method and cyclic voltammetry (CV). Folin-Ciocalteu method was used to quantify total phenolic content (TPC) in Athrixia phylicoides leaves. The influence of chemical and physical parameters on the total phenolic content and antioxidant activity determination were investigated. Results from direct sample and crude sample were compared. Antioxidant activity and phenolic content from Athrixia phylicoides leaves were compared with those from commercialised green tea, black tea and rooibos tea using two chosen antioxidant capacity method with acceptable characteristics. Results from the evaluation of the methods demonstrated excellent recoveries (99 to 103%) consistently, good linearity within the calibration concentration range (R2 = 0.997) and repeatable low coefficient of variation < 5% were indicative of good precision except for CV method. The average total antioxidant activity of various extracts of Athrixia phylicoides leaves ranged from 0.039 to 0.122 mg/mL (EC50), 0.031 to 0.233 mg/mL (EC50) and 339 to 429 mV (anodic potential) for DPPH method, CUPRAC method and CV method, respectively. The total antioxidant activity values for each Athrixia phylicoides samples determined by CUPRAC method were higher than the values produced by DPPH and CV methods. The highest antioxidant activities in the DPPH and CUPRAC methods were found in water extracts (direct sample). However, concentrated samples for DPPH method and CV gave a different trend with the methanol extract (crude sample) displaying the highest antioxidant capacity. Increasing the infusion time only increased total antioxidant activity determined by CUPRAC method, whilst DPPH and CV methods had the highest antioxidant activity in the lowest infusion time (3 min). Even though the results are inconclusive with regard to the effect of solid to solvent ratio effect on the total antioxidant activity, 1:150 ratio and 1:100 ratio extracts for both CUPRAC and DPPH methods and for CV gave the highest antioxidant capacities, respectively. The total antioxidant activities in pure antioxidant standards and in the teas were ranked in the following order by both CUPRAC and DPPH methods: Quercetin > catechin > Trolox and Chinese green tea > Joko black tea > Athrixia phylicoides leaves > Laager rooibos tea, respectively. Comparative study showed the necessity of employing more than one method, as each method for the same sample yielded different results. CUPRAC and DPPH methods displayed higher sensitivity and repeatability as compared to the CV method with poor precision.

APA, Harvard, Vancouver, ISO, and other styles

Khoddami, Ali. "Phenolic Compounds in Grains of Australian-Grown Sorghums: Quantitative Analyses including Impacts of Malting and Effects on Broiler Nutrition." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14985.

Full text

Abstract:

Grain sorghum (Sorghum bicolor) is one of the most important food and animal feed crops in arid and semi-arid regions of the world. Sorghum grain is rich in starch and contains many functional health-promoting compounds including B-group vitamins, vitamin E and a broad range of phenolics. There is increasing interest internationally to extend the commercial use of sorghum grain as an affordable but nutritious source of animal feed and as a functional food. The utilisation of energy by broiler chickens offered sorghum-based diets seems inadequate due to various factors such as kafirin, phytate and phenolic compounds, which may limit energy utilisation. The increased use of sorghum as a human food might be achieved partly through understanding the effects of various forms of grain processing. Malting is a biotechnological process that involves soaking, germination and kilning of the grain. For sorghum, malting has been identified as an effective process to increase the bioavailability of the macro- and micronutrients for sorghum based-foods but many questions concerning the biochemical effects of malting remain unanswered. There were two primary objectives for the research presented in this thesis: (1) To assess whether the abundance of phenolic compounds of a range of different classes influences energy utilisation in broiler chickens fed sorghum-based diets (Chapter 3), and (2) To evaluate the impact of malting on the abundance of several classes of sorghum phenolics (Chapter 4 to 6). A substantial collection of Australian-grown sorghum grains were analyzed for total phenolics, flavan-4-ols, antioxidant activity (DPPH; 2,2-diphenyl-1-picrylhydrazyl and ABTS; 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid)), total flavonoids and total anthocyanins. Separation, identification and quantification of 3-deoxyanthocyanins, flavones, flavanones, as well as free, conjugated and bound phenolic acids, were also performed using high performance liquid chromatography (HPLC) and liquid chromatography coupled with mass spectrometry (LC-MS). Objective (1) was achieved through collaboration with experts in broiler chicken digestive physiology. A pigmented testa was found to be absent in all the Australian-grown sorghum cultivars examined (16 and 8 cultivars for Objectives (1) and (2), respectively), indicating that they were type I sorghums, which (by definition) lack condensed tannin. Analyses and assessments of other polyphenolic compounds, including flavan-4-ols and phenolic acids, appear to show that these have negative influences on broiler growth and meat production. The total phenolic content (TPC), in vitro antioxidant activity (DPPH and ABTS) and level of flavan-4-ols in the Australian sorghum grains ranged from 3.00 to 4.68 mg GAE/g, 8.50 to 14.47 mol TE/g, 18.81 to 33.73 umol TE/g and 0.84 to 7.98 abs/ml/g, respectively, where /g indicates per gram of grain on a dry matter basis in each case, as used for all experiments reported in this thesis. The total anthocyanin and total flavonoid level ranged from 1.30 to 11.55 abs/ml/g and 0.65 to 1.80 mg CE/g among the Australian sorghums tested. Levels of 3-deoxyanthocyanin ranged from 10.07 to 63.80 μg/g. The flavones detected in sorghum grain were apigenin (pale yellow) and luteolin (yellow). The flavone level ranged from 5.76 to 17.55 μg/g. The total content of flavanones (eriodictyol and naringenin) ranged from 29.39 to 189.62 μg/g, of which the eriodictyol content varied from 28.1 to 55.5% of total flavanones. Naringenin represented all of the flavanone content in one of the cultivars tested (cv. Block). Ferulic, caffeic, p-coumaric, syringic, vanillic, p-hydroxybenzoic and sinapic acids were detected in the grains of all sorghum cultivars tested. The total abundance of free phenolic acids ranged from 9.20 to 38.55 g/g. The most abundant of the free phenolic acids was caffeic acid, which varied from 1.47 to 18.35 g/g. Levels of total soluble conjugated phenolic acids in the sorghum grains varied from 44.50 to 96.76 g/g. Bound phenolic acids were the most abundant form of phenolic acids, with 228.57 to 580.33 g/g. Ferulic and p-coumaric acids were the predominant conjugated and bound phenolic acids among all the sorghum cultivars examined. In determining the effects of malting (soaking, germination and kilning) on the abundance of the grain phenolic compounds, eight different sorghum hybrids harvested from three different regions in eastern Australia in 2011 were analyzed. All the sorghum grains were tannin free based on both a bleach test and a vanillin-HCl assay. Malting decreased the total phenolic content and in vitro antioxidant activity in all samples. The grand means for total phenolics among all the sorghum cultivars were 2.77 and 2.48 mg GAE/g for raw and malted grain, respectively. For flavan-4-ols, the grand means for raw and malted sorghum grains were 2.98 and 2.23 abs/ml/g, respectively. On average, malting reduced the content of flavan-4-ols by 25%. Total anthocyanin levels more than doubled upon malting the sorghum whereas the total flavonoid level decreased by 12%. Luteolinidin, apigeninidin, 5-methoxy-luteolinidin and 7-methoxy-apigeninidin, which were detected as major 3-deoxyanthocyanins in all raw sorghum grains, were all found to increase in abundance upon malting. The content of luteolinindin and apigeninidin increased dramatically from 4.28 to 43.93 μg/g and from 4.43 to 37.89 μg/g, respectively. Overall, the level of flavones (apigenin and luteolin) increased by 68% after sorghum malting, whereas the level of flavanones decreased by 50%. The grand means for total free phenolic acids in raw and malted grains among the eight sorghum cultivars were 29.65 and 22.33 g/g, respectively. Reflecting the result for the distinct set of cultivars analysed above, caffeic acid was the most abundant free phenolic acid. The grand means for conjugated phenolic acids in the raw and malted sorghums were 74.88 and 73.46 g/g, respectively. While these values are very similar, malting did significantly affect the abundance of all conjugated individual phenolic acids. The grand means for bound phenolic acids in the raw and malted sorghums were 391.81 and 378.06 g/g, respectively. There was statistically significant change upon malting in the abundance of ferulic acid as major bound phenolic acid (344.71 and 333.02 g/g in raw and malted grain, respectively). The data obtained in this study on phenolic compounds in sorghum grain should be valuable for sorghum breeders in the selection of lines for specific end uses, food scientists developing sorghum-based products, broiler meat producers, and in the nutraceutical industry.

APA, Harvard, Vancouver, ISO, and other styles

Yeung, Shing Joseph, and 楊誠. "Role of mycophenolic acid in kidney transplantation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31981860.

Full text

APA, Harvard, Vancouver, ISO, and other styles

More sources

Books on the topic "Phenolic acids"

Hänninen, Kari. Phenolic acids in humus chemistry. Helsinki: Suomalainen Tiedeakatemia, 1987.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

Kuiters, Aloysius Theodorus. Phenolic acids and plant growth in forest ecosystems. Amsterdam: Free Univ. Pr., 1987.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

Mrozik, Agnieszka. Zmiany w składzie bakteryjnych kwasów tłuszczowych w czasie rozkładu fenolu w glebie. Katowice: Wydawn. Uniwersytetu Śląskiego, 2000.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

Blum, Udo. Plant-Plant Allelopathic Interactions: Phenolic Acids, Cover Crops and Weed Emergence. Dordrecht: Springer Science+Business Media B.V., 2011.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

Shahrzad, Siranoush. Bestimmung bioaktiver Phenolcarbonsäuren in Säften und Weinen und Ermittlung der Metabolisierung und Biokinetik von Gallussäure beim Menschen. Marburg: Tectum Verlag, 1998.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

Salomonsson, Ann-Christine. Studies on carbohydrates and phenolic acids in grains of normal and high-lysine barley genotypes. Upssala: Swedish University of Agricultural Sciences, Dept. of Chemistry and Molecular Biology, 1985.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

J. J. A. van Loon. Sensory and nutritional effects of amino acids and phenolic plant compounds on the caterpillars of two Pieris species. Wageningen: Landbouwuniversiteit te Wageningen, 1988.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

Caldwell, Charles R. Effect of divalent cations on the phenolic acids and flavonol glycosides of lettuce (Lactuca Sativa L.) leaf tissues. Beltsville, Md: USDA ARS BA, 2001.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

A, Muscolo, and Sidari M, eds. Soil phenols. Hauppauge, N.Y: Nova Science Publishers, 2009.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

Muscolo, A. Soil phenols. Hauppauge, N.Y: Nova Science Publishers, 2009.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

More sources

Book chapters on the topic "Phenolic acids"

Goleniowski, Marta, Mercedes Bonfill, Rosa Cusido, and Javier Palazón. "Phenolic Acids." In Natural Products, 1951–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-22144-6_64.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Kostić, Aleksandar Ž., Yusuf Can Gercek, and Nesrin Ecem Bayram. "Phenolic Acids in Pollen." In Pollen Chemistry & Biotechnology, 103–25. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-47563-4_6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Liberal, Ângela, Rossana V. C. Cardoso, Sandrina A. Heleno, Ângela Fernandes, Lillian Barros, and Anabela Martins. "Phenolic Acids from Fungi." In Natural Secondary Metabolites, 475–95. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-18587-8_14.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Xu, Zhimin. "Analysis Methods of Phenolic Acids." In Analysis of Antioxidant-Rich Phytochemicals, 69–104. Oxford, UK: Wiley-Blackwell, 2012. http://dx.doi.org/10.1002/9781118229378.ch3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Cohen, G. B. "The Analysis of Coffee Phenols and Phenolic Acids." In ACS Symposium Series, 356–63. Washington, DC: American Chemical Society, 2000. http://dx.doi.org/10.1021/bk-2000-0754.ch036.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Mandal, Santi M., and Dipjyoti Chakraborty. "Mass Spectrometric Detection of Phenolic Acids." In Natural Products, 2047–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-22144-6_90.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Yen, Gow-Chin, and Chi-Tai Yeh. "Modulation of Human Phenol Sulfotransferases Expression by Dietary Phenolic Acids." In ACS Symposium Series, 62–80. Washington, DC: American Chemical Society, 2008. http://dx.doi.org/10.1021/bk-2008-0993.ch007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Khatri, Sana, Additiya Paramanya, and Ahmad Ali. "Phenolic Acids and Their Health-Promoting Activity." In Plant and Human Health, Volume 2, 661–80. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-03344-6_27.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Gerothanassis, Ioannis P., Vassiliki Exarchou, Anastasios Troganis, Maria Tsimidou, and Dimitrios Boskou. "NMR methodology for the analysis of phenolic acids in complex phenolic mixtures." In Spectroscopy of Biological Molecules: New Directions, 585–86. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4479-7_262.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Miyanaga, Akimasa, and Yasuo Ohnishi. "Phenolic Lipids Synthesized by Type III Polyketide Synthases." In Biogenesis of Fatty Acids, Lipids and Membranes, 1–11. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-43676-0_14-1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Phenolic acids"

Saldana, Marleny D. "Effect of pressurized fluids on the extraction of phenolics/anthocyanins from crops and by-products." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/pnme7357.

Full text

Abstract:

Phenolics found in various crops and by-products have antioxidant and antimicrobial activities and their consumption have been associated with health benefits. For example, a by-product of the cranberry juice industry is cranberry pomace, which is considered a rich source of anthocyanins. Research in my laboratory has focused on the use of pressurized fluids to extract these phenolic compounds to be used in various applications. Pressurized fluids, such as subcritical water, pressurized ethanol and supercritical CO2 (SC-CO2) as â€œgreenâ€ and environmentally friendly solvents, can be used for the extraction of phenolic compounds from crops and by-products as well as for enzymatic reactions involving phenolic acids. Phenolic compounds were extracted from various crops and by-products using pressurized fluids in stainless steel reactors at different temperatures, pressures and times. Extracts obtained after crop and by-product treatment using pressurized fluids were evaluated for their phenolic content and antioxidant activity. Anthocyanins were obtained from cranberry pomace using pressurized fluids. Results also indicated that the total phenolic content and antioxidant activity of the extracts from other crops and by-products increased with extraction temperature. In addition, a phenolic acid was reacted with triglycerides of flax oil using lipase enzyme in SC-CO2 media in a laboratory-scale supercritical system at different temperatures ranging from 40 to 80ËšC, pressures from 40 to 350 bar and times of up to 53 h. Results have shown that SC-CO2 is a promising green solvent for the enzymatic synthesis of phenolic lipids. Results also have shown that phenolic acids can be processed using pressurized fluids for different applications.

APA, Harvard, Vancouver, ISO, and other styles

Šaćirović, Sabina, Andrija Ćirić, Mališa Antić, and Zoran Marković. "HPLC ANALYSIS OF PHENOLS OF SLOVENIAN RED WINES: CABERNET SAUVIGNON AND MERLOT." In 1st INTERNATIONAL Conference on Chemo and BioInformatics. Institute for Information Technologies, University of Kragujevac, 2021. http://dx.doi.org/10.46793/iccbi21.165s.

Full text

Abstract:

In this study, HPLC-DAD rapid analysis of phenols in wine samples was performed. The recording was performed at different wavelengths: phenolic acid (254nm), flavan-3-ols and stilbene (280nm), flavonoids (340nm) and anthocyanins (520nm). In selected wines, the concentrations of the following compounds were determined and expressed in mg/l of wine. The isolated derivatives were: hydroxybenzoic acids, derivatives of caffeic, ferulic, syringic, and vanillic acids, catechin (flavanol), rutin, myricetin and quercetin (flavonols), and the stilbene derivative-resveratrol. The properties and quantities of phenolic compounds in organic wines were investigated. The results show the content of phenolic compounds in organic wines do not differ qualitatively and quantitatively from those in conventional wines. Wine samples have shown good antioxidative activity according to both DPPH and FRAP analysis, which indicates the good antioxidative potential and high antioxidant concentration in tested wines. Cabernet Sauvignon wines have shown better radical scavenging activity than Merlot, especially when the DPPH test was considered.

APA, Harvard, Vancouver, ISO, and other styles

Milenković, Katarina, Jelena Mrmošanin, Stefan Petrović, Bojan Zlatković, Snežana Tošić, Milan Mitić, and Aleksandra Pavlović. "INFLUENCE OF EXTRACTION SOLVENTS ON THE PHENOLIC PROFILE OF ROSA DUMALIS BECHST. FRUIT SAMPLES." In 2nd International Symposium on Biotechnology. Faculty of Agronomy in Čačak, University of Kragujevac, 2024. http://dx.doi.org/10.46793/sbt29.72km.

Full text

Abstract:

The phenolic content of investigated Rosa dumalis fruit samples were studied. To obtain a more detailed phenolic profile, five solvents with different polarities (water, ethanol, 60% ethanol, methanol and acidified 80% methanol) were used for the preparation of the plant extracts. Individual phenolics were analyzed using high performance liquid chromatography (HPLC). The obtained results indicate that the investigated R. dumalis samples are rich in both phenolic acids and flavonoids. Acidified 80% methanol extracts had the highest yields followed by the 60% ethanol, water, methanol, and ethanol.

APA, Harvard, Vancouver, ISO, and other styles

Mello-Júnior, Ronaldo Elias, João Renato De Jesus Junqueira, Jefferson Luiz Gomes Corrêa, Kamilla Soares de Mendonça, and Lucas Barreto de Carvalho. "Osmotic dehydration of eggplant, carrot and beetroot slices: Effect of vacuum on phenolic acid composition." In 21st International Drying Symposium. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/ids2018.2018.7787.

Full text

Abstract:

The aim of this work was to evaluate the influence of vacuum application on the phenolic acid content of osmodehydrated eggplant, carrot and beetroot samples. The contents of catechins and chlorogenic acid were determined by HPLC analysis. Changes in the contents of phenolic acids after the osmotic processes were observed. It was found a reduction in catechins and chlorogenic acids, probable due to the migration and degradation losses. In a general way, the vacuum reduced the catechin and chlorogenic acid contents, compared to the osmotic dehydration at atmospheric pressure. Keywords: Pulsed vacuum osmotic dehydration; chlorogenic acid; catechins.

APA, Harvard, Vancouver, ISO, and other styles

BICHOT, Aurélie, Jean Philippe DELGENES, Marilena RADOIU, and Diana GARCIA BERNET. "MICROWAVE PRETREATMENT OF LIGNOCELLULOSIC BIOMASS TO RELEASE MAXIMUM PHENOLIC ACIDS." In Ampere 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9629.

Full text

Abstract:

The objectives fixed by world’s governments concerning energy transition have aroused interest on lignocellulosic biomass utilization for bioenergy and green chemistry applications. However, due to their resistant structure, deconstructive pretreatments are necessary to render possible biological conversions of these lignocellulosic residues. Microwave (MW) treatment has been reported as efficient in many biotechnology fields; biomass pretreatment for biorefinery purposes is another possible application. This work presents the effects of MW pretreatment on underexploited natural agri-food biomass of economic interest: wheat bran, miscanthus stalks and corn stalks. Various parameters were studied including solvent, power density, treatment duration, pressure. Effects were evaluated by a complete biomass characterization before and after treatment, with main focus on phenolic acids release. In the tested conditions and when compared to the high NaOH consumption reference extraction method for phenolic acids, the atmospheric pressure (open vessel) microwave treatment did not allow attaining high acid yields (Fig.1). The most important parameters for improving treatment efficiency were power density and solvent. In order to increase yields, microwave treatments under pressure were carried out to reach higher temperatures while taking care as to not exceed the acid denaturation temperature (150°C) and to avoid the formation of inhibitors. Phenolic acids yields and biomass composition are currently being processed and will be discussed.

APA, Harvard, Vancouver, ISO, and other styles

Ohindovschi, Angelica, and Maria Cojocaru-Toma. "Identification of phenolic compounds from extract of Galium verum." In Scientific seminar with international participation "New frontiers in natural product chemistry". Institute of Chemistry, Republic of Moldova, 2023. http://dx.doi.org/10.19261/nfnpc.2023.ab21.

Full text

Abstract:

The species Galium verum has a long history as a traditional healing herb and attracted attention for intense investigation in recent years as it proves to be a safe, affordable and effective natural health remedy as a choleretic, diuretic or spasmolytic [1]. There is detailed research showing a complex and rich content of phytochemicals in the flowers and leaves of G. verum, with the highest total composition of phenols and flavonoids [2]. For the determination of phenolic compounds, the plant extract was obtained from Galii veri herba, collected during the flowering period and treated with 60 % hydro-ethanol solution (ratio of 1:10). The extraction was performed using a water bath, followed by the removal of solvent with rotary evaporator Laborota 4011. Identification of phenolic compounds was carried out by thin layer chromatography (TLC) in three systems: Ist system– butanol-glacial acetic acid-water (4:1:2), IInd system– chloroform-ethyl alcohol (9:1) and IIIrd system–formic acid-water-ethyl acetate (6:9:90). Table 1. Identification of phenolic compounds in extract of Galii veri herba by TLC.In the chromatographic study of the extract from G.veri herba, in all three systems, identified compounds of phenolic nature including four hydroxycinnamic acids (caffeic, chlorogenic, p-coumaric and gallic) and six flavonoids (rutosid, hyperosid, quercetin, isoquercetin, apigenin, quercitrin) with a more successful separation in the chloroform-ethyl alcohol system (9:1). The extract of Galii veri herba is rich in phenolic compounds and can be used for further preclinical and clinical studies.

APA, Harvard, Vancouver, ISO, and other styles

Li, Cunyu, Yun Ma, Hongyang Li, and Guoping Peng. "Concentrating phenolic acids from Lonicera japonica by nanofiltration technology." In 11TH ASIAN CONFERENCE ON CHEMICAL SENSORS: (ACCS2015). Author(s), 2017. http://dx.doi.org/10.1063/1.4977259.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Amić, Ana, and Valentina Bumba. "Antioxidant potential of selected phenolic acids – a theoretical approach." In 7th International Electronic Conference on Medicinal Chemistry. Basel, Switzerland: MDPI, 2021. http://dx.doi.org/10.3390/ecmc2021-11510.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Guardado Yordi, Estela, Maria João Matos, Roxana Castro Pupo, Lourdes Santana, Eugenio Uriarte, and Enrique Molina Pérez. "QSAR Study of the Potential Clastogenic Activity of Phenolic Acids." In The 16th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2012. http://dx.doi.org/10.3390/ecsoc-16-01035.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Kłosok, Konrad, Renata Welc, Monika Szymańska-Chargot, Zbigniew Niewiadomski, and Agnieszka Nawrocka. "Changes within gluten network after supplementation with selected phenolic acids." In 1st International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: ENVIRONMENT – PLANT – ANIMAL – PRODUCT. Publishing House of The University of Life Sciences in Lublin, 2022. http://dx.doi.org/10.24326/icdsupl1.t014.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Phenolic acids"

Naim, Michael, Steven Nagy, Uri Zehavi, and Russell Rouseff. Bound and Free Phenolic Acids as Precursors to Objectional Aroma in Citrus Products. United States Department of Agriculture, December 1992. http://dx.doi.org/10.32747/1992.7603824.bard.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Ozkan, Gursel. Phenolic Compounds, Organic Acids, Vitamin C and Antioxidant Capacity in Prunus spinosa L. Fruits. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, February 2019. http://dx.doi.org/10.7546/crabs.2019.02.17.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Kanner, Joseph, Edwin Frankel, Stella Harel, and Bruce German. Grapes, Wines and By-products as Potential Sources of Antioxidants. United States Department of Agriculture, January 1995. http://dx.doi.org/10.32747/1995.7568767.bard.

Full text

Abstract:

Several grape varieties and red wines were found to contain large concentration of phenolic compounds which work as antioxidant in-vitro and in-vivo. Wastes from wine production contain antioxidants in large amounts, between 2-6% on dry material basis. Red wines but also white wines were found to prevent lipid peroxidation of turkey muscle tissues stored at 5oC. The antioxidant reaction of flavonoids found in red wines against lipid peroxidation were found to depend on the structure of the molecule. Red wine flavonoids containing an orthodihydroxy structure around the B ring were found highly active against LDL and membrane lipid peroxidation. The antioxidant activity of red wine polyphenols were also found to be dependent on the catalyzer used. In the presence of H2O2-activated myoglobin, the inhibition efficiency was malvidin 3-glucoside>catechin>malvidin>resveratol. However, in the presence of an iron redox cycle catalyzer, the order of effectiveness was resveratol>malvidin 3-glucoside = malvidin>catechin. Differences in protein binding were found to affect antioxidant activity in inhibiting LDL oxidation. A model protein such as BSA, was investigated on the antioxidant activity of phenolic compounds, grape extracts, and red wines in a lecithin-liposome model system. Ferulic acid followed by malvidin and rutin were the most efficient in inhibiting both lipid and protein oxidation. Catechin, a flavonal found in red-wines in relatively high concentration was found to inhibit myoglobin catalyzed linoleate membrane lipid peroxidation at a relatively very low concentration. This effect was studied by the determination of the by-products generated from linoleate during oxidation. The study showed that hydroperoxides are catalytically broken down, not to an alcohol but most probably to a non-radical adduct. The ability of wine-phenolics to reduce iron and from complexes with metals were also demonstrated. Low concentration of wine phenolics were found to inhibit lipoxygenase type II activity. An attempt to understand the bioavailability in humans of antocyanins from red wine showed that two antocyanins from red wine were found unchanged in human urine. Other antocyanins seems to undergo molecular modification. In hypercholesterolemic hamsters, aortic lipid deposition was significantly less in animals fed diets supplemented with either catechin or vitamin E. The rate of LDL accumulation in the carotid arteries was also significantly lower in the catechin and vitamin E animal groups. These results suggested a novel mechanism by which wine phenolics are associated with decreased risk of coronary heart diseases. This study proves in part our hypothesis that the "French Paradox" could be explained by the action of the antioxidant effects of phenolic compounds found at high concentration in red wines. The results of this study argue that it is in the interest of public health to increase the consumption of dietary plant falvonoids. Our results and these from others, show that the consumption of red wine or plant derived polyphenolics can change the antioxidant tone of animal and human plasma and its isolated components towards oxidative reactions. However, we need more research to better understand bioavailability and the mechanism of how polyphenolics affect health and disease.

APA, Harvard, Vancouver, ISO, and other styles

Koziel, Jacek, Yael Laor, Jeffrey Zimmerman, Robert Armon, Steven Hoff, and Uzi Ravid. Simultaneous Treatment of Odorants and Pathogens Emitted from Confined Animal Feeding Operations (CAFOs) by Advanced Oxidation Technologies. United States Department of Agriculture, January 2009. http://dx.doi.org/10.32747/2009.7592646.bard.

Full text

Abstract:

A feasibility study was conducted, aiming to explore the potential effectiveness of UV/TiO2/O3 photooxidation technologies for simultaneous treatment of odorant and pathogen emissions from livestock and poultry operations. Several key parameters were tested in laboratory (US) and semi-pilot (Israel) scale conditions including: the effects of light energy dose (treatment time and light intensity), relative humidity and air temperature, UV wavelength, presence of photocatalyst (TiO2) and the presence of ozone. Removal and conversion of odor, target gases (sulfur-containing volatile organic compounds S-VOCs, volatile fatty acids (VFAs), phenolics, and ammonia), and airborne pathogens was tested. Up to 100% removal (below method detection level) of S-VOCs, VFAs, and phenolics, the overall odor, and up to 64.5% of ammonia was achieved with optimized treatment. Treatments involving deep UV band (185 nm) and photocatalyst (TiO2) were more efficient in removal/conversion of odorous gases and odor. The estimate of the operational cost of treatment was based on measured emissions of several odorous VOCs from full scale, commercial swine farm ranges from $0.15 to $0.59 per finisher pig. This figure represents significantly lower cost compared with the cost of biofiltration or air scrubbing.

APA, Harvard, Vancouver, ISO, and other styles

Nicholson, Ralph, Reuven Reuveni, and Moshe Shimoni. Biochemical Markers for Disease Resistance in Corn. United States Department of Agriculture, May 1996. http://dx.doi.org/10.32747/1996.7613037.bard.

Full text

Abstract:

The objective was to screen maize lines for their ability to express resistance based on biochemical traits. Cultivars were screened for retention of the hydroxamic acid DIMBOA and the synthesis of phenols (based on anthocyanin production) as markers for resistance. Lines were selected and inoculated with fungal pathogens (Exserohilum turcicum, Puccinia sorghi, Cochliobolus heterostraphus, Colletotricum graminicola.), and the Maize Dwarf Mosaic and Johnson Grass Mosaic viruses. Lines were screened in the field and greenhouse. Results showed that lines selected for augmented phenol synthesis do exhibit heightened levels of resistance to fungal pathogens. Isolation of mRNA followed by northern analyses for expression of A1 (dihydroflavanol reductase) and peroxidase confirmed that genes for these enzymes were turned on in response to inoculation of lines predicted to exhibit resistance. Peroxidase and b-1,3-glucanase were assayed in breeding lines having or lacking the se gene. A specific ionically-bound peroxidase isozyme and a b-1,3-glucanase isozyme were revealed in lines having the se gene. Data suggest that peroxidase and b-1,3-glucanase isozymes, may be considered as markers to identify resistance to E. turcicum in maize genotypes with the se gene.

APA, Harvard, Vancouver, ISO, and other styles

Carpita, Nicholas C., Ruth Ben-Arie, and Amnon Lers. Pectin Cross-Linking Dynamics and Wall Softening during Fruit Ripening. United States Department of Agriculture, July 2002. http://dx.doi.org/10.32747/2002.7585197.bard.

Full text

Abstract:

Our study was designed to elucidate the chemical determinants of pectin cross-linking in developing fruits of apple and peach and to evaluate the role of breakage cross-linkages in swelling, softening, and cell separation during the ripening. Peaches cell walls soften and swell considerably during the ripening, whereas apples fruit cells maintain wall firmness but cells separate during late stages of ripening. We used a "double-reduction" technique to show that levels of non-methyl esters of polyuronic acid molecules were constant during the development and ripening and decreased only in overripe fruit. In peach, methyl and non-methyl esters increased during the development and decreased markedly during the ripening. Non-methyl ester linkages in both fruit decreased accompanied fruit softening. The identity of the second component of the linkage and its definitive role in the fruit softening remain elusive. In preliminary examination of isolated apples cell walls, we found that phenolic compounds accumulate early in wall development but decrease markedly during ripening. Quantitative texture analysis was used to correlate with changes to wall chemistry from the fresh-picked ripe stage to the stage during storage when the cell separation occurs. Cell wall composition is similar in all cultivars, with arabinose as the principal neutral sugar. Extensive de-branching of these highly branched arabinans pre-stages softening and cell-cell separation during over-ripening of apple. The longer 5-arabinans remain attached to the major pectic polymer rhamnogalacturonan I (RG I) backbone. The degree of RG I branching, as judged from the ratios of 2-Rha:2,4-Rha, also decreases, specially after an extensive arabinan de-branching. Loss of the 4-Rham linkages correlated strongly with the softening of the fruit. Loss of the monomer or polymer linked to the RG I produce directly or indirectly the softening of the fruit. This result will help to understand the fruit softening and to have better control of the textural changes in fruit during the ripening and especially during the storage. 'Wooliness', an undesirable mealy texture that is induced during chilling of some peach cultivars, greatly reduces the fruit storage possibilities. In order to examine the hypothesis that the basis for this disorder is related to abnormality in the cell wall softening process we have carried out a comparative analysis using the resistant cultivar, Sunsnow, and a sensitive one, Hermosa. We investigated the activity of several pectin- and glycan-modifying enzymes and the expression of their genes during ripening, chilling, and subsequent shelf-life. The changes in carbohydrate status and in methyl vs. non-methyl uronate ester levels in the walls of these cultivars were examined as well to provide a basis for comparison of the relevant gene expression that may impact appearance of the wooly character. The activities of the specific polygalacturonase (PGase) and a CMC-cellulase activities are significantly elevated in walls of peaches that have become wooly. Cellulase activities correlated well with increased level of the transcript, but differential expression of PGase did not correspond with the observed pattern of mRNA accumulation. When expression of ethylene biosynthesis related genes was followed no significant differences in ACC synthase gene expression was observed in the wooly fruit while the normal activation of the ACC oxidase was partially repressed in the Hermosa wooly fruits. Normal ripening-related loss of the uronic acid-rich polymers was stalled in the wooly Hermosa inconsistent with the observed elevation in a specific PGase activity but consistent with PG gene expression. In general, analysis of the level of total esterification, degree of methyl esterification and level of non-methyl esters did not reveal any major alterations between the different fruit varieties or between normal and abnormal ripening. Some decrease in the level of uronic acids methyl esterification was observed for both Hermosa and Sunsnow undergoing ripening following storage at low temperature but not in fruits ripening after harvest. Our results support a role for imbalanced cell wall degradation as a basis for the chilling disorder. While these results do not support a role for the imbalance between PG and pectin methyl esterase (PME) activities as the basis for the disorder they suggest a possible role for imbalance between cellulose and other cell wall polymer degradation during the softening process.

APA, Harvard, Vancouver, ISO, and other styles

Bostock, Richard M., Dov Prusky, and Martin Dickman. Redox Climate in Quiescence and Pathogenicity of Postharvest Fungal Pathogens. United States Department of Agriculture, May 2003. http://dx.doi.org/10.32747/2003.7586466.bard.

Full text

Abstract:

Monilinia fructicola causes brown rot blossom blight and fruit rot in stone fruits. Immature fruit are highly resistant to brown rot but can become infected. These infections typically remain superficial and quiescent until they become active upon maturation of the fruit. High levels of chlorogenic acid (CGA) and related compounds occur in the peel of immature fruit but these levels decline during ripening. CGA inhibits cutinase expression, a putative virulence factor, with little or no effect on spore germination or hyphal growth. To better understand the regulation of cutinase expression by fruit phenolics, we examined the effect of CGA, caffeic acid (CA) and related compounds on the redox potential of the growth medium and intracellular glutathione (GSH) levels. The presence of CA in the medium initially lowered the electrochemical redox potential of the medium, increased GSH levels and inhibited cutinase expression. Conidia germinated in the presence of CA, CGA, or GSH produced fewer appressoria and had elongated germ tubes compared to the controls. These results suggest that host redox compounds can regulate fungal infectivity. In order to genetically manipulate this fungus, a transformation system using Agrobacterium was developed. The binary transformation vector, pPTGFPH, was constructed from the plasmid pCT74, carrying green fluorescent protein (GFP) driven by the ToxA promoter of Pyrenophora tritici-repentis and hygromycin B phosphotransferase (hph) under control of the trpC promoter of from Aspergillus nidulans, and the binary vector pCB403.2, carrying neomycin phosphotransferase (nptII) between the T-DNA borders. Macroconidia of M. fructicola were coincubated with A. tumefaciens strain LBA 4404(pPTGFPH) on media containing acetosyringone for two days. Hygromycin- and G418-resistant M. fructicola transformants were selected while inhibiting A. tumefaciens with cefotaxime. Transformants expressing GFP fluoresced brightly, and were formed with high efficiency and frequency of T-DNA integration frequency. The use of these transformants for in situ studies on stone fruit tissues is discussed.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!