Abstract:Oat protein isolates （OPI） were prepared by alkali extraction and isoelectric precipitation fromdefatted oat groats. OPI contains 93.01 % protein. The amino acid composition of the isolates was analyzed， andfound that OPI has more hydrophobic amino acids than soy protein isolates and the amino acids composition ofOPI is close to the ideal model recommended by FAO/WHO. The hydrophobicity and the isolates were measuredusing ANS fluorescent probe method at various pH and different concentration solution with NaCl， sucrose，CaCl2， AlCl3 and urea. The foaming ability of OPI was investigated at the same condition. The results showedthat pH had the highest influence on the surface hydrophobicity of OPI and the hydrophobicity reaches its peakat pH2； the hydrophobicity of OPI at acid pH was much stronger than that at alkali pH. The trend of effect ofdifferent salts on protein hydrophobicity was not same. With AlCl3 and urea concentration increased， the OPIhydrophobicity decreased， but CaCl2 and sucrose was on the contrary. The hydrophobicity decreased in NaClsolution with low concentrations （< 0.6 mol/L） while hydrophobicity enhanced with concentration rising.Different factors had great influence on OPI foaming， the trend was consistent with the hydrophobic. Inaddition， the addition of sucrose can improve foaming stability of OPI， and the accession to the NaCl reduced it.