Effect of Water Hardness on Green Tea Infusions


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  • 水の硬度が緑茶浸出液に及ぼす影響
  • ミズ ノ コウド ガ リョクチャ シンシュツエキ ニ オヨボス エイキョウ

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The effect of water hardness on the palatability of green tea infusions was analyzed by measuring the amounts of chemical components in the infusions and by sensory evaluation. The amount of white precipitate in the infusions increased in proportion to the hardness. The colour of the infusions deepened in proportion to the hardness, because the b* (yellow) value increased and the L* (brightness) value decreased. The concentration of epigallocatechin and epigallocatechin gallate in the infusions decreased with an increase in water hardness. The vitamin C content in the infusions decreased significantly with an increase in water hardness. On the other hand, the concentrations of free amino acids, caffeine, and free sugars in the infusions did not vary significantly with the type of water used.<br>Green tea infused with Filette-brand water was judged to show significantly stronger turbidity and sweetness than tea infused with distilled water. By sensory evaluation, tea infused with Filette-brand water was preferred over that infused with distilled water.



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