The melting points of pure sucrose, stevioside (St) and each stevia amino acid sweetener were determined with a Mel-Temp Apparatus. The solubility in water, ethanol, methanol and chloroform was determined according to the methods described by Soejarto et al. (1983). Heat stabilities of stevia amino acid sweeteners in acidic, neutral and alkaline solutions (at pH range of 2.5–9) at 60 C and 100 C for 2 h were examined by TLC and confirmed by HPLC as described by Chang and Cook (1983).