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Gallic Acid Equivalent (gallic + acid_equivalent)
Selected AbstractsPolyphenolic profile and antioxidant activity of five apple cultivars grown under organic and conventional agricultural practicesINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2009Athanasios Valavanidis Summary The polyphenols and total antioxidant activities of five apple cultivars, grown by organic and conventional agricultural methods in neighbouring farms, were determined and compared. Total polyphenols in the whole fruit and in the peel were determined by the Folin-Ciocalteu method, and the total antioxidant activity was determined by three established methods, diphenyl picrylhydrazyl (DPPH), azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and ferric reducing/antioxidant power (FRAP). Polyphenolic content for the whole fruit was in the range of 80,196 and for the peel 165,400 (mg Gallic Acid Equivalent (GAE)/100 g fresh weight) for both types of agricultural practices. Antioxidant activities of fruit extracts were also relatively similar and well correlated to their polyphenolic content. High-performance liquid chromatography (HPLC) analysis of the most important polyphenolics (chlorogenic acid, catechin, epicatechin, procyanidin B1 and B2, cyaniding 3-galactoside, phloridzin, quercetin 3-galactoside and quercetin 3-arabinoside) also showed that concentrations do not differentiate significantly between the organic and conventional apples. Statistical significance of differences in antioxidant activities among the same cultivars was relatively small (flesh + peel or peel only) for both types of apples. These results indicate that organic apples do not present higher antioxidant or nutritional value compared with conventionally grown ones, as far as polyphenolic content and total antioxidant activities are concerned. [source] Production of Garcinia wine: changes in biochemical parameters, organic acids and free sugars during fermentation of Garcinia mustINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2010Amit Kumar Rai Summary Garcinia wine was prepared by fermentation of ameliorated must of Garcinia xanthochymus using Saccharomyces cerevisiae. The present studies focused on changes in biochemical parameters (brix, pH, aldehydes, esters and alcohols), organic acids (reduction of oxalic acid), free sugars and antioxidant activities on fermentation of Garcinia must. The wine had higher amount of residual sugars contributing to the calorific value. The aldehydes and esters content in the final wine were 0.034% and 0.26%, respectively. There was reduction of citric acid and oxalic acid (antinutritional factor) and synthesis of aspartic acid and glutamic acid. Garcinia beverage was accepted on sensory analysis with high score for desirable attributes and overall quality with alcohol content of 6.1%. There was increase in total phenolics (0.039% gallic acid equivalent) and reducing power on fermentation but decrease in 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. [source] ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY OF DIFFERENT FLORAL ORIGIN HONEYS FROM TURKIYEJOURNAL OF FOOD BIOCHEMISTRY, Issue 2010ESRA ULUSOY ABSTRACT The bioactivities of phenolic extracts of nine Turkish honeys from different floral sources were investigated. The antioxidant properties of the extracts were assessed by ferric reducing/antioxidant power (FRAP) assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and cupric reducing antioxidant capacity (CUPRAC) assay. The total phenolic contents measured by Folin,Ciocalteau method varied from 66 to 223 mg/g extract as gallic acid equivalent. The antioxidant activities found with CUPRAC, expressed as trolox equivalent antioxidant capacity, ranged from 124.8 to 532 µmol/g, those determined with DPPH· expressed as IC50 ranged from 84 to 296 µg/mL, and those determined with FRAP expressed as trolox equivalent were in 33,166 µmol/g range. The antioxidant activities showed a marked correlation with total phenolics. In the antimicrobial tests using six bacteria and a yeast, Escherichia coli was moderately sensitive to each extract. There was no correlation between antimicrobial activity and total phenolic contents. PRACTICAL APPLICATIONS Honey has functional properties and promotes human health, and such properties depend largely on the floral source. Although studies on screening the antimicrobial and antioxidant activity of raw honey samples have been done densely, studies on phenolic compounds of honey are very limited. The present study demonstrates that honey phenolic compounds are partially responsible for honey antioxidant activity, displaying the relevance of honey as both healthy foodstuff and source of antioxidant. [source] Essential oils of Origanum vulgare L. subsp. glandulosum (Desf.) Ietswaart from Tunisia: chemical composition and antioxidant activityJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2010Kaouther Mechergui Abstract BACKGROUND: Characterisation of the essential oils from O. glandulosum collected in three locations of Tunisia, chemical composition and the evaluation of their antioxidant activities were carried out. RESULTS: The essential oils from Origanum vulgare L. subsp. glandulosum (Desf.) Ietswaart collected from three localities of north Tunisia,Krib, Bargou and Nefza,were obtained in yields of 2.5, 3.0 and 4.6% (v/w), respectively. The essential oils were analysed by GC and GC/MS and assayed for their total phenolics content, by the Folin,Ciocalteu method, and antioxidant effectiveness, using the 2,2-diphenyl-1-picrylhydrazil (DPPH) radical scavenging assay. The main components of these essential oils, from Nefza, Bargou and Krib, were p -cymene (36%, 40% and 46%), thymol (32%, 39% and 18%), ,-terpinene (24%, 12% and 16%) and carvacrol (2%, 2% and 15%), respectively). The ability to scavenge the DPPH radicals, expressed by IC50, ranged from 59 to 80 mg L,1. The total phenolic content, expressed in gallic acid equivalent (GAE) g kg,1 dry weight, varied from 9.37 to 17.70 g kg,1 dw. CONCLUSIONS: A correlation was identified between the total phenolic content of the essential oils and DPPH radical scavenger capacity. The occurrence of a p -cymene chemotype of O. glandulosum in the northern region of Tunisia is demonstrated. Copyright © 2010 Society of Chemical Industry [source] Antioxidant and antimicrobial activities of Polygonum cognatum Meissn extractsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2003Ali Y Abstract The antioxidant activities, reducing powers, 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical-scavenging activities, total phenolic compound contents and antimicrobial activities of ether, ethanol and hot water extracts of Polygonum cognatum Meissn were studied in vitro. The highest antioxidant activity was found in the water extract. However, there were no statistically significant differences among 15,µg,ml,1 extract-containing samples in linoleic acid emulsion (0.02,M, pH 7.0) during 120,h of incubation (P,>,0.05). The reducing power of the water extract was the highest, but its reducing power was markedly lower than that of ascorbic acid. The highest DPPH radical-scavenging activity was found in the water extract, with 50% DPPH radical scavenging at a concentration of 100,µg,ml,1 dried water extract, while at the same concentration of dried ethanol extract the value was 12%. Surprisingly, no DPPH radical-scavenging activity was observed in the ether extract. The concentrations of phenolic compounds found were 0.48, 0.50 and 0.01,µg,ml,1 gallic acid equivalent in 10,µg,ml,1 water, ethanol and ether extracts respectively. The ether and ethanol extracts showed antimicrobial activity against Staphylococcus aureus and Bacillus subtilis. The water extract did not show antimicrobial activity against the studied micro-organisms. © 2002 Society of Chemical Industry [source] Antioxidant activities of organic grape, pomace, juice, must, wine and their correlation with phenolic contentINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2005Hatice K. Y Summary The highest values of antioxidant activity (AOA), inhibition of low-density lipoproteins (LDL-diene, LDL-MDA) and total phenols were determined in pomace (82.30 and 82.60%), grapes (68.91%) and must [2750 mg L,1 gallic acid equivalents (GAE)], respectively. For all parameters (AOA, iLDL-diene, iLDL-MDA, total phenols) the highest values were obtained in Cabernet Sauvignon and Merlot grape varieties. Positive correlations were determined between AOA and iLDL-diene (r = 0.809); AOA and total phenols (r = 0.528); total phenols and iLDL-diene (r = 0.451) with significance of P < 0.005. The results of principal component analysis demonstrated that the location of iLDL-diene and AOA is the same for pomace, must and red wines. The total phenols are found in the same place in red wines, red grapes, pomace and must. The results emphasize the importance of must, pomace and red wine for inhibiting LDL-oxidation. [source] Ascorbic acid improves the antioxidant activity of European grape juices by improving the juices' ability to inhibit lipid peroxidation of human LDL in vitroINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2001Anne-Katrine Landbo Antioxidant activities of red and white European grape juices towards copper induced lipid oxidation of human low-density lipoproteins (LDL) were examined in vitro. LDL lipid peroxidation was assessed spectrophotometrically by monitoring the development of conjugated lipid hydroperoxides at 234 nm. Red grape juice concentrate inhibited lipid peroxidation of LDL by prolonging the lag phase by 2.7 times relative to a control when evaluated at a total phenolic concentration of 10 ,M gallic acid equivalents (GAE). Both red grape juices tested blocked lipid peroxidation of LDL at 20 ,M GAE. White grape juice exerted prooxidant activity at 5,20 ,M GAE. The antioxidant activity, inhibition of lipid peroxidation of LDL in vitro, was correlated with the juices' levels of total phenols (r > 0.98, P < 0.01), anthocyanins (r > 0.99, P < 0.01), flavan-3-ols (r > 0.97, P < 0.05), and hydroxybenzoates (r > 0.96, P < 0.05) when the phenolic composition of each grape juices was analysed by HPLC. 5 ,M ascorbic acid alone did not exert antioxidant activity towards LDL, but combinations of 5 ,M ascorbic acid with 5 ,M GAE juice phenols eliminated the prooxidant activity of white grape juice, and significantly improved the antioxidant activities of red grape juices. [source] In vitro antioxidant studies and free radical reactions of triphala, an ayurvedic formulation and its constituentsPHYTOTHERAPY RESEARCH, Issue 7 2005G. H. Naik Abstract The aqueous extract of the fruits of Emblica officinalis (T1), Terminalia chebula (T2) and Terminalia belerica (T3) and their equiproportional mixture triphala were evaluated for their in vitro antioxidant activity. , -Radiation induced strand break formation in plasmid DNA (pBR322) was effectively inhibited by triphala and its constituents in the concentration range 25,200 µg/mL with a percentage inhibition of T1 (30%,83%), T2 (21%,71%), T3 (8%,58%) and triphala (17%,63%). They also inhibited radiation induced lipid peroxidation in rat liver microsomes effectively with IC50 values less than 15 µg/mL. The extracts were found to possess the ability to scavenge free radicals such as DPPH and superoxide. As the phenolic compounds present in these extracts are mostly responsible for their radical scavenging activity, the total phenolic contents present in these extracts were determined and expressed in terms of gallic acid equivalents and were found to vary from 33% to 44%. These studies revealed that all three constituents of triphala are active and they exhibit slightly different activities under different conditions. T1 shows greater efficiency in lipid peroxidation and plasmid DNA assay, while T2 has greater radical scavenging activity. Thus their mixture, triphala, is expected to be more efficient due to the combined activity of the individual components. Copyright © 2005 John Wiley & Sons, Ltd. [source] Oak leaf extract as topical antioxidant: Free radical scavenging and iron chelating activities and in vivo skin irritation potentialBIOFACTORS, Issue 4 2008Isabel F. Almeida Abstract The topical application of antioxidants may be beneficial for the protection of the skin against UV damage. An extract of Quercus robur leaves was prepared and evaluated considering its putative application as topical antioxidant. The solvent and extractive method selection was monitored by 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging activity and polyphenols extraction (measured by the Folin Ciocalteu assay). Iron chelating activity and the phenolic composition (HPLC/DAD) were assessed on the extract obtained under optimized conditions. Skin irritation potential was investigated by performing an in vivo patch test in 19 volunteers. The extraction solvent which resulted in the highest activity was ethanol:water (4:6) and thus it was selected for further preparation of this extract. The IC50a for the iron chelation and DPPH scavenging assays were 153.8 ± 26.3 ,g.mL,1 and 7.53 ± 0.71 ,g.mL,1 (mean ± SD), respectively. The total phenolic content was found to be 346.3 ± 6.7 mg gallic acid equivalents (GAE)/g extract (mean ± SD). Three phenolic compounds were identified in the extract namely: ellagic acid, rutin and hyperoside. The major identified component was ellagic acid. The patch test carried out showed that the extract can be regarded as safe for topical application. [source] | ||||||||||