Abstract:

A novel low-denaturation extraction method, salt method, was applied to extract pea protein isolate from
commercial pea flour and the gelation characteristics of this protein isolate were determined by a rheometer. The minimum
gelation concentration of salt extracted pea protein isolate (PPIs) was 5.5 g/100 mL. No correlation was noted between
the gelation point and concentration of PPIs, but the gelling point showed a tendency of increasing with heating rate.
Meanwhile, higher heating and cooling rates resulted in decreased final G’ (storage modulus) and G” (loss modulus), thus
reducing the gel stiffness. Higher protein concentration induced greater gel stiffness, and higher G’ and G” values. It was
found that there were power law relationships between protein concentration and either G’ or G” values. Tan delta value
decreased with increasing protein concentration, and weak gel was formed when protein concentration was greater than
5 g/100 mL; however, when protein concentration was greater than 7 g/100 mL, tan delta kept almost constant, which
indicated that gel elasticity was constant within this concentration range. When comparing gelation properties of PPIs to
commercial pea protein isolate (PPIc), the gel stiffness of PPIs was much greater than that of PPIc. Therefore, PPIs may
have greater market prospect than PPIc in emulsified meat products.

Key words: pea protein isolate, salt extraction, gelation, gelling point, minimum gelation mass concentration, heating and cooling rate, salt concentration