Off-Flavors of Tea

Chen, A.O.; Tsai, Yu-Shiuan; Chiu, W. T.-F.

doi:10.1016/b978-0-444-88558-6.50019-2

Cited by 5 publications

(5 citation statements)

References 16 publications

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“…Grassy note 1‐penten‐3‐ol and (Z)‐3‐hexen‐ol resulting from lipid degradation as well as ‘stale’ and ‘resinous’ (E,E)‐2,4‐heptadienal could impact an inferior aroma quality to tea (Chen & Tsai, ). The level of these three undesirable odorants in low grade of Dianhong tea was 2.9 and 3.4 times that of middle‐ and high‐grade tea.…”

Section: Resultsmentioning

confidence: 99%

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: 99%

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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“…The total concentration of alcohols in Gyokuro was only half that in low grade Sen-cha, and that in high grade Sen-cha was intermediate between those of low grade Sen-cha and Gyokuro. Two isomers of pentenol, which have a strong stinging green odor (Chen et al, 1992), were contained in Gyokuro in higher levels, but…”

Section: Resultsmentioning

confidence: 99%

“…It was shown that the total concentration of aldehydes in low grade Sen-cha was 2 times higher compared to that in high grade Sen-cha. Since aliphatic aldehydes have a greenish and sickening odor (Chen et al, 1992), whether a tea infusion was described as Sinsen-ka or Ao-shu might be determined by the balance in aliphatic aldehydes and alcohols. (E,Z)-2,4-Heptadienal, which smelled oily green (Chen et al, 1992), was detected in a quite large amount only in low grade Sen-cha.…”

Section: Resultsmentioning

confidence: 99%

“…Since aliphatic aldehydes have a greenish and sickening odor (Chen et al, 1992), whether a tea infusion was described as Sinsen-ka or Ao-shu might be determined by the balance in aliphatic aldehydes and alcohols. (E,Z)-2,4-Heptadienal, which smelled oily green (Chen et al, 1992), was detected in a quite large amount only in low grade Sen-cha. On the other hand, CE,E)-2,4-heptadienal, whose threshold was much higher than that of (EJS)-2,4-heptadienal (Belitz and Grosch, 1987c), was found in all grades of green tea, and a large quantity was contained in low grade Sen-cha and Gyokuro.…”

Section: Resultsmentioning

confidence: 99%

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Comparison of Volatile Compounds among Different Grades of Green Tea and Their Relations to Odor Attributes

Shimoda¹,

Shigematsu²,

Shiratsuchi³

et al. 1995

J. Agric. Food Chem.

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“…D'autres denrées alimentaires et boissons telles que jus d'orange (Sattar et al, 1989), bière (Kamimura et Kaneda, 1992), thé (Chen et al, 1992), champagne (Maujean et Seguin, 1983), saké (Ohba et Akiyama, 1992) et huile de citron (Neumann et Garcia, 1992) ont fait l'objet d'investigations analogues.…”

Section: Introductionunclassified

Influence de la translucidité de l'emballage sur la conservation du lait et des produits laitiers

Bosset

Gallmann

Sieber

1993

Lait

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Résumé -Le présent travail opère une synthèse des connaissances et des résultats acquis par les auteurs et leurs collègues au cours des 10 demières années lors d'une série d'essais consacrés à l'étude de la photosensibilité du lait et des produits laitiers, du yoghourt et du beurre en particulier. Il complète cette synthèse par une .vaste revue bibliographique des publications qui ont paru sur ce sujet jusqu'à aujourd'hui. Deux aspects importants y sont particulièrement traités : les principaux facteurs extrinsèques et intrinsèques qui influencent la photodégradation ainsi que les effets proprement dits de la lumière sur quelques constituants chimiques et grandeurs chimico-physiques du lait et des produits laitiers. Parmi les principaux facteurs extrinsèques qui peuvent diminuer ou accroître la photo-oxydation, on peut citer le spectre, l'intensité et la durée de la lumière incidente, la translucidité de l'emballage et sa perméabilité à l'oxygène, de même que la température du stockage. Le choix de ces facteurs doit chaque fois être opéré en fonction des facteurs intrinsèques qui détermi-nent la photosensibilité du produit considéré. Au nombre de ces facteurs, on peut mentionner la composition globale (en particulier la teneur en substances oxydantes et réductrices), la valeur du pH, le potentiel d'oxydo-réduction ainsi que le traitement technologique du produit. Les principaux effets de la lumière sur le lait et les produits laitiers sont les suivants : pertes en vitamines, en particulier en riboflavine (qui agit comme photosensibilisateur), en~-carotène et en acide ascorbique, production ou dégradation d'acides aminés libres, augmentatipn de l'indice de peroxydes, altération de la flaveur avec l'apparition de composés désagréables (méthional provenant de la dégradation des protéines, aldéhydes et méthylcétones provenant de celle des lipides) et modification de la couleur du produit photolysé. Ce travail compare encore les cinétiques d'altération èt les seuils de détection des composés impliqués dans les réactions de photodécomposition.Ce travail s'achève par quelques recommandations pratiques générales.lait' produits laitiers 'lumière' photo-oxydatlon , photodégradation' emballage 5ummary -Influence of IIght transmittance of packlng.materlals on the sheif-life of mllk and dairy products -a review.

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Off-Flavors of Tea

Cited by 5 publications

References 16 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

Comparison of Volatile Compounds among Different Grades of Green Tea and Their Relations to Odor Attributes

Influence de la translucidité de l'emballage sur la conservation du lait et des produits laitiers

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