A homogeneity evaluation method of food soft matter based on moisture content test by casting-near-infrared spectroscopy

Quantitative evaluation of polymer dispersion homogeneity is crucial for understanding the physicochemical behavior of food soft matter and ensuring processing stability. In this study, a horizontal casting device integrated with a near-infrared (NIR) spectrometer was developed to obtain spatially resolved reflectance spectra during casting. Characteristic absorption bands at 1180 and 1260 nm were identified as moisture-sensitive indicators of structural evolution. Partial least squares (PLS) and principal component analysis (PCA) were employed to construct predictive models for moisture-related spectral responses and to evaluate homogeneity across radial positions. PLS consistently outperformed PCA, yielding higher predictive accuracy (<i>R</i> ² > 0.85) and lower error (<2%). These findings demonstrate that NIR-based spectral mapping enables real-time characterization of hydration uniformity and compatibility within soft matter dispersions. This approach offers practical value for process monitoring, formulation optimization, and quality control in hydrocolloid-based food manufacturing.