用含钙离子水冲泡速溶茶粉,研究了不同浓度钙离子对绿茶茶汤沉淀形成的影响,以及钙离子对不同发酵程度茶类茶汤沉淀形成的影响。结果表明,随着钙离子质量浓度（5~40 mg·L-1）的增加,绿茶茶汤的沉淀量呈逐渐增加趋势,钙离子质量浓度与绿茶沉淀量之间具有显著正相关（r=0.98,P<0.01）,而沉淀中的茶多酚（r=0.95,P<0.01）、总糖（r=0.99,P<0.01）和咖啡碱（r=0.82,P<0.05）含量也与沉淀量呈显著正相关。相同钙离子浓度下,绿茶、铁观音、武夷岩茶、红茶、普洱茶茶汤沉淀形成量差异较大。随着茶叶发酵程度的加重,茶汤沉淀量呈增加的趋势,而钙离子对茶汤沉淀形成的促进作用逐步降低。通过分析发现,钙离子促进沉淀形成的增长率与茶汤中茶多酚所占的比率有显著相关性（r=0.78,P<0.05）,说明钙离子可能是主要通过影响茶多酚的络合作用来促进茶汤沉淀的形成。
In order to investigate the effect of Ca2+ on sediment formation in tea infusion, which was prepared by dissolving different instant tea powders with the water containing different concentrations of Ca2+, the amount and chemical components contents of tea sediment were analyzed. The results showed that, the amount of tea sediment increased with the increasing concentration of Ca2+ (5 to 40 mg·L-1) in green tea infusion and there was significant positive correlation (r=0.98,P<0.01) between the amount of tea sediment and Ca2+ concentration. The contents of polyphenols (r=0.95,P<0.01), total sugars (r=0.99,P<0.01), caffeine (r=0.82,P<0.05) were also found to be highly correlated with the amount of tea sediment. Under the treatment of the same Ca2+ concentration, the amount of tea sediment of green tea, Tiguanyin tea, Wuyi tea, black tea and Pu′er tea were significant different. With the deepening of fermentation degree of different teas, the amount of sediment in different tea infusion increased. However, the effect of Ca2+ on tea sediment formation decreased. After analysis, there was a significant correlation (r=0.78,P<0.05) between the polyphenols contents in tea infusions and the increasing rates of tea sediments. It indicated that Ca2+ could improve tea sediment formation by affecting the behavior of polyphenols.
[1] Xu Y Q, Chen S Q, Shen D Y, et al. Effects of Chemical Components on the Amount of Green Tea Cream[J]. Agricultural Sciences in China, 2011, 10(6): 969-974.
[2] 许勇泉, 陈根生, 袁海波, 等. 浸提时间对绿茶茶汤沉淀形成的影响[J]. 中国食品学报, 2012, 12(12): 98-102.
[3] Liang Y R, Xu Y R.Effect of extraction temperature on cream and extractability of black tea[J]. International Journal of Food Science and Technology, 2003, 38: 37-45.
[4] Liang Y R, Xu Y R.Effect of pH on cream particle formation and solids extraction yield of black tea[J]. Food Chemistry, 2001. 74: 155-160.
[5] Yin J F, Xu Y Q, Yuan H B, et al. Cream formation and main chemical components of green tea infusions processed from different parts of new shoots[J]. Food Chemistry, 2009, 114(2): 665-670.
[6] Mossion A, Potin-Gautier M, Delerue S, et al. Effect of Water Composition on Aluminium, Calcium and Organic Carbon Extraction in Tea Infusions[J]. Food Chemistry, 2008, 106: 1467-1475.
[7] 钟小玉, 许勇泉, 尹军峰, 等. Ca2+-Mg2+-Al3+复配对绿茶茶汤感官及理化品质的影响[J]. 中国农学通报, 2012, 28(6): 227-231.
[8] 许勇泉, 陈根生, 钟小玉, 等. 钙离子对绿茶浸提茶汤理化与感官品质的影响[J]. 茶叶科学, 2011, 31(3): 230-236.
[9] 郭炳莹, 程启坤. 茶汤组分与金属离子的络合性能[J]. 茶叶科学, 1991, 11(2): 139-144.
[10] Kim Y, Talcott S T.Tea Creaming in Nonfermented Teas from Camellia Sinensis and Ilex Vomitoria[J]. Journal of Agricultural and Food Chemistry, 2012, 60: 11793-11799.
[11] Xu Y Q, Zhong X Y, Yin J F, et al. The impact of Ca2+ combination with organic acids on green tea infusions[J]. Food Chemistry, 2013, 139: 944-948.
[12] Jackson L S, Lee K.Chemical Forms of Iron, Calcium, Magnesium and Zinc in Black, Oolong, Green and Instant Black Tea[J]. Journal of Food Science, 1988, 50: 181-184.
[13] 钟萝. 茶叶品质理化分析[M]. 上海: 上海科学技术出版社, 1989: 250-350.
[14] Liang Y, Lu J, Zhang L.Comparative study of cream in infusions of black tea and green tea[J]. International Journal of Food Science and Technology, 2002, 37: 627-634.
[15] Sato T, Kinoshita Y, Tsutusmi H, et al. Characterization of Creaming Precipitate of Tea Catechins and Caffeine in Aqueous Solution[J]. Chem Pharm Bull, 2012, 60(9): 1182-1187.
[16] Jobstl E, Fairclough J P A, Davies A P, et al. Creaming in Black Tea[J]. Journal of Agricultural and Food Chemistry, 2005, 53(20): 7997-8002.
[17] Couzinet-Mossion A, Balayssac S, Gilard V, et al. Interaction mechanisms between caffeine and polyphenols in infusions of Camellia Sinensis leaves[J]. Food Chemistry, 2010, 119: 173-181.
[18] Kolayl S, Ocak M, Küçük M, et al. Does caffeine bind to metal ions?[J]. Food Chemistry, 2004, 84: 383-388.
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