scholarly journals Differential Contribution of Jasmine Floral Volatiles to the Aroma of Scented Green Tea

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Jian-Xia Shen ◽  
Mohammad M. Rana ◽  
Guo-Feng Liu ◽  
Tie-Jun Ling ◽  
Margaret Y. Gruber ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Green Tea ◽  
Manufacturing Processes ◽  
Floral Volatiles ◽  
Methyl Anthranilate ◽  
Tea Quality ◽  
Potent Odorants ◽  
Floral Volatile ◽  
Jasminum Sambac ◽  
Differential Contribution

Tea volatiles’ generation and retention over manufacturing processes are crucial for tea quality. In this study, floral volatile adsorption and retention in green tea scented with Jasminum sambac flowers were examined over the scenting process. Out of 34 enhanced volatiles in the scented tea, β-ionone, β-linalool, indole, and methyl anthranilate were the most potent odorants with 5.1–45.2-fold higher odor activity values than the corresponding controls in the nonscented tea. Scenting efficiencies for the floral volatiles retained in the scented tea (the percentage of volatile abundance over its corresponding amount in jasmine flowers) ranged from 0.22% for α-farnesene to 75.5% for β-myrcene. Moreover, due to additional rounds of heat treatment for scented green tea manufacturing, some volatiles such as carotenoid-derived geraniol and β-ionone and lipid-derived (Z)-jasmone were heat-enhanced and others such as nonanal were heat-desorbed in the scented green tea. Our study revealed that dynamic volatile absorption and desorption collectively determined tea volatile retention and tea aroma. Our findings may have a great potential for practical improvement of tea aroma.

scholarly journals Effects of steaming conditions on tea quality in the manufacturing of green tea (Sencha).

1987 ◽  
pp. 73-80 ◽  
Author(s):  
Kaoru OHMORI ◽  
Shinichiro NAKAMURA ◽  
Toshiro WATANABE ◽  
Kazuya KATSUKI
Keyword(s):  
Green Tea ◽  
Tea Quality

Comparison of Antimutagenic Effect of Various Tea Extracts (Green, Oolong, Pouchong, and Black Tea)

1994 ◽  
Vol 57 (1) ◽  
pp. 54-58 ◽  
Author(s):  
GOW-CHIN YEN ◽  
HUI-YIN CHEN
Keyword(s):  
Salmonella Typhimurium ◽  
Green Tea ◽  
Aflatoxin B1 ◽  
Black Tea ◽  
Inhibitory Effect ◽  
Manufacturing Processes ◽  
Antimutagenic Effect ◽  
Oolong Tea ◽  
Tea Extract

The antimutagenic effects of various tea extracts prepared from nonfermented tea (green tea), semifermented tea (oolong tea and pouchong tea), and fermented tea (black tea) were investigated by Salmonella/microsome assay. No mutagenicity or toxicity in Salmonella typhimurium TA98 and TA100 was observed with any tea extract. The tea extracts markedly inhibited the mutagenicity of 2-amino-3-methylimidazo(4,5-f)quinoline, 3-amino-1,4-dimethyl-5H-pyridol(4,3-b)indole,2-amino-6-methyldipyrido(l,2-a:3′,2′-d)imidazole, benzo[a]pyrene, and aflatoxin B1 toward S. typhimurium TA98 and TA100 in the presence of S9 mixture, especially those of oolong and pouchong teas inhibited over 90% mutagenicity of these five mutagens at the dosage of 1 mg per plate. Among four tea extracts, black tea exhibited the weakest inhibitory effect on mutagenicity of these five mutagens. The mutagenicity of 4-nitroquinoline-N-oxide, a direct mutagen, was not inhibited by black and oolong tea extracts to S. typhimurium TA98 in the absence of S9 mixture but was increased by the tea extracts at the dose of 1 mg per plate to S. typhimurium TA100. As the antimutagenic effect of semifermented tea was stronger than nonfermented and fermented teas, some antimutagenic substances might be formed during manufacturing processes of tea.

Search for Effective Sites of Proximity Gettering Induced by Ion Implantation in Si Wafers with First Principles Calculation

2015 ◽  
Vol 242 ◽  
pp. 271-276
Author(s):  
Sho Shirasawa ◽  
Koji Sueoka
Keyword(s):  
Heat Treatment ◽  
Binding Energy ◽  
Ion Implantation ◽  
Point Defects ◽  
First Principles ◽  
First Principles Calculation ◽  
Manufacturing Processes ◽  
Intrinsic Point Defects

Fe, Ni and Cu atoms diffuse very quickly in Si and are the main targets for metal gettering. W, Hf, and Mo atoms, for example, which diffuse very slowly in Si have also recently become gettering targets in addition to these metals. Therefore, proximity gettering techniques by using ion implantation are being considered. Not only implanted elements but intrinsic point defects exist and form several complexes after the heat treatment for Si crystal recovery. This research systematically investigated the binding energy of twelve important metals (Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Hf, Ta, and W) with implanted dopants (B, C, P, and As) and their complexes with intrinsic point defects (vacancies (Vs) and self-interstitials (Is)) by using first principles calculation. These data should be useful in the design of proximity gettering in LSI manufacturing processes.

Quality Characteristics of Basic Hand Tools Sold in Nigeria

2009 ◽  
Vol 62-64 ◽  
pp. 708-714
Author(s):  
F.A. Oyawale ◽  
M.A. Ogunmolati
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Energy ◽  
Quality Characteristics ◽  
Alloying Elements ◽  
Manufacturing Processes ◽  
Hand Tools ◽  
Three Samples ◽  
Major Property

Hand tools sold in Nigeria have become increasingly unreliable due to critical failures during use. The objective of this study is to test samples of these tools vis-à-vis manufacturer’s claims. A total of fifteen (15) hand tools from six (6) different countries available on the Nigerian market were tested for their quality characteristics. The tested tools included spanners, hammers, screwdrivers, pliers and chisels. Three samples of each of the groups of hand tools were ranked in accordance to their impact energy which is a major property of percussion tools. The results showed that built-in mechanical properties of these hand tools were largely controlled by their alloying elements, manufacturing processes and heat-treatment. Five (5) of the fifteen (15) selected hand tools conformed to BS 876, 1981 and were adjudged safe and reliable.

scholarly journals Chlorophyll as an indicator of green tea quality

2014 ◽  
Vol 83 (10) ◽  
pp. S103-S109 ◽  
Author(s):  
Martina Ošťádalová ◽  
Bohuslava Tremlová ◽  
Jana Pokorná ◽  
Martin Král
Keyword(s):  
Chlorophyll Content ◽  
Green Tea ◽  
Storage Time ◽  
Chlorophyll Concentration ◽  
Storage Period ◽  
Storage Conditions ◽  
Qualitative Variable ◽  
Chlorophyll Contents ◽  
Tea Quality ◽  
The Relationship

The objective of this work was to study the changes in chlorophyll contents in green teas stored under different conditions and to suggest the most suitable way and length of green tea storage. A secondary aim was to evaluate the possibility of using the chlorophyll content as an indicator of tea freshness. Samples for analysis were obtained from a range of tea-growing regions. Chlorophyll contents were measured using UV-vis spectrophotometry. Chlorophyll absorbance was measured at 642.5 and 660 nm. Prior to storage, chlorophyll concentration in teas ranged from 1.12 to 1.89 mg per 1 g of tea, which corresponded to data given by other authors. Storage was found to lead to a decline in chlorophyll concentration. From the 6th month of storage onwards, a significant decrease (P < 0.05) was observed in all samples, irrespective of storage conditions. Based on the findings of this study, original and metal packaging can be considered the most chlorophyll-friendly. On the other hand, glass and paper packaging stored in direct daylight were found to have the strongest impact on chlorophyll concentration. Overall, it can be concluded that the storage time can have a strong influence on oolong green tea colour as an important qualitative variable. Thus, the shelf-life of tea should be shorter than the 12 months claimed by most manufacturers. Once the relationship between changes in chlorophyll concentration and length of the storage period had been established, the chlorophyll content was suggested as an indicator of the storage time (freshness) of a tea substance.

Identification of Potent Odorants in Chinese Jasmine Green Tea Scented with Flowers ofJasminum sambac

2002 ◽  
Vol 50 (17) ◽  
pp. 4878-4884 ◽  
Author(s):  
Yuriko Ito ◽  
Akio Sugimoto ◽  
Takami Kakuda ◽  
Kikue Kubota
Keyword(s):  
Green Tea ◽  
Potent Odorants

scholarly journals Effect of Ferrous Ion on Heat-Induced Aroma Deterioration of Green Tea Infusion

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4255
Author(s):  
Ying Gao ◽  
Jie-Qiong Wang ◽  
Jian-Xin Chen ◽  
Fang Wang ◽  
Gen-Sheng Chen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Hydrogen Peroxide ◽  
Green Tea ◽  
Underlying Mechanism ◽  
Ferrous Ion ◽  
Tea Infusion ◽  
Ms Analysis ◽  
Production Of Hydrogen ◽  
Aroma Characteristics

Aroma deterioration is one of the biggest problems in processing tea beverages. The aroma of tea infusion deteriorates fast during heat sterilization and the presence of ferrous ion (Fe2+) aggravates it. The underlying mechanism remains unveiled. In this study, Fe2+ was verified to deteriorate the aroma quality of green tea infusion with heat treatment. Catechins were necessary for Fe2+-mediated aroma deterioration. By enhancing the degradation of catechins, Fe2+ dramatically increased the production of hydrogen peroxide (H2O2). Fe2+ and H2O2 together exacerbated the aroma of green tea infusion with heat treatment. GC-MS analysis revealed that the presence of Fe2+ enhanced the loss of green/grassy volatiles and promoted the formation of new volatiles with diversified aroma characteristics, resulting in a dull scent of green tea infusion. Our results revealed how Fe2+ induced aroma deterioration of green tea infusion with heat treatment and could help guide tea producers in attenuating the aroma deterioration of tea infusion during processing.

Powdered Metal Heat Treatment Apparatus Designed for a Laboratory

2020 ◽  
Author(s):  
Jacob Porter ◽  
John Parmigiani
Keyword(s):  
Heat Treatment ◽  
Additive Manufacturing ◽  
Material Properties ◽  
Powder Flow ◽  
Manufacturing Processes ◽  
Metal Production ◽  
Handling System ◽  
Powdered Metal ◽  
Flow Through ◽  
Metal Additive

Abstract Metal additive manufacturing is a rapidly growing and sophisticated industry however the manufacturing processes and equipment for the heat treatment of the needed powdered metals is underdeveloped. Heat treatment is a key step in the powdered metal production process and is often needed to produce desired material properties. The objective of this paper is to examine the design of a heat treatment machine that addresses the needs of a laboratory performing research on powdered metals. The device was designed to address the three criteria of a heat treatment device; treatment, environment, and containment. The treatment criterion is accomplished by continuous powder flow through a furnace. The environment criterion is accomplished through a gas handling system capable of creating both an argon and vacuum environment. Finally, the containment criterion is accomplished through a network of tubes that provides structure to contain the powder. The design of this machine will allow research and development labs to heat treat powdered to a higher quality at a significantly faster rate.

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