Effect of pulsed electric field on Zophobas morio: evaluation on the lipid extraction yield, techno-functional properties, and protein characterization

Abstract

The effect of pulsed electric field (PEF) on Zophobas morio (ZM) and its influence on the techno-functional properties, lipid extraction yield, and protein characterization is presented in the herein dissertation. Briefly, the document is composed of six chapters. The first one gives the problem statement, which is followed by the theoretical framework, in which the importance of the consumption of edible insects and the nutritional composition of ZM is addressed. Followed by a review of the mechanisms and critical parameters of PEF and its applications in extractions; then, the technological properties (water and oil holding capacity (WHC and OHC), foaming capacity (FC), and emulsifying capacity (EC)), and protein characterization (protein solubility, digestibility, and SDS-PAGE) theory. The third chapter constitutes the hypothesis, objectives, and research plan. Then, chapter four is composed of the manuscript “Effect of pulsed electric field on Zophobas morio: evaluation on the lipid extraction yield, techno-functional properties, and protein characterization”, where the characterization of ZM and the effect of PEF on ZM was evaluated. PEF was applied at different parameters (1-5.6 kV/cm; 10 and 200 pulses; 4 μs; 200 Hz), and the lipids extraction yield, techno-functional properties (WHC, OHC, FC, and emulsion activity index (EAI)), and protein characterization (solubility, digestibility, and SDS-PAGE) were assessed. PEF-treated flours were compared to untreated ZM flour. The WHC and OHC values of the PEF-treated flours increased and decreased, respectively with the applied treatment. EC and FC displayed no differences. The highest lipids extraction yields were achieved at 5.6 kV/cm (200 and 10 pulses), and 3 kV/cm (200 pulses) leading to 77.60, 64.38, and 64.48% yield. After defatting the PEF-treated flours, the WHC, OHC, FC, and EAI were also enhanced. The solubility was decreased at 5.6 kV/cm and 200 pulses. The digestibility was 78.68-79.86%, and no molecular weight differences were observed on SDS-PAGE among samples. In the fifth chapter, the scientific poster presentation for the 37th EFFoST International Conference 2023 is presented. Finally, the appendix section includes the fully described methodologies of the analyses and the abbreviations and acronyms used. In conclusion, this research demonstrated that ZM has a high nutritional value due to its rich content of lipids and protein, amino acids, and fatty acids. The use of PEF could be used to enhance the extraction of lipids and to tailor the techno-functional properties, and due to its high digestibility, the resulting ZM PEF-treated flours further add to the application of ZM in food formulations.