Using HPMC to improve sensory properties of vegan omelet analogue: Effect of HPMC on water retention, oil adsorption, and thermal gelation

Abstract

There is a growing need throughout the world for vegan egg analogues in recent years. In this study, the impact of hydroxypropyl methylcellulose (HPMC) on the mouthfeel perception of the vegan omelets was evaluated. Additionally, the effects of HPMC on water retention, oil adsorption, thermal gelation, intermolecular interactions, microstructures, and in vitro digestion of the vegan eggs were investigated. The formulation with 1.5% HPMC (1.5HPMC) approached the sensory perception of egg omelet, in terms of fluffiness (6.8 vs. 7.4), softness (7.3 vs. 6.1), smoothness (5.8 vs. 6.8), crispiness (6.3 vs. 7.9), and silkiness (6.4 vs. 7.0). This could be attributed to the gelling and water holding capacities of HPMC that hindered moisture diffusion within the omelet matrix. Moreover, HPMC could induce the increasing exposure of non-polar sites, thereby improving oil adsorption as well as oil-related sensory attributes. On the other hand, the added HPMC may wrap the protein, starch, and oil components through the hydrogen bonding and/or hydrophobic interactions and compete with them for free water. This would affect the thermal gelation process and textural profiles of the vegan eggs. The matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS)- and nuclear magnetic resonance (NMR) spectroscopy-based metabolomic analyses verified the above findings. It was reported that the 1.5HPMC omelet released less amino acid, fatty acid, and saccharide metabolites than the non-HPMC-modified omelet after in vitro digestion. Through understanding the mechanisms on how HPMC improved the mouthfeel sensation of vegan omelets, this study advises more conceivable roles of HPMC in novel food development.