Effect of maturity and curing on peanut proteins. Changes in protein surface hydrophobicity

A hydrophobic fluorescence probe, 1,8-anilinonaphthalene sulfonate (ANS), was used to study the changes in protein surface hydrophobicity (PSH) occurring during peanut maturation and curing. PSH increased with the degree of maturity and during curing (windrow drying). The increase of PSH during curing or heating was more pronounced in immature peanuts than their mature counterparts, suggesting that more hydrophobic sites are hidden in the former proteins. PSH decreased when proteins were chemically modified with phenylglyoxal (an arginine-modifying agent), suggesting that arginine might play a role in hydrophobicity. The findings indicate that maturation and curing affect PSH, and that there is a relationship between PSH and peanut maturity. Possible factors contributing to the increase of PSH are discussed.