Heat-induced structural and functional modification of peanut protein isolate for enhancing peanut butter quality and stability

Abstract

Oil separation limits peanut butter quality and shelf life. This study investigated the effect of heat-induced aggregation of peanut protein isolate (PPI) at 60–100 °C on its structural, functional properties, and evaluated its application as a stabilizer in peanut butter. Thermal treatment altered PPI conformation—most notably a reduction in α-helix and an increase in β-sheet content—leading to enhanced surface hydrophobicity, emulsifying capacity, and oil-binding ability. PPI treated at 100 °C (PPI-100) exhibited the strongest stabilizing performance, and its incorporation (2%) into peanut butter reduced oil separation by 20.1% while improving rheological and textural attributes. During 60 days of room-temperature storage, peanut butter formulated with PPI-100 showed only 5.2% phase separation, confirming markedly improved physical stability. These findings highlight the potential of heat-treated PPI, within the tested upper thermal limit of 100 °C, as a viable clean-label stabilizer for emulsion foods including peanut butter.