The improvement role of peanut roasting conditioning before oil extraction on protein functional properties

Effects of peanut roasting conditioning before aqueous ethanol extraction of oil on the functional properties and structure of peanut protein isolate (PPI) and peanut protein concentrate (PPC) were investigated to facilitate value-added utilization of low-denatured meal from oil aqueous extraction. Except for solubility, the functional properties of PPI and PPC were maintained or improved after roasting. Specifically, the solubility (36.99%), foam stability (78.64%), emulsification activity index (27.37 m²/g) and emulsification stability index (23.18 min) of PPI were 1.54, 1.87, 1.17 and 1.26 times those of commercially available soy protein isolate (SPI), respectively. PPI exhibited reductions of 4.63% in α-helix and 6.03% in β-sheet, while PPC showed an increase of 0.67% in α-helix but a decrease of 7.04% in β-sheet. These results revealed that roasting induced structural disorders of peanut proteins, thereby improving their functionality, which provide a theoretical basis and new approach for improving protein properties and broadening their application.