Black Tea Liquor Research Articles

Revolutionizing Sustainable Fashion: Jute–Mycelium Vegan Leather Reinforced with Polyhydroxyalkanoate Biopolymer Crosslinking from Novel Bacteria

Vegan leather derived from mushroom mycelium is a revolutionary technology that addresses the issues raised by bovine and synthetic leather. Jute–mycelium-based vegan leather was constructed using hessian jute fabric, natural rubber solution, and extracted polyhydroxyalkanoate (PHA) biopolymer from Bacillus subtilis strain FPP-K isolated from fermented herbal black tea liquor waste. The bacterial strain was confirmed using 16S rRNA genomic sequencing. The structural characteristics of sustainable mycelium vegan leather were identified using FTIR, SEM, and TGA methods. To address the functional features of the developed vegan leather, solubility, swelling degree, WVP, WCA, and mechanical strength were also evaluated. Mycelium networking was further validated by micromorphological examination (SEM) of the leather sample’s cross-sectional area. Jute–mycelium leather demonstrated a tensile strength of 8.62 MPa and a % elongation of 8.34, which were significantly greater than the control sample. Vegan leather displayed a strong peak in the O ═ H group of carbohydrates in the examination of chemical bonds. A high-frequency infrared wavelength of 1,462 cm−1 revealed the amide group of protein due to the presence of mycelium, while the absorption peak at 1,703 cm−1 in leather indicated the crosslinking of PHA. Moreover, the TGA study finalized the thermal stability of leather. The enhanced hydrophobicity and reduced swelling degree and solubility also endorsed the water resistance properties of the leather. The results of the investigation substantiated the potential properties of mycelium vegan leather as animal- and environment-free leather.

Effect of Tea Infusion Strength on Equivalent Circuit Parameters of Multielectrode Voltammetric Sensor System

Analysis of voltammetric response obtained from black tea liquor samples has been used extensively in research to evaluate tea quality. The recent system identification-based quality estimation method of black tea uses the equivalent circuit parameters of the voltammetric system. This work reports the analysis of these equivalent circuit parameters of a multielectrode voltammetric system in correlation with the change in concentration of black tea liquor. In this work, the experimental input–output data obtained using the voltammetric analysis of tea liquor is subjected to the system identification to obtain the system process model. The model hence obtained is subjected to a network synthesis procedure to estimate the equivalent circuit parameters of the system with various electrodes and at different concentrations of tea samples. Therefore, the tea infusion strength is simulated by varying concentrations. The performance parameters of the models identified for all the electrode–analyte combinations are calculated by comparing the experimental and the simulated waveforms. The study of the concentration of tea samples and circuit parameters agrees with the theoretical concepts. This work therefore also provides a legitimate validation to the established equivalent circuit for the voltammetric taste measurement system (electronic tongue). The cluster analysis performed here reveals a potential application of this work in the domain of electronic tongue.

Research on the Manufacture of Moringa Milky Tea

In this research, moringa, black tea, milk powder, white sugar and sucrose ester were used as raw materials, and the optimal processing technology of moringa milky tea was studied by single factor and orthogonal experiments. These results showed that the optimal formula for moringa milky tea was: 7:8 of ratio of tea liquor (black tea liquor: moringa liquor), 11% of milk powder, 4% of white sugar and 0.9% of sucrose ester. Moreover, the milky tea processed with this formula has a strong milk flavor, a delicate and soft taste.

An Improved Fractional-Order Circuit Model for Voltammetric Taste Sensor System With Infused Tea as Analyte

This paper presents a fractional-order equivalent circuit to better model the voltammetric sensor response in comparison with some existing fractional circuits generally used to model various electrochemical phenomena. The true behaviour of an electrochemical process is often described by a fractional-order model (FOM). Here, we propose a fractional-order circuit to model the current response of the voltammetric taste sensor system for black tea liquor. This current is due to the electrochemical reactions that occur when a voltage pulse is applied across the electrodes. So far, the change in model order to a fraction has not been considered in a circuit model of taste measurement systems. Therefore, this work estimates the equivalent circuit in the fractional-order domain to obtain a more pragmatic model of such a system. The methodology selects the most suitable fractional-order transfer function (FOTF) structure, optimally estimates the model parameters, and decomposes the FOTF into a fractional-order equivalent circuit. The effect of concentration of tea samples on the parameters values and the significance of electrodes towards potential discrimination of samples is also investigated. The estimation of such circuits without direct measurement of complex impedance is the main advantage of the approach.

Optical Properties and Relative Determination of Caffeine in Black Tea Liquor

Caffeine is one of main quality parameter for teas, known for its ability to increase alertness, and has a slightly bitter flavor. As quality parameter, caffeine content will later determine flavor and aroma profile for teas that affect the price in global market. There were many factors that affected chemical compounds in tea, one of it was growth altitude. This research aimed to characterize caffeine spectra from tea liquor using UV-Vis visible which later can be used to relate caffeine content with the altitude of tea sample plantation. The optical transition of caffeine from brewed tea leaves liquor was measured from a variety of black tea products produced according to quality standards for global market. A total of 63 tea samples from four different grades (FANN, PekoFANN, FANN2, and Dust) and from 12 different tea estates in Indonesia have been replicated in their optical transitions and classified on the basis of caffeine content. It was found that caffeine content in tea products may vary depending on the grade and origin of the tea plantation. FANN grade has higher caffeine content that other grades while products from highland tea plantation generally have more caffeine content for all tea grades.

Black Tea with Averrhoa Bilimbi L Extract: A Healthy Beverage

Abstract The information about addition of Averrhoa bilimbi L (AB) extract in black tea liquor still poor, the antioxidant and the phenolic content in the beverage presented in this research. The purpose of present study was to evaluate the antioxidant activity, the total phenolic content, vitamin C and total sugar toward the addition of AB extract at some various level into black tea extract. The results showed that the addition of AB extract have significant effect on antioxidant activity, total polyphenols, vitamin C, and total sugars. The results of sensory tests showed that the treatment D as the most preferred product due to color (70%), taste (75%) and aroma (80%).

Black tea liquor ultrafiltration: Effect of ethanol pre-treatment upon fouling and cleaning characteristics

This paper reports on the use of polymeric ultrafiltration (UF) membrane ethanol pre-treatment as a strategy to improve filtration performance in terms of both flux increase, and membrane water flux recovery following cleaning. A 4-fold pure water flux (PWF) increase was observed for a 100kDa polysulfone membrane. Marked increases in permeate flux were recorded for ethanol treated UF membranes over a range of molecular weight cut-off values. Ethanol treatment also aided fluxes over multiple foul-clean cycles, and enabled the enhanced transmission of polyphenols during UF for the clarification of black tea liquor. Following tea fouling and NaOH cleaning repetitions, PWF values of treated membranes were returned to values of >150% of the untreated virgin membrane PWF over 4/5 consecutive cycles, indicating that the ethanol pre-treatment strategy adopted had a prolonged effect upon subsequent performance.

Ultrafiltration of black tea using diafiltration to recover valuable components

Ultrafiltration of black tea liquor in a constant volume diafiltration regime has been carried out to remove the haze characteristically associated with this product. Commercial polymeric membranes with a range of molecular weight cut-offs (25, 50, and 100 kDa) fabricated from both polysulphone (PS) and fluoropolymer (FP) were used to assess the total solids throughput of the system. A shortfall in the amount of polyphenols transmission over the amount of residual tea solids transmission is the main driver for operating in this regime. The result of this shortfall means membrane permeates are impaired in terms of colour, flavour and health-giving properties. From an initial tea concentration of 1.0 wt.%, diafiltration was carried out, with rejection coefficients for total solids and total solids being assessed continuously. An acceptable (but not ideal) permeate product was the result, which showed excellent clarity (<2.0 nephelometric turbidity units (NTU) in the majority of cases) although the associated transmission in polyphenols meant the tea has lost some of the deep red colour associated with a higher-quality tea infusion. This shortfall in polyphenols transmission gave rise to higher concentrations of polyphenols in the retained side of the process than for original raw tea. In addition, membranes were pre-treated using ethanol, which had a significant effect on both their water permeability and zeta potential. When used in a filtration environment, fluxes increased for all membranes following treatment, with the 100 kDa PS membrane recording a 41% increase in terminal filtration flux. With the exception of the 25 kDa PS membrane, alcohol treatment resulted in all membranes showing increases in the total solids throughput, with the proportion of polyphenols transmitting through the membrane increased to a greater degree over all other components. The disproportionate increase in polyphenols transmission was attributed to reduced charge interactions following ethanol treatment. The results show that as fouling builds up, the separation of polyphenols from all other tea solids increases, meaning that small batches (relative to membrane area) and short-term operation are favoured, in order to maximise polyphenol content in the product stream. In summary, the operation of UF in a diafiltration regime is shown to be an effective industrial processing option for the clarification of black tea liquors.

Germplasm appraisal of western Himalayan tea: a breeding strategy for yield and quality improvement

Western Himalayan tea represents the status of Geographical Indication in the form of “Kangra Tea” which is unique to the tea grown world over due to its delicate flavor and high quality. The tea germplasm resources of western Himalayan region include selections from the commercial tea estates, abandoned tea gardens of Kangra valley and elite tea clones of CSIR-IHBT, Palampur. Data were recorded for different morphological traits contributing to yield and the biochemical parameters were evaluated using standard HPLC procedures. Multivariate clustering of the data differentiated the germplasm resources into distinct groups based on comparisons among the clusters for leaf size and biochemical parameters. Leaf size differentiated the tea accessions into six phenotypic groups, while shoot density which is an important yield parameter was observed to be independent of leaf size. On the basis of total catechin and caffeine contents, tea accessions were differentiated into nine groups of which Group I in comparison with other groups, recorded the highest total catechin content, moderate to high caffeine level and high astringency factor (AF). Epicatechin gallate (ECG) had a significantly high correlation with AF, implying that high levels of ECG are critical along with corresponding levels of Epigallocatechin gallate (EGCG) for the production of Theaflavin 3,3′digallate (TFDG) which is an important quality constituent providing astringency and briskness to black tea liquor. Sustainability of tea breeding programme can be achieved through organization of germplasm resources and by utilizing elite tea genotypes in breeding programme.

Impedance Study of Tea with Added Taste Compounds Using Conducting Polymer and Metal Electrodes

In this study the sensing capabilities of a combination of metals and conducting polymer sensing/working electrodes for tea liquor prepared by addition of different compounds using an impedance mode in frequency range 1 Hz-100 KHz at 0.1 V potential has been carried out. Classification of six different tea liquor samples made by dissolving various compounds (black tea liquor + raw milk from milkman), (black tea liquor + sweetened clove syrup), (black tea liquor + sweetened ginger syrup), (black tea liquor + sweetened cardamom syrup), (black tea liquor + sweet chocolate syrup) and (black tea liquor + vanilla flavoured milk without sugar) using six different working electrodes in a multi electrode setup has been studied using impedance and further its PCA has been carried out. Working electrodes of Platinum (Pt), Gold (Au), Silver (Ag), Glassy Carbon (GC) and conducting polymer electrodes of Polyaniline (PANI) and Polypyrrole (PPY) grown on an ITO surface potentiostatically have been deployed in a three electrode set up. The impedance response of these tea liquor samples using number of working electrodes shows a decrease in the real and imaginary impedance values presented on nyquist plots depending upon the nature of the electrode and amount of dissolved salts present in compounds added to tea liquor/solution. The different sensing surfaces allowed a high cross-selectivity in response to the same analyte. From Principal Component Analysis (PCA) plots it was possible to classify tea liquor in 3-4 classes using conducting polymer electrodes; however tea liquors were well separated from the PCA plots employing the impedance data of both conducting polymer and metal electrodes.

THE INTERACTION OF PROTEIN AND POLYPHENOL SPECIES IN READY TO DRINK BLACK TEA LIQUOR PRODUCTION

ABSTRACT Haze and tea cream generation is a serious problem in the production of ready‐to‐drink (RTD) black tea liquors. Such precipitates consist primarily of proteins and polyphenols. Tea protein and tea polyphenol have been separated successfully in this study. The interactions of (1) tea protein and mixed TF; and (2) tea protein and total tea polyphenol were studied by ITC. A series of techniques, including gel filtration chromatography, sodium dodecyl sulfate polyacrylamide gel electrophoresis, CBB assay and fourier transform infrared spectroscopy (FTIR), have been used to determine the quantity and properties of proteins isolated from black tea powder. The molecular mass of the tea protein was detected to be approximately 11 kD at pH 5.0. The purity of this protein isolate was 51.4 wt % and a possible β‐sheet secondary structure was indicated from FTIR spectra. The total phenols in the tea polyphenol sample separated by Zn 2+ precipitation under alkali conditions (pH 7.5) was increased to approximately 65 wt % of the sample tested. The binding mechanism of tea protein and TF was somewhat different from that of tea protein and total tea polyphenol, although both interactions were successfully fitted using a sequential sites binding model.PRACTICAL APPLICATIONSIn black tea liquor production, polyphenols tend to interact with proteins, caffeine and metal cations to form colloidal suspensions of haze and “tea cream”, which are detrimental to product appearance and taste. This is a key concern in the production of ready‐to‐drink (RTD; iced tea) beverages, which are typically made from reconstituted spray dried tea powders and stored at low temperatures (potentially leading to precipitation). Tea cream and haze are traditionally removed by dissolution through pH adjustment. The size of haze and tea cream aggregates means that membrane technology can offer an alternative nonchemical separation option.To facilitate the removal of haze and tea cream in commercial RTD tea production, it is important to increase the level of understanding of polyphenol or tea protein interactions that occur in black tea liquor. Such interactions are the focus of this paper.

THE ROLE OF BLACK TEA FEED CONDITIONS UPON ULTRAFILTRATION PERFORMANCE DURING MEMBRANE FOULING AND CLEANING

ABSTRACT This article demonstrates the importance of feed condition upon filtration performance as a result of variations in fouling mechanism and cleaning efficiency during the clarification of black tea liquor by ultrafiltration. The filters studied were (1) FP and (2) RC ultrafiltration membranes. Specific fouling resistances, apparent membrane rejections and cleaning efficiencies were analyzed for variations in feed concentration, TMP, temperature, ionic strength and calcium content. Concentration polarization contributed predominantly to the increased total fouling resistance of both membranes as feed concentration was increased, although there was no extra effect upon deposit formation on the RC membrane, whereas rinsable fouling deposit did increase on the FP membrane because of slightly stronger interaction of the foulant with the membrane surface. Increasing the ionic strength increased the total fouling resistance, thus reducing performance while decreasing the severity of deposition fouling as a result of increased concentration polarization. Addition of calcium to the feed stream caused a significant increase in irreversible fouling deposition because of polar group–calcium complexation (bridging). This deposition could not be adequately removed by using standard sodium hydroxide cleaning protocols, or by the addition of surfactants and chelating agents. PRACTICAL APPLICATIONSThe nature of complex feeds and membrane filtration usually results in a progressive flux decline that has a marked effect upon the process economics and viability. The effect of black tea feed condition upon ultrafiltration as a clarification method is reported in this article. Membrane–foulant interactions and overall performance are discussed and are relevant to the optimization and clarification of black tea and other protein/polyphenol containing beverages during industrial processing in factory operation. Although cleaning of membranes is inevitably required during filtration of such a complex feed, an understanding of fouling can help reduce the frequency and environmental impact of cleaning in industrial practice.

Studies on radical scavenging activity of tea leaves and effect of additives on activities of black tea liquor

SummaryGreen tea is proved to be a source of various biochemicals, which projects tea to be a health drink. The study investigated free radical scavenging activity of leaf extracts of south Indian tea clones, individual catechin molecules and documented the influence of various additives on the scavenging activity of black tea infusion. Among the tea clones, UPASI‐17 contained higher quantum of catechins. Lower content of catechins correlated with low 1,1‐diphenyl‐2‐picrylhydrazyl and hydroxyl scavenging activities. Low scavenging activity was noticed in gallocatechin. A wide variation was found in free radical scavenging activity of individual molecules, leaf extracts, tea liquor and its combination with the additives. Tea liquor along with lemon juice showed the highest free radical scavenging activity. When sugar and lemon juice were amended with tea liquor, free radical scavenging activity declined marginally. Addition of milk and sugar with tea liquor declined the free radical scavenging activity significantly.

Measurement of polyphenol–membrane interaction forces during the ultrafiltration of black tea liquor

This paper reports the use of atomic force microscopy (AFM) surface interaction measurements for a model polyphenol present in tea (theaflavin-3-gallate) with a regenerated cellulose ultrafiltration membrane. Differently treated membranes from throughout the fouling cleaning cycle were investigated. The adhesion of the foulant to the virgin and the fouled once/cleaned once (F1C1) membrane surface was stronger than that recorded for foulant–foulant interactions (1.87 and 1.72 N m −2, respectively, matching curves ranging between 0 and 5.5 N m −2 with a single shallow peak). Interestingly, NaOH cleaning of the virgin conditioned membrane reduced foulant–membrane adhesion compared to the virgin or F1C1 surface (0.96 N m −2) with a narrow spread of the adhesion (80% of measurements being within the range 0.5–0.99 N m −2). The uniform narrow distribution of attraction (approach) forces to the fouled and cleaned surfaces helps explain this due to uniformly charged foulant/hydroxyl ions adhering to these membrane surfaces, whereas the virgin membrane distribution was very wide demonstrating no charge modification of this surface. The present study has demonstrated how the AFM coated colloid probe technique can be used with multiple (200×) measurements across a surface to further aid understanding of the nature of fouling and cleaning mechanisms, particularly in protein/polyphenol systems.

The influence of hydrophobicity, roughness and charge upon ultrafiltration membranes for black tea liquor clarification

This paper investigates the clarification of black tea using UF membranes. The efficiency of separation and the final product quality were investigated using regenerated cellulose (RC) and fluoropolymer (FP) membranes of different nominal molar mass cut-off values. Changes during filtration in the hydrophobicity, surface charge on the pore walls, surface roughness and chemical properties were investigated. Results indicate that both of the membrane materials studied produced clarified tea liquors with polyphenol transmission rates of ca. 90%. Increased fouling was present on rougher, more hydrophobic FP surfaces. When roughness, charge and hydrophobicity were similar (i.e. for the RC membrane), variation in pore size was not found to affect the filtration properties significantly over the range investigated. Porous structures with isoelectric points at the pH of the liquor being filtered were linked to an increased fouling tendency. All RC and FP100 kg mol −1 membranes were cleaned relatively easily. FP10 kg mol −1 and FP30 kg mol −1 membranes were found to have undergone surface modification, including increased negative charge and changes in hydrophobicity. The dominant fouling mechanism during all ultrafiltration experiments was found to be cake filtration. The cake formed on RC membranes is thought to dominate filtration properties due to similar transmissions detected through varied pore sizes.

THE FOULING AND CLEANING OF ULTRAFILTRATION MEMBRANES DURING THE FILTRATION OF MODEL TEA COMPONENT SOLUTIONS

ABSTRACT Proteins and polyphenols are the principal fouling constituents in the ultrafiltration (UF) of black tea liquor. The aim of this study was to determine the relative importance of individual components in the fouling process, to investigate any synergetic interactions that were occurring and to compare the cleaning characteristics of different fouled membranes. A 30‐kD molecular weight cutoff polysulfone UF membrane in dead‐end mode was challenged with model solutions of tea components. Model solutions consisted of tea proteins, theaflavins (TFs), thearubigins and caffeine. Sodium hydroxide was used as a cleaning reagent. Permeate flux decline curves were presented for single components and mixtures. Individual component transfer fluxes and rejections were also presented. An unexpected finding was that protein in a mixture with TFs could permeate the membrane to a degree, while a protein solution in the absence of the polyphenol was completely rejected. The inspection of membranes fouled by different solutions revealed different foulant morphologies. Membrane cleaning with 0.2 wt % sodium hydroxide was generally found to be effective.

Solute-Membrane Fouling Interactions During the Ultrafiltration of Black Tea Liquor

This paper reports experimental results concerning the ultrafiltration of hot tea extract reconstituted from tea powder. The filters studied [fluoropolymer (FP) and regenerated cellulose (RC)] were effective at reducing the degree of haze from the tea solutions tested. Results are presented indicating that fluoropolymer, the more hydrophobic of the two materials examined, became fouled with hydrophilic tea species which were not totally removed during cleaning. These deposits became modified on the membrane, producing a more hydrophilic surface than the original membrane. This observation demonstrates an advantage in using moderately hydrophobic membranes for tea filtration, providing the potential for increased permeate flux following multiple fouling and cleaning cycles.

Changes in thearubigin fractions and theaflavin levels due to variations in processing conditions and their influence on black tea liquor brightness and total colour

Increase in coarser plucking standards significantly (P<0.05) depressed levels of theaflavin (TF; μmol/g), total colour and brightness (spectrophotometer) of black tea. But total thearubigins (TR) TRSI, TRSII and brightness (taster) levels did not significantly (P<0.05) change with plucking standards. Increasing fermentation duration led to rise in TF (μmol/g), total TR, total colour, TRSI and TRSII, liquor brightness (taster) but not liquor brightness determined by spectrophotometer method (P<0.05). Correlation analysis showed that total TR and TRSII had negative correlations (r=−0.66 and −0.77, P<0.01), respectively, while total TF levels had positive correlation with taster brightness (r=0.57, P<0.01). Total TF level had highest correlation with spectrophotometer liquor brightness (r=0.87, P<0.01) for a single substance. TRSII and total TR gave an r of 0.86 indicating that the two groups of substances were strongly correlated to each other. Regression analysis showed that the direct linear model gave the best fit for the sample data studied. The coefficient of multiple determination (R2) was 0.606 in linear model I for the tasters’ liquor brightness. Thus, the independent variables TF and total TR explained 60.6% of the total variation in liquor brightness scores observed. When TRSI and TRSII were included in the linear model II instead of total TR, but with TF maintained, the coefficient of multiple determination improved to 78.9%. This confirmed that the brightness attribute of black tea, assessed by the taster, could best be explained by the combination of TF and TRSII and that TRSI had a lesser role in the tasters’ evaluation of liquor brightness. Indeed, the test statistic in linear model I showed that the coefficient of TF positively and significantly influenced liquor brightness at P<0.01 whereas the coefficient of total TR negatively and significantly influenced liquor brightness (P<0.0001). However, in linear model II the effect of total TR on the taster brightness was clearly unmasked and the influence of each individual component well elucidated. The coefficient of TRSII was negative and significantly explained liquor brightness at 0.01% level (P<0.0001). The coefficient of TRSI was negative but insignificant. Hence it has no discernible influence on the taster liquor brightness. The coefficient of TF was positive and significantly explained taster liquor brightness (P<0.01). Thus, TF and TRSII explain taster liquor brightness and the lower the level of TRSII the higher the score for brightness. The situation for spectrophotometer brightness was somewhat different. The coefficient of multiple determination was 0.896 in linear model I. Thus, TF and total TR explained 89.6% of the variation in spectrophotometer brightness. The coefficient of TF was positive whereas that of total TR was negative. Both coefficients were significant (P<0.0001). When TRSI and TRSII were included in the linear model II instead of total TR, R2 improved to 91%. Unlike for the tasters’ brightness, the coefficient of TRSI was now significant (P<0.05). The coefficient of TRSII was negative and significant (P<0.01) whereas the coefficient of TF was positive and significant (P<0.0001). The differences in the contributions of TRSI and TRSII to black tea liquor brightness and the observed discrepancy between the test methods, due to variations in plucking standards and fermentation duration, are discussed.

The phenolic pigment composition of black tea liquors—part II: Discriminating origin

AbstractThe phenolic constituents of 95 black teas, from nine countries, were analysed by HPLC. The procedure resolved 38 coloured phenolic components which were classified as theaflavins (4), thearubigins (22) and flavonol glycosides (11). One of the thearubigin constituents was unresolved chromatographically, but nevertheless quantified as a hump. The relative levels of these substances for different regions and countries of origin were compared. Statistical analysis of the HPLC results with discriminant analysis or canonical variant analysis and ANOVA, highlighted the characteristic differences in phenolic substance levels which contributed most powerfully to the discrimination between origins. Discriminant analysis revealed a discrimination rule based on phenolic composition which achieved a country of origin classification success of 94%. This type of approach highlights which substances are most important in defining origin in terms of tasters' assessments.

The phenolic pigment composition of black tea liquors—part I: Predicting quality

AbstractThe phenolic constituents of 95 black teas, representing nine countries, were analysed and assessed by HPLC. The procedure resolved 38 coloured phenolic components which were classified as theaflavins (4), thearubigins (23) and flavonol glycosides (11). The relative levels of these constituents were monitored by HPLC. One of the thearubigin constituents was unresolved chromatographically, but nevertheless quantified as a hump. The data set was statistically analysed using principal component analysis (PCA) and multiple regression PCA indicated that three of the quality attributes, quality/flavour, brightness/briskness and quality with milk, were strongly correlated with each other. The fourth attribute, colour/strength, was found to be the most effective in discriminating between teas, particularly between high strength teas from Assam and Tanzania and low strength teas from Sri Lanka and Malawi. Multiple regression was used to investigate the relationship between tasters' scores and the chemical constituents. The model established gives an R2 of 63% based on six components; five resolved thearubigins and the unresolved thearubigin hump. These results indicate the potential to develop objective chemical assessment procedures for determining the quality of teas and is the first report of the flavour impact of individual thearubigins constituents.