Pepsin

Tilapia bone was provided from Ocean King Fisheries Co. Ltd. (Yunnan, China). Papain, pepsin, flavoring protease, neutral protease, complex protease, basic protease, and trypsin protease were provided by Shanghai Yuanye Biological Technology Co. Ltd. (Shanghai, China), and animal protease was provided by Pangbo Biological Engineering Co. Ltd. (Nanjing, China). Peptides were produced by Shanghai Synpeptide Co. Ltd. (Shanghai, China). Hydrolytic protease was obtained from Novozymes Biotechnology Co. Ltd. (Beijing, China). Acetonitrile and trifluoroacetic acid (TFA) of mass spectroscopic grade were obtained from Merck KGaA (Darmstadt, Germany). Raw 264.7 and MC3T3-E1 cells were obtained from the Kunming Institute of Zoology cell bank. Tartrate resistant acid phosphatase (TRAP) kit, acid phosphatase (ALP) kit, alizarin red staining kit, and BCA Protein Assay Kit were obtained from Beyotieme Co. Ltd. (Shanghai, China). TRAP/ALP stain kit was obtained from Wako Co. Ltd. (Wako, Japan). All the other chemicals and reagents were of analytical grade.

HAuCl₄^.4H₂O was purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Cellulase, pepsin, trypsin and AA were obtained from Yuanye Biotechnology Co., Ltd. (Shanghai, China). Histidine, threonine, lysine, glycine, glutathione (GSH), maltose, sucrose, glucose and metal ions were acquired from Sangon Biotechnology Co., Ltd. (Shanghai, China). All reagents were of analytical purity and used directly. Milli-Q purified water prepared by the PR03200 ultra-pure water meter (Zhongshan Keningte Cleaning Supplies Co., Ltd.) was utilized in all experiments.

Wheat flour and yeast were purchased from Biyoute market (Shenyang, China). Fucoidan isolated from the brown seaweed species, Undaria pinnatifida, was purchased from Auckland, New Zealand. Glycine was purchased from Saiguo Biotech Co., Ltd. (Guangzhou, China) and trichloroacetic acid was obtained from Eon Chemical Technology Co., Ltd. (Shanghai, China). Artificial saliva, artificial gastric fluid (pH 1.5) and artificial intestinal fluid (pH 6.8) were purchased from Chuangfeng Automation Technology Co., Ltd. (Dongguan, China). 3,5-Dinitrosalicylic acid (DNS) reagent was purchased from Coolaber Science & Technology Co, Ltd. (Beijing, China). 1-Diphenyl-2-picrylhydrazyl (DPPH) was obtained from Ruiyong Biotechnology Co., Ltd. (Shanghai, China). The starch content assay kit was obtained from Solarbio Science & Technology Co., Ltd. (Beijing, China). 2,3-Dihydroxysuccinic acid and β-mercaptoethanol were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China). Urea, guanidine hydrochloride (GuHCl), 5,5′-dithiobis-2-nitrobenoic acid (DTNB), α-amylase (5 U/mg), pepsin (30,000 U/g), pancreatin (4000 U/g), amyloglucosidase (100,000 U/mL) and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) were obtained from Yuanye Bio-Technology Co., Ltd. (Shanghai, China).

Red pitaya fruits were purchased from a local market in Guangzhou. Soy lecithin and cholesterol were of analytical grade and purchased from Yuanye Biotech Co., Ltd. (Shanghai, China). Sephadex G50 was obtained from Yika Biotech Co., Ltd. (Shanghai, China). DPPH was obtained from Sigma Chemical Company (St. Louis, MO, USA). Pepsin (10,000 u/mg), pancreatin (250 USPu/mg), and bile salts from pig were purchased from Yuanye Biotech Co., Ltd. (Shanghai, China). All other reagents used were analytical grade.

Akebia trifoliata fruits were sourced from a local plantation in Zunyi city, Guizhou, China. Cellulase (15,000 μ/g), α-amylase (40,000 μ/g), papain (800,000 μ/g), α-glucosidase, pepsin, pancreatic lipase, 1,1-diphenyl-2-picrylhydrazine (DPPH), 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,4,6-tripyridyltriazine (TPTZ), p-nitrophenyl-α-D-glucopyranoside (PNPG) and cholesterol were purchased from Shanghai Yuanye Bio-Technology Co., Ltd., Shanghai, China. Monosaccharide standards were obtained from Sigma Chemical Co., St. Louis, MO, USA. All other chemicals and reagents of analytical grade were obtained from Sinopharm Chemical Reagent, Shanghai, China.

Pepsin (1:10,000), oxgall, porcine α-amylase and acarbose were purchased from Shanghai yuanye Bio-Technology Co., Ltd. (Shanghai, China). Sodium thioglycolate (THIO) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) were purchased from Shanghai Macklin Biochemical Co., Ltd. (Shanghai, China). Dulbecco’s modified eagle medium (DMEM) with high-glucose, fetal bovine serum and Penicillin-Streptomycin were purchased from Hyclone (Thermo, Beijing, China). α-Glucosidase, pNPG and DPP4 inhibitor screening kits were purchased from Sigma-Aldrich (St. Louis, MO, USA). In addition, 3,5-dinitrosalicylic acid (DNS) was purchased from Beijing Solarbio Science & Technology Co., Ltd. (Beijing, China). A Total Antioxidant Capacity Assay Kit and Total Superoxide Dismutase Assay Kit were purchased from Beyotime Institute of Biotechnology (Shanghai, China). A Hydroxyl Free Radical assay kit was purchased from the Nanjing Jiancheng Bioengineering Institute (Nanjing, China). Antibiotic discs were purchased from Hangzhou Binhe Microorganism Reagent Co., Ltd. (Hangzhou, China). The HT-29 human colon adenocarcinoma cell line was purchased from the type culture cell bank of the Chinese Academy of Sciences (Shanghai, China).

Proso millet (Panicum miliaceum L.), cornmeal, cake flour, and white sugar were purchased from Fugu County Tianmo Agricultural Products Co., Ltd. (Yulin, China). α-amylase (4000 u/g), papain (800,000 u/g), glucoamylase (100,000 u/g), pepsin (800,000 u/g), trypsin (400 U/L), glycolytic enzyme (10,000 U/L), and gallic acid were purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China). 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) were purchased from Shanghai Taitan Technology Co., Ltd. (Shanghai, China). Other reagents were of analytical grade.