The Experts below are selected from a list of 3360 Experts worldwide ranked by ideXlab platform
Ziyin Yang - One of the best experts on this subject based on the ideXlab platform.
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formation of and changes in phytohormone levels in response to stress during the manufacturing process of Oolong Tea camellia sinensis
Postharvest Biology and Technology, 2019Co-Authors: Lanting Zeng, Fang Dong, Xuewen Wang, Yinyin Liao, Dachuan Gu, Ziyin YangAbstract:Abstract As important upstream signals, phytohormones regulate the plant volatiles’ biosynthesis under various stresses. The formation of some characteristic aromas during the manufacturing process of Oolong Tea (postharvest stage) is due to the defense responses of Tea leaves to stress. This study investigates the formation of phytohormone in response to stresses during the manufacturing process of Oolong Tea. Jasmonic acid (JA) and abscisic acid (ABA) levels enhanced during the manufacturing processes (enzyme-active stage) of Oolong Tea. Wounding from plucking activated JA synthetic gene expression, resulting in increased levels of JA (p ≤ 0.01), and continuous wounding from the turn over stage further enhanced JA synthesis (p ≤ 0.05). Dehydration stress during the withering stage activated ABA synthetic gene expression resulting in an increase of ABA (p ≤ 0.01). The study advances the understanding of key upstream signals, JA and ABA, during the manufacturing process of Oolong Tea.
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does Oolong Tea camellia sinensis made from a combination of leaf and stem smell more aromatic than leaf only Tea contribution of the stem to Oolong Tea aroma
Food Chemistry, 2017Co-Authors: Lanting Zeng, Ying Zhou, Xiumin Fu, Fang Dong, Sihua Cheng, Jinchi Tang, Ziyin YangAbstract:Abstract The raw materials used to make Oolong Tea (Camellia sinensis) are a combination of leaf and stem. Oolong Tea made from leaf and stem is thought to have a more aromatic smell than leaf-only Tea. However, there is no available evidence to support the viewpoint. In this study, sensory evaluation and detailed characterization of emitted and internal volatiles (not readily emitted, but stored in samples) of dry Oolong Teas and infusions indicated that the presence of stem did not significantly improve the total aroma characteristics. During the enzyme-active processes, volatile monoterpenes and theanine were accumulated more abundantly in stem than in leaf, while jasmine lactone, indole, and trans-nerolidol were lower in stem than in leaf. Tissue-specific aroma-related gene expression and availability of precursors of aroma compounds resulted in different aroma distributions in leaf and stem. This study presents the first determination of the contribution of stem to Oolong Tea aroma.
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formation of volatile Tea constituent indole during the Oolong Tea manufacturing process
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Lanting Zeng, Ying Zhou, Xiumin Fu, Yunpeng Zhen, Tingxiang Ye, Bing Du, Fang Dong, Naoharu Watanabe, Ziyin YangAbstract:Indole is a characteristic volatile constituent in Oolong Tea. Our previous study indicated that indole was mostly accumulated at the turn over stage of Oolong Tea manufacturing process. However, formation of indole in Tea leaves remains unknown. In this study, one tryptophan synthase α-subunit (TSA) and three tryptophan synthase β-subunits (TSBs) from Tea leaves were isolated, cloned, sequenced, and functionally characterized. Combination of CsTSA and CsTSB2 recombinant protein produced in Escherichia coli exhibited the ability of transformation from indole-3-glycerol phosphate to indole. CsTSB2 was highly expressed during the turn over process of Oolong Tea. Continuous mechanical damage, simulating the turn over process, significantly enhanced the expression level of CsTSB2 and amount of indole. These suggested that accumulation of indole in Oolong Tea was due to the activation of CsTSB2 by continuous wounding stress from the turn over process. Black Teas contain much less indole, although wounding stre...
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does enzymatic hydrolysis of glycosidically bound volatile compounds really contribute to the formation of volatile compounds during the Oolong Tea manufacturing process
Journal of Agricultural and Food Chemistry, 2015Co-Authors: Xiumin Fu, Ying Zhou, Fang Dong, Naoharu Watanabe, Tsuyoshi Katsuno, Rufang Deng, Xinlan Xu, Linyun Zhang, Ziyin YangAbstract:It was generally thought that aroma of Oolong Tea resulted from hydrolysis of glycosidically bound volatiles (GBVs). In this study, most GBVs showed no reduction during the Oolong Tea manufacturing process. β-Glycosidases either at protein or gene level were not activated during the manufacturing process. Subcellular localization of β-primeverosidase provided evidence that β-primeverosidase was located in the leaf cell wall. The cell wall remained intact during the enzyme-active manufacturing process. After the leaf cell disruption, GBV content was reduced. These findings reveal that, during the enzyme-active process of Oolong Tea, nondisruption of the leaf cell walls resulted in impossibility of interaction of GBVs and β-glycosidases. Indole, jasmine lactone, and trans-nerolidol were characteristic volatiles produced from the manufacturing process. Interestingly, the contents of the three volatiles was reduced after the leaf cell disruption, suggesting that mechanical damage with the cell disruption, whi...
Lanting Zeng - One of the best experts on this subject based on the ideXlab platform.
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formation of and changes in phytohormone levels in response to stress during the manufacturing process of Oolong Tea camellia sinensis
Postharvest Biology and Technology, 2019Co-Authors: Lanting Zeng, Fang Dong, Xuewen Wang, Yinyin Liao, Dachuan Gu, Ziyin YangAbstract:Abstract As important upstream signals, phytohormones regulate the plant volatiles’ biosynthesis under various stresses. The formation of some characteristic aromas during the manufacturing process of Oolong Tea (postharvest stage) is due to the defense responses of Tea leaves to stress. This study investigates the formation of phytohormone in response to stresses during the manufacturing process of Oolong Tea. Jasmonic acid (JA) and abscisic acid (ABA) levels enhanced during the manufacturing processes (enzyme-active stage) of Oolong Tea. Wounding from plucking activated JA synthetic gene expression, resulting in increased levels of JA (p ≤ 0.01), and continuous wounding from the turn over stage further enhanced JA synthesis (p ≤ 0.05). Dehydration stress during the withering stage activated ABA synthetic gene expression resulting in an increase of ABA (p ≤ 0.01). The study advances the understanding of key upstream signals, JA and ABA, during the manufacturing process of Oolong Tea.
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does Oolong Tea camellia sinensis made from a combination of leaf and stem smell more aromatic than leaf only Tea contribution of the stem to Oolong Tea aroma
Food Chemistry, 2017Co-Authors: Lanting Zeng, Ying Zhou, Xiumin Fu, Fang Dong, Sihua Cheng, Jinchi Tang, Ziyin YangAbstract:Abstract The raw materials used to make Oolong Tea (Camellia sinensis) are a combination of leaf and stem. Oolong Tea made from leaf and stem is thought to have a more aromatic smell than leaf-only Tea. However, there is no available evidence to support the viewpoint. In this study, sensory evaluation and detailed characterization of emitted and internal volatiles (not readily emitted, but stored in samples) of dry Oolong Teas and infusions indicated that the presence of stem did not significantly improve the total aroma characteristics. During the enzyme-active processes, volatile monoterpenes and theanine were accumulated more abundantly in stem than in leaf, while jasmine lactone, indole, and trans-nerolidol were lower in stem than in leaf. Tissue-specific aroma-related gene expression and availability of precursors of aroma compounds resulted in different aroma distributions in leaf and stem. This study presents the first determination of the contribution of stem to Oolong Tea aroma.
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formation of volatile Tea constituent indole during the Oolong Tea manufacturing process
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Lanting Zeng, Ying Zhou, Xiumin Fu, Yunpeng Zhen, Tingxiang Ye, Bing Du, Fang Dong, Naoharu Watanabe, Ziyin YangAbstract:Indole is a characteristic volatile constituent in Oolong Tea. Our previous study indicated that indole was mostly accumulated at the turn over stage of Oolong Tea manufacturing process. However, formation of indole in Tea leaves remains unknown. In this study, one tryptophan synthase α-subunit (TSA) and three tryptophan synthase β-subunits (TSBs) from Tea leaves were isolated, cloned, sequenced, and functionally characterized. Combination of CsTSA and CsTSB2 recombinant protein produced in Escherichia coli exhibited the ability of transformation from indole-3-glycerol phosphate to indole. CsTSB2 was highly expressed during the turn over process of Oolong Tea. Continuous mechanical damage, simulating the turn over process, significantly enhanced the expression level of CsTSB2 and amount of indole. These suggested that accumulation of indole in Oolong Tea was due to the activation of CsTSB2 by continuous wounding stress from the turn over process. Black Teas contain much less indole, although wounding stre...
Fang Dong - One of the best experts on this subject based on the ideXlab platform.
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formation of and changes in phytohormone levels in response to stress during the manufacturing process of Oolong Tea camellia sinensis
Postharvest Biology and Technology, 2019Co-Authors: Lanting Zeng, Fang Dong, Xuewen Wang, Yinyin Liao, Dachuan Gu, Ziyin YangAbstract:Abstract As important upstream signals, phytohormones regulate the plant volatiles’ biosynthesis under various stresses. The formation of some characteristic aromas during the manufacturing process of Oolong Tea (postharvest stage) is due to the defense responses of Tea leaves to stress. This study investigates the formation of phytohormone in response to stresses during the manufacturing process of Oolong Tea. Jasmonic acid (JA) and abscisic acid (ABA) levels enhanced during the manufacturing processes (enzyme-active stage) of Oolong Tea. Wounding from plucking activated JA synthetic gene expression, resulting in increased levels of JA (p ≤ 0.01), and continuous wounding from the turn over stage further enhanced JA synthesis (p ≤ 0.05). Dehydration stress during the withering stage activated ABA synthetic gene expression resulting in an increase of ABA (p ≤ 0.01). The study advances the understanding of key upstream signals, JA and ABA, during the manufacturing process of Oolong Tea.
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does Oolong Tea camellia sinensis made from a combination of leaf and stem smell more aromatic than leaf only Tea contribution of the stem to Oolong Tea aroma
Food Chemistry, 2017Co-Authors: Lanting Zeng, Ying Zhou, Xiumin Fu, Fang Dong, Sihua Cheng, Jinchi Tang, Ziyin YangAbstract:Abstract The raw materials used to make Oolong Tea (Camellia sinensis) are a combination of leaf and stem. Oolong Tea made from leaf and stem is thought to have a more aromatic smell than leaf-only Tea. However, there is no available evidence to support the viewpoint. In this study, sensory evaluation and detailed characterization of emitted and internal volatiles (not readily emitted, but stored in samples) of dry Oolong Teas and infusions indicated that the presence of stem did not significantly improve the total aroma characteristics. During the enzyme-active processes, volatile monoterpenes and theanine were accumulated more abundantly in stem than in leaf, while jasmine lactone, indole, and trans-nerolidol were lower in stem than in leaf. Tissue-specific aroma-related gene expression and availability of precursors of aroma compounds resulted in different aroma distributions in leaf and stem. This study presents the first determination of the contribution of stem to Oolong Tea aroma.
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formation of volatile Tea constituent indole during the Oolong Tea manufacturing process
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Lanting Zeng, Ying Zhou, Xiumin Fu, Yunpeng Zhen, Tingxiang Ye, Bing Du, Fang Dong, Naoharu Watanabe, Ziyin YangAbstract:Indole is a characteristic volatile constituent in Oolong Tea. Our previous study indicated that indole was mostly accumulated at the turn over stage of Oolong Tea manufacturing process. However, formation of indole in Tea leaves remains unknown. In this study, one tryptophan synthase α-subunit (TSA) and three tryptophan synthase β-subunits (TSBs) from Tea leaves were isolated, cloned, sequenced, and functionally characterized. Combination of CsTSA and CsTSB2 recombinant protein produced in Escherichia coli exhibited the ability of transformation from indole-3-glycerol phosphate to indole. CsTSB2 was highly expressed during the turn over process of Oolong Tea. Continuous mechanical damage, simulating the turn over process, significantly enhanced the expression level of CsTSB2 and amount of indole. These suggested that accumulation of indole in Oolong Tea was due to the activation of CsTSB2 by continuous wounding stress from the turn over process. Black Teas contain much less indole, although wounding stre...
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does enzymatic hydrolysis of glycosidically bound volatile compounds really contribute to the formation of volatile compounds during the Oolong Tea manufacturing process
Journal of Agricultural and Food Chemistry, 2015Co-Authors: Xiumin Fu, Ying Zhou, Fang Dong, Naoharu Watanabe, Tsuyoshi Katsuno, Rufang Deng, Xinlan Xu, Linyun Zhang, Ziyin YangAbstract:It was generally thought that aroma of Oolong Tea resulted from hydrolysis of glycosidically bound volatiles (GBVs). In this study, most GBVs showed no reduction during the Oolong Tea manufacturing process. β-Glycosidases either at protein or gene level were not activated during the manufacturing process. Subcellular localization of β-primeverosidase provided evidence that β-primeverosidase was located in the leaf cell wall. The cell wall remained intact during the enzyme-active manufacturing process. After the leaf cell disruption, GBV content was reduced. These findings reveal that, during the enzyme-active process of Oolong Tea, nondisruption of the leaf cell walls resulted in impossibility of interaction of GBVs and β-glycosidases. Indole, jasmine lactone, and trans-nerolidol were characteristic volatiles produced from the manufacturing process. Interestingly, the contents of the three volatiles was reduced after the leaf cell disruption, suggesting that mechanical damage with the cell disruption, whi...
Xiumin Fu - One of the best experts on this subject based on the ideXlab platform.
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does Oolong Tea camellia sinensis made from a combination of leaf and stem smell more aromatic than leaf only Tea contribution of the stem to Oolong Tea aroma
Food Chemistry, 2017Co-Authors: Lanting Zeng, Ying Zhou, Xiumin Fu, Fang Dong, Sihua Cheng, Jinchi Tang, Ziyin YangAbstract:Abstract The raw materials used to make Oolong Tea (Camellia sinensis) are a combination of leaf and stem. Oolong Tea made from leaf and stem is thought to have a more aromatic smell than leaf-only Tea. However, there is no available evidence to support the viewpoint. In this study, sensory evaluation and detailed characterization of emitted and internal volatiles (not readily emitted, but stored in samples) of dry Oolong Teas and infusions indicated that the presence of stem did not significantly improve the total aroma characteristics. During the enzyme-active processes, volatile monoterpenes and theanine were accumulated more abundantly in stem than in leaf, while jasmine lactone, indole, and trans-nerolidol were lower in stem than in leaf. Tissue-specific aroma-related gene expression and availability of precursors of aroma compounds resulted in different aroma distributions in leaf and stem. This study presents the first determination of the contribution of stem to Oolong Tea aroma.
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formation of volatile Tea constituent indole during the Oolong Tea manufacturing process
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Lanting Zeng, Ying Zhou, Xiumin Fu, Yunpeng Zhen, Tingxiang Ye, Bing Du, Fang Dong, Naoharu Watanabe, Ziyin YangAbstract:Indole is a characteristic volatile constituent in Oolong Tea. Our previous study indicated that indole was mostly accumulated at the turn over stage of Oolong Tea manufacturing process. However, formation of indole in Tea leaves remains unknown. In this study, one tryptophan synthase α-subunit (TSA) and three tryptophan synthase β-subunits (TSBs) from Tea leaves were isolated, cloned, sequenced, and functionally characterized. Combination of CsTSA and CsTSB2 recombinant protein produced in Escherichia coli exhibited the ability of transformation from indole-3-glycerol phosphate to indole. CsTSB2 was highly expressed during the turn over process of Oolong Tea. Continuous mechanical damage, simulating the turn over process, significantly enhanced the expression level of CsTSB2 and amount of indole. These suggested that accumulation of indole in Oolong Tea was due to the activation of CsTSB2 by continuous wounding stress from the turn over process. Black Teas contain much less indole, although wounding stre...
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does enzymatic hydrolysis of glycosidically bound volatile compounds really contribute to the formation of volatile compounds during the Oolong Tea manufacturing process
Journal of Agricultural and Food Chemistry, 2015Co-Authors: Xiumin Fu, Ying Zhou, Fang Dong, Naoharu Watanabe, Tsuyoshi Katsuno, Rufang Deng, Xinlan Xu, Linyun Zhang, Ziyin YangAbstract:It was generally thought that aroma of Oolong Tea resulted from hydrolysis of glycosidically bound volatiles (GBVs). In this study, most GBVs showed no reduction during the Oolong Tea manufacturing process. β-Glycosidases either at protein or gene level were not activated during the manufacturing process. Subcellular localization of β-primeverosidase provided evidence that β-primeverosidase was located in the leaf cell wall. The cell wall remained intact during the enzyme-active manufacturing process. After the leaf cell disruption, GBV content was reduced. These findings reveal that, during the enzyme-active process of Oolong Tea, nondisruption of the leaf cell walls resulted in impossibility of interaction of GBVs and β-glycosidases. Indole, jasmine lactone, and trans-nerolidol were characteristic volatiles produced from the manufacturing process. Interestingly, the contents of the three volatiles was reduced after the leaf cell disruption, suggesting that mechanical damage with the cell disruption, whi...
Yukio Kakuda - One of the best experts on this subject based on the ideXlab platform.
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production quality and biological effects of Oolong Tea camellia sinensis
Food Reviews International, 2010Co-Authors: Yulong Chen, Jun Duan, Yueming Jiang, Litao Peng, Yukio KakudaAbstract:Oolong Tea is a semi-fermented Chinese traditional Tea that dates back centuries and now its unique characteristics are attracting more and more consumers worldwide. The formation of Oolong Tea's special quality is attributed to the proper processing of the fresh Tea leaf. The quality of Oolong Tea can be evaluated by aroma, flavor, color, and appearance with aroma and flavor being the two most important quality indices. The formation of the distinct aroma of Oolong Tea depends largely on the decomposition of lipids and carotenoids. However, other compounds that can be hydrolyzed and/or oxidized also contribute to Oolong Tea's special aroma. During the processing of Oolong Tea, some major flavor compounds are formed by the oxidation of catechins, amino acids, and sugars. The flavor of Oolong Tea is complex due to the interaction of many different flavor compounds. Oolong Tea exhibits antioxidant, anticancer, antiobesity, prevention of atherosclerosis and heart disease, antidiabetes, and antiallergic effec...
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variation in catechin contents in relation to quality of huang zhi xiang Oolong Tea camellia sinensis at various growing altitudes and seasons
Food Chemistry, 2010Co-Authors: Yulong Chen, Jun Duan, Yueming Jiang, Yukio KakudaAbstract:Abstract The variations in the contents of catechins and phenolic compounds in relation to the quality scores (QS) and taste scores (TS) in the ‘ Huang Zhi Xiang ’ Oolong Tea grown in different seasons and at different altitudes were determined. The study demonstrated that the contents of (−)-epigallocatechin gallate (EGCG), catechin gallate (CG), and total catechins (TC) in the Oolong Teas grown at a high altitude were significantly higher than those grown at a low altitude. Furthermore, the contents of EGCG, CG, and TC in the autumn Tea were significantly higher than those from the spring Tea grown at a low altitude. However, no significant differences in the contents of EGCG, CG, and TC were observed between the spring and autumn Teas grown at a high altitude. In addition, the contents of (−)-epigallocatechin (EGC), (+)-catechin (C), (−)-gallocatechin (GC), and simple catechins (SC) in the spring Tea leaves were significantly higher than those in the autumn Tea leaves grown at a low altitude, but they were not significantly different from those in the autumn Tea leaves grown at a high altitude. The contents of EGCG, CG, and TC in the Oolong Teas were positively and significantly correlated to the taste score (TS) and quality score (QS) of the Oolong Tea. Thus, the contents of EGCG, CG, and TC could be the important quality parameters of the ‘ Huang Zhi Xiang ’ Oolong Tea. This work suggested that the production of the ‘ Huang Zhi Xiang ’ Oolong Tea grown at low altitudes should utilize the autumn Tea leaves while the production of Oolong Tea grown at high altitudes can use both the spring and autumn Tea leaves.
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Effects of soaking conditions on the antioxidant potentials of Oolong Tea
Journal of Food Composition and Analysis, 2006Co-Authors: Xinguo Su, Jun Duan, Yueming Jiang, Yukio KakudaAbstract:Abstract The antioxidant properties of water extracts of Oolong Tea (Commercial name: Fenghuangdancong) prepared using different soaking temperatures and times were investigated. The yield of powdered extract ranged from 6.7% at 80 °C for 3 min soaking to 22.7% at 100 °C for 10-min soaking. Oolong Tea extracts reduced peroxidation of peanut oil and delayed the time of POV20 (peroxide value). Among these soaking treatments, soaking for 10 min in 100 °C water produced extracts with the greatest ability to inhibit the peroxidation of peanut oil. As well, the SC50 (scavenging-percentage) of the α , α -diphenyl- β -picrylhydrazyl radical (DPPH radical) was 0.119 mL of Oolong Tea extract using 3-min soaking at 100 °C, which is closed to the SC50 of 0.109 mL (2 mg/mL) for vitamin C. The DPPH radical scavenging activity of Oolong Tea extracts increased with increasing temperature of the soaking water indicating greater extraction of antioxidant compounds. In addition, inhibition of oxidation of peanut oil and DPPH radical scavenging activity by water extract of Oolong Tea was associated with polyphenol concentrations. Sensory assessment, found that the water extract of Oolong Tea using 3-min soaking at 95 °C had the strongest aroma and sweetness attributes.
