Preparation and stabilizing behavior of octenyl succinic esters of soybean soluble polysaccharide in acidified milk beverages

Soybean soluble polysaccharide (SSPS) is anionic polysaccharide extracted from the by-product of isolated soy protein production. In this study, a simple and eco-friendly procedure had been developed to prepare high-molecular-weight octenyl succinic esters of SSPS (OSA-SSPS) via the esterification between SSPS and octenyl succinic anhydride (OSA). The absolute molecular weights of OSA-SSPS and SSPS were 620 kDa and 53 kDa, respectively. OSA-SSPS had some similar properties to SSPS, such as microstructure and viscosity of 1 wt% concentration. However, compared to SSPS, OSA-SSPS showed different milk protein stabilization properties. The stabilizing behavior of OSA-SSPS was better than that of SSPS at pH range of 3.8-4.6, and poorer at pH 3.6. The model mixture of OSA-SSPS had smaller particle sizes at pH range of 3.8-4.6 and larger absolute negative charges at pH 2.0-10.0. In addition, from the molecular diameter measured by DLS and AFM image, the surface concentration of OSA-SSPS was larger than that of SSPS, which indicated that the thicker OSA-SSPS layer produces larger steric repulsion to milk protein particles. The mechanism for the greater ability of OSA-SSPS to stabilize milk proteins was proposed on the basis of the results discussed in this research. (C) 2016 Elsevier Ltd. All rights reserved.