Effects of transglutaminase catalyzed crosslinking on physicochemical characteristics of arachin and conarachin-rich peanut protein fractions

Arachin and conarachin-rich fractions of peanut protein were extracted by using cryoprecipitation followed by centrifugation. These two fractions were individually crosslinked using transglutaminase (TG). The physicochemical characteristics including aggregation due to crosslinking, solubility, thermal denaturation temperature (Td) and denaturation enthalpy (△ H), morphology of microstructure and surface hydrophobicity (H0) of TG-treated and untreated arachin and conarachin-rich fractions were determined. The relative contents of arachin and conarachin in arachin and conarachin-rich fractions were 75% and 65%, respectively. Conarachin-rich fractions were found to more conveniently aggregate than arachin-rich from the results of SDS-PAGE. The solubility of treated arachin and conarachin-rich fractions was decreased by 66.13% and 36.91%, respectively. Only marginal increase in Td was observed in the case of crosslinked arachin-rich fraction while significant increase in Td (of the order of 10 °C) was observed in crosslinked conarachin-rich fraction. The H0 values of both crosslinked arachin and conarachin-rich fractions decreased significantly. The treated arachin and conarachin-rich fractions had more compact microstructure compared to their untreated samples. Hence, the comparison of arachin and conarachin-rich in crosslinking and the mechanism of properties enhancement by TG is the aim of the research.