Epigallocatechin Contents Research Articles

Antioxidant Capacity of Black Tea Obtained Using Tyrosinase and Tannase Treatment

Black tea has a lower antioxidant capacity than other teas, such as green tea, white tea, and oolong tea. Tannase and tyrosinase can be used as a treatment to improve the quality of black tea infusion. Tannase has been reported to be an effective way to enhance antioxidant activity in black tea infusion. Meanwhile, tyrosinase could produce higher theaflavin content than thearubigin. Research about Ready-to-Drink (RTD) black tea preparation with the addition of tannase and tyrosinase to fresh tea leaves before pasteurization has not been reported. This study aimed to find a good combination of tannase (1 mg/ml) and tyrosinase (111; 446; 1785 U/ml) to produce high antioxidant activity of RTD black tea. The results showed that higher tyrosinase concentration decreased the antioxidant activity (DPPH and reducing power), epicatechin (EC), epigallocatechin (EGC), and epigallocatechin gallate (EGCG) content yet increased the theaflavin content and theaflavin (TF)/thearubigin (TR) ratio in the tannase-tyrosinase treated black tea. Still, the highest concentration of tyrosinase (1785 U/ml) in tannase-tyrosinase black tea produces higher antioxidant activities, gallic acid, EC, and EGC content than commercial black tea and tyrosinase without tannase-treated black tea. Thus, the combination of tannase (1 mg/ml) and tyrosinase (1785 U/ml) could be the best treatment to produce high-antioxidant black tea.

Correlation between color parameters and bioactive compound content during cocoa seed transformation under controlled process conditions

The quality demanded by consumers in the cocoa sector has led to carrying out the postharvest transformation of cocoa, directing efforts to highlight properties of cocoa beans, such as the content of bioactive compounds, due to its beneficial effects on health, as well as its color, which varies from the typical brown color to the recently developed red-pink hues. This work aims to establish a correlation between the color parameters of a cocoa matrix obtained during the transformation of cocoa seeds under controlled process conditions (temperature, organic acid, and its concentration, and time) and the flavan-3-ols content (catechin, epicatechin, and epigallocatechin), methylxanthines content (theobromine, caffeine), and total phenolic content (TPC) through image analysis of color. The results showed that the content of flavan-3-ols and methylxanthines decreased as the controlled transformation advanced. However, the content of these bioactive compounds is retained by applying mild temperature conditions (30 °C) and low concentrations of organic acid (1 g/L) to transform cocoa seeds. Furthermore, the color parameters respond to changes in the internal pH of the seeds, and the red-pink hues are favored when using high concentrations of organic acid (30 g/L). Based on these findings, it was possible to establish a correlation between epigallocatechin content and four color parameters (a*,b*, hab* and Cab*) through a multiple linear regression model. In this way, color image analysis could be an appropriate alternative to predict the concentration of quality-related compounds in cocoa matrices.

Light control of catechin accumulation is mediated by photosynthetic capacity in tea plant (Camellia sinensis)

BackgroundCatechins are crucial in determining the flavour and health benefits of tea, but it remains unclear that how the light intensity regulates catechins biosynthesis. Therefore, we cultivated tea plants in a phytotron to elucidate the response mechanism of catechins biosynthesis to light intensity changes.ResultsIn the 250 μmol·m− 2·s− 1 treatment, the contents of epigallocatechin, epigallocatechin gallate and total catechins were increased by 98.94, 14.5 and 13.0% respectively, compared with those in the 550 μmol·m− 2·s− 1 treatment. Meanwhile, the photosynthetic capacity was enhanced in the 250 μmol·m− 2·s− 1 treatment, including the electron transport rate, net photosynthetic rate, transpiration rate and expression of related genes (such as CspsbA, CspsbB, CspsbC, CspsbD, CsPsbR and CsGLK1). In contrast, the extremely low or high light intensity decreased the catechins accumulation and photosynthetic capacity of the tea plants.The comprehensive analysis revealed that the response of catechins biosynthesis to the light intensity was mediated by the photosynthetic capacity of the tea plants. Appropriately high light upregulated the expression of genes related to photosynthetic capacity to improve the net photosynthetic rate (Pn), transpiration rate (Tr), and electron transfer rate (ETR), which enhanced the contents of substrates for non-esterified catechins biosynthesis (such as EGC). Meanwhile, these photosynthetic capacity-related genes and gallic acid (GA) biosynthesis-related genes (CsaroB, CsaroDE1, CsaroDE2 and CsaroDE3) co-regulated the response of GA accumulation to light intensity. Eventually, the epigallocatechin gallate content was enhanced by the increased contents of its precursors (EGC and GA) and the upregulation of the CsSCPL gene.ConclusionsIn this study, the catechin content and photosynthetic capacity of tea plants increased under appropriately high light intensities (250 μmol·m− 2·s− 1 and 350 μmol·m− 2·s− 1) but decreased under extremely low or high light intensities (150 μmol·m− 2·s− 1 or 550 μmol·m− 2·s− 1). We found that the control of catechin accumulation by light intensity in tea plants is mediated by the plant photosynthetic capacity. The research provided useful information for improving catechins content and its light-intensity regulation mechanism in tea plant.

Characterization of nitrite degradation by polyphenols in sea buckthorn (Hippophaë rhamnoides L.) by density function theory calculations

The objective of this study was to investigate the nitrite-degrading capacity of polyphenols in sea buckthorn and explore the relationship between structures and degradation capacity with quantum chemistry. The results showed that polyphenols in sea buckthorn had a higher nitrite degrading capacity than other compounds, with the nitrite-degrading rate of 75.9%, the chlorogenic acid, isorhamnetin, luteolin-3′-O-arabinoside, L-epicatechin, isosinensetin, rutin, luteolin-3′-O-beta-D-glucuronide, catechin, quercetin-3′-O-glucoside, epigallocatechin contents changed significantly in the presence of nitrite. The bonding dissociation energy indicated the ΔE of chlorogenic acid for the 7-OH site was 290.2853 kcal/mol, lower than other phenolic monomers, while Mulliken electron density difference of oxygen and hydrogen in corresponding hydroxyl group was larger than other polyphenols, which were in accordance with the higher nitrite degradation. These results indicated that the nitrite degradation rates were closely related to bonding dissociation energy and Mulliken electron density, and could be estimated by the two indicators.

Antioxidant capacity and flavanol composition of seed extracts from a Grenache × Tempranillo population: Effect of sex and color

Wine grapes contain a great number of phenolic compounds, especially flavanols, which are related to organoleptic and health promoting properties. In this study, flavanol content and the relationship with the antioxidant capacity of seed extracts from a Grenache × Tempranillo progeny segregating for color and sex were evaluated. (+)-Catechin, (-)-epicatechin, (-)-epigallocatechin, and adducts of two cis-units were detected in all samples. The progeny presented high flavanol composition variability. Genotypes were clustered into 5 different groups based on monomer content and length of proanthocyanidins. Female genotypes contained more monomers and shorter proanthocyanidins with less galloylated subunits than hermaphrodites. In red grapes, the epigallocatechin content in polymers and the main degree of polymerization were higher than in white grapes. Environmental conditions influenced total flavanol content; there was a greater number of proanthocyanidins in warm and dry weather. Higher antioxidant capacity was observed in extracts with higher monomer content, and shorter, and less galloylated proanthocyanidins. Among monomers, cis-forms presented stronger influence on antioxidant capacity. Knowing the genetic factors and environmental pressures that determine the synthesis of these compounds could help design agricultural practices aimed at obtaining products enriched with healthy compounds.

Antioxidant, antimicrobial, and antiproliferative activity-based comparative study of peel and flesh polyphenols from Actinidia chinensis.

BackgroundKiwifruit (Actinidia chinensis) peel has been always considered as useless because of the harsh taste. To promote the full utilization of kiwifruit resources it is essential to explore the nutritional benefits of kiwifruit peel.ObjectiveOur studies explored the difference in polyphenolic composition and biological activity including antioxidant, antimicrobial, and antiproliferative activity of the flesh and peel of kiwifruit.DesignAntioxidant activity of the extracted polyphenols of the peel and flesh of A. chinensis was checked by 2,2-diphenyl-1-picrylhydrazyl, 2,2’-azino-bis3-ethylbenzothiazoline-6-sulphonic acid (ABTS), hydroxyl ion reduction, and ion chelating ability. Antibacterial activity against Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus and antiproliferative activity against HepG2 was tested in a dose- and time-dependent manner. Liquid chromatography/mass spectrometry (LC/MS) chromatogram of the peel and flesh further differentiated the phenolic acid profile.ResultsThe pericarp of kiwifruit was found to be more abundant in polyphenols and flavonoids than the flesh, with contents of 12.8 mg/g and 2.7 mg/g, respectively. LC/MS analysis revealed that the catachin, quercetin and epigallocatechin content (the main polyphenols in kiwifruit) in the peel was significantly higher than in the flesh (P < 0.05). The antioxidant and antibacterial activity of the peel was significantly higher when compared to the flesh. Moreover, the proliferation of HepG2 cells was time- and dose-dependently inhibited by kiwifruit polyphenols, with IC50 values of 170 μg/mL and 291 μg/mL for peel and flesh polyphenols after 72 h of treatment time, respectively.ConclusionKiwifruit peel, with higher content of phenolics and flavonoids, exerts more potent antioxidant, antibacterial, and anticancer activity than the flesh. Our study provides scientific evidence for the development of kiwifruit, especially peel-based, novel natural products with excellent bioactivity.

Two MYB transcription factors (CsMYB2 and CsMYB26) are involved in flavonoid biosynthesis in tea plant [Camellia sinensis (L.) O. Kuntze

BackgroundFlavonoids are secondary metabolites that play important roles in the entire tea plant life cycle and have potential health-promoting properties. MYB transcription factors (TFs) are considered potentially important regulators of flavonoid biosynthesis in plants. However, the molecular mechanisms by which MYB TFs regulate the flavonoid pathway in tea plant remain unknown.ResultsIn this study, two R2R3-MYB TFs (CsMYB2 and CsMYB26) involved in flavonoid biosynthesis in tea plant were investigated. The genes encoding CsMYB2 and CsMYB26 were cloned from the tea plant cultivar ‘Longjing 43’. Phylogenetic analysis showed that CsMYB2 and CsMYB26 were grouped into the proanthocyanidin biosynthesis-related MYB clade. Multiple sequence alignment revealed that conserved motif 1 in the two MYB factors was related to the bHLH TF. Subcellular localization assays suggested that CsMYB2 localized in the nucleus. Promoter analysis indicated that CsMYB2, CsMYB26 and the related structural genes contain MYB recognition elements. The expression levels of the CsMYB2 and CsMYB26 genes and the structural genes in the flavonoid biosynthesis pathway were determined in leaves from various sites in the two tea plant cultivars ‘Longjing 43’ and ‘Baiye 1 hao’.ConclusionsThe expression levels of these genes were correlated with the accumulated flavonoid content. The results demonstrated that the expression level of CsF3’H may be regulated by CsMYB2 and that CsMYB26 expression is positively correlated with CsLAR expression. The relative transcriptional level of CsMYB26 may be the main reason for the different epigallocatechin contents between the tea plant cultivars ‘Longjing 43’ and ‘Baiye 1 hao’. Our results will serve as a reference for the potential regulatory roles of CsMYB2 and CsMYB26 in flavonoid biosynthesis in tea plant and may also assist biologists in improving tea quality.

Immobilization of Aspergillus ficuum tannase in calcium alginate beads and its application in the treatment of boldo (Peumus boldus) tea

Tannase (tannin acyl hydrolase, E.C. 3.1.1.20) is an enzyme that catalyzes the hydrolysis of ester and depside linkages in hydrolysable tannins such as tannic acid, releasing gallic acid and glucose. It has several commercial applications in food industry, among which are gallic acid production, reduction of tannin content in fruit juices, and preparation of instantaneous tea. In this study we immobilized Aspergillus ficuum tannase in calcium alginate beads and then used it to treat boldo (Peumus boldus) tea. Such a technique allowed entrapping tannase with a 75% efficiency and appreciably increasing its thermal and pH stability compared with the free enzyme. Storage stability and reuse of the immobilized enzyme were very promising, in that about 60% of starting enzyme activity was retained after bead storage for 90 days at 4 °C or after six cycles of use. Boldo tea treatment with immobilized tannase for 120 min at 40 °C led to 31 and 60% removals of tannins and epigallocatechin gallate, an increase of about two orders of magnitude in gallic acid content, 56 and 109% increases in total flavonoids and epigallocatechin contents, a 42.8% increase in antioxidant activity and significant enhancements of tea color, clarity and pH.

The kinetics of oxygen and SO2 consumption by red wines. What do they tell about oxidation mechanisms and about changes in wine composition?

This work seeks to understand the kinetics of O2 and SO2 consumption of air-saturated red wine as a function of its chemical composition, and to describe the chemical changes suffered during the process in relation to the kinetics. Oxygen Consumption Rates (OCRs) are faster with higher copper and epigallocatechin contents and with higher absorbance at 620nm and slower with higher levels of gallic acid and catechin terminal units in tannins. Acetaldehyde Reactive Polyphenols (ARPs) may be key elements determining OCRs. It is confirmed that SO2 is poorly consumed in the first saturation. Phenylalanine, methionine and maybe, cysteine, seem to be consumed instead. A low SO2 consumption is favoured by low levels of SO2, by a low availability of free SO2 caused by a high anthocyanin/tannin ratio, and by a polyphenolic profile poor in epigallocatechin and rich in catechin-rich tannins. Wines consuming SO2 efficiently consume more epigallocatechin, prodelphinidins and procyanidins.

Antibacterial activity of Limonium brasiliense (Baicuru) against multidrug-resistant bacteria using a statistical mixture design

Ethnopharmacological relevanceLimonium brasiliense (Boiss.) Kuntze (Plumbaginaceae) is commonly known as “baicuru” or “guaicuru” and preparations of its dried rhizomes have been popularly used in the treatment of premenstrual syndrome and menstrual disorder, and as an antiseptic in genito-urinary infections. This study evaluated the potential antibacterial activity of rhizome extracts against multidrug–resistant bacterial strains using statistical mixture design. Materials and methodsThe statistical design of four components (water, methanol, acetone, and ethanol) produced 15 different extracts and also a confirmatory experiment, which was performed using water:acetone (3:7, v/v). The crude extracts and their ethyl-acetate fractions were tested against vancomycin–resistant Enterococcus faecium (VREfm), methicillin–resistant Staphylococcus aureus (MRSA) and Klebsiella pneumoniae carbapenemase (KPC)–producing K. pneumoniae, all of which have been implicated in hospital and community–acquired infections. The dry residue, total polyphenol, gallocatechin and epigallocatechin contents of the extracts were also tested and statistical analysis was applied in order to define the fit models to predict the result of each parameter for any mixture of components. The principal component and hierarchical clustering analyses (PCA and HCA) of chromatographic data, as well as mass spectrometry (MS) analysis were performanced to determine the main compounds present in the extracts. ResultsThe Gram-positive bacteria were susceptible to inhibition of bacterial growth, in special the ethyl-acetate fraction of ternary extracts from water:acetone:ethanol and methanol:acetone:ethanol against, respectively, VREfm (MIC=19µg/mL) and MRSA (MIC=39µg/mL). On the other hand, moderate activity of the ethyl-acetate fractions from primary (except water), secondary and ternary extracts (MIC=625µg/mL) was noted against KPC. The quadratic and special cubic models were significant for polyphenols and gallocatechin contents, respectively. Fit models to dry residue and epigallocatechin contents were not possible. PCA and HCA of the chromatographic fingerprints were disturbed by displacement retention time of some peaks, but the ultraviolet spectra indicated the homogeneous presence of flavan-3-ols characteristic of tannins. The MS confirmed the presence of gallic acid, gallocatechin, and epigallocatechin in extracts, and suggested the presence of monomers and dimers of B- and A-type prodelphinidins gallate, as well as a methyl gallate. ConclusionOur results showed the antibacterial potential of L. brasiliense extracts against multidrug–resistant Gram-positive bacteria, such as VREfm and MRSA. The statistical design was a important tool to evaluate the biological activity by optimized form. The presence of some phenolic compounds was also demonstrated in extracts.

Comparison of antioxidant activities among four kinds of Japanese traditional fermented tea.

Antioxidant activities of four kinds of Japanese traditional fermented tea, Gishi‐cha, Ishizuchi‐kurocha, Awa‐bancha, and Batabatacha, were compared. Antioxidant activity was evaluated by three parameters: copper ion reduction ability, radical trapping ability, and oxygen consumption rate. Processes of fermentation of these fermented teas are different. Goichi‐cha and Ishizuchi‐kurocha are produced by a two‐stage fermentation process, aerobic fermentation and subsequent anaerobic fermentation. Awa‐bancha is produced by anaerobic fermentation. And batabata‐cha is produced by aerobic fermentation. Additionally, unfermented green tea was also employed as control. These tea leaves were extracted by boiling water and measured antioxidant activities. And concentrations of caffeine and catechins were measured in green tea and in the four kinds of fermented tea: Ishizuchi‐kurocha, Goishi‐cha, Awa‐Bancha, and Batabata‐cha. Concentrations of caffeine and catechins were lower in the fermented teas than in green tea. Among the fermented teas, epigallocatechin content was the highest in Ishizuchi‐kurocha, whereas Batabata‐cha hardly contained any epigallocatechin. Goichi‐cha, Ishizuchi‐kurocha, and Awa‐bancha showed antioxidative activity regardless of measurement method. Batabatacha had hardly any antioxidative activity. Among the fermented teas, Ishizuchi‐kurocha had the strongest antioxidant activity. The antioxidative activities of green tea and the four kinds of fermented tea were significantly different among each other (p < .01). Implication of this study is as follows: although contents of catechins were lower than that of green tea, three kinds of fermented tea showed antioxidative activity comparable to green tea. The results suggest that anaerobic fermentation process is beneficial at least for antioxidative activity.

Pharmacognostic evaluation, and development and validation of a HPLC-DAD technique for gallocatechin and epigallocatechin in rhizomes from Limonium brasiliense

Limonium brasiliense (Boiss.) Kuntze, Plumbaginaceae, is a plant from the southern coast of Brazilian that is used for the treatment of premenstrual syndrome, menstrual disorders and genito-urinary infections. The aim of the present study was to determine the quality control parameters for rhizomes collected during different periods by pharmacopoeial and non-pharmacopoeial methods, and to develop and validate a HPLC-DAD method for quantitative control of marker substances. The measured parameters were: granulometric analysis (d50=0.21–0.48mm), loss on drying (11.1–12.4%), total ash (4.9–5.7%), dry residue by extraction with acetone:water (7:3, v/v) (30.6–39.5%), total polyphenol content (8.5–15.8%), and chromatographic fingerprint by HPLC and TLC. Besides, the acetone:water (7:3, v/v) extraction solvent in combination with a turbo-extractor, yielded the crude extract with a significant increase in tannins (F4,20=37.0, p<0.001). The antioxidant potential of the crude acetone:water (7:3, v/v) extract, as well as the ethyl acetate and water fractions obtained after the partition process was evaluated by DPPH and the results were, respectively: IC50 6.87, 5.91, and 6.92μg/ml. The validation parameters for the HPLC-DAD method showed adequate specificity, precision and accuracy. The gallo- and epigallocatechin contents were, respectively, 0.8–2.7% and 1.2–2.2%. These data contribute to analysis of the pharmacognostic quality control of the commonly used part from this species.

Quality evaluation of green tea leaf cultured under artificial light condition using gas chromatography/mass spectrometry

For an experimental model to elucidate the relationship between light quality during plant culture conditions and plant quality of crops or vegetables, we cultured tea plants (Camellia sinensis) and analyzed their leaves as tea material. First, metabolic profiling of teas from a tea contest in Japan was performed with gas chromatography/mass spectrometry (GC/MS), and then a ranking predictive model was made which predicted tea rankings from their metabolite profile. Additionally, the importance of some compounds (glutamine, glutamic acid, oxalic acid, epigallocatechin, phosphoric acid, and inositol) was elucidated for measurement of the quality of tea leaf. Subsequently, tea plants were cultured in artificial conditions to control these compounds. From the result of prediction by the ranking predictive model, the tea sample supplemented with ultraviolet-A (315-399nm) showed the highest ranking. The improvement in quality was thought to come from the high amino-acid and decreased epigallocatechin content in tea leaves. The current study shows the use and value of metabolic profiling in the field of high-quality crops and vegetables production that has been conventionally evaluated by human sensory analysis. Metabolic profiling enables us to form hypothesis to understand and develop high quality plant cultured under artificial condition.

Identification of Phenolic Compounds from Seed Coats of Differently Colored European Varieties of Pea (Pisum sativum L.) and Characterization of Their Antioxidant and In Vitro Anticancer Activities

ABSTRACTTo date little has been done on identification of major phenolic compounds responsible for anticancer and antioxidant properties of pea (Pisum sativum L.) seed coat extracts. In the present study, phenolic profile of the seed coat extracts from 10 differently colored European varieties has been determined using ultrahigh-performance liquid chromatography–linear trap quadrupole orbitrap mass spectrometer technique. Extracts of dark colored varieties with high total phenolic content (up to 46.56 mg GAE/g) exhibited strong antioxidant activities (measured by 2,2-diphenyl-1-picrylhydrazyl or DPPH assay, and ferric ion reducing and ferrous ion chelating capacity assays) which could be attributed to presence of gallic acid, epigallocatechin, naringenin, and apigenin. The aqueous extracts of dark colored varieties exert concentration-dependent cytotoxic effects on all tested malignant cell lines (human colon adenocarcinoma LS174, human breast carcinoma MDA-MB-453, human lung carcinoma A594, and myelogenous leukemia K562). Correlation analysis revealed that intensities of cytotoxic activity of the extracts strongly correlated with contents of epigallocatechin and luteolin. Cell cycle analysis on LS174 cells in the presence of caspase-3 inhibitor points out that extracts may activate other cell death modalities besides caspase-3-dependent apoptosis. The study provides evidence that seed coat extracts of dark colored pea varieties might be used as potential cancer-chemopreventive and complementary agents in cancer therapy.

Effect of irrigation regime on perceived astringency and proanthocyanidin composition of skins and seeds of Vitis vinifera L. cv. Syrah grapes under semiarid conditions

In this work, the effect of water availability on astringency of seed and skin extracts of Vitis vinifera cv. Syrah berries under the typical semiarid conditions of Greece was investigated. Moreover, astringency was assessed in relation to proanthocyanidin composition. For this purpose, three irrigation treatments were applied starting at berry set through harvest of 2011 and 2012: full irrigation (FI) at 100% of crop evapotranspiration, deficit irrigation (DI) at 50% and non-irrigated (NI). FI skin and seed extracts were perceived significantly more astringent than NI. Total phenol, total tannin, (+)-catechin, (−)-epicatechin and procyanidin C1 concentrations were positively correlated with astringency. Positive correlations were also obtained among astringency and average degree of polymerization and proportion of the extension units of shorter tannins while astringency of larger tannins was correlated with the proportion of terminal units. On the contrary, total anthocyanin and epigallocatechin contents were negatively correlated with astringency.

Comparative study of catechin compositions in five Japanese persimmons ( Diospyros kaki)

In order to study catechin compositions in five Japanese persimmons: Hiratanenashi (HN), Tone-wase (TW), Ishibashi-wase (IW), Maekawa-jiro (MJ) and Matsumoto-wase-fuyu (MF), the contents of epigallocatechin (EGC), catechin (C), and epicatechin (EC) were determined. Total phenolic contents were also determined for the studies of the catechin composition. Identification and quantification of the catechins were performed by HPLC. The EGC contents in three astringent persimmons (HN, TW and IW) were higher than those of two non-astringent persimmons (MJ and MF). The EGC content in HN (astringent) was the highest among the five Japanese persimmons. The EGC content in MF (non-astringent) was the lowest among the five Japanese persimmons. Therefore, astringent persimmons may be better sources of the natural antioxidant, EGC, than non-astringent persimmons, and HN (astringent) may be the best source of EGC among the five Japanese persimmons. This is the first comparative study of catechin compositions in five Japanese persimmons.

The mouth‐feel properties of grape and apple proanthocyanidins in a wine‐like medium

AbstractA range of structurally defined apple and grape proanthocyanidins was isolated in sufficient amount to carry out a formal sensory descriptive analysis study. Purified proanthocyanidin fractions differed in chain length, degree of galloylation and epigallocatechin content. Astringency attributes of the preparations in a model wine medium were rated while the fractions were held in the mouth and after expectoration. The degree of polymerization appeared to be the variable that discriminated among the fractions to the greatest extent. It affected both the overall astringency and the different individual astringency attributes, with increased ‘drying’, ‘chalky’, ‘adhesive’ and ‘pucker’ characters correlating with increasing chain length. A rougher sensation with increased ‘coarseness’, ‘drying’ and ‘chalkiness’ correlated with an increased degree of galloylation of the fractions. The presence of epigallocatechin units in the proanthocyanidin tended to lower the ‘coarse’ perception. Copyright © 2003 Society of Chemical Industry