Period 6 element also dissolves in alkaline solutions of cyanide, which have been used in mining. Gold dissolves in mercury, forming amalgam alloys. Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to confirm the presence of gold in items, giving rise to the term "the acid test." Gold has been a valuable and highly sought-after precious metal for coinage, jewelry, and other arts since long before the beginning of recorded history. Gold standards have been a common basis for monetary policies throughout human history, later being supplanted by fiat currency starting in
Caftaric acid little to no caftaric acid. Grape reaction product (2-S glutathionyl caftaric acid) is an oxidation compound produced from caftaric acid and found in wine. Malvidin 3-glucoside alone is not oxidized in the presence of grape polyphenol oxidase (PPO), whereas it is degraded in the presence of a crude grape PPO extract and of caftaric acid, forming anthocyanidin-caftaric acid adducts. Caftaric acid Caftaric acid is a non-flavanoid phenolic compound. It is found in the juice of grapes ("Vitis vinifera") and impacts the color of white wine. It is an esterified phenolic acid, composed of caffeic acid, a hydroxycinnamate produced by plants,