Pressure-dependent changes in particle size and quality of Diaoganxing apricot pulp during single-pass high-pressure homogenization

Abstract

High-pressure homogenization (HPH) can modify the dispersion and quality attributes of fruit pulps, but pressure-dependent responses in particle-containing apricot pulp remain unclear. Diaoganxing apricot pulp was subjected to single-pass HPH at 20–100 MPa, with untreated pulp serving as the 0 MPa control. Particle-size distribution, instrumental color, turbidity, 6-day sedimentation index (SI), qualitative optical microscopy, total soluble solids, apparent zeta potential, and texture profile analysis parameters were evaluated. The median particle diameter (D50) decreased from 163.04 μm in the untreated control to 55.51 μm at 60 MPa and increased slightly at 80–100 MPa. Turbidity peaked at 40 MPa, whereas SI decreased from 49.49% to 19.18%, indicating distinct response patterns across the nominal pressure treatments. Cohesiveness reached its maximum at 60 MPa, while total soluble solids and apparent zeta potential did not differ significantly among treatments. Optical microscopy was inconclusive for treatment-specific microstructural interpretation. Because pectin fractions, dietary fiber, viscosity, and product temperature were not measured, explanations involving cavitation or structural modification remain hypotheses. The multi-response ranking depended on user-defined weights, and no treatment maximized all measured responses. These results document non-monotonic, attribute-dependent responses under laboratory-scale, single-pass conditions. The 6-day SI reflects only short-term sedimentation, and the rankings do not identify a universally optimal treatment or directly transferable industrial processing condition.