Formation of casein and maltodextrin conjugates using shear and their effect on the stability of total nutrient emulsion based on homogenization

Abstract

This study aimed to explore the desirable properties of casein and maltodextrin conjugates (PPCs) with simultaneously increased stability of total nutrient emulsion (TNE). Molecular interaction, stability, rheology and microstructure were analyzed. The results exhibited that the D[4,3] of PPCs increased by 169.34% at the shear time of 12 min and zeta-potential increased to 22.56 mV when the shear time was 4 min. The fluorescence spectrum and Raman spectrum analysis showed that the maximum emission wavelength of casein shifted from 347 nm to 336 nm, and the I760 value showed a decreasing trend (0.93–0.41), indicating that the molecular structure of casein stretches and opens under the influence of the shear force, and the hydrophobic groups inside casein are released into the polar environment. Furthermore, the stability index TSI decreases from 1.3 to 0.7, the change rate of backscattered light decreases to 0.6%, and the local particle concentration decreases, suggesting that the stability of the TNE enhanced with the increase of homogenization pressure in a suitable range. Meanwhile, the droplet particles are obviously smaller and there is no cluster phenomenon. After 28 days of storage, the homogeneous pressure of 80 MPa and 100 MPa makes the TNE have smaller TBARS values. This work provides a comprehensive explanation for preparing TNE based on shear and homogenization treatments.