Seasonal variations in the composition of the volatile constituents of black tea. Numerical approach to the correlation between composition and quality of tea aroma

1974 ◽  
Vol 22 (5) ◽  
pp. 758-764 ◽  
Author(s):  
Maurizio A. Gianturco ◽  
Robert E. Biggers ◽  
Brigitte H. Ridling
2019 ◽  
Vol 14 (8) ◽  
pp. 1934578X1987260
Author(s):  
Yuto Nishidono ◽  
Takahiro Chiyomatsu ◽  
Kazuyuki Sanuki ◽  
Yasuhiro Tezuka ◽  
Ken Tanaka

The leaves of Artemisia princeps (Japanese mugwort, “Yomogi”) are traditionally used as a food ingredient to provide a fresh aroma and a deep green color. In this study, the seasonal variations of the volatile constituents in Japanese mugwort leaves collected from several parts of the plants were investigated using gas chromatography and multivariate analysis in order to determine the best time to harvest them and the best parts of the plants from which the leaves can be gathered and utilized as an ingredient in food. As a result, it was clarified that the balance between the amounts of monoterpenes and sesquiterpenes is an important factor that determines the quality of Japanese mugwort. In addition, the amount of β-caryophyllene was found to be the important factor that determines the best time and from which parts of the plant to harvest high-quality Japanese mugwort.


2021 ◽  
Vol 359 ◽  
pp. 129950
Author(s):  
Ai Huang ◽  
Zongde Jiang ◽  
Meng Tao ◽  
Mingchun Wen ◽  
Zhipeng Xiao ◽  
...  

Author(s):  
Jennifer Larisa Liem ◽  
Maria Marina Herawati

Flavonoid compound is an important compound of tea products. However, the flavonoid level content in black tea is lowest than other teas. This is due to the processing of black tea which has an enzymatic oxidation stage and  the tea age leaves when picking. Young tea leaves contain higher total flavonoids than old tea leaves. With an average level of total flavonoids, the young tea leaves is 27.76% qe w / w, while for the old tea leaves 18.61% qe w / w. However, the enzymatic oxidation time treatment did not affect the total flavonoids because the process only affected the quality of black tea steeping, on it’s colour, aroma, and taste. Keywords: age of tea leaves, black tea, enzymatic oxidation, total flavonoids


2018 ◽  
pp. 75-82 ◽  
Author(s):  
Мухендис (Mukhendis) Мамедгусейин оглы (Mamedgusejin ogly) Джахангиров (Cahangirov) ◽  
Микаил (Mikail) Акпер оглы (Аkper ogly) Магеррамов (Маharrаmov)

It was shown that the scent and taste of tea are determined by the level of protein and amino acid. Certainly, protoingens that make up most part of proteins are noted among amino acids. All of them are considered L-shaped. Green tea mostly consists of proteins. Even the high level protein doesn’t adversely impact the quality of tea yet that of black tea might be negatively influenced by that. Also, its taste will also be worsened by that.As a result of analysis 16 amino acids and 8 unsubstituted substance was found. The main part of amino acid is taken by teanin. It take 41.3% of Azerbaijan-1, 38.8% of Kolxida types respectively. In all stages of tea leaf processing the decrease of teanin and increase of glutamin is witnessed. Also, the loss of teanin happens during the purification (by 34%) and the fading stages.As a result of the work carried out, it has been found that the size of the tea leaf particle, the temperature and the extraction time influence the extraction of the theanine. The optimum are: the size of the tea leaf particle is 200–450 mkm, the extraction temperature is 80–85 °C, and the extraction time is 20–25 minutes.


2020 ◽  
Vol 25 (1) ◽  
pp. 9-16
Author(s):  
Erkut Yalçın ◽  
Halil Bilal ◽  
Ayhan Yağcı ◽  
Haluk Erol

A Vibro-Acoustic Finite Element Method (FEM) model capable of calculating the transient sound pressure generated by the door slam of a vehicle was developed in this study. A design sensitivity analysis (DSA) was performed for investigating the effects of major design variables on the related sound quality metrics. The methodology was developed using a sedan-car and its FEM model. This paper shows that a Computer Aided Engineering (CAE) model can be used as a rather powerful tool for giving design change decisions for the door components from sound quality point of view during vehicle body development according to psychoacoustic parameters.


2020 ◽  
Vol 8 (4) ◽  
pp. 1848-1856
Author(s):  
Penghui Yu ◽  
Hao Huang ◽  
Xi Zhao ◽  
Ni Zhong ◽  
Hongfa Zheng ◽  
...  

2019 ◽  
Vol 9 (15) ◽  
pp. 3023 ◽  
Author(s):  
Yonglei Liu ◽  
Xianlong Liu ◽  
Lin Liu ◽  
Fei Wang ◽  
Yuping Zhang ◽  
...  

Ghost imaging (GI) is an indirect imaging approach that can retrieve an object’s image even in a harsh environment through measuring the fourth-order correlation function (FOCF) between the signal and idle optical paths. In this paper, we study lensless GI with a partially coherent beam carrying twist phase, i.e., twisted Gaussian Schell-model (TGSM) beam, in the presence of oceanic turbulence. Explicit expression of the FOCF is derived based on the optical coherence theory and Rytov approximation, and the effects of the twist phase and the oceanic turbulence on the quality and visibility of image are investigated in detail through numerical examples. Our results show that the simulated oceanic turbulence strongly affects the GI. The quality of image decreases monotonously with an increase of the strength of turbulence whereas the visibility increases. When the illumination light carries a twist phase, the visibility of the image is improved while the quality of the image is reduced in contrast to those without a twist phase. By properly selecting the strength of the twist phase, the image can still be maintained at an acceptable level of quality with high visibility. Furthermore, it is found that the quality and visibility of the ghost image are less affected by the oceanic turbulence using a TGSM beam with larger twist factor. Our findings will be useful for the application of GI in an oceanic turbulent environment.


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