Native-state pea albumin and globulin behavior upon transglutaminase treatment

• MTGase thermal and pH-stability were determined for 5 h.
• Optimum MTGase reaction conditions occur at pH 7, 40 °C, 20 mM NaCl for 2 h.
• Pea globulin at native state is moderately good substrate to MTGase.
• Pea albumin at native state is poor substrate to MTGase.

The behavior of pea albumin (Alb) and globulin (Glob) in their native state upon microbial transglutaminase (MTGase) treatment was studied. Only Glob was able to form a gel, at up to a 10% (w/w) concentration, with a minimum gelling concentration of 6% (w/w), and with a cross-linking degree of 25%. The most affected Glob subunits were convicilin (71 kDa), vicilins (55, 50, and 35 kDa), and legumin acidic subunit (40 kDa). In contrast, the legumin basic subunit (20 kDa) and vicilins of molecular weight less than 20 kDa remained mostly intact in all studied conditions. The cross-linking degree of Alb was 12%, which was not sufficient to form MTGase-induced gel. Major albumin polypeptide (PA2 26 kDa) was not affected by the MTGase concentration or by pH variation. Pea Alb and Glob in their native state were ranked as poor and moderately good substrates for MTGase, respectively, and unfolding them by thermal or chemical denaturation could be an interesting way to improve the efficiency of cross-linking.

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