**3. Materials and Methods**

#### *3.1. Chemicals*

D-(+)-Glucose, D-allose, D-galactose, Ag2CO3, L-cysteine methyl ester hydrochloride, phenyl isothiocyanate, pyridine, *i*PrOH, MTBE, porcine pancreatic α-amylase, acarbose, dinitrosalicylic acid, ACN and MeOH HPLC grade, and *n*-hexane, CHCl3, MeOH, ACN, (CH3)2CO and EtOAc technical grade were purchased from Sigma-Aldrich (St. Louis, MO, USA). Nano-pure water HPLC grade (18.2 MΩcm) was obtained from a NANO pure purification system (Barnstead/Thermolyne, Dubuque, IA, USA). Silica gel 60 F254 TLC plates, HCl and H3PO4 were purchased from EMD Millipore, Inc. (Darmstadt, Germany). Silica gel 60 Å 40-63 μm and AcOH glacial were purchased from VWR International LLC (West Chester, PA, Switzerland), while RP-C18 Cosmosil 140 and formic acid were purchased from Nacalai Tesque, Inc., (Kyoto, Japan) and Alfa Aesar (Ward Hill, MA, USA), respectively. MeOH and pyridine NMR (perdeuterated) solvents were purchased from Cambridge Isotope Laboratories (Andover, MA, USA).
