Ethanol

The kraft lignin was produced by acidification of black liquor from kraft pulping process, and it was purified by the alkali-acid treatment as follows. First, the lignin was dissolved with 0.5 mol/L NaOH solution and the insoluble matter was removed by centrifugation, then the lignin was precipitated by adjusting the solution pH to 2.0 with 0.5 mol/L sulfuric acid solution. After centrifugation, the precipitate was washed to neutral and dried in an oven at 60 °C. Sodium methoxide, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDTES) and N,N-dimethylformamide (DMF, 99.5%) were purchased from Shanghai Alighting Reagent Co., Ltd. (Shanghai, China). Ethanol (99.7%), acetone (99.5%), E-44 epoxy resin and 4′4-Methylene bis were purchased from Shanghai McLean Biochemical Technology Co., Ltd. (Shanghai, China). All reagents were used without further purification.

All chemicals used in this work are of analytical level. Peptide with the sequence of KIIIIKYWYAF was bought from the SynPeptide Biotechnology Co., Ltd. (Nanjing, China). Monolayered GO aqueous dispersions (GO-1, 10 mg/g) were provided by the Hangzhou Gaoxi Technology Co., Ltd. (Hangzhou, China). D-anhydrous glucose (AR), phosphoric acid, ethanol, glycerol, glutaraldehyde, NaCl, tryptone, and agar powder were purchased from the Shanghai Maclean Biochemical Technology Co., Ltd. (Shanghai, China).

Tartary buckwheat seeds (Hefeng No. 1) were cultivated in Datong, Shanxi Province, China, and were acquired from Beijing Green Valley Sprout Co., Ltd. (Beijing, China). Rutin, gallic acid, and γ-Amino butyric acid standard were purchased from Shanghai solarbio Bioscience & Technology Co., Ltd. (Shanghai, China). The analytical grade chemicals, such as Folin-Ciocalteu reagent, gallic acid (GA), sodium carbonate, sodium hypochlorite, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, phosphoric acid, glucose anhydrous, aluminum chloride, potassium acetate, o-phthalaldehyde, copper sulfate, potassium sulfate, sulfuric acid, boric acid, ethanol, ethyl acetate, hydrochloric acid, trichloroacetic acid, sodium acetate, phenol, potassium persulfate, sodium hydroxide, and aluminum chloride were purchased from Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China). In addition, 2,2-diphenyl picryl hydrazyl (DPPH), acetone, and methanol (HPLC grade) were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (Shanghai, China). Total antioxidant capacity (T-AOC) kit was purchased from Nanjing Jiancheng Bioengineering Institute (Nanjing, China).