Understanding how food material structures translate into perceived textures is critical for advancing consumer-targeted food innovation. Herein, a series of food-grade protein self-assemblies with distinct morphologies were fabricated by heating β-lactoglobulin (β-lg) solutions at different pHs followed by neutralization, and their composition, structural, surface, mechanical, rheological and tribological properties, as well as their interactions with human saliva, were systematically characterized. The texture attributes of the self-assemblies were also evaluated by a sensory panel, aiming to elucidate the correlation among microstructure, salivary interactions, and tactile perception. The results showed that long, straight fibrils (pH 2), a heterogeneous mixture of nanosized particles and small, curved strands (pH 4), microspheres (pH 5.5), and short, thin strands (pH 7) were formed following heating and subsequent neutralization. Particularly, long fibrils formed at pH 2 partially disassembled at neutral pH, exhibiting the lowest absolute zeta potential and surface hydrophobicity. Upon saliva incorporation, elastic fibrils (pH 2) formed a large network spanning tens of μm or more, while self-assemblies from pH 4 and 5.5 aggregated into larger, irregular forms (up to 10 μm), resulting in the highest perceived thickness and lowest smoothness, respectively. Perceived creaminess and mouthcoating were significantly positively correlated with the coefficient of friction (CoF) measured under simulated oral conditions, whereas perceived thickness and CoF did not maintain this relationship. Furthermore, all texture attributes did not correlate with viscosity regardless of saliva incorporation. This demonstrated that the specific structural features of β-lg self-assemblies played a key role in shaping oral tactile perception. • β-lg self-assemblies formed at varying pHs and neutralized thereafter exhibited distinct structural, rheological and tribological properties. • Incorporation of saliva induced aggregation of β-lg self-assemblies. • The CoF did not correlate with perceived thickness and smoothness, and all texture attributes did not correlate with viscosity. • Self-assembled structures played a key role in shaping oral tactile perception.
Han et al. (Wed,) studied this question.