Structure and thermal properties of arachin from six varieties: effect of 35.5 kDa subunit

Abstract

The subunit composition, and thermal and molecular conformation properties of arachin from six peanut varieties are characterized and compared. The thermal and molecular conformation properties including the thermal stability, steady flow properties, surface hydrophobicity, and sulfhydryl content were determined. Two groups of arachin were identified: one containing the 35.5 kDa subunit and the other one without this specific subunit. The results showed that arachin with the 35.5 kDa subunit was more heat-sensitive (Tonset <100°C), had a significant lower initial denaturation temperature, less disulfide bonds, and more hydrophobic groups. The arachin without the 35.5 kDa subunit was less heat-sensitive to temperature (Tonset >100°C), and a more compact globular structure. The presence or absence of 35.5 kDa subunit in arachin significantly influenced the thermal and molecular conformation properties of arachin. Furthermore, the 35.5 kDa subunit was sequenced by Q-TOF and identified as an isoform of Ara h3. This study can provide useful information for processing peanut protein products with good thermal stability and hypoallergenic properties.