Phenolic composition of black tea liquors as a means of predicting price and country of origin

McDowell, Ian; Feakes, John

doi:10.1002/jsfa.2740550414

Cited by 40 publications

(21 citation statements)

References 13 publications

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“…10′, 20′, 21′, 22′, 23′, 27′, 28′, 33′, 34′, 35′) were dominated by terpene alcohols and their derivatives. The strong aroma impression of geraniol, linalool and its oxides was covered in previous researches of various types of tea (McDowell et al ., ; Schuh & Schieberle, ; Wang et al ., ; Zhao et al ., ). (Z)‐3‐Hexenol found in this study was previously detected to be natural aroma compound of Kangra orthodox black tea (Rawat et al ., ).…”

Section: Resultsmentioning

confidence: 97%

Development of regression model to differentiate quality of black tea (Dianhong): correlate aroma properties with instrumental data using multiple linear regression analysis

Pang

Qin

Zhao

et al. 2012

Int J of Food Sci Tech

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Summary To develop a flexible and objective method to discriminate Dianhong tea quality level, the instrumental analysis of odour‐active compounds of three commercial grades of Dianhong tea and quantitative descriptive analysis of their overall aromas were conducted. Eight aroma properties were then statistically correlated with odorants using stepwise multiple linear regression analysis. Thirty‐nine odour‐active components were screened in Dianhong tea infusion, among which dimethyl disulphide and 1‐(1H‐pyrrol‐2yl)‐ethanone were identified for the first time. Adjusted R2 of multiple regression models for eight sensory properties were all >0.95, except ‘resinous’ attribute (R2 = 0.834), and RMSE were <0.18 for all. Regression models showed that 2‐methylbutanal, 3‐methylbutanal, linalool, geraniol, linalool oxides, phenyl acetaldehyde, methyl salicylate, ethyl 2‐methylbutyrate, 3,7‐dimethyl‐3‐octanol, benzaldehyde and 6,10‐dimethyl‐5,9‐undecadien‐2‐one positively contributed to the Dianhong tea aroma profile, while 1‐penten‐3‐ol, (Z)‐3‐hexen‐1‐ol and (E,E)‐2,4‐heptadienal were negative aroma contributors. Regression model development for Dianhong tea aroma quality would provide a uniform standard for objectively assessing tea quality among different laboratories and cultures.

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Section: Resultsmentioning

confidence: 97%

Development of regression model to differentiate quality of black tea (Dianhong): correlate aroma properties with instrumental data using multiple linear regression analysis

Pang

Qin

Zhao

et al. 2012

Int J of Food Sci Tech

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“…Caffeine plays a vital role in tea quality characteristics such as briskness and other taste properties (Dev Choudhury, Rahman, & Barbora, 1991;Hilton & Ellis, 1972;Roberts, 1962;Sanderson, 1972) and it is an important parameter for quality evaluation (Khokhar & Magnusdottir, 2002;Owuor, Horita, Tsushida, & Murai, 1986;Yao et al, 2006). Liquor brightness and total colour of black tea are critical quality attributes, used in the tea trade to rank and price black teas (Biswas, Sarkar, & Biswas, 1973;McDowell, Feakes, & Gay, 1991). During black tea processing, theaflavins (TF) and thearubigins (TR) and other polymerisation products are formed (Roberts, 1962;Sanderson, Berkowitz, Co, & Graham, 1972).…”

Section: Introductionmentioning

confidence: 99%

Integrating satellite images and spectroscopy to measuring green and black tea quality

Dutta¹,

Stein²,

Bhagat³

2011

Food Chemistry

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“…It is well established that the flavour of tea is principally determined by chemical components it contains, such as volatile compounds contributing to the property of aroma and nonvolatile compounds to the taste (Hara et al ., 1995; Scharbert & Hofmann, 2005). Considerable attempts were made to link the sensory assessment of tea quality index to chemical compounds for black tea (McDowell et al ., 1991; Taylor et al ., 1992; McDowell et al ., 1995; Wright et al ., 2002; Liang et al ., 2003; 2005; Scharbert & Hofmann, 2005). Green tea is a so‐called nonfermented tea as most chlorophylls (Chl), catechins and other polyphenols are preserved after processing owing to inactivation of enzyme by dry heating (mainly for Chinese green teas) or steaming (mainly for Japanese green teas) at the initial step.…”

Section: Introductionmentioning

confidence: 99%

Analysis of chemical components in green tea in relation with perceived quality, a case study with Longjing teas

Wang

Ruan

2009

Int J of Food Sci Tech

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Properties of leaf and infusion colours, chemical components and volatile flavour compounds of Longjing teas and their correlation with perceived quality score given by tea-tasting panel were analysed. The scores for appearance, infused leaves and for the Total Quality Score (TQS) negatively correlated with concentrations of chlorophyll-a (Chl-a), Chl-b and total chlorophyll (r = )0.723 to )0.846, P < 0.01). The perceived taste score positively correlated with the concentration of total free amino acid (r = 0.527, P < 0.05) and theanine (r = 0.511, P < 0.05), whereas the TQS positively correlated with total free amino acid (r = 0.533). The volatile composition and their quantities varied widely among Longjing tea samples. (E)-geraniol, linalool, hexanal, pentanal, heptanal, nonanal and jasmone were prevailing volatile compounds detected in all samples. Principal component analysis (PCA) screened twelve principal components with the first three explaining 18.82%, 15.31% and 11.83% of the total variance respectively. The concentrations of total free amino acids, pentanal and epigallocatechin gallate were with the highest component score coefficients for the first three principal components respectively. Regression analysis upon the twelve principal components formulated a prediction model on the TQS with 77.0% probability.

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Phenolic composition of black tea liquors as a means of predicting price and country of origin

Abstract: ABSTRACT

Cited by 40 publications

References 13 publications

Development of regression model to differentiate quality of black tea (Dianhong): correlate aroma properties with instrumental data using multiple linear regression analysis

Development of regression model to differentiate quality of black tea (Dianhong): correlate aroma properties with instrumental data using multiple linear regression analysis

Integrating satellite images and spectroscopy to measuring green and black tea quality

Analysis of chemical components in green tea in relation with perceived quality, a case study with Longjing teas

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