Calcium chloride dihydrate

Hericium erinaceus was purchased from the Yongding Ecological Farming Family Farm, Ningqiang County, Hanzhong City, Shaanxi Province.
Saliva α amylase (2000 U/g) was obtained from Omega, Cheyenne, WY, USA. Pepsin (250 U/g), pancreatic enzymes (10 U/g), fructose oligosaccharide, salt acid, concentrated sulfuric acid, sodium hydroxide, sodium chloride, ferrous sulfate heptahydrate, manganese sulfate, zinc sulfate heptahydrate, cobalt chloride hexahydrate, nickel chloride, copper sulfate pentahydrate disodium phosphate, potassium chloride, urea, magnesium chloride hexahydrate, calcium chloride dihydrate, metaphosphate, sodium sulfate, acetic acid standard, propionic acid standard, and butyric acid standard were obtained from Sinopharm Group Chemical Reagent Co., Ltd., Shanghai, China. All other chemical reagents were of analytical grade and procured from Aladdin Chemical Reagent Co., Ltd. (Shanghai, China).

Sodium 2-mercaptoethanesulfonate (MES), l-histidine (His) and glucose (glucose) were purchased from Aladdin Reagent Co., Ltd. disodium (DIMESNA) was acquired from ApexBio Reagent Co., Ltd. Cysteine (Cys) and chloroauric acid (HAuCl₄) were obtained from Sigma-Aldrich Reagent Co., Ltd. Potassium chloride (KCl), sodium chloride (NaCl), magnesium chloride hexahydrate (MgCl₂·6H₂O), calcium chloride dihydrate (CaCl₂·2H₂O), aluminum chloride hexahydrate (AlCl₃·6H₂O), potassium bromide (KBr), ammonium chloride (NH₄Cl), iron sulfate heptahydrate (FeSO₄·7H₂O), sodium sulfate (Na₂SO₄), sodium nitrate (NaNO₃), ethylenediaminetetraacetic acid disodium salt (EDTA·Na₂), glutamic acid (Glu) and proline (Hyp) were acquired from Sinopharm Chemical Reagent Co., Ltd. Mesna injection (Uromitexan) was obtained from Qilu Pharmaceutical (Hainan) Co., Ltd. The deionized water was used in this study. All chemicals and solvents were of analytical grade or better and used without further purification.

Different grades of four types of green teas, Xihu Longjing, Qiantang Longjing, Huangshan Maofeng, and Anji Baicha, were bought and used. All of them were products of geographical indications in China, and their information is presented in detail in Table 1. Xihu Longjing labeled A and B, as well as Qiantang Longjing labeled D and E were picked and produced by different tea companies in the same year, and Xihu Longjing labeled B and C, as well as Qiantang Longjing labeled E and G were picked and produced by the same tea company in different years. It should be noted that the grades in Table 1 are self‐determined by the tea companies, and are only valid for green tea produced and sold by the same tea company, and the grades between different tea companies are not comparable. All the green teas were picked before the solar term Qingming, which is around April 5th of every year. Calcium chloride, dihydrate, in the analytical grade were bought from Sinopharm Chemical Reagents Co., Ltd. For the convenience of the experiment, the commercially available Watsons distilled water was used in the experiments.