Mechanism of the NaCl soaking-microwave synergistic pretreatment in suppressing emulsification formation during the aqueous enzymatic extraction of peanut oil

This study investigated the effect of NaCl soaking-microwave synergistic pretreatment (S-MW) on inhibiting the formation of oil bodies emulsion (OBE) during the aqueous enzyme extraction (AEE) of peanut oil and the corresponding mechanism. Firstly, S-MW pretreatment reduced the moisture content, hardness, fracturability, and springiness of peanut kernels, while severely damaging the cell structure and disrupting the integrity of oil bodies membrane, thereby promoting oil release. During enzymatic hydrolysis, the oil aggregated into larger oil droplets, which weakened interactions with interfacial materials and enhanced phase separation. Ultimately, OBE formation capacity and stability were significantly reduced, resulting in a 73.31 % reduction in formation and a free oil recovery rate of 63.16 %. Therefore, the effect of S-MW pretreatment inhibited severe emulsification by influencing the aggregation behaviors of oil. This innovative pretreatment transitions the extraction process from passive demulsification to active emulsion inhibition, thereby optimizing the process of AEE. • Developed a novel NaCl-soaking combined with microwave pretreatment (S-MW) that transforms the aqueous enzymatic extraction process from passive demulsification to active emulsion suppression. • Elucidated that S-MW pretreatment disrupts the integrity of cell and oil body membranes through the synergistic action of salt and microwaves, promoting oil release in a coalesced form and altering interfacial properties to favor phase separation over emulsification. • Achieved a remarkable reduction in emulsion content from 28.92 % to 7.72 % compared to the control group, while increasing free oil recovery rate from 0 % to 63.16 % in the AEE of peanut oil. • Provided a green and efficient pretreatment strategy for the aqueous enzymatic extraction of edible oil.