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Lingyun Zhang - One of the best experts on this subject based on the ideXlab platform.
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application of chemical composition and infusion Colour Difference analysis to quality estimation of jasmine scented tea
International Journal of Food Science and Technology, 2007Co-Authors: Yue-rong Liang, Lingyun ZhangAbstract:Summary Infusion chemical composition, Colour Difference indicators and volatile constituents of seventeen jasmine-scented tea samples and their correlation with sensory total quality score given by tea-tasting panel were studied by techniques of HPLC, Colour Difference metre and gas chromatograph. Spearman's linear correlation analysis showed that concentration of nitrogen, caffeine, catechin, epicatechin, catechin gallate, total catechins, terpineol, nerol and infusion light-black indicator ΔL, yellow-blue indicator Δb, total Colour Difference indicator ΔE were significantly correlated with sensory total quality score, respectively. Regression of the total quality score upon twelve components extracted from thirty-six tested indicators by principal component analysis could properly estimate total quality score of two jasmine-scented tea samples which were not included in the seventeen samples used to construct the regression model.
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estimation of tea quality by infusion Colour Difference analysis
Journal of the Science of Food and Agriculture, 2005Co-Authors: Yue-rong Liang, Lingyun ZhangAbstract:The Colour Differences in terms of deltaL, deltaa, deltab and deltaE between distilled water and infusions of 29 green teas, 16 black teas and 13 oolong teas and their correlation with sensory quality attributes of tea were investigated. The results showed that the deltaL value decreased but the deltaa, deltab and deltaE increased with the degree of fermentation of the three kinds of tea. The deltaL was positively correlated to quality attributes of green tea and oolong tea but negatively correlated to those of black tea. The deltaa of tea infusions is a reliable descriptor to differentiate among green and black teas. The regression of total quality score of green tea (TQSg) upon the deltaa was TQSg = -2.26deltaa + 77.2 (R2 = 0.22, p < 0.01), that of total quality score of black tea (TQSb) upon deltab was TQSb = 0.70deltab + 44.6 (R2 = 0.31, p < 0.05) and that of total quality score of oolong tea (TQSo) upon deltaL was TQSo = 1.09deltaL + 94.5 (R2 = 0.75, p < 0.01). Because the infusion Colour Difference indicators of deltaa, deltab and deltaL can be done rapidly, it could be very useful for on-site or on-line quality monitoring during tea manufacture and storage.
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Estimation of black tea quality by analysis of chemical composition and Colour Difference of tea infusions
Food Chemistry, 2003Co-Authors: Yue-rong Liang, Lingyun ZhangAbstract:Abstract Chemical composition, Colour Differences of black tea infusions and their relationships with sensory quality assessed by tea tasters were analysed. There were significant correlations between the individual quality attributes. Content of caffeine, nitrogen, amino acids, polyphenols, gallocatechin (GC), epigallocatechin (EGC), catechin (C), epicatechin (EC), epicatechin gallate (ECG), catechin gallate (CG), total catechins, theaflavin (TF) and theaflavin-3′-gallate (TF3′G) and infusion Colour indicators of Δ L , Δ a , Δ b and Δ E were significantly correlated to total quality score (TQS). The parameters correlating significantly with the TQS were classified into four groups. Group 1 was compounds containing nitrogen, group 2 phenol compounds, group 3 tea pigments and group 4 infusion Colour indicators. Four principal components were screened from the four groups as independent variables for constructing regression equations for estimation of black tea quality by principal component analysis. The regression of the TQS upon the principal components gives a highly significant relationship.
Yue-rong Liang - One of the best experts on this subject based on the ideXlab platform.
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application of chemical composition and infusion Colour Difference analysis to quality estimation of jasmine scented tea
International Journal of Food Science and Technology, 2007Co-Authors: Yue-rong Liang, Lingyun ZhangAbstract:Summary Infusion chemical composition, Colour Difference indicators and volatile constituents of seventeen jasmine-scented tea samples and their correlation with sensory total quality score given by tea-tasting panel were studied by techniques of HPLC, Colour Difference metre and gas chromatograph. Spearman's linear correlation analysis showed that concentration of nitrogen, caffeine, catechin, epicatechin, catechin gallate, total catechins, terpineol, nerol and infusion light-black indicator ΔL, yellow-blue indicator Δb, total Colour Difference indicator ΔE were significantly correlated with sensory total quality score, respectively. Regression of the total quality score upon twelve components extracted from thirty-six tested indicators by principal component analysis could properly estimate total quality score of two jasmine-scented tea samples which were not included in the seventeen samples used to construct the regression model.
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estimation of tea quality by infusion Colour Difference analysis
Journal of the Science of Food and Agriculture, 2005Co-Authors: Yue-rong Liang, Lingyun ZhangAbstract:The Colour Differences in terms of deltaL, deltaa, deltab and deltaE between distilled water and infusions of 29 green teas, 16 black teas and 13 oolong teas and their correlation with sensory quality attributes of tea were investigated. The results showed that the deltaL value decreased but the deltaa, deltab and deltaE increased with the degree of fermentation of the three kinds of tea. The deltaL was positively correlated to quality attributes of green tea and oolong tea but negatively correlated to those of black tea. The deltaa of tea infusions is a reliable descriptor to differentiate among green and black teas. The regression of total quality score of green tea (TQSg) upon the deltaa was TQSg = -2.26deltaa + 77.2 (R2 = 0.22, p < 0.01), that of total quality score of black tea (TQSb) upon deltab was TQSb = 0.70deltab + 44.6 (R2 = 0.31, p < 0.05) and that of total quality score of oolong tea (TQSo) upon deltaL was TQSo = 1.09deltaL + 94.5 (R2 = 0.75, p < 0.01). Because the infusion Colour Difference indicators of deltaa, deltab and deltaL can be done rapidly, it could be very useful for on-site or on-line quality monitoring during tea manufacture and storage.
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Estimation of black tea quality by analysis of chemical composition and Colour Difference of tea infusions
Food Chemistry, 2003Co-Authors: Yue-rong Liang, Lingyun ZhangAbstract:Abstract Chemical composition, Colour Differences of black tea infusions and their relationships with sensory quality assessed by tea tasters were analysed. There were significant correlations between the individual quality attributes. Content of caffeine, nitrogen, amino acids, polyphenols, gallocatechin (GC), epigallocatechin (EGC), catechin (C), epicatechin (EC), epicatechin gallate (ECG), catechin gallate (CG), total catechins, theaflavin (TF) and theaflavin-3′-gallate (TF3′G) and infusion Colour indicators of Δ L , Δ a , Δ b and Δ E were significantly correlated to total quality score (TQS). The parameters correlating significantly with the TQS were classified into four groups. Group 1 was compounds containing nitrogen, group 2 phenol compounds, group 3 tea pigments and group 4 infusion Colour indicators. Four principal components were screened from the four groups as independent variables for constructing regression equations for estimation of black tea quality by principal component analysis. The regression of the TQS upon the principal components gives a highly significant relationship.
B. Rigg - One of the best experts on this subject based on the ideXlab platform.
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comparing large Colour Difference data sets
Color Research and Application, 2010Co-Authors: Shao Ying Zhu, Ming Ronnier Luo, Guihua Cui, B. RiggAbstract:This study investigated the Differences between different large Colour-Difference (LCD) data sets (with a mean ΔE value about 10). Six data sets were studied. For each data set, various CIELAB based Colour Difference models were derived to fit the data. These models were compared to shed light on the Difference between the different data sets. It was found that all data sets have very similar characteristics except for the Munsell data. Detailed investigation showed that the discrepancy is mainly due to the balance between the lightness and chromatic Differences used previously for the Munsell data set. It was found that one unit of Munsell Value appears to be three times as large Colour Difference as one unit of Munsell Chroma at least under the experimental conditions for the data sets studied here. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2011
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bfd l c Colour Difference formula part 2 performance of the formula
Journal of The Society of Dyers and Colourists, 2008Co-Authors: M R Luo, B. RiggAbstract:The available experimental data relating to small Colour Differences between pairs of surface Colours have been combined together into two sets including perceptibility results (CP) and acceptability results (CA). A new Colour-Difference formula, BFD(\:c) has been developed using the combined experimental results. For small Colour Differences, particularly when perceptibility judgements are involved, the new formula represents a substantial improvement over other fomulae. For large Colour-Differences the new formula is close to the best available formula. Different 1 values are required for perceptibility and acceptability judgements, and for large Colour Differences, but c=1 in all cases. The BFD formula gives the best possible results obtainable with currently available data. Analysis shows that results from different studies, including those based on perceptibility and acceptability judgements, are compatible in many respects. Discrepancies that were detected seemed to be due to experimental error, or problems in scaling the visual results. However, there are major Differences between the results for small Differences between surface Colours and those implicit in the Munsell system and MacAdam ellipses.
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modification to the jpc79 Colour Difference formula
Journal of The Society of Dyers and Colourists, 2008Co-Authors: F J J Clarke, R Mcdonald, B. RiggAbstract:The JPC79 Colour–Difference formula has represented a substantial improvement over earlier formulae and is being applied successfully in industrial shade passing. Modifications are described which overcome certain problems and, to some extent, simplify the formula. With available experimental data, the modified version performed even better than the original formula. Perceptibility data are fitted better by increasing the JPC79 lightness weighting by a factor of two. The new formula, designated CMC (: c), has the best overall performance of any formula so far published.
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a Colour Difference formula for surface Colours under illuminant a
Journal of The Society of Dyers and Colourists, 2008Co-Authors: Ming Ronnier Luo, B. RiggAbstract:The available experimental data for small Colour Differences between surface Colours under illuminant A have been analysed in a manner similar to that used earlier for the comparable results under daylight. Chromaticity discrimination ellipses were calculated from the results for each Colour centre. The size of the ellipses varied with chromaticity in an irregular manner suggesting that the visual results for the different centres were effectively on different scales. New experiments, carried out using a grey scale method for the visual assessments, allowed the relative sizes of ellipses to be adjusted. After adjustment the size of the ellipses varied much more systematically with chromaticity. Similar adjustments allowed all the results to be combined together and used to develop a new Colour-Difference formula suitable for assessments under illuminant A. Values of ΔE from the new formula gave a better fit to the visual results than those from other formulae. Earlier formulae were intended to be used with results for daylight. Using chromatic adaption formulae to transform the illuminant A results to illuminant D65 improved the agreement, but the results were still not as good as those obtained with the new formula.
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uniform Colour space based on the cmc l c Colour Difference formula
Journal of The Society of Dyers and Colourists, 2008Co-Authors: Ming Ronnier Luo, B. RiggAbstract:The CMC(c) Colour-Difference formula agrees more closely with visual assessments than does the CIE L*a*b* formula, but hitherto there has been no associated ‘uniform Colour space’. A new Colour space similar in form to CIE L*a*b* space has been derived in which distances agree closely with the corresponding ΔE(CMC) values. The new space was extensively tested using real and hypothetical pairs of samples. In each case the distance, in the space, between a pair of samples was compared with the ΔE(CMC) value. The disagreement rarely exceeded 20%, while discrepancies between distances in CIE L*a*b* space and those implied by the CMC formula can exceed 500%. It is easy to construct ‘micro-spaces’ apparently corresponding to the CMC formula which should be applicable to small regions of Colour space and hence useful for applications such as Colour sorting. Such micro-spaces did not agree with the CMC formula as well as did the new space. The new space represents a substantial improvement over CIE L*a*b* space with respect to uniformity; its form is similar to CIE L*a*b* and so is easy to use.
Mariusz Tryznowski - One of the best experts on this subject based on the ideXlab platform.
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improvement of light fastness of water based printing inks with addition of glycerol derivative containing thiol groups
Coloration Technology, 2018Co-Authors: Joanna Izdebskapodsiadly, Zuzanna żolektryznowska, Tatiana Annusik, Mariusz TryznowskiAbstract:The aim of this work was to study the influence of a glycerol derivative with thiol groups, 3,6-dithia-1,8-octanediol (DTO), on light fastness of prints overprinted with water-based flexographic printing inks. Laboratory printing was performed on various plastic films (BOPP and PE). The effect of a small amount of DTO on printing ink Colour was examined by studying the optical density of a full tone area, relative printing contrast and the Colour values (CIELAB), and the total Colour Difference, ΔEab∗. Artificial ageing was applied in order to investigate DTO influence on Colourfastness of CMY printing inks. Densitometry and spectrophotometric parameters were measured during artificial ageing by irradiation. Additionally, FTIR spectroscopy was used to observe the changes in ink film on printing bases before and after ageing. The print quality of investigated prints is widely discussed. In general, DTO addition influenced the printability of the plastic film and the optical density of a full tone area with an acceptable total Colour Difference ΔEab∗. Furthermore, printing inks with added DTO exhibited higher optical density and smaller changes of ΔEab∗ during artificial ageing. Moreover, the FTIR spectra of printing ink films with added DTO after ageing did not exhibit any perceptible changes in contrast with the original printing ink.
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branched polyglycerols as performance additives for water based flexographic printing inks
Progress in Organic Coatings, 2015Co-Authors: Zuzanna żolektryznowska, Joanna Izdebska, Mariusz TryznowskiAbstract:Abstract The aim of this work was to study the influence of polyglycerols on the selected properties of water-based printing ink and prints overprinted with water-based flexographic printing inks. Modified flexographic inks were laboratory printed on polyethylene plastic film. The impact of small amounts of various commercially available polyglycerols on printing ink Colour was examined for the optical density of the full-tone area, Colour values (CIELAB) and total Colour Difference Δ E a b * and the gloss of the dried ink film. The dry and wet rub resistance of overprinted samples was investigated. In general, the addition of polyglycerols improved the wet and rub resistance of water-based flexographic printing ink with an acceptable total Colour Difference Δ E a b * . The optical density and the gloss increased for those printing inks containing polyglycerols as compared to original printing ink. The small addition of glycerol ethoxylate to the water-based printing ink improved the wettability of the plastic film and the wet and dry rub resistance.
Zuzanna żolektryznowska - One of the best experts on this subject based on the ideXlab platform.
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improvement of light fastness of water based printing inks with addition of glycerol derivative containing thiol groups
Coloration Technology, 2018Co-Authors: Joanna Izdebskapodsiadly, Zuzanna żolektryznowska, Tatiana Annusik, Mariusz TryznowskiAbstract:The aim of this work was to study the influence of a glycerol derivative with thiol groups, 3,6-dithia-1,8-octanediol (DTO), on light fastness of prints overprinted with water-based flexographic printing inks. Laboratory printing was performed on various plastic films (BOPP and PE). The effect of a small amount of DTO on printing ink Colour was examined by studying the optical density of a full tone area, relative printing contrast and the Colour values (CIELAB), and the total Colour Difference, ΔEab∗. Artificial ageing was applied in order to investigate DTO influence on Colourfastness of CMY printing inks. Densitometry and spectrophotometric parameters were measured during artificial ageing by irradiation. Additionally, FTIR spectroscopy was used to observe the changes in ink film on printing bases before and after ageing. The print quality of investigated prints is widely discussed. In general, DTO addition influenced the printability of the plastic film and the optical density of a full tone area with an acceptable total Colour Difference ΔEab∗. Furthermore, printing inks with added DTO exhibited higher optical density and smaller changes of ΔEab∗ during artificial ageing. Moreover, the FTIR spectra of printing ink films with added DTO after ageing did not exhibit any perceptible changes in contrast with the original printing ink.
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branched polyglycerols as performance additives for water based flexographic printing inks
Progress in Organic Coatings, 2015Co-Authors: Zuzanna żolektryznowska, Joanna Izdebska, Mariusz TryznowskiAbstract:Abstract The aim of this work was to study the influence of polyglycerols on the selected properties of water-based printing ink and prints overprinted with water-based flexographic printing inks. Modified flexographic inks were laboratory printed on polyethylene plastic film. The impact of small amounts of various commercially available polyglycerols on printing ink Colour was examined for the optical density of the full-tone area, Colour values (CIELAB) and total Colour Difference Δ E a b * and the gloss of the dried ink film. The dry and wet rub resistance of overprinted samples was investigated. In general, the addition of polyglycerols improved the wet and rub resistance of water-based flexographic printing ink with an acceptable total Colour Difference Δ E a b * . The optical density and the gloss increased for those printing inks containing polyglycerols as compared to original printing ink. The small addition of glycerol ethoxylate to the water-based printing ink improved the wettability of the plastic film and the wet and dry rub resistance.
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ionic liquids as performance additives for water based printing inks
Coloration Technology, 2014Co-Authors: Zuzanna żolektryznowska, Joanna Izdebska, Malgorzata GoląbekAbstract:For the first time, the use of ionic liquids as additives for printing inks in order to improve the wettability of the printing base by the ink is presented. The aim of this work was to study the influence of ionic liquids on the selected properties of water-based printing ink and the prints. The contact angles of the printing inks on the printing base were measured. Modified flexographic inks were laboratory printed on polypropylene plastic film. The impact of small amounts of various ionic liquids on printing ink Colour was examined in terms of the optical density of the full-tone area, the Colour parameters (L*, a*, b*, CIE), the total Colour Difference, and the gloss of the dried ink film. The influence of ionic liquids on the ink contact angle, the optical density, and the L*a*b* coordinates is discussed. In general, the investigated ionic liquids improve the wettability of water-based flexographic printing ink, with an acceptable total Colour Difference. The optical density is increased for printing inks containing ionic liquids in comparison with the original flexographic printing ink, Process.