Hydrochloric acid (hcl)

Flavor protease and trypsin used for the enzymolysis of peanut meal were purchased from Novozymes (Bagsvaerd, Denmark). Acetonitrile (chromatographically pure) used for gel exclusion chromatography (GEC) was purchased from TEDIA (Fairfield, OH, America). Monosodium glutamate (MSG), citric acid, tannic acid, sugar, and salt used as the five standard taste samples were obtained from commercial suppliers. Standard chemicals such as 1 mol/L hydrochloric acid, 0.1 MSG, and sodium chloride were supplied by Alpha M.O.S. (Toulouse, France), which had to be diluted with distilled water prior to use.

Sucrose was purchased from a local supermarket (Publix Super Markets, Fort Pierce, FL, USA), citric acid from SAFC Supply Solutions (St. Louis, MO, USA), potassium chloride from Sigma Aldrich (St. Louis, MO, USA), limonin and nomilin from 2A PharmaChem USA (Lisle, IL, USA) and ethanol (200 Proof-Absolute, Anhydrous ACS/UPS Grade) from Pharmco-AAPER (Brookfield, CT, USA). Hydrochloric acid, sodium chloride and monosodium glutamate used for assessing the performance and calibration of the electronic tongue were obtained from Alpha-MOS (Toulouse, France). Limonin glucoside, hesperetin and hesperidin were obtained from purified authentic standards.