Effects of high-pressure homogenization on tea residue mesophyll cell-based Pickering emulsion stabilizers: Property modulation and emulsification enhancement mechanisms

Abstract

Collecting tea residue mesophyll cells (TRMCs) pioneers a novel process enabling industrial-scale, cost-effective leaf protein recovery with high yields, surpassing conventional extraction barriers. However, their food applications are constrained by large particle size and poor fluidity, leading to low interfacial adsorption efficiency in emulsions. In this study, high-pressure homogenization (HPH) technology, outperforming airflow ultrafine grinding and ultrasonic crushing, was used to enhance the performance of TRMCs. The effects of different intensities of HPH treatment (100–500 bar for 1–5 min) on the basic composition, microstructure, physicochemical properties, and functional characteristics of TRMCs were investigated, and the underlying mechanism of their emulsification improvement was analyzed. The results showed that HPH treatment only slightly affected basic components (such as protein and total sugar) and the color of TRMCs but significantly reduced the particle size (D_(3,2) as low as 5.1 μm). The treatment also eliminated the aggregation and improved the dispersion stability by enhancing electrostatic repulsion. In addition, HPH treatment balanced surface hydrophilicity-hydrophobicity (contact angle increased from 46.6° to 69.2°), exposing hydrophobic domains and more protein and polysaccharide structures, increased the emulsification activity index by 1.3 times, and decreased creaming index by 1.7 times. Unlike traditional Pickering emulsion stabilizers requiring chemical modification or multi-step assembly, HPH-treated TRMCs achieved superior emulsification through synergistic physical fragmentation and chemical group exposure, maintaining natural biocompatibility.