Protein extraction from yellow mealworm (Tenebrio molitor) assisted by pulsed electric fields: Effect on foaming properties

This study focuses on the use of Pulsed Electric Field (PEF) as a non-thermal technology to extract proteins from defatted Yellow Mealworm (Tenebrio molitor) meal. Additionally, the effect of PEF on the foaming properties of the extracted proteins was evaluated. An experimental design with two-factors and two levels, including the central point, was carried out: electric field (E: 1.5, 3.125 and 5 kV/cm) and number of pulses (N: 200, 1100 and 2000). The response variables studied were the protein extraction yield, the foam capacity (FC), and the foam stability constant (k) that was calculated by fitting the foam stability (FS) over the time to a first order exponential decrement equation. A positive effect of the crossed factor (EN) to the protein yield was found. Moreover, an increment of 27 % of the protein yield was observed when comparing PEF-based extracts to the control. Our results indicated that PEF contributed to reduce the molecular weight of the extracted proteins when compared with the control. Moreover, PEF induced modification of the protein structure as indicated by a reduction in fluorescence and content of β-sheet. The changes observed have an impact on the foaming properties measured, especially on FS which has decreased when applying PEF.