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Phenolic Composition (phenolic + composition)
Selected AbstractsPhenolic Composition of Authentic Pineapple JuiceJOURNAL OF FOOD SCIENCE, Issue 1 2002L. Wen ABSTRACT: The phenolic composition of authentic pineapple juice concentrate was analyzed by HPLC. Nine major peaks accounting for 70% of total peak area were characterized and their concentrations measured in 54 commercial samples. Means and standard deviations were as follows (mg/100 mL single-strength juice, normalized to 12.8 °Brix): tyrosine, 3.6(1.4); serotonin, 1.8(0.8); dimethylhydroxylfuranone, 1.4(0.7); dimethylhydroxylfuranone ,-glucoside, 6.2(3.0); tryptophan, 2.2(0.9); S-sinapyl-L-cysteine, 1.1(0.6); N-,-L-glutamyl-S-sinapyl-L-cysteine, 2.3(1.1); S-sinapyl glutathione, 5.4(1.4); and a p -coumaric acid-like phenolic compound (calculated as p -coumaric acid), 0.5(0.4). This information will be useful for evaluation of authenticity and quality. [source] Effect of location on virgin olive oils of the two main Tunisian olive cultivarsEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 9 2009Mokhtar Guerfel Abstract The olive oil content in phenolic compounds depends on the variety of the fruit used for its extraction as well as on the predominant climate conditions in the tree cultivation area. Here, we report on the characterization of virgin olive oil samples obtained from fruits of the main Tunisian olive cultivars Chemlali and Chétoui, grown in three different Tunisian locations, Zaghouan (North), Sousse (Center) and Sfax (South). Chétoui olive oil samples obtained from fruits of olive trees cultivated in Zaghouan and Chemlali olive oil samples obtained from fruits of olive trees cultivated in Sousse were found to have a higher mean total phenol content (1004 and 330,mg/kg, respectively). Olive oil samples obtained from fruits of both cultivars had different phenolic profiles and a higher content in 3,4-DHPEA-EDA when the olive trees were cultivated in Zaghouan. Both olive cultivars were found to have different responses to environmental conditions. Chétoui olive oil showed decreased oxidative stability when the fruits were obtained from olive trees cultivated in the center of Tunisia (34.8,h) and in Sfax (16.17,h). Furthermore, statistical data showed that the phenolic composition and oxidative stability of Chétoui olive oil varied more by location than those of Chemlali olive oils. [source] Ozone exposure over two growing seasons alters root-to-shoot ratio and chemical composition of birch (Betula pendula Roth)GLOBAL CHANGE BIOLOGY, Issue 10 2003K. Yamaji Abstract Physiological and chemical responses of 17 birch (Betula pendula Roth) clones to 1.5,1.7 × ambient ozone were studied in an open-field experiment over two growing seasons. The saplings were studied for growth, foliar visible injuries, net photosynthesis, stomatal conductance, and chlorophyll, carotenoid, Rubisco, total soluble protein, macronutrient and phenolic concentrations in leaves. Elevated ozone resulted in growth enhancement, changes in shoot-to-root (s/r) ratio, visible foliar injuries, reduced stomatal conductance, lower late-season net photosynthesis, foliar nutrient imbalance, changes in phenolic composition, and reductions in pigment, Rubisco and soluble protein contents indicating accelerated leaf senescence. Majority of clones responded to ozone by changing C allocation towards roots, by stomatal closure (reduced ozone uptake), and by investment in low-cost foliar antioxidants to avoid and tolerate ozone stress. A third of clones, showing increased s/r ratio, relied on inducible efficient high-cost antioxidants, and enhanced leaf production to compensate ozone-caused decline in leaf-level net photosynthesis. However, the best ozone tolerance was found in two s/r ratio-unaffected clones showing a high constitutive amount of total phenolics, investment in low-cost antioxidants and N distribution to leaves, and lower stomatal conductance under ozone stress. The results highlight the importance of phenolic compounds in ozone defence mechanisms in the birch population. Depending on the genotype, ozone detoxification was improved by an increase in either efficient high-cost or less efficient low-cost antioxidative phenolics, with close connections to whole-plant physiology. [source] Evaluation of the extraction efficiency for polyphenol extracts from by-products of green kiwifruit juicingINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 12 2009Dongxiao Sun-Waterhouse Summary The health benefits of fruits are attributable in part to their bioactive components such as phenolics and pectic polysaccharides. By-products derived from kiwifruit processing can be a good source of such bioactive compounds. Extracts were produced using different concentrations of ethanol in water (0%, 30%, 50%, 74% and 96% v/v) from by-products (skin, residue and pulp) of the green-fleshed kiwifruit (Actinidia deliciosa,Hayward') juicing process. The amounts of phenolic compounds and uronic acid (UA) as well as the phenolic composition in each extract were determined. Results show that different by-products contained different concentrations of phenolics and pectic polysaccharides. Based on total phenolic contents, 96% v/v ethanol appeared to be the best extraction medium. The 30% or 74% ethanolic dilution was the second best medium for phenolic extraction from skin and pulp/residue, respectively. Water was a good medium for extracting satisfactory quantities of phenolics as well as the highest concentration of pectic polysaccharides. Phenolic profiling by high-performance liquid chromatography (HPLC) was used to detect individual phenolic compounds in an extract. Results using HPLC showed that alkali pre-treatment has improved the extraction efficiency of phenolics as a function of alkali concentration, fruit tissue type, extraction media, by-product preparation method, and class of polyphenols. As a result more efficient methods for both extraction and characterisation of polyphenols could be evaluated. [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] Modifications of mechanical characteristics and phenolic composition in berry skins and seeds of Mondeuse winegrapes throughout the on-vine drying process,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2009Luca Rolle Abstract BACKGROUND: Among several common drying systems used in the enological sector the dry-on-vine (DOV) method assumes particular importance because famous wines such as Sauternes, Tokay and Ice Wines are produced by grapes dried using this system. Knowledge about trends in mechanical properties and phenolic composition during on-vine grape drying is scarce. The objective of this current study is therefore to increase the knowledge on these aspects. RESULTS: Berry skin break energy (+0.10 N) and berry skin thickness (+69 µm) values increase during grape dehydration, while the peduncle detach force decreases (,0.86 N). Large reductions in the anthocyanin content have also been observed (,40%), but their profile does not show significant changes. Seed hardness (,7.10 N, ,1.40 mJ) decreases during the withering, and higher seed springiness has been observed. Seed proanthocyanidins (+2050 mg kg berry,1) and flavanols vanillin assay (+670 mg kg berry,1) increase progressively throughout the withering. In contrast, a distinct lowering of these substances in the skins was noted. CONCLUSION: Many modifications in the chemical,physical characteristics of berries of Mondeuse winegrapes throughout the DOV process were found. The mechanical characteristics of grapes, in particular the peduncle detachment force, are important parameters in assessing their suitability for the drying-on-plant process. Copyright © 2009 Society of Chemical Industry [source] Use of a lactic acid bacteria starter culture during green olive (Olea europaea L cv Ascolana tenera) processingJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2005Vincenzo Marsilio Abstract Among the Italian olive germplasm, ,Ascolana tenera' is one of the best varieties for table olive production. This research addressed the impact of different processing types (Greek-style and Spanish-style) on the fermentation and phenolic composition of olive fruit. In particular, the effects of a lactic acid bacteria (LAB) starter culture on the fermentation of naturally green olives processed according to the traditional Greek method were studied. Results revealed that Spanish-style processing produced a dramatic loss of total phenolics, while natural olive processing favoured a higher retention of biophenols. Oleoside 11-methylester, a phenol-related compound, and hydroxytyrosol, tyrosol, vanillic acid, 3,4-dihydroxyphenylglycol, oleuropein and oleuropein aglycons, as the main phenols, were detected in olive fruit. More interestingly, this research indicated that inoculation with LAB affected the pH, total acidity, microbial profile and palatability of olives. Olives fermented with the LAB starter culture were perceived by panellists to be less bitter and more aromatic than those spontaneously fermented. Thus the use of LAB inoculants during olive fermentation could be applied with the currently available technology. Copyright © 2005 Society of Chemical Industry [source] Sherry wine vinegar: physicochemical changes during the acetification processJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2001L Morales Abstract The quality of a wine vinegar is determined by the raw wine substrate and the acetification process employed in its production. Attempts to characterise vinegars have been based on these two features, along with variables such as total extract, glycerol, organic acids, volatile compounds and phenolic composition. When the final products are analysed, it is difficult to evaluate to what extent quality differences are due to the raw material or to differences in production methods, so it is necessary to determine the influence of each feature separately. The present work focuses on monitoring physicochemical changes during the acetification of sherry wine by submerged culture. ANOVA showed significant differences for ethanol, acetic and lactic acids and some volatile compounds (methanol, 1-propanol, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, acetoin, acetaldehyde, ethyl acetate and ethyl lactate). However, no statistical changes were found for phenolic compounds during acetification. The phenolic composition of the final product was determined by the substrate employed. In addition, the influence of cycle duration on the chemical composition was studied; the only compound affected by this factor was 2-methyl-1-butanol. © 2001 Society of Chemical Industry [source] Mouthfeel of white wines made with and without pomace contact and added anthocyaninsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2009A. OBERHOLSTER Abstract Background and Aims:, The contribution of anthocyanins or tannin,anthocyanin reaction products to the mouthfeel properties of wines prepared from both red and white fruit with and without pomace contact and anthocyanin addition was investigated. Methods and Results:, A trained sensory panel rated mouthfeel and taste attributes in wines after 6 months of bottle storage and phenolic measures were obtained. A white wine made in the same manner to how a red wine is made did not exhibit the same mouthfeel sensory attributes of a red wine: it was lower in viscosity, less particulate in nature and lower in intensity for the astringency descriptors fine emery, dry and grippy. Conclusions:, It was found that differences in ratings of mouthfeel attributes could not be related closely to phenolic composition or structure. This study has shown that the presence of anthocyanins during fermentation increases the intensity of astringency attributes. Significance of the Study:, Using the mouthfeel wheel, the differences between a white wine made like a red wine and a red wine could be quantified. It was also shown that the presence of anthocyanins in red wine can explain the differences perceived between the mouthfeel properties of a white and a red wine. [source] Relationships between wine phenolic composition and wine sensory properties for Cabernet Sauvignon (Vitis vinifera L.)AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 3 2008H.E. HOLT Abstract Background and Aims:, Winemakers from a commercial winery observed sensory differences in Cabernet Sauvignon wines made from three pruning treatments in a single vineyard, particularly in mouthfeel characteristics. This study examined the relationships between wine composition and wine sensory characteristics, then related these to berry weight and composition and wine quality scores. Methods and Results:, Cabernet Sauvignon from three pruning treatments , Machine, Cane and Spur , was harvested at commercial harvest date, and replicate wines were made from each for three vintages. The composition of the wines from all three pruning systems was generally similar. Differences in individual descriptive attributes did not separate the wines from the three treatments, or across vintages, despite differences in overall quality scores. Principal component analysis (PCA) could separate the wines by pruning and by vintage using wine composition or sensory parameters. Higher concentrations of anthocyanins, tannins and phenolics in berries did not always result in higher concentrations in wines. Conclusions:, In this study, higher wine tannin or wine phenolic concentrations did not result in higher wine astringency, and wine colour measures and phenolic composition were not good indicators of individual wine sensory properties or wine quality. Wine composition was not necessarily directly influenced by berry composition. Significance of the Study:, Few studies focus on the berry to wine to sensory continuum, particularly over more than one vintage or in a commercial context. This study highlighted how complex the relationships among berries, wine sensory properties and wine quality can be, particularly within a single vineyard. [source] In vivo Skin Irritation Potential of a Castanea sativa (Chestnut) Leaf Extract, a Putative Natural Antioxidant for Topical ApplicationBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2008Isabel F. Almeida However, natural products can provoke skin adverse effects, such as allergic and irritant contact dermatitis. Skin irritation potential of Castanea sativa leaf ethanol:water (7:3) extract was investigated by performing an in vivo patch test in 20 volunteers. Before performing the irritation test, the selection of the solvent and extraction method was guided by the 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging test and polyphenols extraction (measured by the Folin Ciocalteu assay). Iron-chelating activity and the phenolic composition (high performance liquid chromatography/diode array detection) were evaluated for the extract obtained under optimized conditions. The extraction method adopted consisted in 5 short extractions (10 min.) with ethanol:water (7:3), performed at 40°. The IC50 found for the iron chelation and DPPH scavenging assays were 132.94 ± 9.72 and 12.58 ± 0.54 µg/ml (mean ± S.E.M.), respectively. The total phenolic content was found to be 283.8 ± 8.74 mg GAE/g extract (mean ± S.E.M.). Five phenolic compounds were identified in the extract, namely, chlorogenic acid, ellagic acid, rutin, isoquercitrin and hyperoside. The patch test carried out showed that, with respect to irritant effects, this extract can be regarded as safe for topical application. [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] | |||||||||||||