O phthaldialdehyde

Djulis (Chenopodium formosanum) was purchased from Taitung country farmers’ association (Taitung, Taiwan). Wheat flour was purchased from Yifeng food company (New Taipei City, Taiwan). MRS broth was purchased from Hardy Diagnostics (Santa Maria, CA, USA). Peptone and Bacto agar were purchased from Bioshop (Burlington, ON, Canada). Glucose, sucrose, lactose, magnesium sulfate, sodium phosphate dibasic, potassium phosphate dibasic 2-mercaptoethanol, sodium dodecyl sulfate, sodium tetraborate, monosodium dihydrogen orthophosphate, sodium phosphate dibasic, 2,2-diphenyl-1-picrylhydrazyl, sodium chloride, sodium carbonate, potassium persulfate, hydrochloric acid, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), trolox (6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid) were purchased from Sigma-Aldrich (St. Louis, MO, USA). o-Phthaldialdehyde was purchased from Merck (Darmstadt, Germany).

A high-molecular-weight marker was obtained from Bio-Rad Laboratories (Hercules, CA, USA) and N,N,N,N-tetramethyl ethylene diamine (TEMED) was purchased from Sigma Aldrich (St. Louis, MO, USA). Trypsin (from bovine pancreas; ≥7500 U/g) and pepsin (from porcine gastric mucosa; ≥500 U/g) were purchased from Sigma Chemical Co. (St, Louis, MO, USA). Alcalase (protease from Bacillus licheniformis; ≥2.4 U/g), Neutrase (protease from Bacillus amyloliquefaciens; ≥0.8 U/g), papain (from papaya latex), and Flavourzyme (protease from Aspergillus oryzae; ≥500 U/g) were purchased from Sigma Chemical Co. (Bagsveard, Denmark). O-Phthaldialdehyde, 8-anilo-1-naphthalenesulfonic acid (ANS), Coomassie Brilliant Blue R-250, sodium dodecyl sulfate (SDS), and β-mercaptoethanol (βME) were purchased from Merck (Darmstadt, Germany). All other chemicals and reagents used were of analytical grade.

Methanol was provided by VWR (Barcelona, Spain), while sodium bicarbonate, acetate sodium, galic acid, and hydrochloric acid (HCl) were acquired from Merck (Darmstad, Germany). The ABTS (2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt was obtained from Amresco (Solon, OH, USA). 2,4,6-Tri(2-pyridyl)-s-triazine (TPTZ), and iron (III) chloride for the ferric-reducing power (FRAP) assay was from Fluka Chemicals (Fluka Chemicals, Madrid, Spain). Trolox ((±)-6-Hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid), Folin–Ciocalteu reagent, all phenolic compounds, diethyl ether, Methanol, α-amylase from human saliva (A1031), pepsin from porcine gastric mucosa (P6887), pancreatin from porcine pancreas (P7545), bile salts (B8756), sodium dodecyl sulfate (SDS), o-phthaldialdehyde (OPA), DL-dithiothreitol (DTT), L-serine, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) (HEPES), tert-butylhydroperoxide (t-BOOH), the cell culture media, and cell culture-grade chemicals were from Sigma-Aldrich (Sigma-Aldrich, St. Louis, MO, USA). The chemicals were all of high purity or analytical reagent grade. Bi-distilled deionized water (Milli-Q purification system, Millipore, Bedford, MA, USA) was used. Ingredients for biscuits’ preparation were purchased from local supermarkets.