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Giacomin CE, Chen RY, Hack E, Fischer P. Tea film formation in artificial tap water. SOFT MATTER 2023; 19:5967-5977. [PMID: 37491884 PMCID: PMC10411494 DOI: 10.1039/d3sm00169e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/19/2023] [Indexed: 07/27/2023]
Abstract
On the surface of tea infusions, the formation of a transparent, shiny film which cracks upon disturbance can often be observed. This study aims to determine how water composition, tea varieties, and tea additives impact the formation and properties of tea film, often also called tea scum. The strength of the surface film, composed of polyphenols complexed with various ions from tap water, was investigated by interfacial rheology. Microscopy and ellipsometry were used to investigate structure and thickness of the adsorption layer, respectively. We find that green tea forms more visible layers than black tea in soft and moderate artificial tap water, but in these same waters, black tea demonstrated greater surface strength. In hard artificial tap water, green tea demonstrated greater surface strength than black. No visible layer nor surface strengthening was observed on rooibos tea. Brews in hard artificial tap water formed brittle films for green tea, fracturing at strains one order of magnitude lower than in soft or moderate. Despite large variations in film strength, black tea at all water hardness levels tested formed a film with 20 nm thickness. In black tea an increased resilience to deformation was found when adding β-casein, a protein found in milk.
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Affiliation(s)
- Caroline E Giacomin
- ETH Zürich, Institute of Food Nutrition and Health, Schmelzbergstrasse 7, 8092 Zürich, Switzerland.
| | - Rebecca Yun Chen
- ETH Zürich, Institute of Food Nutrition and Health, Schmelzbergstrasse 7, 8092 Zürich, Switzerland.
| | - Erwin Hack
- EMPA, Transport at Nanoscale Interfaces, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Peter Fischer
- ETH Zürich, Institute of Food Nutrition and Health, Schmelzbergstrasse 7, 8092 Zürich, Switzerland.
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Xu H, Luo Z, Hu W, Jia Y, Wang Y, Ye X, Li Y, Chen LS, Guo J. Magnesium absorption, translocation, subcellular distribution and chemical forms in citrus seedlings. TREE PHYSIOLOGY 2022; 42:862-876. [PMID: 34791459 DOI: 10.1093/treephys/tpab148] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 11/02/2021] [Indexed: 05/27/2023]
Abstract
Magnesium (Mg) is an essential macronutrient for plant growth and development; however, the adaptive mechanisms of Mg deficiency to underlying changes in Mg translocation, subcellular distribution and chemical forms in citrus plants are unknown. In this study, we conducted a sand culture experiment with 0 (Mg-deficiency) or 2 (Mg-sufficiency) mmol l-1 Mg2+ treatments to investigate the responses underlying Mg adaptability, as well as the resulting growth and Mg transport features in citrus seedlings [Citrus sinensis (L.) Osbeck cv. 'Xuegan']. We found that Mg-deficiency significantly depressed biomass by 39% in the whole plant and by 66% in branch organs compared with Mg-sufficient conditions, which further resulted in a subsequent decrease in Mg concentration and accumulation with changes in its distribution in different organs and a reduction in root growth. Under Mg-sufficiency, >50% of Mg was sequestered in the soluble fraction and this was reduced by 30% under Mg-deficiency. Furthermore, >70% of Mg existed as inorganic (42%) and water-soluble (31%) forms with high mobility across treatments and organs. Under Mg-deficiency, the proportion of water-soluble Mg was reduced in leaf and increased in root, whereas the proportion of inorganic Mg increased in main stem leaves and decreased in branch leaves and root. However, under Mg-deficiency, the proportion of Mg forms with low mobility, including pectates and proteins, phosphates, oxalates and residues, was increased in leaf and root organs, with the exception of pectate and protein Mg, which was decreased in root. The Mg transfer factor showed that Mg-deficiency improved Mg transport from parent to branch organs, which was related to Mg subcellular distribution and chemical forms. Taken together, our study establishes a defined process to clarify the mechanisms of Mg absorption and translocation and reveals a possible strategy to effectively improve Mg mobility and availability in citrus plants.
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Affiliation(s)
- Hao Xu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
| | - Ziwei Luo
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
- International Magnesium Institute, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
| | - Wenlang Hu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
| | - Yamin Jia
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
- College of Forestry, Guangxi University, No. 100 Daxuedong Road, Xixiangtang District, Nanning 530004, China
| | - Yuwen Wang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
- International Magnesium Institute, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
| | - Xin Ye
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
| | - Yan Li
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
| | - Li-Song Chen
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
| | - Jiuxin Guo
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
- International Magnesium Institute, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou 350002, China
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Determination of aluminum and zinc in Iranian consumed tea. ENVIRONMENTAL MONITORING AND ASSESSMENT 2007; 144:23-30. [PMID: 18046615 DOI: 10.1007/s10661-007-0006-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Accepted: 08/27/2007] [Indexed: 12/07/2022]
Abstract
To determine aluminum and zinc in Iranian consumed tea, 31 tea samples were analysed for Al and Zn concentration of tea leaves and tea infusion. The results show that average concentration of Al and Zn in tea leaves was 326 and 50.7 mg. Kg(-1) respectively in this regard Nemoneh and Shahrzad show the highest and lowest concentration respectively in term of Al, also Debsh and Alkozi follow same situation in Zn concentration. Also the solubility of metals in the first infusion was significantly (Al, Zn: P < 0.01) higher than the second infusion and the solubility in the second infusion was also significantly higher than the third infusion (Al: P < 0.01; Zn: P < 0.05). Al leachate in the first infusion (2 min) for Mosama and Seilan tea was highest and lowest respectively. Also in the second and third infusion (5 and 10 min) Golkis and Nemoneh tea show the highest and lowest figures respectively. On the other hand, data from Zn transfer in tea infusion in the first infusion show that Mosama and Ahmad Atry tea have the highest and lowest leachate percentage respectively, while in the second and third infusion Mosama and Golkis tea follow the same situation. Calculation of percentage 'available' Al and Zn to the human system showed that 1 l of tea can provide 37.2% of the daily dietary intake of Al, the percentage 'available' for absorption in the intestine is only 1.78% for overall mean Al concentration. Also daily dietary intake of Zn was 2.13% while percentage available for absorption in the intestine was 0.72%.
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Nas S, Gokalp HY, Sahin Y. K and Ca content of fresh green tea, black tea, and tea residue determined by X-ray fluorescence analysis. ZEITSCHRIFT FUR LEBENSMITTEL-UNTERSUCHUNG UND -FORSCHUNG 1993; 196:32-7. [PMID: 8438623 DOI: 10.1007/bf01192981] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
X-Ray fluorescence (XRF) can be successfully used for the qualitative and quantitative elemental analysis of various agricultural products. Its simplicity, high throughput and the possibility of automation make it useful for screening large numbers of samples. The K and Ca content of 138 samples of fresh green tea, black tea and black tea residues were determined by applying the XRF system. Such a method of mineral analysis of food products is not very common. Tea from different tea-growing areas of Turkey, green tea of different shooting periods, black tea processed at different tea plants and tea residues from these black tea were analysed. The K content of green tea, processed black tea and tea residues after brewing were found to have ranges of 19,049-26,254 mg/kg, 21,904-26,883 mg/kg and 9,468-13,778 mg/kg, respectively. In the same samples the Ca content was determined as 3,580-4,799 mg/kg, 3,370-4,823 mg/kg, and 3,743-5,733 mg/kg, respectively. These findings were compared with the results of atomic emission techniques and it was concluded that the XRF system could be effectively used for quantitative analysis of the K and Ca content of tea samples.
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Affiliation(s)
- S Nas
- Atatürk University, Food Science-Technology Department, Erzurum, Turkey
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