Oleogels based on peanut protein isolate fibrils: Structural characterization dependent on induction time and suitability in marguerite biscuits

In order to develop new plant protein-based lipid substitutes to deal with health problems caused by animal fats or trans-fatty acids, the emulsion stablized by acid-heat (90 °C, pH 2.0) induced aggregation of peanut protein isolate (PPI) was used as template to fabricate oleogels. Heating time affected the structure, morphology of PPI and the adsorption characteristics at the O/W interface. The protein with suitable heating time (2-6 h) formed fibrils structure, which was beneficial to the rapid adsorption of aggregates at the O/W interface. Overheating (exceeding 8 h) led to the aggregate of protein fibrils and inhibited the adsorption of proteins at the O/W interface. Therefore, the heating times of 2 h, 4 h and 6 h were selected to prepare the follow-up emulsion and oleogels. Among the four heating times, the emulsion prepared by PPI heating for 6 h showed the best storage stability, ionic strength stability and shear resistance. The resultant oleogels exhibited the least oil loss and the highest freeze-thaw stability. The margarita biscuits prepared with a substitution rate of 50% oleogels to butter presented similar sensory property to the margaritas prepared with butter, indicating that the oleogels possessed favorable shortening properties. The results indicated that PPI fibrils structure could improve the oleogel formaton properties, making it a potential novel additive for the development of new fat substitute products.