The Influence of Oil Concentration on the rheological properties of flaxseed oil emulsion with pregelatinized waxy rice starch
Yulianingsih R (a*)., Gohtani S(b)

a. Department of Biosystem Engineering, Faculty of Agricultural Technology Universitas Brawijaya, Indonesia
b. Faculty of Agriculture, Kagawa University, Japan

Abstract

The rheological properties of an emulsion are closely related to the stability of the emulsion. The research aimed to study the influence of oil concentration on the physical properties of flaxseed oil emulsion stabilized by pregelatinized waxy rice starch (0% amylose). Emulsion with 2.5, 5, 10, and 17.5% oil content contained 5 wt% pregelatinized waxy rice starch were mixed at 8000 then 15000 rpm for 1.5 minutes each. The emulsion was then observed for its stability, microstructure, and rheological characteristics. The results showed that the emulsion was visually stable after two weeks of storage, and there was no visible creaming. The microscopic analysis displayed a change in droplet diameter in emulsion with the oil ratio of 10 and 17.5%. All emulsion shows shear thinning behavior, where the higher the oil ratio, the more pseudoplastic the emulsion. At 2.5 and 5% oil concentrations, emulsions^ rheological characteristics are thought to be prominently influenced by PWRS dispersion. At a high shear rate, the emulsions were rheopectic, where the higher the oil content, the less rheopectic properties. At the low shear rate, the emulsions showed a time-independent behavior.

Keywords: Emulsion, Flaxseed Oil, Waxy Rice Starch, Rheology

Topic: Food safety and security