Physicochemical and functional properties of high pressure-treated isolated pea protein

Commercial isolated yellow field pea protein isolate (IPP) was subjected to 200, 400 and 600 MPa high hydrostatic pressure (HHP) treatments followed by determination of some physicochemical and functional properties. Native polyacrylamide gel electrophoresis confirmed HHP-induced formation of high molecular weight protein aggregates. Intrinsic fluorescence showed most intense at 600 MPa where fluorescence intensity was less than half of the control IPP. The 600 MPa-treated IPP also showed more unfolded structure with an extensive red shift (384 nm) in wavelength of maximum tryptophan fluorescence. However, solubility profile was very similar and was not significantly (p > 0.05) affected by HHP treatment. At pH 3.0, HHP-treated IPP formed significantly (p < 0.05) higher quality emulsions with oil droplet sizes (d(4,3)) of 26-68 mu m when compared to 52-92 mu m for the control IPP. Foaming capacity was also higher at pH 3.0 with a maximum value of 81% when compared to maximum values of 38% and 62% obtained, respectively at pH 5.0 and 7.0.