Tailoring Insect Proteins for Emulsification: Modification Approaches and Applications

Identifier:  TDX:4523

Handle: https://hdl.handle.net/20.500.11797/TDX4523

Authors:  Ballon, Aurélie

Abstract:
The increasing global food demand are driving the need to find novel protein sources. Among others, insect proteins are emerging as a promising alternative to conventional animal proteins due to their high nutritional value and low environmental impact. Insect proteins have shown potential as emulsifiers in emulsion-based encapsulation systems. This doctoral thesis aims to explore modification approaches to further enhance and diversify the technofunctionality of insect proteins, focusing on improving the ability to maintain the physical and oxidative stability of oil-in-water (O/W) emulsions. The approaches investigated include the conjugation with polyphenols, thermal treatment, enzymatic hydrolysis coupled or not with physical pretreatment. Conjugating proteins extracted from lesser mealworm (Alphitobius diaperinus, LMPC) larvae with polyphenols (tannic acid and chlorogenic acid) significantly improved their antioxidant properties leading to a significant reduction in lipid oxidation when used to stabilize O/W emulsion. High internal phase emulsions were stabilized with untreated and thermally treated insect proteins. Thermal treatment affected the proteins’ ability to stabilize emulsions (e.g., lower oil loss during storage but higher destabilization during freeze-thaw cycles). The emulsions produced exhibited suitable rheological characteristics to be used as edible food ink in 3D printing. Finally, enzymatic hydrolysis of LMPC significantly increased the protein extraction yield. Emulsifying and antioxidant properties varied depending on the enzyme used and hydrolysis conditions. Physical pretreatment, such as ultrasound, before hydrolysis led to a reduction in droplet size of O/W emulsions. However, insect protein hydrolysates were less effective in reducing lipid oxidation compared to sodium caseinate. Emulsifiers with a wider range of functionality were obtained using the different strategies, broadening the potential of insect proteins as emulsifier for food applications.