Effect of combined pH-Shifting and high-intensity ultrasound treatment on the structural, functional, and foaming properties of Tenebrio Molitor Protein

With the development of the food industry and the increasing variety of emerging foods, the foaming properties of proteins have gained attention in the production of blowing agents. As a novel source of protein supplementation, insect protein has recently garnered widespread interest for its applications in food. However, Tenebrio Molitor Protein (TMP) has not been utilized in the production of aerated foods due to its inherently poor water-air interfacial properties. To improve the foaming properties of TMP, a combined modification treatment involving extreme pH-shifting and high-intensity ultrasound (HIUS) was applied. The results showed that under highly alkaline conditions, TMP is more susceptible to the effects of HIUS. Under these conditions, protein molecules unfold, and the cavitation effect of ultrasound disrupts numerous non-covalent bonds, leading to the dissociation of a significant number of soluble aggregates. This reduces the particle size of the protein, exposes hydrophobic groups, enhances surface hydrophobicity, and increases the free sulfhydryl content. Additionally, the secondary and tertiary structures of TMP were altered by the modification treatment: the content of α-helices increased, while the contents of β-turns and β-sheets decreased. These structural changes enhanced proteins' interfacial properties at the water-air interface, enabling the modified protein (UTMP-12) to achieve excellent foaming properties. This study provides a new approach for the application of TMP in aerated food products.