Rheological and Ultrastructural Properties and Particle Size Distribution of Soymilk as Affected by Processing Methods

Abstract

Soymilk was prepared from boiled and unboiled comminuted suspensions of dehulled soybean and water using pressurized homogenization (one pass and two pass). Particle size showed significant differences between soymilks homogenized by one pass and two pass. Apparent viscosities and total solid contents showed significant differences between boiled and unboiled treatments. Soymilks exhibited pseudoplastic and thixotropic behavior and Arrhenius model was fitted to express temperature dependence of apparent viscosity. Microscopic images showed hydrated, separated, uniformly distributed, and homogeneous particles in boiled two-pass soymilk as they were disrupted easily and it was selected as the best treatment for processing soymilk containing all of the soybean solids.

Keywords:

• Homogenization
• Soymilk
• Viscosity
• Particle size distribution
• Ultrastructure

ACKNOWLEDGMENTS

This project was supported by National Research Initiative Grant no. 2005–35503–15374 from the USDA Cooperative State Research, Education and Extension Service NCGP program. This paper was presented in the Institute of Food Technologists 2006 annual meeting at Orlando, FL, USA as a poster. Dr. Diana Hartle, Reference Instruction Librarian, Reference Department, Science Library, The University of Georgia, Athens, GA, USA, for her support with the EndNote reference used in this paper.